JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Kinetics of polio shedding following oral vaccination as measured by qRT-PCR versus culture.
J. Clin. Microbiol.
PUBLISHED: 11-08-2014
Show Abstract
Hide Abstract
Amidst polio eradication efforts, detection of oral polio vaccine (OPV) virus in stool can inform rates of mucosal immunity and estimate the poliovirus reservoir. We developed a multiplex one-step qRT-PCR for detection of OPV Sabin strains 1, 2, 3 directly in stool samples, with an extrinsic control to normalize samples for viral quantity, and compared its performance with viral culture. We applied the assay to infants in Dhaka, Bangladesh after administration of trivalent OPV (tOPV) at weeks 14 and 52 of life (on days 0 (pre-OPV), +4, +11, +18, and +25 relative to vaccination). Of 1350 stools tested the sensitivity and specificity of qPCR was 89% and 91% compared with culture. A quantitative relationship was observed between culture+/qPCR+ and culture-/qPCR+ stools. Kinetics of shedding as revealed by qPCR and culture were similar. qPCR quantitative cutoffs using the day +11 or +18 stools could be used to identify the culture-positive shedders as well as the long duration or high-frequency shedders. Interestingly, qPCR revealed that a small minority (7%) of infants contributed the vast majority (93-100%) of total estimated viral excretion across all subtypes at each time point. This qPCR assay for OPV can simply and quantitatively detect all 3 Sabin strains directly from stool to approximate shedding both qualitatively and quantitatively.
Related JoVE Video
The MAL-ED cohort study in Mirpur, Bangladesh.
Clin. Infect. Dis.
PUBLISHED: 10-12-2014
Show Abstract
Hide Abstract
The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) study site in Bangladesh is located in the capital city of Dhaka in an urban slum that has one of the highest population densities in the world. The site is in the Bauniabadh area of Mirpur, Dhaka. A typical squatter settlement, the average family size of households in Mirpur Bauniabadh is 4.5, with 48% females. About 20% of households have a monthly income of only US$62. About 30% of mothers never attended school, and only 3% obtained secondary school education. The majority of the people are day laborers, garment workers, and transport workers. About 72% of caregivers always wash their hands after helping the child defecate and 6.6% never wash their hands. The diarrheal attack rate for Mirpur is 4.69 episodes per child per year. The study site is representative of a typical urban slum of Dhaka city in terms of demographics, socioeconomic status, and general health indicators.
Related JoVE Video
Assessment of environmental enteropathy in the MAL-ED cohort study: theoretical and analytic framework.
Clin. Infect. Dis.
PUBLISHED: 10-12-2014
Show Abstract
Hide Abstract
Individuals in the developing world live in conditions of intense exposure to enteric pathogens due to suboptimal water and sanitation. These environmental conditions lead to alterations in intestinal structure, function, and local and systemic immune activation that are collectively referred to as environmental enteropathy (EE). This condition, although poorly defined, is likely to be exacerbated by undernutrition as well as being responsible for permanent growth deficits acquired in early childhood, vaccine failure, and loss of human potential. This article addresses the underlying theoretical and analytical frameworks informing the methodology proposed by the Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) cohort study to define and quantify the burden of disease caused by EE within a multisite cohort. Additionally, we will discuss efforts to improve, standardize, and harmonize laboratory practices within the MAL-ED Network. These efforts will address current limitations in the understanding of EE and its burden on children in the developing world.
Related JoVE Video
Microbiologic methods utilized in the MAL-ED cohort study.
Clin. Infect. Dis.
PUBLISHED: 10-12-2014
Show Abstract
Hide Abstract
A central hypothesis of The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) study is that enteropathogens contribute to growth faltering. To examine this question, the MAL-ED network of investigators set out to achieve 3 goals: (1) develop harmonized protocols to test for a diverse range of enteropathogens, (2) provide quality-assured and comparable results from 8 global sites, and (3) achieve maximum laboratory throughput and minimum cost. This paper describes the rationale for the microbiologic assays chosen and methodologies used to accomplish the 3 goals.
Related JoVE Video
Amebic liver abscess in northern region of Bangladesh: sociodemographic determinants and clinical outcomes.
BMC Res Notes
PUBLISHED: 09-04-2014
Show Abstract
Hide Abstract
Amebic liver abscess (ALA) is endemic in Bangladesh since historical age but its epidemiology and sociodemographic determinants are not well described in the literatures. This paper focuses on the endemicity, sociodemographic determinants and clinical outcomes of ALA patients from certain northern districts in Bangladesh. Ninety hospitalized ALA patients enrolled from 6 northern districts of Bangladesh during July 2008 to June 2010 were analyzed.
Related JoVE Video
Mutations in Plasmodium falciparum K13 propeller gene from Bangladesh (2009-2013).
Malar. J.
PUBLISHED: 09-01-2014
Show Abstract
Hide Abstract
Bangladesh is a malaria hypo-endemic country sharing borders with India and Myanmar. Artemisinin combination therapy (ACT) remains successful in Bangladesh. An increase of artemisinin-resistant malaria parasites on the Thai-Cambodia and Thai-Myanmar borders is worrisome. K13 propeller gene (PF3D7_1343700 or PF13_0238) mutations have been linked to both in vitro artemisinin resistance and in vivo slow parasite clearance rates. This group undertook to evaluate if mutations seen in Cambodia have emerged in Bangladesh where ACT use is now standard for a decade.
Related JoVE Video
Members of the human gut microbiota involved in recovery from Vibrio cholerae infection.
Nature
PUBLISHED: 08-06-2014
Show Abstract
Hide Abstract
Given the global burden of diarrhoeal diseases, it is important to understand how members of the gut microbiota affect the risk for, course of, and recovery from disease in children and adults. The acute, voluminous diarrhoea caused by Vibrio cholerae represents a dramatic example of enteropathogen invasion and gut microbial community disruption. Here we conduct a detailed time-series metagenomic study of faecal microbiota collected during the acute diarrhoeal and recovery phases of cholera in a cohort of Bangladeshi adults living in an area with a high burden of disease. We find that recovery is characterized by a pattern of accumulation of bacterial taxa that shows similarities to the pattern of assembly/maturation of the gut microbiota in healthy Bangladeshi children. To define the underlying mechanisms, we introduce into gnotobiotic mice an artificial community composed of human gut bacterial species that directly correlate with recovery from cholera in adults and are indicative of normal microbiota maturation in healthy Bangladeshi children. One of the species, Ruminococcus obeum, exhibits consistent increases in its relative abundance upon V. cholerae infection of the mice. Follow-up analyses, including mono- and co-colonization studies, establish that R. obeum restricts V. cholerae colonization, that R. obeum luxS (autoinducer-2 (AI-2) synthase) expression and AI-2 production increase significantly with V. cholerae invasion, and that R. obeum AI-2 causes quorum-sensing-mediated repression of several V. cholerae colonization factors. Co-colonization with V. cholerae mutants discloses that R. obeum AI-2 reduces Vibrio colonization/pathogenicity through a novel pathway that does not depend on the V. cholerae AI-2 sensor, LuxP. The approach described can be used to mine the gut microbiota of Bangladeshi or other populations for members that use autoinducers and/or other mechanisms to limit colonization with V. cholerae, or conceivably other enteropathogens.
Related JoVE Video
Development and assessment of molecular diagnostic tests for 15 enteropathogens causing childhood diarrhoea: a multicentre study.
Lancet Infect Dis
PUBLISHED: 07-09-2014
Show Abstract
Hide Abstract
Childhood diarrhoea can be caused by many pathogens that are difficult to assay in the laboratory. Molecular diagnostic techniques provide a uniform method to detect and quantify candidate enteropathogens. We aimed to develop and assess molecular tests for identification of enteropathogens and their association with disease.
Related JoVE Video
Serological surveillance development for tropical infectious diseases using simultaneous microsphere-based multiplex assays and finite mixture models.
PLoS Negl Trop Dis
PUBLISHED: 07-01-2014
Show Abstract
Hide Abstract
A strategy to combat infectious diseases, including neglected tropical diseases (NTDs), will depend on the development of reliable epidemiological surveillance methods. To establish a simple and practical seroprevalence detection system, we developed a microsphere-based multiplex immunoassay system and evaluated utility using samples obtained in Kenya.
Related JoVE Video
The macrophage migration inhibitory factor homolog of Entamoeba histolytica binds to and immunomodulates host macrophages.
Infect. Immun.
PUBLISHED: 05-12-2014
Show Abstract
Hide Abstract
The host inflammatory response contributes to the tissue damage that occurs during amebic colitis, with tumor necrosis factor alpha (TNF-?) being a key mediator of the gut inflammation observed. Mammalian macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays an important role in the exacerbation of a wide range of inflammatory diseases, including colitis. We identified a MIF gene homolog in the Entamoeba histolytica genome, raising the question of whether E. histolytica MIF (EhMIF) has proinflammatory activity similar to that of mammalian MIF. In this report, we describe the first functional characterization of EhMIF. Antibodies were prepared against recombinantly expressed EhMIF and used to demonstrate that EhMIF is expressed as a 12-kDa protein localized to the cytoplasm of trophozoites. In a manner similar to that of mammalian MIF, EhMIF interacted with the MIF receptor CD74 and bound to macrophages. EhMIF induced interleukin-6 (IL-6) production. In addition, EhMIF enhanced TNF-? secretion by amplifying TNF-? production by lipopolysaccharide (LPS)-stimulated macrophages and by inhibiting the glucocorticoid-mediated suppression of TNF-? secretion. EhMIF was expressed during human infection, as evidenced by the presence of anti-EhMIF antibodies in the sera of children living in an area where E. histolytica infection is endemic. Anti-EhMIF antibodies did not cross-react with human MIF. The ability of EhMIF to modulate host macrophage function may promote an exaggerated proinflammatory immune response and contribute to the tissue damage seen in amebic colitis.
Related JoVE Video
Persistent gut microbiota immaturity in malnourished Bangladeshi children.
Nature
PUBLISHED: 04-29-2014
Show Abstract
Hide Abstract
Therapeutic food interventions have reduced mortality in children with severe acute malnutrition (SAM), but incomplete restoration of healthy growth remains a major problem. The relationships between the type of nutritional intervention, the gut microbiota, and therapeutic responses are unclear. In the current study, bacterial species whose proportional representation define a healthy gut microbiota as it assembles during the first two postnatal years were identified by applying a machine-learning-based approach to 16S ribosomal RNA data sets generated from monthly faecal samples obtained from birth onwards in a cohort of children living in an urban slum of Dhaka, Bangladesh, who exhibited consistently healthy growth. These age-discriminatory bacterial species were incorporated into a model that computes a 'relative microbiota maturity index' and 'microbiota-for-age Z-score' that compare postnatal assembly (defined here as maturation) of a child's faecal microbiota relative to healthy children of similar chronologic age. The model was applied to twins and triplets (to test for associations of these indices with genetic and environmental factors, including diarrhoea), children with SAM enrolled in a randomized trial of two food interventions, and children with moderate acute malnutrition. Our results indicate that SAM is associated with significant relative microbiota immaturity that is only partially ameliorated following two widely used nutritional interventions. Immaturity is also evident in less severe forms of malnutrition and correlates with anthropometric measurements. Microbiota maturity indices provide a microbial measure of human postnatal development, a way of classifying malnourished states, and a parameter for judging therapeutic efficacy. More prolonged interventions with existing or new therapeutic foods and/or addition of gut microbes may be needed to achieve enduring repair of gut microbiota immaturity in childhood malnutrition and improve clinical outcomes.
Related JoVE Video
Indoor exposure to particulate matter and age at first acute lower respiratory infection in a low-income urban community in Bangladesh.
Am. J. Epidemiol.
PUBLISHED: 03-06-2014
Show Abstract
Hide Abstract
The timing of a child's first acute lower respiratory infection (ALRI) is important, because the younger a child is when he or she experiences ALRI, the greater the risk of death. Indoor exposure to particulate matter less than or equal to 2.5 µm in diameter (PM2.5) has been associated with increased frequency of ALRI, but little is known about how it may affect the timing of a child's first ALRI. In this study, we aimed to estimate the association between a child's age at first ALRI and indoor exposure to PM2.5 in a low-income community in Dhaka, Bangladesh. We followed 257 children from birth through age 2 years to record their age at first ALRI. Between May 2009 and April 2010, we also measured indoor concentrations of PM2.5 in children's homes. We used generalized gamma distribution models to estimate the relative age at first ALRI associated with the mean number of hours in which PM2.5 concentrations exceeded 100 µg/m(3). Each hour in which PM2.5 levels exceeded 100 µg/m(3) was independently associated with a 12% decrease (95% confidence interval: 2, 21; P = 0.021) in age at first ALRI. Interventions to reduce indoor exposure to PM2.5 could increase the ages at which children experience their first ALRI in this urban community.
Related JoVE Video
Mirincamycin, an old candidate for malaria combination treatment and prophylaxis in the 21st century: in vitro interaction profiles with potential partner drugs in continuous culture and field isolates.
Malar. J.
PUBLISHED: 02-28-2014
Show Abstract
Hide Abstract
Spreading resistance of Plasmodium falciparum to existing drugs calls for the search for novel anti-malarial drugs and combinations for the treatment of falciparum malaria.
Related JoVE Video
The prevalence and impact of intimate partner violence on maternal distress in a community of low-income Bangladeshi and displaced ethnic Bihari mothers: Dhaka, 2008-2009.
Violence Against Women
PUBLISHED: 02-26-2014
Show Abstract
Hide Abstract
Low-income, ethnic, and/or displaced mothers are frequently victimized; we explored the burden of intimate partner violence (IPV) among such women. Teams administered IPV and maternal distress questionnaires to quantify victimization after the birth of a child. Of 250 mothers reporting abuse, 133 (53%) reported their husband hitting; 111 (44%) kicking, dragging, or beating; 61 (24%) choking or burning; and 33 (13%) injuring them with a knife or gun (12 case-patients per 100 person-years). Women who experienced more forms of victimization reported more distress (p = .01). Mothers in this low-income community experienced severe victimization and distress.
Related JoVE Video
A new visually improved and sensitive loop mediated isothermal amplification (LAMP) for diagnosis of symptomatic falciparum malaria.
Acta Trop.
PUBLISHED: 02-12-2014
Show Abstract
Hide Abstract
Molecular diagnosis of malaria by nucleotide amplification requires sophisticated and expensive instruments, typically found only in well-established laboratories. Loop-mediated isothermal amplification (LAMP) has provided a new platform for an easily adaptable molecular technique for molecular diagnosis of malaria without the use of expensive instruments. A new primer set has been designed targeting the 18S rRNA gene for the detection of Plasmodium falciparum in whole blood samples. The efficacy of LAMP using the new primer set was assessed in this study in comparison to that of a previously described set of LAMP primers as well as with microscopy and real-time PCR as reference methods for detecting P. falciparum. Pre-addition of hydroxy napthol blue (HNB) in the LAMP reaction caused a distinct color change, thereby improving the visual detection system. The new LAMP assay was found to be 99.1% sensitive compared to microscopy and 98.1% when compared to real-time PCR. Meanwhile, its specificity was 99% and 100% in contrast to microscopy and real-time PCR, respectively. Moreover, the LAMP method was in very good agreement with microscopy and real-time PCR (0.94 and 0.98, respectively). This new LAMP method can detect at least 5parasites/?L of infected blood within 35min, while the other LAMP method tested in this study, could detect a minimum of 100parasites/?L of human blood after 60min of amplification. Thus, the new method is sensitive and specific, can be carried out in a very short time, and can substitute PCR in healthcare clinics and standard laboratories.
Related JoVE Video
Febrile illness and pro-inflammatory cytokines are associated with lower neurodevelopmental scores in Bangladeshi infants living in poverty.
BMC Pediatr
PUBLISHED: 02-11-2014
Show Abstract
Hide Abstract
An estimated one-third of children younger than 5 years in low- and middle-income countries fail to meet their full developmental potential. The first year of life is a period of critical brain development and is also when most of the morbidity from infection is suffered. We aimed to determine if clinical and biological markers of inflammation in the first year of life predict cognitive, language, and motor outcomes in children living in an urban slum in Bangladesh.
Related JoVE Video
High prevalence and genetic diversity of Plasmodium malariae and no evidence of Plasmodium knowlesi in Bangladesh.
Parasitol. Res.
PUBLISHED: 01-28-2014
Show Abstract
Hide Abstract
Although the prevalence of malaria remains high in parts of Bangladesh, there continues to be a substantial shortage of information regarding the less common malaria parasites such as Plasmodium malariae or Plasmodium knowlesi. Recent studies indicate that P. malariae may be extremely rare, and so far, there are no data on the presence (or absence) of P. knowlesi in southeastern Bangladesh. Genus- and species-specific nested polymerase chain reaction (PCR) analysis of the small subunit ribosomal RNA gene was performed to assess the presence and prevalence of P. malariae and P. knowlesi in 2,246 samples originating from asymptomatic and febrile participants of a cross-sectional and a febrile illnesses study in the Chittagong Hill Tracts in southeastern Bangladesh. P. malariae was detected in 60 samples (2.7%) corresponding to 8% of the 746 samples giving positive PCR results for Plasmodium sp., mainly because of the high prevalence (9.5%) among asymptomatic study participants testing positive for malaria. Symptomatic cases were more common (4.3% of all symptomatic malaria cases) during the dry season. Parasitemias were low (1,120-2,560/?l in symptomatic and 120-520/?l in asymptomatic carriers). Symptomatic patients presented mild to moderate symptoms like fever, chills, headache, dizziness, fatigue and myalgia.Although both the intermediate as well as the definite host are known to be endemic in southeastern Bangladesh, no evidence for the presence of P. knowlesi was found. We conclude that the role of P. malariae is highly underestimated in rural Bangladesh with major implications for malaria control and elimination strategies.
Related JoVE Video
Detection of Campylobacter in stool and determination of significance by culture, enzyme immunoassay, and PCR in developing countries.
J. Clin. Microbiol.
PUBLISHED: 01-22-2014
Show Abstract
Hide Abstract
Campylobacter is a common bacterial enteropathogen that can be detected in stool by culture, enzyme immunoassay (EIA), or PCR. We compared culture for C. jejuni/C. coli, EIA (ProSpecT), and duplex PCR to distinguish Campylobacter jejuni/C. coli and non-jejuni/coli Campylobacter on 432 diarrheal and matched control stool samples from infants in a multisite longitudinal study of enteric infections in Tanzania, Bangladesh, and Peru. The sensitivity and specificity of culture were 8.5% and 97.6%, respectively, compared with the results of EIA and 8.7% and 98.0%, respectively, compared with the results of PCR for C. jejuni/C. coli. Most (71.6%) EIA-positive samples were positive by PCR for C. jejuni/C. coli, but 27.6% were positive for non-jejuni/coli Campylobacter species. Sequencing of 16S rRNA from 53 of these non-jejuni/coli Campylobacter samples showed that it most closely matched the 16S rRNA of C. hyointestinalis subsp. lawsonii (56%), C. troglodytis (33%), C. upsaliensis (7.7%), and C. jejuni/C. coli (2.6%). Campylobacter-negative stool spiked with each of the above-mentioned Campylobacter species revealed reactivity with EIA. PCR detection of Campylobacter species was strongly associated with diarrhea in Peru (odds ratio [OR] = 3.66, P < 0.001) but not in Tanzania (OR = 1.56, P = 0.24) or Bangladesh (OR = 1.13, P = 0.75). According to PCR, Campylobacter jejuni/C. coli infections represented less than half of all infections with Campylobacter species. In sum, in infants in developing country settings, the ProSpecT EIA and PCR for Campylobacter reveal extremely high rates of positivity. We propose the use of PCR because it retains high sensitivity, can ascertain burden, and can distinguish between Campylobacter infections at the species level.
Related JoVE Video
Evidence of a major reservoir of non-malarial febrile diseases in malaria-endemic regions of Bangladesh.
Am. J. Trop. Med. Hyg.
PUBLISHED: 01-13-2014
Show Abstract
Hide Abstract
In malaria-endemic regions any febrile case is likely to be classified as malaria based on presumptive diagnosis largely caused by a lack of diagnostic resources. A district-wide prevalence study assessing etiologies of fever in 659 patients recruited in rural and semi-urban areas of Bandarban district in southeastern Bangladesh revealed high proportions of seropositivity for selected infectious diseases (leptospirosis, typhoid fever) potentially being misdiagnosed as malaria because of similarities in the clinical presentation. In an area with point prevalences of more than 40% for malaria among fever cases, even higher seroprevalence rates of leptospirosis and typhoid fever provide evidence of a major persistent reservoir of these pathogens.
Related JoVE Video
High prevalence of asymptomatic malaria in south-eastern Bangladesh.
Malar. J.
PUBLISHED: 01-09-2014
Show Abstract
Hide Abstract
The WHO has reported that RDT and microscopy-confirmed malaria cases have declined in recent years. However, it is still unclear if this reflects a real decrease in incidence in Bangladesh, as particularly the hilly and forested areas of the Chittagong Hill Tract (CHT) Districts report more than 80% of all cases and deaths. surveillance and epidemiological data on malaria from the CHT are limited; existing data report Plasmodium falciparum and Plasmodium vivax as the dominant species.
Related JoVE Video
Etiology of diarrhea in Bangladeshi infants in the first year of life analyzed using molecular methods.
J. Infect. Dis.
PUBLISHED: 09-16-2013
Show Abstract
Hide Abstract
Diarrhea causes enormous morbidity and mortality in developing countries, yet the relative importance of multiple potential enteropathogens has been difficult to ascertain.
Related JoVE Video
Cluster-randomised controlled trials of individual and combined water, sanitation, hygiene and nutritional interventions in rural Bangladesh and Kenya: the WASH Benefits study design and rationale.
BMJ Open
PUBLISHED: 09-03-2013
Show Abstract
Hide Abstract
Enteric infections are common during the first years of life in low-income countries and contribute to growth faltering with long-term impairment of health and development. Water quality, sanitation, handwashing and nutritional interventions can independently reduce enteric infections and growth faltering. There is little evidence that directly compares the effects of these individual and combined interventions on diarrhoea and growth when delivered to infants and young children. The objective of the WASH Benefits study is to help fill this knowledge gap.
Related JoVE Video
Performance of a HRP-2/pLDH based rapid diagnostic test at the Bangladesh-India-Myanmar border areas for diagnosis of clinical malaria.
Malar. J.
PUBLISHED: 09-02-2013
Show Abstract
Hide Abstract
The rapid diagnostic test (RDT) has been adopted in contemporary malaria control and management programmes around the world as it represents a fast and apt alternative for malaria diagnosis in a resource-limited setting. This study assessed the performance of a HRP-2/pLDH based RDT (Parascreen(R) Pan/Pf) in a laboratory setting utilizing clinical samples obtained from the field.
Related JoVE Video
Oral polio vaccine response in breast fed infants with malnutrition and diarrhea.
Vaccine
PUBLISHED: 07-25-2013
Show Abstract
Hide Abstract
Oral vaccines for polio (OPV) and rotavirus are less effective in children in the developing world. The reasons for this are not well understood. We tested for risk factors for poor response to OPV in infants from an urban slum of Dhaka, Bangladesh. Diminished serum neutralizing response to OPV, but not failure of intramuscularly administered vaccines, was associated with malnutrition, diarrhea, and shorter breastfeeding duration. Children with malnutrition (WAZ <-2) had significantly lower OPV 3 titers (p=0.029). Children who had 2 or more diarrhea episodes during the 1st months of life were more than twice as likely to experience OPV failure as those who had 1 diarrhea episode or no diarrhea (p=0.0245). In contrast, each additional month in exclusive breastfeeding was associated with an increase in OPV 3 titer by 0.41 (p=0.0072) and 0.16 (p=0.0065) at the 25th and 50th percentiles of OPV 3 titers respectively. These data are consistent with a defect in induction of immunity in the gut for OPV but not parenteral vaccines, a defect that may be amenable to intervention in part via promotion of exclusive breastfeeding.
Related JoVE Video
Comparison of PCR-based diagnoses for visceral leishmaniasis in Bangladesh.
Parasitol. Int.
PUBLISHED: 07-15-2013
Show Abstract
Hide Abstract
The diagnosis of visceral leishmaniasis (VL) is performed using multiple methods encompassing parasitological, serological and nucleic acid-based diagnostic tools, each method with its own unique advantages and disadvantages. Conventional parasitological methods are risky for the patient and require skilled personnel to collect specimens from spleen or bone marrow, and hence they are not generally available in impoverished areas. Polymerase chain reaction (PCR) has been validated as an excellent alternative to microscopy in terms of sensitivity and specificity. Here, we evaluate four different PCR assays targeting ITS1, ITS2, mini-exon and small subunit-rRNA (SSUrRNA) using DNA extracted from peripheral blood buffy coat in order to avoid more invasive processes. A total of 61 VL patients and 75 non-VL infected control individuals were enrolled. The VL patients were confirmed to be positive for Leishmania amastigotes in splenic smears by microscopy. Sensitivities of the PCR targeting ITS1, ITS2, SSUrRNA and mini-exon were 96.7%, 91.8%, 88.5% and 34.4%, respectively, while the specificity was 98.7% for all methods. Nested PCR for ITS1 resulted in 100% sensitivity. The efficacy of each PCR was evaluated with various Leishmania amastigote parasite loads in each spleen smear, graded from 1+ to 5+. The PCR targeting ITS1 showed 100% sensitivity for the detection of Leishmania donovani in all samples from grades ?3, ?4, and ?5, respectively. The restriction fragment length polymorphism observed in ITS1 amplicons digested by HaeIII classified the parasite into L. donovani complex. The ITS1 PCR was found to be equal to conventional, but very invasive and risky parasitological diagnoses and superior to other PCR based methods in sensitivity and examination of genetic heterogeneity. We recommend the PCR targeting ITS1 using peripheral blood buffy coat DNA as an alternate, less invasive diagnostic choice for the confirmation of L. donovani infection.
Related JoVE Video
Entamoeba histolytica brain abscess.
Handb Clin Neurol
PUBLISHED: 07-09-2013
Show Abstract
Hide Abstract
Brain abscess due to Entamoeba histolytica is most commonly seen in a small percentage of patients who also have an amebic liver abscess. The typical patient is a young man who after treatment for liver abscess with apparent improvement develops symptoms and signs of central nervous system involvement. The average age of the patient is 30 years, and common presentations include headache, vomiting, and altered mental status. Signs of amebic brain abscess include most commonly meningeal signs, facial nerve (VII) palsy, motor paralysis, and seizure. Most patients have abnormal cerebrospinal fluid although there is no special or characteristic abnormality. Diagnosis is by serology and PCR of brain abscess aspirate or CSF and treatment is with metronidazole.
Related JoVE Video
Clinical and immunological aspects of post-kala-azar dermal leishmaniasis in Bangladesh.
Am. J. Trop. Med. Hyg.
PUBLISHED: 07-01-2013
Show Abstract
Hide Abstract
We conducted active surveillance for kala-azar and post-kala-azar dermal leishmaniasis (PKDL) in a population of 24,814 individuals. Between 2002 and 2010, 1,002 kala-azar and 185 PKDL cases occurred. Median PKDL patient age was 12 years; 9% had no antecedent kala-azar. Cases per 10,000 person-years peaked at 90 for kala-azar (2005) and 28 for PKDL (2007). Cumulative PKDL incidence among kala-azar patients was 17% by 5 years. Kala-azar patients younger than 15 years were more likely than older patients to develop PKDL; no other risk factors were identified. The most common lesions were hypopigmented macules. Of 98 untreated PKDL patients, 48 (49%) patients had resolution, with median time of 19 months. Kala-azar patients showed elevated interferon-? (IFN?), tumor necrosis factor-? (TNF?), and interleukin 10 (IL-10). Matrix metalloproteinase 9 (MMP9) and MMP9/tissue inhibitor of matrix metalloproteinase-1 (TIMP1) ratio were significantly higher in PKDL patients than in other groups. PKDL is frequent in Bangladesh and poses a challenge to the current visceral leishmaniasis elimination initiative in the Indian subcontinent.
Related JoVE Video
Household environmental conditions are associated with enteropathy and impaired growth in rural Bangladesh.
Am. J. Trop. Med. Hyg.
PUBLISHED: 04-29-2013
Show Abstract
Hide Abstract
We assessed the relationship of fecal environmental contamination and environmental enteropathy. We compared markers of environmental enteropathy, parasite burden, and growth in 119 Bangladeshi children (? 48 months of age) across rural Bangladesh living in different levels of household environmental cleanliness defined by objective indicators of water quality and sanitary and hand-washing infrastructure. Adjusted for potential confounding characteristics, children from clean households had 0.54 SDs (95% confidence interval [CI] = 0.06, 1.01) higher height-for-age z scores (HAZs), 0.32 SDs (95% CI = -0.72, 0.08) lower lactulose:mannitol (L:M) ratios in urine, and 0.24 SDs (95% CI = -0.63, 0.16) lower immunoglobulin G endotoxin core antibody (IgG EndoCAb) titers than children from contaminated households. After adjusting for age and sex, a 1-unit increase in the ln L:M was associated with a 0.33 SDs decrease in HAZ (95% CI = -0.62, -0.05). These results are consistent with the hypothesis that environmental contamination causes growth faltering mediated through environmental enteropathy.
Related JoVE Video
REG1B as a predictor of childhood stunting in Bangladesh and Peru.
Am. J. Clin. Nutr.
PUBLISHED: 04-03-2013
Show Abstract
Hide Abstract
Undernutrition remains a significant problem worldwide, with environmental enteropathy implicated as a contributing factor. An understanding of the pathogenesis and identification of children at risk are critical to the design of more-effective interventions.
Related JoVE Video
Global microRNA expression profiling: curcumin (diferuloylmethane) alters oxidative stress-responsive microRNAs in human ARPE-19 cells.
Mol. Vis.
PUBLISHED: 03-13-2013
Show Abstract
Hide Abstract
In recent years, microRNAs (miRNAs) have been reported to play important roles in a broad range of biologic processes, including oxidative stress-mediated ocular diseases. In addition, the polyphenolic compound curcumin has been shown to possess anti-inflammatory, antioxidant, anticancer, antiproliferative, and proapoptotic activities. The aim of this study was to investigate the impact of curcumin on the expression profiles of miRNAs in ARPE-19 cells exposed to oxidative stress.
Related JoVE Video
Low prevalence of Leishmania donovani infection among the blood donors in kala-azar endemic areas of Bangladesh.
BMC Infect. Dis.
PUBLISHED: 01-31-2013
Show Abstract
Hide Abstract
Visceral leishmaniasis (VL) is a major public health problem in Bangladesh with the highest disease burden in the Mymensingh District. The disease is transmitted by sand fly bites, but it may also be transmitted through blood transfusions. No information is available about the prevalence of Leishmania infection among blood donors in Bangladesh; therefore we aimed to investigate this question.
Related JoVE Video
Distinct distal gut microbiome diversity and composition in healthy children from Bangladesh and the United States.
PLoS ONE
PUBLISHED: 01-22-2013
Show Abstract
Hide Abstract
Our current understanding of the composition and stability of the human distal gut microbiota is based largely on studies of infants and adults living in developed countries. In contrast, little is known about the gut microbiota and its variation over time in older children and adolescents, especially in developing countries.
Related JoVE Video
Contribution of enteric infection, altered intestinal barrier function, and maternal malnutrition to infant malnutrition in Bangladesh.
Clin. Infect. Dis.
PUBLISHED: 11-21-2011
Show Abstract
Hide Abstract
Malnourished children are at increased risk for death due to diarrhea. Our goal was to determine the contribution of specific enteric infections to malnutrition-associated diarrhea and to determine the role of enteric infections in the development of malnutrition.
Related JoVE Video
Evaluation of rapid antigen point-of-care tests for detection of Giardia and Cryptosporidium species in human fecal specimens.
J. Clin. Microbiol.
PUBLISHED: 11-09-2011
Show Abstract
Hide Abstract
In Bangladesh, a new parasite rapid antigen test was investigated demonstrating accuracy and feasibility. For Giardia species, it had a sensitivity and specificity of 94% and 100%, respectively. For Cryptosporidium species, it had a sensitivity and specificity of 100% and 100%, respectively. These are higher than or equal to the sensitivities and specificities of other tests on the market.
Related JoVE Video
Simultaneous detection of six diarrhea-causing bacterial pathogens with an in-house PCR-luminex assay.
J. Clin. Microbiol.
PUBLISHED: 11-09-2011
Show Abstract
Hide Abstract
Diarrhea can be caused by a range of pathogens, including several bacteria. Conventional diagnostic methods, such as culture, biochemical tests, and enzyme-linked immunosorbent assay (ELISA), are laborious. We developed a 7-plex PCR-Luminex assay to simultaneously screen for several of the major diarrhea-causing bacteria directly in fecal specimens, including pathogenic Aeromonas, Campylobacter jejuni, Campylobacter coli, Salmonella, Shigella, enteroinvasive Escherichia coli (EIEC), Vibrio, and Yersinia. We included an extrinsic control to verify extraction and amplification. The assay was first validated with reference strains or isolates and exhibited a limit of detection of 10(3) to 10(5) CFU/g of stool for each pathogen as well as quantitative detection up to 10(9) CFU/g. A total of 205 clinical fecal specimens from individuals with diarrhea, previously cultured for enteric pathogens and tested for Campylobacter by ELISA, were evaluated. Using these predicate methods as standards, sensitivities and specificities of the PCR-Luminex assay were 89% and 94% for Aeromonas, 89% and 93% for Campylobacter, 96% and 95% for Salmonella, 94% and 94% for Shigella, 92% and 97% for Vibrio, and 100% and 100% for Yersinia, respectively. All discrepant results were further examined by singleplex real-time PCR assays targeting different gene regions, which revealed 89% (55/62 results) concordance with the PCR-Luminex assay. The fluorescent signals obtained with this approach exhibited a statistically significant correlation with the cycle threshold (C(T)) values from the cognate real-time PCR assays (P < 0.05). This multiplex PCR-Luminex assay enables sensitive, specific, and quantitative detection of the major bacterial causes of gastroenteritis.
Related JoVE Video
Serial quantitative PCR assay for detection, species discrimination, and quantification of Leishmania spp. in human samples.
J. Clin. Microbiol.
PUBLISHED: 11-02-2011
Show Abstract
Hide Abstract
The Leishmania species cause a variety of human disease syndromes. Methods for diagnosis and species differentiation are insensitive and many require invasive sampling. Although quantitative PCR (qPCR) methods are reported for leishmania detection, no systematic method to quantify parasites and determine the species in clinical specimens is established. We developed a serial qPCR strategy to identify and rapidly differentiate Leishmania species and quantify parasites in clinical or environmental specimens. SYBR green qPCR is mainly employed, with corresponding TaqMan assays for validation. The screening primers recognize kinetoplast minicircle DNA of all Leishmania species. Species identification employs further qPCR set(s) individualized for geographic regions, combining species-discriminating probes with melt curve analysis. The assay was sufficient to detect Leishmania parasites, make species determinations, and quantify Leishmania spp. in sera, cutaneous biopsy specimens, or cultured isolates from subjects from Bangladesh or Brazil with different forms of leishmaniasis. The multicopy kinetoplast DNA (kDNA) probes were the most sensitive and useful for quantification based on promastigote standard curves. To test their validity for quantification, kDNA copy numbers were compared between Leishmania species, isolates, and life stages using qPCR. Maxicircle and minicircle copy numbers differed up to 6-fold between Leishmania species, but the differences were smaller between strains of the same species. Amastigote and promastigote leishmania life stages retained similar numbers of kDNA maxi- or minicircles. Thus, serial qPCR is useful for leishmania detection and species determination and for absolute quantification when compared to a standard curve from the same Leishmania species.
Related JoVE Video
Melatonin synthesis in retina: cAMP-dependent transcriptional regulation of chicken arylalkylamine N-acetyltransferase by a CRE-like sequence and a TTATT repeat motif in the proximal promoter.
J. Neurochem.
PUBLISHED: 08-22-2011
Show Abstract
Hide Abstract
Arylalkylamine N-acetyltransferase (AANAT) is the key regulatory enzyme controlling the daily rhythm of melatonin biosynthesis. In chicken retinal photoreceptor cells, Aanat transcription and AANAT activity are regulated in part by cAMP-dependent mechanisms. The purpose of this study was to identify regulatory elements within the chicken Aanat promoter responsible for cAMP-dependent induction. Photoreceptor-enriched retinal cell cultures were transfected with a luciferase reporter construct containing up to 4 kb of 5-flanking region and the first exon of Aanat. Forskolin treatment stimulated luciferase activity driven by the ?4 kb promoter construct and by all 5-deletion constructs except the smallest, Aanat (-217 to +120)luc. Maximal basal and forskolin-stimulated expression levels were generated by the Aanat (-484 to +120)luc construct. This construct lacks a canonical cyclic AMP-response element (CRE), but contains two other potentially important elements in its sequence: an eight times TTATT repeat (TTATT?) and a CRE-like sequence. Electrophoretic mobility shift assays, luciferase reporter assays, chromatin immunoprecipitation, and siRNA experiments provide evidence that these elements bind c-Fos, JunD, and CREB to enhance basal and forskolin-stimulated Aanat transcription. We propose that the CRE-like sequence and TTATT? elements in the 484 bp proximal promoter interact to mediate cAMP-dependent transcriptional regulation of Aanat.
Related JoVE Video
The role of age, ethnicity and environmental factors in modulating malaria risk in Rajasthali, Bangladesh.
Malar. J.
PUBLISHED: 07-21-2011
Show Abstract
Hide Abstract
Malaria is endemic in the Rajasthali region of the Chittagong Hill Tracts in Bangladesh and the Rajasthali region is the most endemic area of Bangladesh. Quantifying the role of environmental and socio-economic factors in the local spatial patterns of malaria endemicity can contribute to successful malaria control and elimination. This study aimed to investigate the role of environmental factors on malaria risk in Rajasthali and to quantify the geographical clustering in malaria risk unaccounted by these factors.
Related JoVE Video
Short communication: evaluation of a new rapid diagnostic test for quality assurance by kala azar elimination programme in bangladesh.
J Parasitol Res
PUBLISHED: 07-09-2011
Show Abstract
Hide Abstract
In Bangladesh, serological tests have been widely used for the primary screening of visceral leishmaniasis (VL). Several serologic tests are available for the diagnosis of VL. Selection of the best test is important to permit diagnostic differentiation between symptomatic and asymptomatic patients and to reduce cross-reactivity. We evaluated the effectiveness of a new serological test "Onsite Leishmania Ab Rapid Test" as a part of "quality assurance" activities for the kala azar elimination programme of the Government of Bangladesh. Plasma samples of 100 parasitologically confirmed cases of VL along with 101 healthy controls were tested, and "Onsite Leishmania Ab Rapid Test" strip tests were positive in 94 out of 100 confirmed VL cases, whereas four out of 51 healthy subjects from the VL endemic areas also tested positive. All the 50 healthy volunteers tested negative. Thus, the sensitivity and specificity of "Onsite Leishmania Ab Rapid Test" strip test were found to be 94% (95% CI: 87-98) and 96% (95% CI: 90-99), respectively. This study showed that the performance of the "Onsite Leishmania Ab Rapid Test" strip tests was up to the recommended level.
Related JoVE Video
Survey of domestic cattle for anti-Leishmania antibodies and Leishmania DNA in a visceral leishmaniasis endemic area of Bangladesh.
BMC Vet. Res.
PUBLISHED: 06-08-2011
Show Abstract
Hide Abstract
Visceral leishmaniasis (VL), caused by an intracellular parasite Leishmania donovani in the Indian subcontinent, is considered to be anthroponotic. The role of domestic animals in its transmission is still unclear. Although cattle are the preferred blood host for Phlebotomus argentipes, the sandfly vector of VL in the Indian subcontinent, very little information is available for their role in the disease transmission. In this study, we examined domestic cattle for serological and molecular evidence of Leishmania infection in a VL-endemic area in Bangladesh. Blood samples from 138 domestic cattle were collected from houses with active or recently-treated VL and post-kala-azar dermal leishmaniasis patients. The presence of anti-leishmanial antibodies in serum was investigated using enzyme-linked immunosorbent assay (ELISA) and then with direct agglutination tests (DAT). Nested PCR (Ln PCR) was performed to amplify the ssu-rRNA gene using the DNA extracted from Buffy coat. Recently-developed molecular assay loop-mediated isothermal amplification (LAMP) was also performed for further sensitive detection of parasite DNA.
Related JoVE Video
Real-time PCR assay and rapid diagnostic tests for the diagnosis of clinically suspected malaria patients in Bangladesh.
Malar. J.
PUBLISHED: 04-17-2011
Show Abstract
Hide Abstract
More than 95% of total malaria cases in Bangladesh are reported from the 13 high endemic districts. Plasmodium falciparum and Plasmodium vivax are the two most abundant malaria parasites in the country. To improve the detection and management of malaria patients, the National Malaria Control Programme (NMCP) has been using rapid diagnostic test (RDT) in the endemic areas. A study was conducted to establish a SYBR Green-based modified real-time PCR assay as a gold standard to evaluate the performance of four commercially-available malaria RDTs, along with the classical gold standard- microscopy.
Related JoVE Video
Malaria prevalence, risk factors and spatial distribution in a hilly forest area of Bangladesh.
PLoS ONE
PUBLISHED: 03-23-2011
Show Abstract
Hide Abstract
Malaria is a major public health concern in Bangladesh and it is highly endemic in the Chittagong Hill Tracts where prevalence was 11.7% in 2007. One sub-district, Rajasthali, had a prevalence of 36%. Several interventions were introduced in early 2007 to control malaria. This study was undertaken to evaluate the impacts of these intensive early stage interventions on malaria in Bangladesh. This prevalence study assesses whether or not high malaria prevalence remains, and if so, which areas and individuals remain at high risk of infection.
Related JoVE Video
A mutation in the leptin receptor is associated with Entamoeba histolytica infection in children.
J. Clin. Invest.
PUBLISHED: 03-12-2011
Show Abstract
Hide Abstract
Malnutrition substantially increases susceptibility to Entamoeba histolytica in children. Leptin is a hormone produced by adipocytes that inhibits food intake, influences the immune system, and is suppressed in malnourished children. Therefore we hypothesized that diminished leptin function may increase susceptibility to E. histolytica infection. We prospectively observed a cohort of children, beginning at preschool age, for infection by the parasite E. histolytica every other day over 9 years and evaluated them for genetic variants in leptin (LEP) and the leptin receptor (LEPR). We found increased susceptibility to intestinal infection by this parasite associated with an amino acid substitution in the cytokine receptor homology domain 1 of LEPR. Children carrying the allele for arginine (223R) were nearly 4 times more likely to have an infection compared with those homozygous for the ancestral glutamine allele (223Q). An association of this allele with amebic liver abscess was also determined in an independent cohort of adult patients. In addition, mice carrying at least 1 copy of the R allele of Lepr were more susceptible to infection and exhibited greater levels of mucosal destruction and intestinal epithelial apoptosis after amebic infection. These findings suggest that leptin signaling is important in mucosal defense against amebiasis and that polymorphisms in the leptin receptor explain differences in susceptibility of children in the Bangladesh cohort to amebiasis.
Related JoVE Video
The expression of REG 1A and REG 1B is increased during acute amebic colitis.
Parasitol. Int.
PUBLISHED: 02-09-2011
Show Abstract
Hide Abstract
Entamoeba histolytica, a protozoan parasite, is an important cause of diarrhea and colitis in the developing world. Amebic colitis is characterized by ulceration of the intestinal mucosa. We performed microarray analysis of intestinal biopsies during acute and convalescent amebiasis in order to identify genes potentially involved in tissue injury or repair. Colonic biopsy samples were obtained from 8 patients during acute E. histolytica colitis and again 60 days after recovery. Gene expression in the biopsies was evaluated using microarray, and confirmed by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). REG 1A and REG 1B were the most up-regulated of all genes in the human intestine in acute versus convalescent E. histolytica disease: as determined by microarray, the levels of induction were 7.4-fold and 10.7 fold for REG 1A and B; p=0.003 and p=0.006 respectively. Increased expression of REG 1A and REG 1B protein in the colonic crypt epithelial cells during acute amebiasis was similarly observed by immunohistochemistry. Because REG 1 protein is anti-apoptotic and pro-proliferative, and since E. histolytica induces apoptosis of the intestinal epithelium as part of its disease process, we next tested if REG 1 might be protective during amebiasis by preventing parasite-induced apoptosis. Intestinal epithelial cells from REG 1-/- mice were found to be more susceptible to spontaneous, and parasite-induced, apoptosis in vitro (p=0.03). We concluded that REG 1A and REG 1B were upregulated during amebiasis and may function to protect the intestinal epithelium from parasite-induced apoptosis.
Related JoVE Video
High throughput multiplex PCR and probe-based detection with Luminex beads for seven intestinal parasites.
Am. J. Trop. Med. Hyg.
PUBLISHED: 02-05-2011
Show Abstract
Hide Abstract
Polymerase chain reaction (PCR) assays for intestinal parasites are increasingly being used on fecal DNA samples for enhanced specificity and sensitivity of detection. Comparison of these tests against microscopy and copro-antigen detection has been favorable, and substitution of PCR-based assays for the ova and parasite stool examination is a foreseeable goal for the near future. One challenge is the diverse list of protozoan and helminth parasites. Several existing real-time PCR assays for the major intestinal parasites-Cryptosporidium spp., Giardia intestinalis, Entamoeba histolytica, Ancylostoma duodenale, Ascaris lumbricoides, Necator americanus, and Strongyloides stercoralis-were adapted into a high throughput protocol. The assay involves two multiplex PCR reactions, one with specific primers for the protozoa and one with specific primers for the helminths, after which PCR products are hybridized to beads linked to internal oligonucleotide probes and detected on a Luminex platform. When compared with the parent multiplex real-time PCR assays, this multiplex PCR-bead assay afforded between 83% and 100% sensitivity and specificity on a total of 319 clinical specimens. In conclusion, this multiplex PCR-bead protocol provides a sensitive diagnostic screen for a large panel of intestinal parasites.
Related JoVE Video
Mapping hypoendemic, seasonal malaria in rural Bandarban, Bangladesh: a prospective surveillance.
Malar. J.
PUBLISHED: 02-02-2011
Show Abstract
Hide Abstract
Until recently the Chittagong Hill tracts have been hyperendemic for malaria. A past cross-sectional RDT based survey in 2007 recorded rates of approximately 15%. This study was designed to understand the present epidemiology of malaria in this region, to monitor and facilitate the uptake of malaria intervention activities of the national malaria programme and to serve as an area for developing new and innovative control strategies for malaria.
Related JoVE Video
Malnutrition and helminth infection affect performance of an interferon gamma-release assay.
Pediatrics
PUBLISHED: 11-08-2010
Show Abstract
Hide Abstract
We sought to compare the tuberculin skin test (TST) to the QuantiFERON-TB Gold In-Tube assay (QFT-IT) and assess the effects of malnourishment and intestinal helminth infection on QFT-IT results.
Related JoVE Video
Mapping malaria risk in Bangladesh using Bayesian geostatistical models.
Am. J. Trop. Med. Hyg.
PUBLISHED: 10-05-2010
Show Abstract
Hide Abstract
Background malaria-control programs are increasingly dependent on accurate risk maps to effectively guide the allocation of interventions and resources. Advances in model-based geostatistics and geographical information systems (GIS) have enabled researchers to better understand factors affecting malaria transmission and thus, more accurately determine the limits of malaria transmission globally and nationally. Here, we construct Plasmodium falciparum risk maps for Bangladesh for 2007 at a scale enabling the malaria-control bodies to more accurately define the needs of the program. A comprehensive malaria-prevalence survey (N = 9,750 individuals; N = 354 communities) was carried out in 2007 across the regions of Bangladesh known to be endemic for malaria. Data were corrected to a standard age range of 2 to less than 10 years. Bayesian geostatistical logistic regression models with environmental covariates were used to predict P. falciparum prevalence for 2- to 10-year-old children (PfPR(2-10)) across the endemic areas of Bangladesh. The predictions were combined with gridded population data to estimate the number of individuals living in different endemicity classes. Across the endemic areas, the average PfPR(2-10) was 3.8%. Environmental variables selected for prediction were vegetation cover, minimum temperature, and elevation. Model validation statistics revealed that the final Bayesian geostatistical model had good predictive ability. Risk maps generated from the model showed a heterogeneous distribution of PfPR(2-10) ranging from 0.5% to 50%; 3.1 million people were estimated to be living in areas with a PfPR(2-10) greater than 1%. Contemporary GIS and model-based geostatistics can be used to interpolate malaria risk in Bangladesh. Importantly, malaria risk was found to be highly varied across the endemic regions, necessitating the targeting of resources to reduce the burden in these areas.
Related JoVE Video
Evaluation of rK-39 strip test using urine for diagnosis of visceral leishmaniasis in an endemic area in Bangladesh.
Parasit Vectors
PUBLISHED: 09-09-2010
Show Abstract
Hide Abstract
Diagnosis of visceral leishmaniasis (VL) by demonstration of parasites in tissue smears obtained from bone marrow, spleen or lymph nodes is risky, painful, and difficult. The rK-39 strip test is widely used for the diagnosis of VL using blood/serum samples in endemic countries. The aim of the study was to evaluate the rK-39 strip test using urine sample as a non-invasive means for the diagnosis of VL. The rk-39 strip test was performed using urine from 100 suspected VL cases along with 25 disease control (malarial febrile cases) and 50 healthy control (from endemic and non-endemic areas). All the VL suspected cases were positive with the rK-39 strip test using serum. The sensitivity and specificity of the rK-39 strip test using urine samples was 95% and 93.3%, respectively, compared to serum based rK-39 test. The findings suggest that the urine based rK-39 test could be a practical and efficient tool for the diagnosis of VL patients in rural areas, particularly where resources are limited.
Related JoVE Video
Low-dose beta-carotene supplementation and deworming improve serum vitamin A and beta-carotene concentrations in preschool children of Bangladesh.
J Health Popul Nutr
PUBLISHED: 07-20-2010
Show Abstract
Hide Abstract
Despite the national vitamin A and antihelminthic prophylaxis programmes, both intestinal geohelminths and subclinical vitamin A deficiency continue to be prevalent among children in developing countries. Studies on potential synergistic effects of vitamin A supplementation and deworming on retinol status have inconsistent results. The purpose of the present study was to investigate the impacts of low-dose beta-carotene supplementation and antihelminthic therapy on serum retinol and beta-carotene concentrations in preschool children of Bangladesh. Two hundred and forty-four children, known to be infected with Ascaris lumbricoides, were randomized into four treatment groups: I-IV. Group I and II received two oral doses of 400 mg of albendazole each, the first dose at baseline and the second dose after four months; Group III and IV received placebo in place of albendazole. In addition, Group I and III received 1.2 mg of beta-carotene powder in capsule daily for six months, and Group II and IV received placebo in place of beta-carotene. Serum retinol and beta-carotene levels were measured before and after six months of the interventions. Serum retinol and beta-carotene increased significantly in Group I where both antihelminthic therapy and daily beta-carotene supplementation were given (p<0.05 and p<0.001 respectively). Antihelminthic therapy alone only improved serum beta-carotene concentration (p<0.0001). Low-dose beta-carotene supplementation, along with an antihelminthic therapy, synergistically improved vitamin A status. This finding has public-health implications for improving vitamin A status of children in developing countries.
Related JoVE Video
Indigenous Plasmodium ovale malaria in Bangladesh.
Am. J. Trop. Med. Hyg.
PUBLISHED: 07-03-2010
Show Abstract
Hide Abstract
In spite of the high prevalence of malaria in Southeastern Bangladesh, there remains a significant shortage of information regarding the presence of three of five human malaria parasites: Plasmodium ovale, P. malariae, and P. knowlesi. The presence of P. ovale and P. knowlesi has previously never been reported from Bangladesh. We used a genus- and species-specific nested polymerase chain reaction, targeting highly conserved regions of the small subunit ribosomal RNA (SSU rRNA) gene, to investigate the presence of malaria parasites in a total number of 379 patient samples in a survey of patients with febrile illnesses in the Chittagong Hill Tracts in Southeastern Bangladesh. We identified the first cases of P. ovale in Bangladesh. They were confirmed by sequence analysis; 189 of 379 samples (49.9%; 95% confidence interval = 44.9-54.9%) were positive for Plasmodium sp. by PCR. P. falciparum monoinfections accounted for 68.3% (61.3-74.5%), followed by P. vivax (15.3%; 10.9-21.2%), P. malariae (1.6%; 0.5-4.6%), P. ovale (1.6%; 0.5-4.6%), and mixed infections (13.2%; 9.1-18.8%). We found no evidence of P. knowlesi in this region.
Related JoVE Video
Azithromycin combination therapy for the treatment of uncomplicated falciparum malaria in Bangladesh: an open-label randomized, controlled clinical trial.
J. Infect. Dis.
PUBLISHED: 06-19-2010
Show Abstract
Hide Abstract
In recent studies, the combination of azithromycin and artesunate has proven to be a promising alternative for the treatment of uncomplicated falciparum malaria.
Related JoVE Video
Diagnosis of amebic liver abscess and amebic colitis by detection of Entamoeba histolytica DNA in blood, urine, and saliva by a real-time PCR assay.
J. Clin. Microbiol.
PUBLISHED: 06-09-2010
Show Abstract
Hide Abstract
The noninvasive diagnosis of amebic liver abscess is challenging, as most patients at the time of diagnosis do not have a concurrent intestinal infection with Entamoeba histolytica. Fecal testing for E. histolytica parasite antigen or DNA is negative in most patients. A real-time PCR assay was evaluated for detection of E. histolytica DNA in blood, urine, and saliva samples from amebic liver abscess as well as amebic colitis patients in Bangladesh. A total of 98 amebic liver abscess and 28 amebic colitis patients and 43 control subjects were examined. The real-time PCR assay detected E. histolytica DNA in 49%, 77%, and 69% of blood, urine, and saliva specimens from the amebic liver abscess patients. For amebic colitis the sensitivity of the real-time PCR assay for detection of E. histolytica DNA in blood, urine, and saliva was 36%, 61%, and 64%, respectively. All blood, urine, and saliva samples from control subjects were negative by the real-time PCR assay for E. histolytica DNA. When the real-time PCR assay results of the urine and saliva specimens were taken together (positive either in urine or saliva), the real-time PCR assay was 97% and 89% sensitive for detection of E. histolytica DNA in liver abscess and intestinal infection, respectively. We conclude that the detection of E. histolytica DNA in saliva and urine could be used as a diagnostic tool for amebic liver abscess.
Related JoVE Video
Association between TNF-alpha and Entamoeba histolytica diarrhea.
Am. J. Trop. Med. Hyg.
PUBLISHED: 03-30-2010
Show Abstract
Hide Abstract
An association between tumor necrosis factor alpha (TNF-alpha) and Entamoeba histolytica diarrhea was assessed in a cohort of 138 non-related Bangladeshi children who have been prospectively followed since 2001. Peripheral blood mononuclear cells (PBMCs) obtained at study entry were purified, cultured, and stimulated with soluble amebic antigen before cytokine measurement from supernatant. Higher levels of TNF-alpha were associated with increased risk of first (P = 0.01) and recurrent E. histolytica-related diarrheal episodes (P = 0.005). Children who developed E. histolytica diarrhea had significantly higher TNF-alpha protein levels than those who experienced asymptomatic E. histolytica infection (P value = 0.027) or no infection (P value = 0.017). Microarray studies performed using RNA isolated from acute and convalescent whole blood and colon biopsy samples revealed higher but non-significant TNF-alpha messenger RNA (mRNA) levels in subjects with acute E. histolytica diarrhea compared with convalescence. We conclude that there is an association between higher TNF-alpha production and E. histolytica diarrhea.
Related JoVE Video
CLOCK and NPAS2 have overlapping roles in the circadian oscillation of arylalkylamine N-acetyltransferase mRNA in chicken cone photoreceptors.
J. Neurochem.
PUBLISHED: 03-24-2010
Show Abstract
Hide Abstract
Circadian clocks in vertebrates are thought to be composed of transcriptional-translational feedback loops involving a highly conversed set of clock genes namely, period (Per1-3) and cryptochrome (Cry1-2), which encode negative transcriptional regulators; and Bmal1, Clock, and Npas2, which encode positive regulators. Aanat, which encodes arylalkylamine N-acetyltransferase (AANAT), the key regulatory enzyme that drives the circadian rhythm of melatonin synthesis, contains a circadian E-box element (CACGTG) in its proximal promoter that is potentially capable of binding CLOCK : BMAL1 and NPAS2 : BMAL1 heterodimers. The present study was conducted to investigate whether CLOCK and/or NPAS2 regulates Aanat expression in photoreceptor cells. Npas2 and Clock are both expressed in photoreceptor cells in vivo and in vitro. To assess the roles of CLOCK and NPAS2 in Aanat expression, gene-specific micro RNA vectors were used to knock down expression of these clock genes in photoreceptor-enriched cell cultures. The knockdown of CLOCK protein significantly reduced the circadian expression of Npas2, Per2, and Aanat transcripts but had no effect on the circadian rhythm of Bmal1 transcript level. The knockdown of NPAS2 significantly damped the circadian rhythm of Aanat mRNAs but had no effect on circadian expression of any of clock genes examined, except Npas2 itself. Chromatin immunoprecipitation studies indicated that both CLOCK and NPAS2 bound to the Aanat promoter in situ. Thus, CLOCK and NPAS2 have overlapping roles in the clock output pathway that regulates the rhythmic expression of Aanat in photoreceptors. However, CLOCK plays the predominant role in the chicken photoreceptor circadian clockwork mechanism, including the regulation of NPAS2 expression.
Related JoVE Video
The Jacob2 lectin of the Entamoeba histolytica cyst wall binds chitin and is polymorphic.
PLoS Negl Trop Dis
PUBLISHED: 03-22-2010
Show Abstract
Hide Abstract
The infectious and diagnostic form of Entamoeba histolytica (Eh), cause of amebic dysentery and liver abscess, is the quadranucleate cyst. The cyst wall of Entamoeba invadens (Ei), a model for Eh, is composed of chitin fibrils and three sets of chitin-binding lectins that cross-link chitin fibrils (multivalent Jacob lectins), self-aggregate (Jessie lectins), and remodel chitin (chitinase). The goal here was to determine how well the Ei model applies to Entamoeba cysts from humans.
Related JoVE Video
Progress and challenges to control malaria in a remote area of Chittagong hill tracts, Bangladesh.
Malar. J.
PUBLISHED: 03-17-2010
Show Abstract
Hide Abstract
Malaria is endemic in 13 eastern districts where the overall infection prevalence is 3.97%. In 2006, Bangladesh received US$ 36.9 million from the Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) to support the national malaria control programme of Bangladesh.
Related JoVE Video
Enhanced case detection and improved diagnosis of PKDL in a Kala-azar-endemic area of Bangladesh.
PLoS Negl Trop Dis
PUBLISHED: 01-27-2010
Show Abstract
Hide Abstract
To support the Bangladesh National Kala-azar Elimination Programme (NKEP), we investigated the feasibility of using trained village volunteers for detecting post-kala-azar dermal leishmaniasis (PKDL) cases, using polymerase chain reaction (PCR) for confirmation of diagnosis and treatment compliance by PKDL patients in Kanthal union of Trishal sub-district, Mymensingh, Bangladesh.
Related JoVE Video
Spatial prediction of malaria prevalence in an endemic area of Bangladesh.
Malar. J.
PUBLISHED: 01-25-2010
Show Abstract
Hide Abstract
Malaria is a major public health burden in Southeastern Bangladesh, particularly in the Chittagong Hill Tracts region. Malaria is endemic in 13 districts of Bangladesh and the highest prevalence occurs in Khagrachari (15.47%).
Related JoVE Video
Prevalence of anopheline species and their Plasmodium infection status in epidemic-prone border areas of Bangladesh.
Malar. J.
PUBLISHED: 01-14-2010
Show Abstract
Hide Abstract
Information related to malaria vectors is very limited in Bangladesh. In the changing environment and various Anopheles species may be incriminated and play role in the transmission cycle. This study was designed with an intention to identify anopheline species and possible malaria vectors in the border belt areas, where the malaria is endemic in Bangladesh.
Related JoVE Video
Association of malnutrition with amebiasis.
Nutr. Rev.
PUBLISHED: 11-13-2009
Show Abstract
Hide Abstract
Observation of a cohort of preschool children in Dhaka, Bangladesh, is beginning to reveal the contributions of environment, host, and parasite to amebiasis. Reviewed here are the associations and interactions of malnutrition, IgA and interferon-gamma, human leukocyte antigen alleles, and parasite genotypes to the outcome of infection. Future efforts aimed at understanding the mechanisms of these effects are described.
Related JoVE Video
Use of metagenomics to understand the genetic basis of malnutrition.
Nutr. Rev.
PUBLISHED: 11-13-2009
Show Abstract
Hide Abstract
Childhood malnutrition is not just due to lack of nutrients, it can also be caused by enteric infections leading to intestinal inflammation and malabsorption of nutrients. Human genetic polymorphisms can alter host genes that affect nutrient absorption and metabolism. Changes in intestinal microbial ecology and the microbiome (the collective genome of the intestinal microbiota) can also affect the harvest of nutrients from the diet. A substantial proportion of malnourished children fail to recover due to inappropriate treatment. However, there may be other causes for treatment failure, including changes in the microbiome and infection with an enteropathogen, and a genetic predisposition to malnutrition may exist. It is, therefore, logical to undertake the following: 1) investigate genetic predisposition to malnutrition, 2) determine the genetic markers and biomarkers that can help identify children at risk of malnutrition, and 3) look for new treatment modalities that can improve the clinical management of children with malnutrition.
Related JoVE Video
Deficient serum mannose-binding lectin levels and MBL2 polymorphisms increase the risk of single and recurrent Cryptosporidium infections in young children.
J. Infect. Dis.
PUBLISHED: 10-16-2009
Show Abstract
Hide Abstract
Mannose-binding lectin (MBL) is an evolutionarily conserved protein that functions in human innate immunity by binding to microbial surfaces and promoting opsonophagocytosis. MBL has been shown to bind to Cryptosporidium sporozoites, and earlier work has suggested that the protective role of MBL may be most important in childhood. We evaluated the association between polymorphisms in the MBL gene (MBL2), serum MBL deficiency, and infection with Cryptosporidium, Entamoeba histolytica, and Giardia intestinalis in children. A large, prospective cohort of Bangladeshi preschool children was followed up for >3 years. Clinical outcomes, serum MBL levels, and MBL2 polymorphisms and haplotypes were determined. Statistically significant associations with E. histolytica and G. intestinalis were not found. Serum MBL deficiency, polymorphisms in the -221 promoter region, and the YO/XA MBL2 haplotype were strongly associated with Cryptosporidium infections, particularly recurrent infection. Children with multiple infections with Cryptosporidium were more likely to be MBL deficient (odds ratio [OR], 10.45), carry the -221 promoter variant (OR, 4.02), and have the YO/XA haplotype (OR, 4.91). We have identified a potentially important component of the human innate immune response to Cryptosporidum infection. Further work is needed to evaluate the mechanism of protection of MBL in Cryptosporidium infection.
Related JoVE Video
Malaria prevalence in endemic districts of Bangladesh.
PLoS ONE
PUBLISHED: 05-06-2009
Show Abstract
Hide Abstract
Following the 1971 ban of DDT in Bangladesh, malaria cases have increased steadily. Malaria persists as a major health problem in the thirteen south-eastern and north-eastern districts of Bangladesh. At present the national malaria control program, largely supported by the Global Fund for AIDS, Tuberculosis and Malaria (GFATM), provides interventions including advocacy at community level, Insecticide Treated Net (ITN) distribution, introduction of Rapid Diagnostic Tests (RDT) and combination therapy with Coartem. It is imperative, therefore, that baseline data on malaria prevalence and other malaria indicators are collected to assess the effectiveness of the interventions and rationalize the prevention and control efforts. The objective of this study was to obtain this baseline on the prevalence of malaria and bed net use in the thirteen malaria endemic districts of Bangladesh.
Related JoVE Video
Attribution of malnutrition to cause-specific diarrheal illness: evidence from a prospective study of preschool children in Mirpur, Dhaka, Bangladesh.
Am. J. Trop. Med. Hyg.
PUBLISHED: 05-02-2009
Show Abstract
Hide Abstract
We examined whether malnutrition (underweight [WAZ] < -2) increased the risk of diarrhea equally for all enteropathogens. The study was conducted prospectively between January 1999 and July 2002 in Mirpur, an urban slum in Dhaka. Two hundred eighty-nine Bangladeshi children (147 male and 142 female) 2-5 years of age were included in the study. Malnutrition was present in 39% of the children at the time of enrollment. The parents and children were visited and interviewed every other day by health care workers for details about any diarrheal episodes. Stool samples were successfully collected from 62% of episodes of diarrhea. Of the identified enteropathogens, only enterotoxigenic Escherichia coli (ETEC), Cryptosporidium sp., and Entamoeba histolytica were significantly more prevalent in malnourished children. We concluded that the malnutrition attributed risk is not equal for enteric pathogens associated with diarrheal illness.
Related JoVE Video
Relationship between sand fly fauna and kala-azar endemicity in Bangladesh.
Acta Trop.
PUBLISHED: 04-20-2009
Show Abstract
Hide Abstract
An entomological survey was carried out in Mymensingh district which contributes the highest incidence of visceral leishmaniasis (kala-azar) in Bangladesh. For the first time in Bangladesh CDC miniature light trap was used for indoor collection of sand flies. A total of 726 sand fly specimens belonging to nine species, one species of the genus Phlebotomus and eight species Sergentomyia genus were collected. Phlebotomus argentipes Annaandale Brunetti made up 59.2% of the total collection. Among Sergentomyia species Sergentomyia shorttii Adler & Theodor contributed 14.4% of the total collection. Density of sand flies both vector and non-vector species were significantly higher in endemic areas than non-endemic areas.
Related JoVE Video
Spatial malaria epidemiology in Bangladeshi highlands.
Malar. J.
PUBLISHED: 04-08-2009
Show Abstract
Hide Abstract
Malaria is a major public health burden in the south-eastern part of Bangladesh, particularly in the Chittagong Hill Tracts region. In 2007, BRAC and ICDDR,B carried out a malaria prevalence survey in the endemic regions including the Khagrachari District.
Related JoVE Video
Prospective case-control study of the association between common enteric protozoal parasites and diarrhea in Bangladesh.
Clin. Infect. Dis.
PUBLISHED: 03-28-2009
Show Abstract
Hide Abstract
The parasitic causes of diarrhea have historically been identified by use of microscopy; however, the use of this technique does not allow one to distinguish between subspecies or genotypes of parasites. Our objective was to determine, by use of modern diagnostic methods, the proportion of diarrhea cases in Bangladesh attributable to Cryptosporidium hominis, Cryptosporidium parvum, Entamoeba histolytica, and Giardia lamblia assemblages A and B.
Related JoVE Video
Knowledge on the transmission, prevention and treatment of malaria among two endemic populations of Bangladesh and their health-seeking behaviour.
Malar. J.
PUBLISHED: 03-12-2009
Show Abstract
Hide Abstract
Data on sociological and behavioural aspects of malaria, which is essential for an evidence-based design of prevention and control programmes, is lacking in Bangladesh. This paper attempts to fill this knowledge gap by using data from a population-based prevalence survey conducted during July to November 2007, in 13 endemic districts of Bangladesh.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.