This study investigated the transmission and prevalence of Leishmania parasite infection of humans in two foci of Visceral Leishmaniasis (VL) in Georgia, the well known focus in Tbilisi in the East, and in Kutaisi, a new focus in the West of the country. The seroprevalence of canine leishmaniasis was investigated in order to understand the zoonotic transmission. Blood samples of 1575 dogs (stray and pet) and 77 wild canids were tested for VL by Kalazar Detect rK39 rapid diagnostic tests. Three districts were investigated in Tbilisi and one in Kutaisi. The highest proportions of seropositive pet dogs were present in District #2 (28.1%, 82/292) and District #1 (26.9%, 24/89) in Tbilisi, compared to 17.3% (26/150) of pet dogs in Kutaisi. The percentage of seropositive stray dogs was also twice as high in Tbilisi (16.1%, n?=?670) than in Kutaisi (8%, n?=?50); only 2/58 wild animals screened were seropositive (2. 6%). A total of 873 Phlebotomine sand flies were collected, with 5 different species identified in Tbilisi and 3 species in Kutaisi; 2.3% of the females were positive for Leishmania parasites. The Leishmanin Skin Test (LST) was performed on 981 human subjects in VL foci in urban areas in Tbilisi and Kutaisi. A particularly high prevalence of LST positives was observed in Tbilisi District #1 (22.2%, 37.5% and 19.5% for ages 5-9, 15-24 and 25-59, respectively); lower prevalence was observed in Kutaisi (0%, 3.2% and 5.2%, respectively; P<0.05). This study shows that Tbilisi is an active focus for leishmaniasis and that the infection prevalence is very high in dogs and in humans. Although exposure is as yet not as high in Kutaisi, this is a new VL focus. The overall situation in the country is alarming and new control measures are urgently needed.
Sequence analyses and subtyping of Bacillus anthracis strains from Georgia reveal a single distinct lineage (Aust94) that is ecologically established. Phylogeographic analysis and comparisons to a global collection reveals a clade that is mostly restricted to Georgia. Within this clade, many groups are found around the country, however at least one subclade is only found in the eastern part. This pattern suggests that dispersal into and out of Georgia has been rare and despite historical dispersion within the country, for at least for one lineage, current spread is limited.
A previous surveillance study of human pathogens within ticks collected in the country of Georgia showed a relatively high infection rate for Rickettsia raoultii, R. slovaca, and R. aeschlimannii. These 3 spotted fever group rickettsiae are human pathogens: R. raoultii and R. slovaca cause tick-borne lymphadenopathy (TIBOLA), and R. aeschlimannii causes an infection characterized by fever and maculopapular rash. Three quantitative real-time polymerase chain reaction (qPCR) assays, Rraoul, Rslov, and Raesch were developed and optimized to detect R. raoultii, R. slovaca, and R. aeschlimannii, respectively, by targeting fragments of the outer membrane protein B gene (ompB) using species-specific molecular beacon or TaqMan probes. The 3 qPCR assays showed 100% specificity when tested against a rickettsiae DNA panel (n=20) and a bacteria DNA panel (n=12). The limit of detection was found to be at least 3 copies per reaction for all assays. Validation of the assays using previously investigated tick nucleic acid preparations, which included Rickettsia-free tick samples, tick samples that contain R. raoultii, R. slovaca, R. aeschlimannii, and other Rickettsia spp., gave 100% sensitivity for all 3 qPCR assays. In addition, a total of 65 tick nucleic acid preparations (representing 259 individual ticks) collected from the country of Georgia and the Republic of Azerbaijan in 2009 was tested using the 3 qPCR assays. R. raoultii, R. slovaca, and R. aeschlimannii were not detected in any ticks (n=31) from the Republic of Azerbaijan, but in the ticks from the country of Georgia (n=228) the minimal infection rate for R. raoultii and R. slovaca in Dermacentor marginatus was 10% and 4%, respectively, and for R. aeschlimannii in Haemaphysalis sulcata and Hyalomma spp. it was 1.9% and 20%, respectively.
A survey of potential vector sand flies was conducted in the neighboring suburban communities of Vake and Mtatsminda districts in an active focus of visceral Leishmaniasis (VL) in Tbilisi, Georgia. Using light and sticky-paper traps, 1,266 male and 1,179 female sand flies were collected during 2006-2008. Five Phlebotomus species of three subgenera were collected: Phlebotomus balcanicus Theodor and Phlebotomus halepensis Theodor of the subgenus Adlerius; Phlebotomus kandelakii Shchurenkova and Phlebotomus wenyoni Adler and Theodor of the subgenus Larroussius; Phlebotomus sergenti Perfilev of the subgenus Paraphlebotomus. Phlebotomus sergenti (35.1%) predominated in Vake, followed by P. kandelakii (33.5%), P. balcanicus (18.9%), P. halepensis (12.2%), and P. wenyoni (0.3%). In Mtatsminda, P. kandelakii (76.8%) comprised over three fourths of collected sand flies, followed by P. sergenti (12.6%), P. balcanicus (5.8%), P. halepensis (3.7%), and P. wenyoni (1.1%). The sand fly season in Georgia is exceptionally short beginning in early June, peaking in July and August, then declining to zero in early September. Of 659 female sand flies examined for Leishmania, 12 (1.8%) specimens without traces of blood were infected including 10 of 535 P. kandelakii (1.9%) and two of 40 P. balcanicus (5.0%). Six isolates were successfully cultured and characterized as Leishmania by PCR. Three isolates from P. kandelakii (2) and P. balcanicus (1) were further identified as L. infantum using sequence alignment of the 70 kDa heat-shock protein gene. Importantly, the sand fly isolates showed a high percent identity (99.8%-99.9%) to human and dog isolates from the same focus, incriminating the two sand fly species as vectors. Blood meal analysis showed that P. kandelakii preferentially feeds on dogs (76%) but also feeds on humans. The abundance, infection rate and feeding behavior of P. kandelakii and the infection rate in P. balcanicus establish these species as vectors in the Tbilisi VL focus.
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