Routine serological diagnoses for leishmaniases, except in visceral cases, are performed using whole-parasite antigens. We used enzyme-linked immunosorbent assay (ELISA) to evaluate the performance of Leishmania infantum rHsp83 compared with L. major-like total promastigote antigen in the diagnosis of cutaneous (CL), mucosal (ML), and visceral leishmaniases (VL). ELISA-rHsp83 was significantly more sensitive than ELISA-L. major-like when considering either CL/ML (P = 0.041) or all leishmaniasis patients (P = 0.013). When samples from other infectious disease patients were evaluated for cross-reactivity, ELISA-rHsp83 was more specific than ELISA-L. major-like, specifically for Chagas disease samples (P < 0.001). We also evaluated the anti-rHsp83 antibody titers months after treatment and observed no significant difference in ML (P = 0.607) or CL (P = 0.205). We recommend ELISA-L. infantum-rHsp83 as a routine confirmatory serological assay for the diagnosis of Leishmania infection because of the high sensitivity, the specificity, and the insignificant cross-reactivity with other infectious diseases.
In this study, we detected Leishmania spp. infection in R. sanguineus collected from dogs that were naturally infected with L. (L.) infantum. We examined 35 dogs of both sexes and unknown ages. The infected dogs were serologically positive by the immunofluorescence antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), and Quick Test-DPP (Dual Path Platform), as well as parasitological examination of a positive skin biopsy or sternal bone marrow aspiration. Ten negative dogs were included as controls. The ticks that infested these dogs were collected in pools of 10 adult females per animal. The PCR was performed with specific primers for Leishmania spp., which amplified a 720-bp fragment. Of the 35 analyzed samples, a product was observed in eight samples (8/35; 22.9%). We conclude that the presence of parasite DNA suggests that ticks participate in the zoonotic cycle of canine visceral leishmaniasis, in the city of Teresina, Piauí.
A 21-yr-old female jaguar (Panthera onca) died in a zoo in Teresina, Piaui, Brazil, following a history of abdominal distension, ascites, anorexia, and dyspnea. At necropsy, a dark red, watery, blood-tinged serous fluid was present in the abdominal cavity. The peritoneum was thick with firm, yellow, villous projections. Histologically, the tumors were composed of a biphasic population of cells, which reacted to anti-cytokeratin and anti-vimentin antibodies, consistent with a biphasic benign mesothelioma of peritoneal origin. This is the first reported case of mesothelioma in a captive jaguar.
This study investigated the sero-conversion period in which dogs from endemic areas test positive for visceral leishmaniasis (VL) as well as the early post-infection period in which renal alterations are observed. Dogs that were initially negative for Canine Visceral Leishmaniasis (CVL) were clinically evaluated every three months by serological, parasitological and biochemical tests until sero-conversion was confirmed, and six months later a subsequent evaluation was performed. Samples of kidney tissues were processed and stained with Hematoxylin and Eosin (H&E), Periodic Acid Schiff (PAS) and Massons trichrome stain and lesions were classified based on the WHO criteria. Of the 40 dogs that initially tested negative for VL, 25 (62.5%) exhibited positive serological tests during the study period. Of these 25 dogs, 15 (60%) tested positive within three months, five (20%) tested positive within six months and five (20%) tested positive within nine months. The dogs exhibited antibody titers between 1:40 and 1:80 and 72% of the dogs exhibited clinical symptoms. The Leishmania antigen was present in the kidneys of recently infected dogs. We found higher levels of total protein and globulin as well as lower levels of albumin in the infected dogs when compared to the control dogs. Additionally, infected dogs presented levels of urea and creatinine that were higher than those of the uninfected dogs. Glomerulonephritis was detected in some of the dogs examined in this study. These data suggest that in Teresina, the sero-conversion for VL occurs quickly and showed that the infected dogs presented abnormal serum proteins, as well as structural and functional alterations in the kidneys during the early post-infection period.
Visceral leishmaniasis (VL) has been known to occur in the state of Piauí since 1934. The typically rural disease began to appear in urban areas over time, being concentrated mainly in Teresina, the capital of Piauí. Teresina was also affected by the first urban epidemic of VL in Brazil. Over 1,000 cases of the disease were reported during urbanization (1981-1986). Human population growth and migration led to land occupation on the outskirts of Teresina. These factors have contributed to vector proliferation, increasing the incidence of VL. At present, the incidence of human and canine disease is quite high and uncontrolled in Piauí. It seems that some measures, such as the elimination of seropositive dogs, failed to significantly reduce the number of new VL cases in Teresina. Despite previously conducted studies, little is known about VL epidemiology in urban areas. The aim of this review is to reveal the situation of VL in Teresina during the last 40 years, focusing on the major factors that may contribute to the high incidence and persistence of VL infection.
A recombinant protein, rLdccys1, produced by expression of the gene encoding a 30kDa cysteine proteinase from Leishmania (Leishmania) chagasi, was used to detect specific antibodies in serum by enzyme-linked immunosorbent assays and to test for reactivity in delayed-type hypersensitivity (DTH) responses of dogs from an endemic region of visceral leishmaniasis (VL), Teresina, Piauí State, Brazil. Amastigote or promastigote extracts were also assayed for comparison. The sensitivity for detection of specific antibodies to L. (L.) chagasi using rLdccys1, lysates from L. (L.) chagasi promastigotes and amastigotes was 96%, 68%, and 69%, respectively. No cross-reactivity between rLdccys1 and Chagas disease was observed, and little reactivity was found with sera from dogs with babesiosis and ehrlichiosis. Among 106 sera from symptomatic dogs and 22 from non-infected controls, no false negatives and only two false positive sera were found for rLdccys1. In contrast, amastigote lysates yielded 11 false positives and 13 false negatives, whereas the corresponding numbers for promastigote lysates were 17 and 16. DTH responses were determined after intradermal injection of rLdccys1 or amastigote extract and the induration area was measured at 24, 48 and 72h after injection. All asymptomatic dogs showed a positive intradermal response to rLdccys1 (>10mm) which peaked at 48h, whereas no significant reactivity to the recombinant antigen was found in the symptomatic group. Histological analysis of the intradermal induration showed a predominance of necrotic and hemorrhagic areas in sections from asymptomatic dogs injected with L. (L.) chagasi amastigote extract, whereas a typical granulomatous reaction mediated by mononuclear cells was observed in sections from asymptomatic animals injected with rLdccys1. Grouping data from ELISA and DTH assays with rLdccys1 and L. (L.) chagasi amastigote extracts showed that humoral and cellular responses were inversely correlated during the development of canine VL. Overall, these findings indicate that L. (L.) chagasi recombinant cysteine proteinase is potentially useful for diagnosis of canine VL, as well as for the discrimination of clinical and subclinical forms of the disease.
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