Evaluation of different diagnostic methods of American Cutaneous Leishmaniasis in the Brazilian Amazon

Epidemiological studies have been conducted to better understand the dynamics of American Cutaneous Leishmaniasis (ACL) in the Amazon region where distinct species of Leishmania circulate. In endemic areas, the optimal diagnosis must be made in the earlier clinical presentation to avoid the complications of chronic disease. The scarcity of financial support, laboratory infrastructure and trained persons are the major obstacles in this reality. This paper describes the result of performing different diagnostic methods for ACL in Amazonas State between the years 2010 and 2011. The tests used were the intradermal skin test (Montenegro's skin test), ELISA (Enzyme-Linked Immunosorbent Assay), direct examination, culture isolation and identification of Leishmania species. A total of 38 suspected human cases of ACL were diagnosed by different methods, of which 71.0% (n = 27) were positive by direct examination, 75.6% (n = 28) had positivity in the culture isolates and, of these, 54.0% (n = 19) had infection with Leishmania (Viannia) guyanensis. The positivity of the intradermal skin test with the leishmanin solution was observed in 77.0% of cases analyzed and the serology with detection of IgG and IgM showed the presence of antibodies in 100% of exams realized results, showing variation in the titles of antibodies. The success of Leishmaniasis treatment depends on an effective and early diagnosis. Parasitological diagnosis is highly specific, but sensitivity is subject to variation because the tissue distribution of parasites generally is not homogeneous and depends on the specie of parasite. Moreover, parasitological tests require invasive procedures and depend on restrictive conditions for the collection of biological sample, which limit their use in large-scale for epidemiological studies. ELISA has been the most widely used serological method for the diagnosis of Visceral Leishmaniasis (VL) as it is easy to perform and has a low cost. However, flaws in specificity are observed in the diagnosis of cutaneous leishmaniasis. Actually the diagnosis needs to be done as an associated methods depending on the question to be solved.

Diversity and distribution of sandflies (Diptera: Psychodidae: Phlebotominae) in a military area in the state of Amazonas, Brazil

This study reports the distribution, ecotopes and fauna diversity of sandflies captured in five training bases on a military reserve in Manaus, state of Amazonas (AM). A total of 10,762 specimens were collected, which were distributed among 58 species, with the highest number recorded at Base Instruction 1 (BI1). A higher rate of species richness was found at the Base Instruction Boina Rajada and low levels of diversity associated with a high abundance index with the clear dominance of Lutzomyia umbratilis, Lutzomyia ruii and Lutzomyia anduzei were found at BI1. The abundance of Lu. umbratilis raises the possibility of outbreaks of American cutaneous leishmaniasis by the main vector of the disease in AM.

Leishmania (Viannia) guyanensis induces low immunologic responsiveness in leishmaniasis patients from an endemic area of the Brazilian Amazon Highland

Cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis (CL-Lguy) is endemic in the Brazilian Amazon, differing from L. braziliensis infection in clinical, diagnostic, and therapeutic aspects. T-cell reactivity to leishmanial antigens possibly involved in the pathogenesis of CL-Lguy was studied herein. Variable lymphoproliferative responses (LPRs) to Leishmania antigens were found among the 23 studied patients, and 50% of them showed low or no response to these antigens. Active disease was associated with an enrichment of leishmanial-reactive T lymphocytes, mainly TCD4(+). High and low interferon (IFN)-gamma producers were observed. TNF-alpha, interleukin (IL)-10, and IL-5 were consistently detected. CL-Lguy displayed low antibody response in comparison to L. braziliensis patients. CL caused by L. braziliensis presented positive LPRs and higher IFN-gamma production but undetectable IL-5. L. guyanensis seems to induce a down-regulation of the immune system compared with L. braziliensis. This finding could explain some aspects of clinical presentation of CL-Lguy, such as high tissue parasite burden and frequent resistance to therapy.

Caracterização isoenzimática de isolados humanos de Leishmania sp (Kinetoplastida: Trypanosomatidae) dos municípios de Rio Preto da Eva e Manaus, Estado do Amazonas

Foram caracterizados/identificados por eletroforese de isoenzimas 23 isolados de Leishmania sp de pacientes dos municípios de Rio Preto da Eva e Manaus, analisando-se o grau de similaridade entre os organismos. Os resultados indicaram ocorrência de Leishmania guyanensis e Leishmania naiffi nestes dois ambientes e a heterogeneidade das amostras de Leishmania naiffi.

Infection rates and genotypes of Trypanosoma rangeli and T. cruzi infecting free-ranging Saguinus bicolor (Callitrichidae), a critically endangered primate of the Amazon Rainforest

Parasites of wild primates are important for conservation biology and human health due to their high potential to infect humans. In the Amazon region, non-human primates are commonly infected by Trypanosoma cruzi and T. rangeli, which are also infective to man and several mammals. This is the first survey of trypanosomiasis in a critically endangered species of tamarin, Saguinus bicolor (Callitrichidae), from the Brazilian Amazon Rainforest. Of the 96 free-ranging specimens of S. bicolor examined 45 (46.8%) yielded blood smears positive for trypanosomes. T. rangeli was detected in blood smears of 38 monkeys (39.6%) whereas T. cruzi was never detected. Seven animals (7.3%) presented trypanosomes of the subgenus Megatrypanum. Hemocultures detected 84 positive tamarins (87.5%). Seventy-two of 84 (85.7%) were morphologically diagnosed as T. rangeli and 3 (3.1%) as T. cruzi. Nine tamarins (9.4%) yielded mixed cultures of these two species, which after successive passages generated six cultures exclusively of T. cruzi and two of T. rangeli, with only one culture remaining mixed. Of the 72 cultures positive for T. rangeli, 62 remained as established cultures and were genotyped: 8 were assigned to phylogenetic lineage A (12.9%) and 54 to lineage B (87.1%). Ten established cultures of T. cruzi were genotyped as TCI lineage (100%). Transmission of both trypanosome species, their potential risk to this endangered species and the role of wild primates as reservoirs for trypanosomes infective to humans are discussed.

Feeding preference of the sand flies Lutzomyia umbratilis and L. spathotrichia (diptera: Psychodidae, Phlebotominae) in an urban forest patch in the city of Manaus, Amazonas, Brazil

Precipitin tests were performed on blood meals of 199 sand flies (161 Lutzomyia umbratilis, 34 L. spathotrichia, two Lutzomyia of group shannoni, one L. anduzei) in a non-flooded upland forest on the Campus of the Universidade Federal do Amazonas. This is the second largest forest fragment in an urban setting in Brazil. Results on L. umbratilis, which is considered to be the principal leishmaniasis vector in this region, indicated rodents as its predominant blood source in contrast to previous reports in which blood meal analysis indicated that this species fed principally on Xenarthra (particularly sloths).

A note on reproduction of Didelphis marsupialis in captivity

Conditions leading to successful reproduction of Didelphis marsupialis in captivity are described. A trial involving four mating pairs which had been maintained at least four months in the laboratory resulted in three litters and one false pregnancy. This is, to our knowledge, the first record of successful breeding of this species in captivity.