Navegando por Assunto "Leishmania infantum chagasi"

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Acesso aberto (Open Access)
Canine visceral leishmaniasis due to Leishmania (L.) infantum chagasi in Amazonian Brazil: comparison of the parasite density from the skin, lymph node and visceral tissues between symptomatic and asymptomatic, seropositive dogs
(2010-10) LIMA, Luciana Vieira Rego; CARNEIRO, Liliane Almeida; CAMPOS, Marliane Batista; CHAGAS, Eujênia Janis; LAURENTI, Márcia Dalastra; CORBETT, Carlos Eduardo Pereira; LAINSON, Ralph; SILVEIRA, Fernando Tobias
Canine visceral leishmaniasis (CVL) is recognizable by characteristic signs of disease and is highly lethal. The infection, however, may be quite inapparent in some seropositive dogs, and this has raised the polemic question as to whether or not such animals can be a source of infection for Lutzomyia longipalpis, the vector of American visceral leishmaniasis (AVL). In this study we have examined 51 dogs with acute CVL from an AVL area in Pará State, northern Brazil, and compared the parasite density, amastigotes of Leishmania (L.) infantum chagasi, in the skin, lymph node and viscera of symptomatic with that of nine asymptomatic but seropositive dogs (IFAT-IgG). Post-mortem biopsy fragments of these tissues were processed by immunohistochemistry, using a polyclonal antibody against Leishmania sp. The X2 and Mann Whitney tests were used to evaluate the means of infected macrophage density (p < 0.05). There was no difference (p > 0.05) in the skin (10.7/mm2 x 15.5/mm2) and lymph node (6.3/mm2 x 8.3/mm2), between asymptomatic and symptomatic dogs, respectively. It was higher (p < 0.05), however, in the viscera of symptomatic (5.3/mm2) than it was in asymptomatic (1.4/mm2) dogs. These results strongly suggest that asymptomatic or symptomatic L. (L.) i. chagasi-infected dogs can serve as a source of infection, principally considering the highest (p < 0.05) parasite density from skin (10.7/mm2 x 15.5/mm2), the place where the vetor L. longipalpis takes its blood meal, compared with those from lymph node (6.3/mm2 x 8.3/mm2) and viscera (1.4/mm2x 5.3/mm2).
Acesso aberto (Open Access)
Diagnóstico molecular e frequência de anticorpos anti-Leishmania infantum chagasi em cães do município de Belém, Pará
(2014-03) SCHWANKE, Katiane; SILVA, Aryane Maximina Melo da; OLIVEIRA, Adlilton Pacheco de; SILVA, Michele Bahia do Vale; SILVEIRA, Fernando Tobias; SCOFIELD, Alessandra; CAVALCANTE, Gustavo Góes
Visceral leishmaniasis is a disease whose etiological agent in Brazil is Leishmania infantum chagasi. Dogs are considered urban reservoirs of the disease, being an indicator of the human cases occurrence. The present study aimed to diagnose L. infantum chagasi infection in stray and owned dogs in Belém, Pará State, by polymerase chain reaction (PCR) and indirect immunofluorescence assay (IFA) using two different antigens. Venous blood samples from adult dogs, regardless of gender or breed, of different neighborhoods in Belém-PA, were collected in tubes with and without anticoagulant to obtain DNA and serum, respectively. These animals were divided into two groups: stray dogs captured by the Center for Zoonosis Control (Group A) and owned dogs (Group B). Sera were analyzed by IFA testing for IgG using two different antigens: 1) Bio-Manguinhos/Fiocruz antigen kit (Ag-PRO) containing promastigotes of Leishmania sp. (Complex Major-Like), 2) Instituto Evandro Chagas Antigen (Ag-AMA) consisting of amastigotes of L. infantum chagasi. The evaluation of the two antigens was performed considering positive the reactions above the 1:80 dilution. Already PCR was performed with DNA isolated from whole blood of animals and amplified with the primers RV1 and RV2. Of the 335 samples analyzed, 10.4% (35/335) were positive by IFA (Ag-PRO) and 0.9% (3/335) with the Ag-AMA. The distribution of positive samples is given as follows: Group A 14.8% (25/169) with Ag-PRO and 1.2% (2/169) with Ag-AMA; Group B 6% (10/166) with Ag-PRO and 0.6% (1/166) with Ag-AMA, being that all samples positive by IFA with Ag-AMA also reacted with Ag-PRO, and none of the samples detected DNA of L. infantum chagasi. The findings of this study indicate that Belém can still be considered non-endemic area for canine visceral leishmaniasis and the nature of the antigen influences the result of the IFA for the detection of anti-L. infantum chagasi antibodies in dogs, and the IFA using promastigotes of Leishmania major-like antigen should be used with caution as a confirmatory diagnostic on epidemiological studies in non-endemic areas.