Asymptomatic dogs are highly competent to transmit Leishmania (Leishmania) infantum chagasi to the natural vector
Data de publicação2013-09-23
Direito de acesso
MetadadosExibir registro completo
We evaluated the ability of dogs naturally infected with Leishmania (Leishmania) infantum chagasi to transfer the parasite to the vector and the factors associated with transmission. Thirty-eight infected dogs were confirmed to be infected by direct observation of Leishmania in lymph node smears. Dogs were grouped according to external clinical signs and laboratory data into symptomatic (n= 24) and asymptomatic (n= 14) animals. All dogs were sedated and submitted to xenodiagnosis with F1-laboratory-reared Lutzomyia longipalpis. After blood digestion, sand flies were dissected and examined for the presence of promastigotes. Following canine euthanasia, fragments of skin, lymph nodes, and spleen were collected and processed using immunohistochemistry to evaluate tissue parasitism. Specific antibodies were detected using an enzyme-linked immunosorbent assay. Antibody levels were found to be higher in symptomatic dogs compared to asymptomatic dogs (p= 0.0396). Both groups presented amastigotes in lymph nodes, while skin parasitism was observed in only 58.3% of symptomatic and in 35.7% of asymptomatic dogs. Parasites were visualized in the spleens of 66.7% and 71.4% of symptomatic and asymptomatic dogs, respectively. Parasite load varied from mild to intense, and was not significantly different between groups. All asymptomatic dogs except for one (93%) were competent to transmit Leishmania to the vector, including eight (61.5%) without skin parasitism. Sixteen symptomatic animals (67%) infected sand flies; six (37.5%) showed no amastigotes in the skin. Skin parasitism was not crucial for the ability to infect Lutzomyia longipalpis but the presence of Leishmania in lymph nodes was significantly related to a positive xenodiagnosis. Additionally, a higher proportion of infected vectors that fed on asymptomatic dogs was observed (p= 0.0494). Clinical severity was inversely correlated with the infection rate of sand flies (p= 0.027) and was directly correlated with antibody levels (p= 0.0379). Age and gender did not influence the transmissibility. Our data show that asymptomatic dogs are highly infective and competent for establishing sand fly infection, indicating their role in maintaining L. (L.) infantum chagasi cycle as well as their involvement in VL spreading in endemic areas. © 2013 Elsevier B.V.
Como citar este documento
Este item aparece nas seguintes coleções
Exibindo os itens relacionados pelo título, autor e palavra-chave.
Oliveira, Trícia Maria Ferreira de Sousa; Vasconcelos, Elton José Rosas de; Nakaghi, Andréa Cristina Higa ; Defina, Tânia Paula Aquino; Jusi, Márcia Mariza Gomes ; Baldani, Cristiane Divan ; Cruz, Ângela Kaysel; Machado, Rosangela Zacarias (Revista Brasileira de Parasitologia Veterinária, 2011) [Artigo]A leishmaniose visceral (LV) é uma zoonose amplamente disseminada, causada no Brasil pela Leishmania (Leishmania) infantum chagasi. Flebotomíneos vetores adquirem o agente etiológico, alimentando-se do sangue de animais ...
Influence of apoptosis on the cutaneous and peripheral lymph node inflammatory response in dogs with visceral leishmaniasis Moreira, Pamela Rodrigues Reina ; De Barros Bandarra, Marcio ; Magalhães, Geórgia Modé ; Munari, Danísio Prado ; Machado, Gisele Fabrino ; Prandini, Marcelo Martinasso ; Alessi, Antonio Carlos ; De Oliveira Vasconcelos, Rosemeri (Veterinary Parasitology, 2013) [Artigo]In canine visceral leishmaniasis (CVL), the abnormalities most commonly observed in clinical examination on the animals are lymphadenomegaly and skin lesions. Dogs are the main domestic reservoir for the protozoon Leishmania ...
Marcondes, Mary ; Rossi, Claudio Nazaretian (Brazilian Journal of Veterinary Research and Animal Science, 2013) [Artigo]Visceral leishmaniasis (VL) is among the most important vector-borne diseases that occur in Brazil, mainly due to its zoonotic nature. It is currently present in almost all Brazilian territory, and its control is a challenge ...