Use este identificador para citar ou linkar para este item:
https://www.arca.fiocruz.br/handle/icict/59423
Tipo de documento
ArtigoDireito Autoral
Acesso restrito
Data de embargo
2099-12-31
Coleções
Metadata
Mostrar registro completo
ASYMPTOMATIC DOGS ARE HIGHLY COMPETENT TO TRANSMIT LEISHMANIA (LEISHMANIA) INFANTUM CHAGASI TO THE NATURAL VECTOR
Visceral leishmaniasis
Xenodiagnosis
Lutzomyia longipalpis
Transmissibility
Vector infection rate
Autor(es)
Afiliação
Laboratory of Pathology of Infectious Disease. Medical School, University of São Paulo. São Paulo, SP, Brazil
Department of Clinics. Veterinary Medical School. University of São Paulo. São Paulo, SP, Brazil
Laboratory of Pathology of Infectious Disease. Medical School, University of São Paulo. São Paulo, SP, Brazil
Laboratory of Pathology of Infectious Disease. Medical School, University of São Paulo. São Paulo, SP, Brazil
Laboratory of Pathology of Infectious Disease. Medical School, University of São Paulo. São Paulo, SP, Brazil
Laboratory of Medical Entomology. René Rachou Research Center. Oswaldo Cruz Foundation. Belo Horizonte, MG, Brazil
Laboratory of Medical Entomology. René Rachou Research Center. Oswaldo Cruz Foundation. Belo Horizonte, MG, Brazil
Department of Clinics. Surgery and Animal Reproduction. College of Veterinary Medicine. São Paulo State University. Araçatuba, SP, Brazil
Department of Clinics. Veterinary Medical School. University of São Paulo. São Paulo, SP, Brazil
Laboratory of Pathology of Infectious Disease. Medical School, University of São Paulo. São Paulo, SP, Brazil
Laboratory of Pathology of Infectious Disease. Medical School, University of São Paulo. São Paulo, SP, Brazil
Laboratory of Pathology of Infectious Disease. Medical School, University of São Paulo. São Paulo, SP, Brazil
Laboratory of Medical Entomology. René Rachou Research Center. Oswaldo Cruz Foundation. Belo Horizonte, MG, Brazil
Laboratory of Medical Entomology. René Rachou Research Center. Oswaldo Cruz Foundation. Belo Horizonte, MG, Brazil
Department of Clinics. Surgery and Animal Reproduction. College of Veterinary Medicine. São Paulo State University. Araçatuba, SP, Brazil
Resumo em Inglês
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.
Palavras-chave em inglês
Canine leishmaniasisVisceral leishmaniasis
Xenodiagnosis
Lutzomyia longipalpis
Transmissibility
Vector infection rate
Compartilhar