Parasite load in the blood and skin of dogs naturally infected by Leishmania infantum is correlated with their capacity to infect sand fly vectors.
The sand fly Lutzomyia longipalpis is primarily responsible for the transmission of visceral leishmaniasis (VL) in the New World, and dogs are considered to be the main urban reservoir of this disease. In order to improve the efficacy of control measures, it is essential to assess the transmission capacity of Leishmania infantum to the sand fly vector by naturally infected dogs. The present study investigated the existence of correlations between canine clinical presentation and the intensity of parasite load in the blood, skin and spleen of naturally infected dogs. In addition, we also attempted to establish correlations between the intensity of parasite load in canine tissue and the parasite load detected in sandflies five days after feeding on naturally infected dogs. A total of 23 dogs were examined and classified according to clinical manifestation of canine VL. Blood samples, splenic aspirate and skin biopsies were collected and parasite DNA was quantified by qPCR. Canine capacity to infect Lu. longipalpis with parasites was evaluated by xenodiagnosis and parasite loads were measured five days after feeding. No significant differences were observed with respect to canine clinical manifestation and the parasite loads detected in the blood, skin and spleen samples obtained from naturally infected dogs. Regardless of clinical canine visceral leishmaniasis (CVL) presentation and the degree of parasite burden, almost half of the dogs successfully infected sandflies with parasites, albeit to a low number of sandflies with correspondingly low parasite loads. Parasite loads in both canine blood and skin were shown to be positively correlated with the canine infectiousness to the sand fly vector, and positive correlations were also observed with respect to these tissues and the sand fly infection rate, as well as the parasite load detected in sandflies following xenodiagnosis. In conclusion, this indicates that parasite loads in both blood and skin can function as potentially reliable markers of canine capacity to infect sand fly vector.
Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-FIOCRUZ, Rua Waldemar Falcão, 121, Candeal, 40296-710 Salvador, Bahia, Brazil.
Lairton Souza
LS
Borja
Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-FIOCRUZ, Rua Waldemar Falcão, 121, Candeal, 40296-710 Salvador, Bahia, Brazil.
Orlando Marcos Farias de
OMF
Sousa
Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-FIOCRUZ, Rua Waldemar Falcão, 121, Candeal, 40296-710 Salvador, Bahia, Brazil.
Manuela da Silva
MDS
Solcà
Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-FIOCRUZ, Rua Waldemar Falcão, 121, Candeal, 40296-710 Salvador, Bahia, Brazil.
Leila Andrade
LA
Bastos
Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-FIOCRUZ, Rua Waldemar Falcão, 121, Candeal, 40296-710 Salvador, Bahia, Brazil.
Marcelo
M
Bordoni
Escola de Medicina Veterinária, Universidade Federal da Bahia, Avenida Adhemar de Barros, 500, Ondina, 40170-110 Salvador, Bahia, Brazil.
Jairo Torres
JT
Magalhães
Escola de Medicina Veterinária, Universidade Federal da Bahia, Avenida Adhemar de Barros, 500, Ondina, 40170-110 Salvador, Bahia, Brazil.
Daniela Farias
DF
Larangeira
Escola de Medicina Veterinária, Universidade Federal da Bahia, Avenida Adhemar de Barros, 500, Ondina, 40170-110 Salvador, Bahia, Brazil.
Stella Maria
SM
Barrouin-Melo
Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-FIOCRUZ, Rua Waldemar Falcão, 121, Candeal, 40296-710 Salvador, Bahia, Brazil; Escola de Medicina Veterinária, Universidade Federal da Bahia, Avenida Adhemar de Barros, 500, Ondina, 40170-110 Salvador, Bahia, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais, INCT - DT, Bahia, Brazil.
Deborah Bittencourt Mothé
DBM
Fraga
Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz-FIOCRUZ, Rua Waldemar Falcão, 121, Candeal, 40296-710 Salvador, Bahia, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais, INCT - DT, Bahia, Brazil. Electronic address: pveras@bahia.fiocruz.br.
Patrícia Sampaio Tavares
PST
Veras
D000818:Animals; D004283:Dog Diseases / Q000097:blood / Q000469:parasitology* / Q000635:transmission; D004285:Dogs; D005260:Female; D007303:Insect Vectors; D018314:Leishmania infantum; D007898:Leishmaniasis, Visceral / Q000097:blood / Q000469:parasitology / Q000635:transmission / Q000662:veterinary*; D008297:Male; D059208:Parasite Load; D011576:Psychodidae / Q000469:parasitology* / Q000502:physiology; D012867:Skin / Q000469:parasitology*
Canine infectiousness; Parasite load; Xenodiagnosis