Evaluation of the vectorial capacity of Rhipicephalus sanguineus (Acari: Ixodidae) in the transmission of canine visceral leishmaniasis.
The vectorial capacity of Rhipicephalus sanguineus in the transmission of canine visceral leishmaniasis has been evaluated through a laboratory-controlled experiment. One healthy Leishmania-free dog and two dogs naturally infected with Leishmania were infested with R. sanguineus in various stages of development. Engorged larvae, unfed nymphs, engorged nymphs, unfed adults, engorged female adults and fed male adults were collected from the experimental animals and examined for Leishmania infection by optical microscopy, polymerase chain reaction (PCR) and parasite culture. Leishmania forms were not detected in any of the 433 smears prepared from engorged colonies nor in any of the 118 smears prepared from unfed colonies. However, one flagellate structure was identified in one of the smears. All pools of R. sanguineus that had fed on the infected dogs tested PCR-positive for Leishmania DNA, with the single exception of the pool of engorged larvae. In contrast, all pools of ticks that had fed on the Leishmania-free dog were PCR-negative. Leishmania growth was not observed in any of the tick colonies following incubation on culture medium. Considering that no Leishmania forms were identified in any of the meticulously analysed smears derived from engorged colonies of R. sanguineus, it appears somewhat unlikely that the maintenance and multiplication of Leishmania occurs within the tick.
Paz
Gustavo Fontes
GF
Laboratório de Leishmanioses, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, 30190-002 Belo Horizonte, MG, Brazil.
Ribeiro
Múcio Flávio Barbosa
MF
Michalsky
Erika Monteiro
EM
da Rocha Lima
Ana Cristina Vianna Mariano
AC
França-Silva
João Carlos
JC
Barata
Ricardo Andrade
RA
Fortes-Dias
Consuelo Latorre
CL
Dias
Edelberto Santos
ES
D000818:Animals; D004199:Disease Vectors; D004283:Dog Diseases / Q000469:parasitology / Q000635:transmission*; D004285:Dogs; D005260:Female; D007891:Leishmania / Q000302:isolation & purification*; D007898:Leishmaniasis, Visceral / Q000635:transmission / Q000662:veterinary*; D008297:Male; D048508:Rhipicephalus sanguineus / Q000469:parasitology*; D013987:Ticks