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.
KeywordsVectorial Capacity Leishmania Infection Canine Visceral Leishmaniasis Engorge Nymph European Ground Squirrel
The authors wish to thank the staff of the Secretaria Municipal de Saúde (Bom Sucesso, MG, Brazil) and the Serviço de Controle de Zoonoses (Belo Horizonte, MG, Brazil) for their valuable assistance. Special thanks are due to Prof. Evaldo do Nascimento for assistance with the maintenance of the dogs. The project was financially supported by PAPES V/FIOCRUZ (Proc. 403608/2008-2).
The study was submitted to and approved by the Comissão de Ética no Uso de Animais (CEUA/FIOCRUZ) under protocol no. L-044/08. All procedures involving experimental animals were conducted according to the guidelines of Colégio Brasileiro de Experimentação Animal (COBEA).
Conflict of interest
- Balashov YS (1972) Bloodsucking ticks (Ixodidae)—vectors of diseases of man and animals. Misc Publ Entomol Soc Am 8:161–376Google Scholar
- Blanc G, Caminopetros J (1930) La transmission du Kala-Azar méditerraneén par une tique: Rhipicephalus sanguineus. C R Acad Sci 191:1162–1164Google Scholar
- França-Silva JC, Barata RA, Costa RT, Monteiro EM, Machado-Coelho GL, Vieira EP, Prata A, Mayrink W, Nascimento E, Fortes-Dias CL, Da Silva JC, Dias ES (2005) Importance of Lutzomyia longipalpis in the dynamics of transmission of canine visceral leishmaniasis in the endemic area of Porteirinha Municipality, Minas Gerais, Brazil. Vet Parasitol 10:213–220CrossRefGoogle Scholar
- Gothe R, Wegerot S, Walden R, Walden A (1989) Epidemiology of Babesia canis and Babesia gibsoni infections in dogs in Germany. Kieintierpraxis 34:309–320Google Scholar
- Labruna MB, Pereira MC (2001) Carrapato em cães no Brasil. Clin Vet 30:24–32Google Scholar
- Malaquias LC, Do Carmo Romualdo R, Do Anjos JB Jr, Giunchetti RC, Corrêa-Oliveira R, Reis AB (2007) Serological screening confirms the re-emergence of canine leishmaniosis in urban and rural areas in Governador Valadares, Vale do Rio Doce, Minas Gerais, Brazil. Parasitol Res 100:233–239CrossRefPubMedGoogle Scholar
- Michalsky EM, Rocha MF, Da Rocha Lima AC, França-Silva JC, Pires MQ, Oliveira FS, Pacheco RS, Dos Santos SL, Barata RA, Romanha AJ, Fortes-Dias CL, Dias ES (2007) Infectivity of seropositive dogs, showing different clinical forms of leishmaniasis, to Lutzomyia longipalpis phlebotomine sand flies. Vet Parasitol 147:67–76CrossRefPubMedGoogle Scholar
- Obenchain FD, Galun R (1982) Physiology of ticks. Pergamon, OxfordGoogle Scholar
- Ribeiro MFB, Lima JD, Guimarães AM (1988) Occurrence of Trypanosoma theileri, Laveran 1902, in Boophilus microplus in the State of Minas Gerais, Brazil. Arq Esc Vet UFMG 35:65–68Google Scholar
- Soulsby EJL (1966) Biology of parasites, emphasis on veterinary parasite. Academic, New York, pp 72–77Google Scholar