Ticks, ivermectin, and experimental Chagas disease.
Following an infestation of dogticks in kennels housing dogs used for long-term studies of the pathogenesis of Chagas disease, we examined the effect of ivermectin treatment on the dogs, ticks, trypanosome parasites, and also on triatomine vectors of Chagas disease. Ivermectin treatment was highly effective in eliminating the ticks, but showed no apparent effect on the dogs nor on their trypanosome infection. Triatominae fed on the dogs soon after ivermectin treatment showed high mortality, but this effect quickly declined for bugs fed at successive intervals after treatment. In conclusion, although ivermectin treatment may have a transient effect on peridomestic populations of Triatominae, it is not the treatment of choice for this situation. The study also showed that although the dogticks could become infected with Trypanosoma cruzi, this only occurred when feeding on dogs in the acute phase of infection, and there was no evidence of subsequent parasite development in the ticks.
Dias
João Carlos Pinto
JC
Pathogen Molecular Biology Unit, London School of Hygiene and Tropical Medicine, London, UK. jcpdias@cpqrr.fiocruz.br
Schofield
Christopher J
CJ
Machado
Evandro Mm
EM
Fernandes
Alexandre José
AJ
D000208:Acute Disease; D000818:Animals; D000977:Antiparasitic Agents / Q000627:therapeutic use*; D014355:Chagas Disease / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D002908:Chronic Disease; D004283:Dog Diseases / Q000188:drug therapy* / Q000469:parasitology; D004285:Dogs; D007559:Ivermectin / Q000627:therapeutic use*; D048508:Rhipicephalus sanguineus / Q000187:drug effects* / Q000469:parasitology; D012239:Rhodnius / Q000187:drug effects / Q000469:parasitology; D013984:Tick Infestations / Q000188:drug therapy / Q000662:veterinary*; D013997:Time Factors; D016896:Treatment Outcome; D014224:Triatoma / Q000187:drug effects / Q000469:parasitology; D014349:Trypanosoma cruzi / Q000187:drug effects*
D000977:Antiparasitic Agents; D007559:Ivermectin