Domestic dogs and cats as sources ofTrypanosoma cruziinfection in rural northwestern Argentina

Abstract

SUMMARYThe reservoir capacity of domestic cats and dogs for Trypanosoma cruzi infection and the hostfeeding patterns of domestic Triatoma infestans were assessed longitudinally in 2 infested rural villages in north-western Argentina. A total of 86 dogs and 38 cats was repeatedly examined for T. cruzi infection by serology and/or xenodiagnosis. The composite prevalence of infection in dogs (60%), but not in cats, increased significantly with age and with the domiciliary density of infected T. infestans. Dogs and cats had similarly high forces of infection, prevalence of infectious hosts (41-42%), and infectiousness to bugs at a wide range of infected bug densities. The infectiousness to bugs of seropositive dogs declined significantly with increasing dog age and was highly aggregated. Individual dog infectiousness to bugs was significantly autocorrelated over time. Domestic T. infestans fed on dogs showed higher infection prevalence (49%) than those fed on cats (39%), humans (38%) or chickens (29%) among 1085 bugs examined. The basic reproduction number of T. cruzi in dogs was at least 8·2. Both cats and dogs are epidemiologically important sources of infection for bugs and householders, dogs nearly 3 times more than cats.

Coexistence of Trypanosoma cruzi Genotypes in Wild and Periodomestic Mammals in Chile

“…In addition, other trypanosomatids different from T. cruzi may infect theses mammals, as reported in Argentina. 49 The coexistence of mixed parasite infections in mammals in wild and peridomestic cycles of Chagas disease may depend on several factors. Trypanosoma cruzi genotypes circulating in the blood can be affected by the vertebrate host immune system, intrinsic properties of each T. cruzi clone, such as a histotrophic preference for different tissues, 50,51 or clinical phase of the disease.…”

Molecular epidemiology of domestic and sylvatic Trypanosoma cruzi infection in rural northwestern Argentina

“…Xenodiagnosis was performed using 20-30 laboratory-reared, third-or fourth-instar nymphs of Tr. infestans per animal (Gürtler et al, 2007a). Bugs were provided by the insectary of the National Vector Control Coordination based in Córdoba, Argentina.…”

“…Natural infection by T. cruzi has been found in several local species of sylvatic mammals (Carcavallo and Martínez, 1968;Ceballos et al, 2006;Diosque et al, 2003;Yeo et al, 2005), whereas the putative sylvatic vectors have only been identified in Bolivia (Noireau et al, 2000). In the Gran Chaco, the bug Triatoma infestans is the main or single domiciliary vector; dogs, humans and chickens are usually the main blood meal sources of domestic bugs, and dogs and cats are considered the most important domestic reservoir hosts of T. cruzi (Minter, 1976;Gürtler et al, 1997Gürtler et al, , 2007a.…”

“…We also examined the distribution of T. cruzi lineages among bugs, dogs and cats at a household level. Based on previous evidence (Cardinal et al, , 2007Gürtler et al, 2005Gürtler et al, , 2007a, we hypothesized that domestic Tr. infestans and reservoir hosts from the same house compound would share the same parasite lineages.…”

Advances and challenges towards a vaccine against Chagas disease

“…In addition, in some regions, domestic animals such as dogs, have been found to play an important role as reservoir of the parasite and its transmission to human. [11][12][13][14] Control of infection in these animals has thus been proposed as an important complementary strategy to vector control, for example using insecticide-impregnated collars. 15 However, a veterinary vaccine, either preventive or therapeutic, would thus also greatly contribute to Chagas disease control by reducing infectiousness of the main domestic reservoir …”