Epidemiological role of humans, dogs and cats in the transmission of Trypanosoma cruzi in a central area of Argentina

Abstract

SUMMARYTrypanosoma cruzi prevalence rates of human, dog and cat populations from 47 households of 3 rural localities of the phytogeographical Chaquena area of Argentina were determined both by serological and xenodiagnostic procedures. Human prevalence rates were uniform and ranged from 49.6 to 58.7%. Overall pre valence rate in dogs (75.0%) was significantly higher than in humans (51.0%). The overall proportion of parasitemia individuals assessed by xenodiagnosis was significantly higher in either dog (64.2%) or cat (63.6%) populations than among humans (12.5%). Although both the average number of resident as well as in fected individuals per household was higher for people than for dogs (6.5 vs. 3.3, and 3.4 vs. 2.4, respectively), the reverse was recorded when parasitemic indi viduals were considered (1.0 vs. 2.1). Results are discussed in relation to dog between dogs and people, and dogs and bugs. In the light of present data, dogs must be considered as the major donors of parasites to vector bugs and thus, principal contributors to transmission in this region of Argentina.

Dynamics of transmission of Trypanosoma cruzi in a rural area of Argentina: III. Persistence of T. cruzi parasitemia among canine reservoirs in a two-year follow-up

“…On the other hand, the high detection rate of T. cruzi observed among dogs in the present and in pre vious studies made by us 18 agrees with data cf other researchers obtained in different ex perimental settings and with different parasite strains 8 (M. LAURICELLA, unpubl. res.…”

“…This oustanding feature, coupled with high T. infestans feeding frequencies upon dogs in Argentina 17 > 19 , reinforces previous suggestions made upon the amplifying role dogs possess in transmission cycles from this area 5 . Consequently, a synergistic effect traduced in an increased number of infected vectors in the household may be expected from domestic infestation plus the presence of infected dogs, which gives even more relevance to the epidemiological role appointed for canine reservoirs s ' 18 . In relation to cats, although its infective force is similar to that of dogs, exposure to T. infestans bites seems not to be suitable, as indicated by blood meal studies and already discussed I8 .…”

Infected dogs as a risk factor in the transmission of human Trypanosoma cruzi infection in western Venezuela

“…It is relevant to note that in localities of the states of Barinas and Portuguesa, two well known endemic areas for Chagas disease in Venezuela (Añez et al, 1999(Añez et al, , 2004a, high proportions of reactive dogs were detected with values of 86 and 91%, respectively. Therefore, results obtained lead us to conclude that dogs in rural localities of Venezuela may be consider an important domestic reservoir likewise in other countries (Zeledon, 1974;Wisniveski-Collie et al, 1985;Cohen and Gürtler, 2001;Beard et al, 2003;Reithinger et al, 2005). The fact that almost all the studied localities had infected dogs beside the high proportion of infection detected in both population of dogs and humans, allow us to consider this animal as an important factor in the maintenance of T. cruzi as a source for infection to human in the study area, assuming that the nearest the reservoir the more successful the transmission.…”

Natural Trypanosoma cruzi infection in dogs of endemic areas of the Argentine Republic

“…In endemic areas of our country, the prevalence of infection detected by serology, for dogs from ur ban areas, was of 17.59r 5 . However, the highest indices (64.291 and 65.29r for xenodiagnosis and serology respectively) corresponded to dogs Irom rural areas in the Province of Santiago del Este ro 27 .…”