Incidence and prevalence of Trypanosoma cruziinfection in dogs from a rural area under entomological surveillance

CARDINAL MV; LAURICELLA MA; KITRON, U; GÜRTLER, RE

Rosario, Pcia de Santa Fe.

Congreso; XX Reunión Anual de la Sociedad Argentina de Protozoología.; 2004

Sociedad Argentina de Protozoología.

Dogs are one of the main domestic Trypanosoma cruzi reservoirs in rural areas of the Argentinean Chaco and they represent a risk factor of infection to humans cohabiting with them. Besides, because of their high susceptibility to T. cruzi infection, high abundance and their close relation with their owners; they have been suggested as natural sentinels of the vectorial transmission of T. cruzi in rural areas under entomological surveillance. The aims of the present study were to 1) determine the incidence and prevalence rate of T. cruzi infection in dogs from a rural area under regular entomological surveillance activities since 1992; 2) detect new infected native-born dogs and explain the possible transmission routes involved. Overall prevalence of T. cruzi infection, diagnosed by ELISA, IFAT and IHA or xenodiagnosis was of 4,7% among 256 dogs examined in November 2002. In native dogs the age-prevalence rate was of 4,3% in dogs younger than 1 year, nil in dogs from 1 to 3 years-old and showed an increasing trend from 4,0% to 16,7% in dogs from 4-5 years old and older. Of 81 dogs surveyed in May 2000 and November 2002 no seroconversion was registered. This nil incidence is a consequence of diminishing the abundance of T. infestans caused by a massive spray done in 1992 combined with community-based regular surveillance and selective sprayings. We identified the external clinical aspect of the dog, cohabiting with one or more infected dogs and the T. cruzi infection status of the mother as significant risk factors associated with T. cruzi infection; determined by a bivariated analysis of the odds ratios. In the absence of seroconversions among dogs, we could expect the absence of seroconversion among humans.