INTERACTION BETWEEN DIDELPHIS-ALBIVENTRIS AND TRIATOMA-INFESTANS IN RELATION TO TRYPANOSOMA-CRUZI TRANSMISSION

This paper attempts to prove if a high Trypanosoma cruzi prevalence of opossums might be reached with few potential infective contacts. One non-infected Didelphis albiventris to T. cruzi and 10 infected nymphs of Triatoma infestans were left together during 23 hr in a device that simulated a natural opossum burrow. Twenty-six replicates were perfor med using marsupials and triatomines only once. Potentially infective contacts occurred in ail the trials. From the 26 opossums used in tria ls, 54% did not eat any bug. Of the 260 bugs used, 21% were predated I n the 25 trials involving 205 surviving bugs, 36% of them did not feed In 15/25 cases, greater than or equal to 60% of the triatomines were able to feed. The parasitological follow-up of 24 opossums showed that among 10 that had eaten bugs, 4 turned out infected and among the 14 that had not predate, 3 (21%) became positive. In sum, 7/24 (29%) of t he marsupials acquired the infection after the experiment. This infect ion rate was similar to the prevalences found for the opossum populati on of Santiago del Estero, Argentina, suggesting that the prevalences observed in the field might be reached if each marsupial would encount er infected bugs just once in its lifetime.