Epidemiological Pattern of Chagas' Disease in an Endemic Area of Costa Rica *

Probability of Trypanosoma cruzi transmission by Triatoma infestans (Hemiptera: Reduviidae) to the opossum Didelphis albiventris (Marsupialia: Didelphidae).

“…Table 2 shows the experimental results in terms of the variables X, W, and Y. A contingency test using the ''biting'' and predation frequencies of Table 2 showed that the ''bit- Probability that a ''bite'' will infect an opossum p 2 Probability that a bug that has been eaten by an opossum will infect it, either because it had ''bitten'' the opossum previously, or as a direct result of having been ingested p 3 Probability that if a bug is ingested it will infect the opossum exclusively because of the ingestion itself p 4 Probability that an ingested bug might have ''bitten'' the opossum before being eaten p 5 Probability that, faced with a triatomine for 23 hr, the opossum will eat it p 6 Probability that, exposed for 23 hr to one infected triatomine, the opossum will become infected * For definition of a ''bite,'' see Materials and Methods. The experimental results showed that p 5 ϭ 0.254 (33 of 130 triatomines were eaten, see Table 2).…”

“…This prevalence of this host coexists with a very low triatomine (particularly for Triatoma guasayana) infection, sometimes less than 1%. 6,10 Near 40 years ago, the dilemma of how such a high opossum T. cruzi infection rates could be maintained with the observed low infection rates of triatomines was posed by McKeever and others 11 and since then remains unanswered. Opossums are known to become infected with T. cruzi after being ''bitten'' by and/or ingesting triatomines.…”

“…In all countries where the role of opossums as reservoirs of Trypanosoma cruzi has been studied, a relatively high prevalence of 20-100% was found. [1][2][3][4][5][6][7][8] In Argentina, Didelphis albiventris is the most important wild reservoir of T. cruzi, with an annual prevalence in Santiago del Estero that varied between 29% and 50% (Schweigmann N, unpublished data). This prevalence of this host coexists with a very low triatomine (particularly for Triatoma guasayana) infection, sometimes less than 1%.…”

Evidence of colonization of man-made ecotopes by Triatoma dimidiata (Latreille, 1811) in Costa Rica

“…They are also common behind pictures or wall papers, in hanging garments or in accumulated objects of different kinds, but usually their colonies do not surpass one or two dozen individuals. In the surroundings of the houses, bugs are found hidden in all sorts of stored objects, particularly in fire wood piles and in chicken coops (Zeledón et al 1975). They are also associated with houses with dirt floors where the nymphs camouflage themselves by covering their bodies with debris, a phenomenon with epidemiological implications (Zeledón et al 1969, Starr et al 1991.…”

Ghosts of Christmas past?: absence of trypanosomes in feral cats and black rats from Christmas Island and Western Australia

“…Experimental infections in cats have also been reported for T. congolense and T. gambiense. Trypanosoma cruzi is the most widely reported species occurring in cats with most cases originating from Latin America and prevalences ranging from 2.9 to 63.6% (Zeledón et al 1975;Mott et al 1978;Wisnivesky-Colli et al 1985). However, many indigenous Australian mammal species are thought to be susceptible to infection by exotic Trypanosoma species if they were to establish in Australia (Thompson, 2013).…”