Elimination of Rhodnius prolixus in Central America

Abstract

Rhodnius prolixus is one of the main vectors of Trypanosoma cruzi, causative agent of Chagas disease. In Central America, it was first discovered in 1915 in El Salvador, from where it spread northwest to Guatemala and Mexico, and southeast to Nicaragua and Costa Rica, arriving also in Honduras in the late 1950s. Indoor residual spraying (IRS) by the antimalaria services of Costa Rica prevented its spread southwards, and similar IRS programmes appear to have eliminated it from El Salvador by the late 1970s. In 1997, by resolution of the Ministers of Health of the seven Central American countries, a multinational initiative against Chagas disease (IPCA) was launched with one of the specific objectives being the elimination of R. prolixus from the region. As a result, more and more infested areas were encountered, and progressively sprayed using an IRS strategy already deployed against Triatoma infestans in the southern cone countries of South America. In 2008, Guatemala became the first of these countries to be formally certified as free of Chagas disease transmission due to R. prolixus. The other infested countries have since been similarly certified, and none of these has reported the presence of R. prolixus since June 2010. Further surveillance is required, but current evidence suggests that R. prolixus may now been eliminated from throughout the mesoamerican region, with a corresponding decline in the incidence of T. cruzi infections.

Figure 1

Changes in the distribution of Rhodnius prolixus in Mesoamerica. a - 1915-1953, first encounter in El Salvador and initial spread NW into Guatemala and Mexico, and SE into Nicaragua and Costa Rica; b - 1954-1979, further spread into Honduras, but elimination from Costa Rica; c - 1980-1996, limited reports due to political unrest; d - 1997-2010, extended surveys following launch of IPCA initiative, accompanied by IRS campaigns in Guatemala, Honduras, El Salvador and Nicaragua; e - 2010, the last four foci remaining in Honduras. Since June 2010, there have been no further reports of R. prolixus in Mesoamerica.