Who, how, what and where?

Chagas disease is a disease of Latin America. In spite of extensive control efforts it is so prevalent that in some areas, such as within the Gran Chaco (see Chagas disease in the Chaco, on page S18), one person in 16 is infected.

Map

Figure 1

Data refer to the year 2005, derived from Jannin, J. & Salvatella, R. (PAHO, 2006).

(Box 1)

(Box 2)

Box 1: Trypanosoma cruzi strains

Approximate distributions of Trypanosoma cruzi lineages (discrete typing units or DTUs; see The promise of T. cruzi genomics, on page S16). TcI is a principal agent of Chagas disease north of the Amazon. TcII, TcV and TcVI are the main agents of Chagas disease in the Southern Cone region. As yet, TcIII and TcIV only sporadically infect humans. TcIV has divergent genotypes in South America and North America. Maps courtesy of Martin S. Llewellyn and Michael A. Miles.

Box 2: Vector distribution

The three main domestic vectors of Chagas disease are Triatoma dimidiata, Rhodnius prolixus and Triatoma infestans. The Southern Cone Initiative (INCOSUR) has largely eliminated domestic T. infestans, and the Central American Initiative (IPCA) has had a similar effect on R. prolixus, with just a few foci remaining in Guatemala and Honduras (see Country by country, on page S10). The heavy blue lines indicate approximate northern and southern limits of all Triatominae in the Americas. Other significant vectors (not shown here) include Triatoma brasiliensis in northeastern Brazil, Rhodnius ecuadoriensis in southern Ecuador and northwestern Peru, Rhodnius pallescens in Panama and northwestern Colombia, and members of the Triatoma phyllosoma and Triatoma protracta complexes widely distributed in Mexico.

Map compiled by C. J. Schofield and D. E. Gorla from recently published information, and INCOSUR and IPCA reports, with additional data from J. Ramsey (Mexico), M. Grijalva (Ecuador) and K. Hashimoto (Central America). The Triatoma dimidiata distribution is based on both published reports and model predictions (Ibarra-Cerdeña, C. N. et al. Acta Trop. 110, 178–186, 2009). The actual T. dimidiata distribution might be more extensive than shown, but confirmatory evidence is limited.