Figure 2. Total of pregnant women screened and seroprevalence 2004–2009.

The 1^st phase includes the departments of Cochabamba, Tarija, and Chuquisaca, with a large seroprevalence in Chagas disease. The 2^nd phase additionally includes the departments of Santa Cruz, La Paz and Potosi, with a lower seroprevalence. The average prevalence decreases as the total of women screened increases in less endemic areas.