Molecular Epidemiology of Plasmodium falciparum Malaria Outbreak, Tumbes, Peru, 2010-2012

Abstract

During 2010-2012, an outbreak of 210 cases of malaria occurred in Tumbes, in the northern coast of Peru, where no Plasmodium falciparum malaria case had been reported since 2006. To identify the source of the parasite causing this outbreak, we conducted a molecular epidemiology investigation. Microsatellite typing showed an identical genotype in all 54 available isolates. This genotype was also identical to that of parasites isolated in 2010 in the Loreto region of the Peruvian Amazon and closely related to clonet B, a parasite lineage previously reported in the Amazon during 1998-2000. These findings are consistent with travel history of index case-patients. DNA sequencing revealed mutations in the Pfdhfr, Pfdhps, Pfcrt, and Pfmdr1 loci, which are strongly associated with resistance to chloroquine and sulfadoxine/pyrimethamine, and deletion of the Pfhrp2 gene. These results highlight the need for timely molecular epidemiology investigations to trace the parasite source during malaria reintroduction events.

Keywords: Falciparum malaria; Peru; Plasmodium; malaria; microsatellite markers; parasites.

Figure 1

Peru, showing the department of Tumbes (black shading), the city of Iquitos, and the Requena district located in the Loreto region of the Peruvian Amazon (A) and the 13 districts in the department of Tumbes (B). Gray shading indicates the 4 districts (Tumbes, Corrales, Aguas Verdes, and San Juan de la Virgen) where the 210 cases were reported during the 2010–2012 outbreak of Plasmodium falciparum malaria; blue lines indicate travel routes by river; red line indicates travel route by road.

Figure 2

Temporal distribution of cases of falciparum malaria reported to the Tumbes Regional Health Directorate, Peru, October 2010–June 2012. Black bar sections indicate number of cases with samples available for analysis.