Frequency of Plasmodium vivax circumsporozoite protein genotypes in humans and anopheline mosquitoes in an endemic area of southeastern Pará State, Brazil

Abstract

The objective of this study was therefore to investigate the frequency of circumsporozoite protein (CSP) genotypes in human blood and their correlation with parasitemia, as well as to evaluate the presence of these genotypes in Anopheles in the Municipality of Goianésia do Pará, an endemic area of southeastern Pará State, Brazil from 2012-2013. Blood samples were collected from 118 patients with Plasmodium vivax and 369 anopheline mosquitoes. The CSP gene was genotyped using the polymerase chain reaction/restriction fragment length polymorphism technique, and the infectivity of the anophelines was determined using ELISA. Parasitemia ranged from 5-70,000 parasites/mm³, and the three genotypes (VK210, VK247, and P. vivax-like) were detected both in single and mixed infections. No sample exhibited mixed infection with all three genotypes. The most frequent genotype was VK210 followed by VK247 and the latter associated with the highest parasitemia values (p < 0.0001). Among the identified mosquitoes, only 11 specimens were infected; of the seven Anopheles darlingi specimens four were infected with Plasmodium falciparum, two with VK210, and one with VK247. The three Anopheles albitarsis specimens were infected with VK247, and one Anopheles nuneztovari specimen was infected with VK210. The VK210 genotype continues to be the most prevalent in southeastern Pará; however, a new evidence shows the adaptation of VK247. The species An. darlingi, An. albitarsis, and An. nuneztovari play an important role in the transmission of CSP genotypes in the study area. This finding may be a public health concern due to the possibility of resurgence of P. vivax malaria epidemics in susceptible communities.