Characterization of Plasmodium malariae transmission in four malaria endemic regions in Colombia

Abstract

The number of cases of Plasmodium malariae in Colombia shows a percent distribution concentrated in the Pacific Coast where it reaches 95% compared with 5% of casual cases in other areas of the country. Valle del Cauca region presents 85% of the cases, while 15% of the remaining cases correspond to Chocó and Cauca regions. Zacarias has 70% of the cases, followed by 30% in the areas of Citronela, Puerto Merizalde, Anchicayá, Meseta and Boca Dagua. An active search for malaria cases in Zacarias (Buenaventura) using thick smears demonstrated a prevalence of 9.1% of P malariae cases. Blood samples of gametocyte carriers were used to feed Anopheles albimanus mosquitoes and the reproduction of the sporogonic malaria cycle was successfully achieved. The presence of specific antibodies to P malariae was analyzed in 242 plasma samples obtained from individuals living in Zacarías and Punta Soldado (Valle), as well as in Pizarro (Chocó). It was found that 9.1% of the samples had specific antibodies as determined by an Elisa technique using a P malariae crude antigen preparation, whereas 42.1% of the samples showed specific antibodies when Elisa was performed using the (NAAG),synthetic peptide derived from the circumsporozoite (CS) protein. Samples from Bajo Guaviare region displayed a prevalence of 16% of anti-(NAAG), peptide antibodies. These results suggest that Zacarias on the Pacific Coast is the main focus of P malariae cases, but also that transmission of this parasite species coud occur in other regions of Colombia not yet reported.