Asymptomatic Plasmodium vivax malaria in the Brazilian Amazon: Submicroscopic parasitemic blood infects Nyssorhynchus darlingi.

Individuals with asymptomatic infection due to Plasmodium vivax are posited to be important reservoirs of malaria transmission in endemic regions. Here we studied a cohort of P. vivax malaria patients in a suburban area in the Brazilian Amazon. Overall 1,120 individuals were screened for P. vivax in...

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Bibliographic Details
Published in:PLOS Neglected Tropical Diseases
Main Authors: Gregório Guilherme Almeida, Pedro Augusto Carvalho Costa, Maísa da Silva Araujo, Gabriela Ribeiro Gomes, Alex Fiorini Carvalho, Maria Marta Figueiredo, Dhelio Batista Pereira, Mauro Shugiro Tada, Jansen Fernandes Medeiros, Irene da Silva Soares, Luzia Helena Carvalho, Flora Satiko Kano, Marcia Caldas de Castro, Joseph Michael Vinetz, Douglas Taylor Golenbock, Lis Ribeiro do Valle Antonelli, Ricardo Tostes Gazzinelli
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2021
Subjects:
Online Access:https://doi.org/10.1371/journal.pntd.0009077
https://doaj.org/article/45036c5e023e43b9bd4464695abd2692
Description
Summary:Individuals with asymptomatic infection due to Plasmodium vivax are posited to be important reservoirs of malaria transmission in endemic regions. Here we studied a cohort of P. vivax malaria patients in a suburban area in the Brazilian Amazon. Overall 1,120 individuals were screened for P. vivax infection and 108 (9.6%) had parasitemia detected by qPCR but not by microscopy. Asymptomatic individuals had higher levels of antibodies against P. vivax and similar hematological and biochemical parameters compared to uninfected controls. Blood from asymptomatic individuals with very low parasitemia transmitted P. vivax to the main local vector, Nyssorhynchus darlingi. Lower mosquito infectivity rates were observed when blood from asymptomatic individuals was used in the membrane feeding assay. While blood from symptomatic patients infected 43.4% (199/458) of the mosquitoes, blood from asymptomatic infected 2.5% (43/1,719). However, several asymptomatic individuals maintained parasitemia for several weeks indicating their potential role as an infectious reservoir. These results suggest that asymptomatic individuals are an important source of malaria parasites and Science and Technology for Vaccines granted by Conselho Nacional de may contribute to the transmission of P. vivax in low-endemicity areas of malaria.