symptomatic Plasmodium vivax malaria in the Brazilian Amazon: Submicroscopic parasitemic blood infects Nyssorhynchus darling

Author(s):Show less -

Almeida, Gregorio Guilherme ^{[1, 2]} ; Carvalho Costa, Pedro Augusto ^[1] ; Araujo, Maisa da Silva ^[3] ; Gomes, Gabriela Ribeiro ^[1] ; Carvalho, Alex Fiorini ^{[4, 5]} ; Figueiredo, Maria Marta ^{[4, 5]} ; Pereira, Dhelio Batista ^[6] ; Tada, Mauro Shugiro ^[6] ; Medeiros, Jansen Fernandes ^[3] ; Soares, Irene da Silva ^[7] ; Carvalho, Luzia Helena ^[8] ; Kano, Flora Satiko ^[8] ; de Castro, Marcia Caldas ^[9] ; Vinetz, Joseph Michael ^[10] ; Golenbock, Douglas Taylor ^[11] ; do Valle Antonelli, Lis Ribeiro ^[1] ; Gazzinelli, Ricardo Tostes ^{[2, 11]}

Affiliation:Show less -

^[1] Fundacao Oswaldo Cruz, Lab Biol & Imunol Doencas Infecciosas & Parasitar, Inst Rene Rachou, Belo Horizonte, MG - Brazil

^[2] Fundacao Oswaldo Cruz, Lab Imunopatol, Inst Rene Rachou, Belo Horizonte, MG - Brazil

^[3] Fiocruz Rondonia, Lab Entomol, Porto Velho, Rondonia - Brazil

^[4] Fundacao Oswaldo Cruz, Inst Rene Rachou, Belo Horizonte, MG - Brazil

^[5] Univ Fed Minas Gerais, CT Vacinas, Belo Horizonte, MG - Brazil

^[6] Ctr Pesquisa Med Trop, Ambulatorio Malaria, Porto Velho, Rondonia - Brazil

^[7] Univ Fed Sao Paulo, Dept Microbiol Imunol & Parasitol, Sao Paulo, SP - Brazil

^[8] Fundacao Oswaldo Cruz, Lab Biol Mol & Imunol Malaria, Inst Rene Rachou, Belo Horizonte, MG - Brazil

^[9] Harvard TH Chan Sch Publ Hlth, Dept Global Hlth & Populat, Boston, MA - USA

^[10] Yale Sch Med, Dept Internal Med, Sect Infect Dis, New Haven, CT - USA

^[11] Univ Massachusetts, Med Sch, Dept Med, Worcester, MA 01605 - USA

• Document type: Journal article
• Source: PLoS Neglected Tropical Diseases; v. 15, n. 10 OCT 2021.
• Web of Science Citations: 0

Abstract

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.</p> Author summary Malaria still poses as one of the most important parasitic diseases in the world. The advance of molecular diagnosis brought to light the existence of asymptomatic infections, which may represent most of the infections in some areas. Importantly, the role of asymptomatic carriers in the natural history of malaria is not completely understood. Herein we describe the general characteristics of asymptomatic individuals infected with Plasmodium vivax, and provide evidence of their potential as parasitic reservoirs, even when molecular methods fail to detect the infection. Our findings reinforce the need for better diagnostic tests and open a new window of complexity to be considered in control programs.</p> (AU)

• FAPESP's process: 16/23618-8 - Immunological mechanisms of resistance and disease in malaria
• Grantee: João Santana da Silva
• Support Opportunities: Research Projects - Thematic Grants