Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jun 1;66(12):1883-1891.
doi: 10.1093/cid/cix1123.

The Relative Contribution of Symptomatic and Asymptomatic Plasmodium vivax and Plasmodium falciparum Infections to the Infectious Reservoir in a Low-Endemic Setting in Ethiopia

Fitsum G Tadesse  1   2   3 , Hannah C Slater  4 , Wakweya Chali  2 , Karina Teelen  1 , Kjerstin Lanke  1 , Mulualem Belachew  5 , Temesgen Menberu  5 , Girma Shumie  5 , Getasew Shitaye  5 , Lucy C Okell  4 , Wouter Graumans  1 , Geert-Jan van Gemert  1 , Soriya Kedir  5 , Addisu Tesfaye  5 , Feleke Belachew  5 , Wake Abebe  5 , Hassen Mamo  6 , Robert Sauerwein  1 , Taye Balcha  2   7 , Abraham Aseffa  2 , Delenasaw Yewhalaw  8   9 , Endalamaw Gadisa  2 , Chris Drakeley  10 , Teun Bousema  1   10
Affiliations
Free article

The Relative Contribution of Symptomatic and Asymptomatic Plasmodium vivax and Plasmodium falciparum Infections to the Infectious Reservoir in a Low-Endemic Setting in Ethiopia

Fitsum G Tadesse et al. Clin Infect Dis. .
Free article

Abstract

Background: The majority of Plasmodium vivax and Plasmodium falciparum infections in low-endemic settings are asymptomatic. The relative contribution to the infectious reservoir of these infections compared to clinical malaria cases is currently unknown.

Methods: We assessed infectivity of passively recruited symptomatic malaria patients (n = 41) and community-recruited asymptomatic individuals with microscopy-detected (n = 41) and polymerase chain reaction (PCR)-detected infections (n = 82) using membrane feeding assays with Anopheles arabiensis mosquitoes in Adama, Ethiopia. Malaria incidence and prevalence data were used to estimate the contributions of these populations to the infectious reservoir.

Results: Overall, 34.9% (29/83) of P. vivax- and 15.1% (8/53) P. falciparum-infected individuals infected ≥1 mosquitoes. Mosquito infection rates were strongly correlated with asexual parasite density for P. vivax (ρ = 0.63; P < .001) but not for P. falciparum (ρ = 0.06; P = .770). Plasmodium vivax symptomatic infections were more infectious to mosquitoes (infecting 46.5% of mosquitoes, 307/660) compared to asymptomatic microscopy-detected (infecting 12.0% of mosquitoes, 80/667; P = .005) and PCR-detected infections (infecting 0.8% of mosquitoes, 6/744; P < .001). Adjusting for population prevalence, symptomatic, asymptomatic microscopy-detected, and PCR-detected infections were responsible for 8.0%, 76.2%, and 15.8% of the infectious reservoir for P. vivax, respectively. For P. falciparum, mosquito infections were sparser and also predominantly from asymptomatic infections.

Conclusions: In this low-endemic setting aiming for malaria elimination, asymptomatic infections were highly prevalent and responsible for the majority of onward mosquito infections. The early identification and treatment of asymptomatic infections might accelerate elimination efforts.

PubMed Disclaimer

Publication types

MeSH terms