Fitsum G Tadesse1,2,3, Hannah C Slater4, Wakweya Chali2, Karina Teelen1, Kjerstin Lanke1, Mulualem Belachew5, Temesgen Menberu5, Girma Shumie5, Getasew Shitaye5, Lucy C Okell4, Wouter Graumans1, Geert-Jan van Gemert1, Soriya Kedir5, Addisu Tesfaye5, Feleke Belachew5, Wake Abebe5, Hassen Mamo6, Robert Sauerwein1, Taye Balcha2,7, Abraham Aseffa2, Delenasaw Yewhalaw8,9, Endalamaw Gadisa2, Chris Drakeley10, Teun Bousema1,10. 1. Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands. 2. Armauer Hansen Research Institute, Addis Ababa University, Ethiopia. 3. Institute of Biotechnology, Addis Ababa University, Ethiopia. 4. Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analysis and Modelling, Imperial College London, United Kingdom. 5. Adama Regional Laboratory, Oromia Region Health Bureau, Adama, Ethiopia. 6. Department of Microbial, Cellular and Molecular Biology, College of Natural Sciences, Addis Ababa University, Ethiopia. 7. Department of Translational Medicine, Clinical Infection Medicine, Lund University, Malmö, Sweden. 8. Tropical and Infectious Diseases Research Center, Jimma University, Ethiopia. 9. Department of Medical Laboratory Sciences and Pathology, Faculty of Health Sciences, Jimma University, Ethiopia. 10. Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, United Kingdom.
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.
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 malariapatients (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.
Authors: Marta Moreno; Katherine Torres; Carlos Tong; Stefano S García Castillo; Gabriel Carrasco-Escobar; Gerson Guedez; Lutecio Torres; Manuela Herrera-Varela; Layné Guerra; Mitchel Guzman-Guzman; Daniel Wong; Roberson Ramirez; Alejandro Llanos-Cuentas; Jan E Conn; Dionicia Gamboa; Joseph M Vinetz Journal: Am J Trop Med Hyg Date: 2022-06-13 Impact factor: 3.707
Authors: Sujata Balasubramanian; Rifat S Rahman; Chanthap Lon; Christian Parobek; Ratawan Ubalee; Nicholas Hathaway; Worachet Kuntawunginn; Mok My; Dav Vy; Jeremy Saxe; Charlotte Lanteri; Feng-Chang Lin; Michele Spring; Steven R Meshnick; Jonathan J Juliano; David L Saunders; Jessica T Lin Journal: J Infect Dis Date: 2020-01-14 Impact factor: 5.226
Authors: Chonge Kitojo; Frank Chacky; Emmanuel S Kigadye; Joseph P Mugasa; Abdallah Lusasi; Ally Mohamed; Erik J Reaves; Julie R Gutman; Deus S Ishengoma Journal: Malar J Date: 2021-06-08 Impact factor: 2.979
Authors: Simon Gubbins; Philippa M Beard; Beatriz Sanz-Bernardo; Ismar R Haga; Najith Wijesiriwardana; Sanjay Basu; Will Larner; Adriana V Diaz; Zoë Langlands; Eric Denison; Joanne Stoner; Mia White; Christopher Sanders; Philippa C Hawes; Anthony J Wilson; John Atkinson; Carrie Batten; Luke Alphey; Karin E Darpel Journal: J Virol Date: 2021-04-12 Impact factor: 5.103