Ashenafi Assefa1,2, Ahmed Ali Ahmed3, Wakgari Deressa3, G Glenn Wilson4, Amha Kebede5, Hussein Mohammed6, Maruon Sassine7, Mebrahtom Haile8, Dereje Dilu8, Hiwot Teka9, Matthew W Murphy10, Sheila Sergent7, Eric Rogier7, Zhou Zhiyong7, Brian S Wakeman7, Chris Drakeley11, Ya Ping Shi7, Lorenz Von Seidlein12, Jimee Hwang13. 1. Ethiopian Public Health Institute, Arbegnoch Street, Mail Box: 19922, Addis Ababa, Ethiopia. ashyaega@yahoo.com. 2. School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia. ashyaega@yahoo.com. 3. School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia. 4. Department of Biology, University of Southern Denmark, 5230, Odense M, Denmark. 5. African Society for Laboratory Medicine, Addis Ababa, Ethiopia. 6. Ethiopian Public Health Institute, Arbegnoch Street, Mail Box: 19922, Addis Ababa, Ethiopia. 7. Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA. 8. Disease Prevention and Control Directorate, Federal Ministry of Health, Addis Ababa, Ethiopia. 9. U.S. President's Malaria Initiative, United States Agency for International Development, Addis Ababa, Ethiopia. 10. Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, U.S. President's Malaria Initiative, Addis Ababa, Ethiopia. 11. London School of Hygiene and Tropical Medicine, London, UK. 12. Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand. 13. Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, U.S. President's Malaria Initiative, Atlanta, GA, USA.
Abstract
BACKGROUND: Ethiopia has set a goal for malaria elimination by 2030. Low parasite density infections may go undetected by conventional diagnostic methods (microscopy and rapid diagnostic tests) and their contribution to malaria transmission varies by transmission settings. This study quantified the burden of subpatent infections from samples collected from three regions of northwest Ethiopia. METHODS: Sub-samples of dried blood spots from the Ethiopian Malaria Indicator Survey 2015 (EMIS-2015) were tested and compared using microscopy, rapid diagnostic tests (RDTs), and nested polymerase chain reaction (nPCR) to determine the prevalence of subpatent infection. Paired seroprevalence results previously reported along with gender, age, and elevation of residence were explored as risk factors for Plasmodium infection. RESULTS: Of the 2608 samples collected, the highest positive rate for Plasmodium infection was found with nPCR 3.3% (95% CI 2.7-4.1) compared with RDT 2.8% (95% CI 2.2-3.5) and microscopy 1.2% (95% CI 0.8-1.7). Of the nPCR positive cases, Plasmodium falciparum accounted for 3.1% (95% CI 2.5-3.8), Plasmodium vivax 0.4% (95% CI 0.2-0.7), mixed P. falciparum and P. vivax 0.1% (95% CI 0.0-0.4), and mixed P. falciparum and Plasmodium malariae 0.1% (95% CI 0.0-0.3). nPCR detected an additional 30 samples that had not been detected by conventional methods. The majority of the nPCR positive cases (61% (53/87)) were from the Benishangul-Gumuz Region. Malaria seropositivity had significant association with nPCR positivity [adjusted OR 10.0 (95% CI 3.2-29.4), P < 0.001]. CONCLUSION: Using nPCR the detection rate of malaria parasites increased by nearly threefold over rates based on microscopy in samples collected during a national cross-sectional survey in 2015 in Ethiopia. Such subpatent infections might contribute to malaria transmission. In addition to strengthening routine surveillance systems, malaria programmes may need to consider low-density, subpatent infections in order to accelerate malaria elimination efforts.
BACKGROUND: Ethiopia has set a goal for malaria elimination by 2030. Low parasite density infections may go undetected by conventional diagnostic methods (microscopy and rapid diagnostic tests) and their contribution to malaria transmission varies by transmission settings. This study quantified the burden of subpatent infections from samples collected from three regions of northwest Ethiopia. METHODS: Sub-samples of dried blood spots from the Ethiopian Malaria Indicator Survey 2015 (EMIS-2015) were tested and compared using microscopy, rapid diagnostic tests (RDTs), and nested polymerase chain reaction (nPCR) to determine the prevalence of subpatent infection. Paired seroprevalence results previously reported along with gender, age, and elevation of residence were explored as risk factors for Plasmodiuminfection. RESULTS: Of the 2608 samples collected, the highest positive rate for Plasmodiuminfection was found with nPCR 3.3% (95% CI 2.7-4.1) compared with RDT 2.8% (95% CI 2.2-3.5) and microscopy 1.2% (95% CI 0.8-1.7). Of the nPCR positive cases, Plasmodium falciparum accounted for 3.1% (95% CI 2.5-3.8), Plasmodium vivax 0.4% (95% CI 0.2-0.7), mixed P. falciparum and P. vivax 0.1% (95% CI 0.0-0.4), and mixed P. falciparum and Plasmodium malariae 0.1% (95% CI 0.0-0.3). nPCR detected an additional 30 samples that had not been detected by conventional methods. The majority of the nPCR positive cases (61% (53/87)) were from the Benishangul-Gumuz Region. Malaria seropositivity had significant association with nPCR positivity [adjusted OR 10.0 (95% CI 3.2-29.4), P < 0.001]. CONCLUSION: Using nPCR the detection rate of malaria parasites increased by nearly threefold over rates based on microscopy in samples collected during a national cross-sectional survey in 2015 in Ethiopia. Such subpatent infections might contribute to malaria transmission. In addition to strengthening routine surveillance systems, malaria programmes may need to consider low-density, subpatent infections in order to accelerate malaria elimination efforts.
Entities:
Keywords:
Asymptomatic infections; Ethiopia; Malaria; Sub microscopic infections; Subpatent infections
Authors: Ana Caroline Barbosa França; Kátia Sanches Françoso; Rodolfo Ferreira Marques; Gustavo H G Trossini; Renan A Gomes; Marinete M Póvoa; Maristela G Cunha; Eduardo L V Silveira; Irene S Soares Journal: Front Cell Infect Microbiol Date: 2021-03-16 Impact factor: 5.293
Authors: Wilfred Ouma Otambo; Julius O Olumeh; Kevin O Ochwedo; Edwin O Magomere; Isaiah Debrah; Collins Ouma; Patrick Onyango; Harrysone Atieli; Wolfgang R Mukabana; Chloe Wang; Ming-Chieh Lee; Andrew K Githeko; Guofa Zhou; John Githure; James Kazura; Guiyun Yan Journal: Malar J Date: 2022-04-22 Impact factor: 2.979