The prevalence of onchocerciasis in Africa and Yemen, 2000–2018: a geospatial analysis

Chris A. Schmidt, Elizabeth A. Cromwell, Elex Hill, Katie M. Donkers, Megan F. Schipp, Kimberly B. Johnson, David M. Pigott, Simon I. Hay, Jaffar Abbas, Victor Adekanmbi, Olatunji O. Adetokunboh, Muktar Beshir Ahmed, Fahad Mashhour Alanezi, Turki M. Alanzi, Vahid Alipour, Catalina Liliana Andrei, Tudorel Andrei, Davood Anvari, Seth Christopher Yaw Appiah, Muhammad AqeelJalal Arabloo, Mohammad Asghari Jafarabadi, Marcel Ausloos, Atif Amin Baig, Maciej Banach, Till Winfried Bärnighausen, Krittika Bhattacharyya, Zulfiqar A. Bhutta, Ali Bijani, Oliver J. Brady, Nicola Luigi Bragazzi, Zahid A. Butt, Felix Carvalho, Vijay Kumar Chattu, Saad M. A. Dahlawi, Giovanni Damiani, Feleke Mekonnen Demeke, Kebede Deribe, Samath Dhamminda Dharmaratne, Daniel Diaz, Alireza Didarloo, Lucas Earl, Maysaa El Sayed Zaki, Maha El Tantawi, Nazir Fattahi, Eduarda Fernandes, Nataliya A. Foigt, Masoud Foroutan, Richard Charles Franklin, Yuming Guo, Arvin Haj-Mirzaian, Samer Hamidi, Hadi Hassankhani, Claudiu Herteliu, Tarig B. Higazi, Mostafa Hosseini, Mehdi Hosseinzadeh, Mowafa Househ, Olayinka Stephen Ilesanmi, Irena M. Ilic, Milena D. Ilic, Seyed Sina Naghibi Irvani, Ravi Prakash Jha, John S. Ji, Jost B. Jonas, Jacek Jerzy Jozwiak, Leila R. Kalankesh, Naser Kamyari, Behzad Karami Matin, Salah Eddin Karimi, Gbenga A. Kayode, Ali Kazemi Karyani, Ejaz Ahmad Khan, Md Nuruzzaman Khan, Khaled Khatab, Mona M. Khater, Neda Kianipour, Yun Jin Kim, Soewarta Kosen, Dian Kusuma, Carlo La Vecchia, Van Charles Lansingh, Paul H. Lee, Shanshan Li, Shokofeh Maleki, Mohammad Ali Mansournia, Francisco Rogerlândio Martins-Melo, Colm McAlinden, Walter Mendoza, Tomislav Mestrovic, Masoud Moghadaszadeh, Abdollah Mohammadian-Hafshejani, Seyyede Momeneh Mohammadi, Shafiu Mohammed, Rahmatollah Moradzadeh, Paula Moraga, Mehdi Naderi, Ahamarshan Jayaraman Nagarajan, Ionut Negoi, Cuong Tat Nguyen, Huong Lan Thi Nguyen, Bogdan Oancea, Andrew T. Olagunju, Ahmed Omar Bali, Obinna E. Onwujekwe, Adrian Pana, Vafa Rahimi-Movaghar, Kiana Ramezanzadeh, David Laith Rawaf, Salman Rawaf, Reza Rawassizadeh, Aziz Rezapour, Ana Isabel Ribeiro, Abdallah M. Samy, Masood Ali Shaikh, Kiomars Sharafi, Aziz Sheikh, Jasvinder A. Singh, Eirini Skiadaresi, Shahin Soltani, Wilma A. Stolk, Mu’awiyyah Babale Sufiyan, Alan J. Thomson, Bach Xuan Tran, Khanh Bao Tran, Bhaskaran Unnikrishnan, Francesco S. Violante, Giang Thu Vu, Tomohide Yamada, Sanni Yaya, Paul Yip, Naohiro Yonemoto, Chuanhua Yu, Yong Yu, Maryam Zamanian, Yunquan Zhang, Zhi-Jiang Zhang, Arash Ziapour

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Abstract

Background: Onchocerciasis is a disease caused by infection with Onchocerca volvulus, which is transmitted to humans via the bite of several species of black fly, and is responsible for permanent blindness or vision loss, as well as severe skin disease. Predominantly endemic in parts of Africa and Yemen, preventive chemotherapy with mass drug administration of ivermectin is the primary intervention recommended for the elimination of its transmission. Methods: A dataset of 18,116 geo-referenced prevalence survey datapoints was used to model annual 2000–2018 infection prevalence in Africa and Yemen. Using Bayesian model-based geostatistics, we generated spatially continuous estimates of all-age 2000–2018 onchocerciasis infection prevalence at the 5 × 5-km resolution as well as aggregations to the national level, along with corresponding estimates of the uncertainty in these predictions. Results: As of 2018, the prevalence of onchocerciasis infection continues to be concentrated across central and western Africa, with the highest mean estimates at the national level in Ghana (12.2%, 95% uncertainty interval [UI] 5.0–22.7). Mean estimates exceed 5% infection prevalence at the national level for Cameroon, Central African Republic, Democratic Republic of the Congo (DRC), Guinea-Bissau, Sierra Leone, and South Sudan. Conclusions: Our analysis suggests that onchocerciasis infection has declined over the last two decades throughout western and central Africa. Focal areas of Angola, Cameroon, the Democratic Republic of the Congo, Ethiopia, Ghana, Guinea, Mali, Nigeria, South Sudan, and Uganda continue to have mean microfiladermia prevalence estimates exceeding 25%. At and above this level, the continuation or initiation of mass drug administration with ivermectin is supported. If national programs aim to eliminate onchocerciasis infection, additional surveillance or supervision of areas of predicted high prevalence would be warranted to ensure sufficiently high coverage of program interventions.
Original languageEnglish (US)
JournalBMC Medicine
Volume20
Issue number1
DOIs
StatePublished - Sep 7 2022

ASJC Scopus subject areas

  • Medicine(all)

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