Risk of imported malaria infections in Zanzibar: a cross-sectional study

Infectious Diseases of Poverty

Research Article

Abdallah Mbena¹  Imani Irema¹  Ramadhan Abdul²  Bakar S. Fakih³  Aurel Holzschuh⁴  Günther Fink⁵  Amanda Ross⁵  Sumaiyya G. Thawer⁵  Manuel W. Hetzel⁵  Joshua Yukich⁶  Logan Stuck⁷  Abdullah Ali⁸  Shija J. Shija⁸  Abdul-Wahid H. Al-Mafazy⁸  Safia M. Aliy⁸ 

[1] Ifakara Health Institute, Dar es Salaam, Tanzania;Ifakara Health Institute, Dar es Salaam, Tanzania;Amsterdam Institute for Global Health and Development, Amsterdam, Netherlands;Ifakara Health Institute, Dar es Salaam, Tanzania;Swiss Tropical and Public Health Institute, Allschwil, Switzerland;University of Basel, Basel, Switzerland;Swiss Tropical and Public Health Institute, Allschwil, Switzerland;Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, USA;Swiss Tropical and Public Health Institute, Allschwil, Switzerland;University of Basel, Basel, Switzerland;Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA;Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA;Amsterdam Institute for Global Health and Development, Amsterdam, Netherlands;Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania;

关键词: Malaria;    Importation;    Travel;    Zanzibar;    Tanzania;    Elimination;   

DOI  :  10.1186/s40249-023-01129-5

 received in 2023-04-11, accepted in 2023-08-11,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundZanzibar has made substantial progress in malaria control with vector control, improved diagnosis, and artemisinin-based combination therapy. Parasite prevalence in the population has remained around 1% but imported infections from mainland Tanzania contribute to sustained local transmission. Understanding travel patterns between mainland Tanzania and Zanzibar, and the risk of malaria infection, may help to control malaria importation to Zanzibar.MethodsA rolling cross-sectional survey linked to routine reactive case detection of malaria was carried out in Zanzibar between May 2017 and October 2018. Households of patients diagnosed with malaria at health facilities were surveyed and household members were tested for malaria using rapid diagnostic tests and a sub-sample by quantitative PCR (qPCR). Interviews elicited a detailed travel history of all household members who had travelled within the past two months, including trips within and outside of Zanzibar. We estimated the association of malaria infection with travel destinations in pre-defined malaria endemicity categories, trip duration, and other co-variates using logistic regression.ResultsOf 17,891 survey participants, 1177 (7%) reported a recent trip, of which 769 (65%) visited mainland Tanzania. Among travellers to mainland Tanzania with travel destination details and a qPCR result available, 241/378 (64%) reported traveling to districts with a ‘high’ malaria endemicity and for 12% the highest endemicity category was ‘moderate’. Travelers to the mainland were more likely to be infected with malaria parasites (29%, 108/378) than those traveling within Zanzibar (8%, 16/206) or to other countries (6%, 2/17). Among travellers to mainland Tanzania, those visiting highly endemic districts had a higher odds of being qPCR-positive than those who travelled only to districts where malaria-endemicity was classified as low or very low (adjusted odd ratio = 7.0, 95% confidence interval: 1.9–25.5). Among travellers to the mainland, 110/378 (29%) never or only sometimes used a mosquito net during their travel.ConclusionsStrategies to reduce malaria importation to Zanzibar may benefit from identifying population groups traveling to highly endemic areas in mainland Tanzania. Targeted interventions to prevent and clear infections in these groups may be more feasible than attempting to screen and treat all travellers upon arrival in Zanzibar.

【 授权许可】

CC BY   
© National Institute of Parasitic Diseases 2023

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