Malaria outbreak in Riaba district, Bioko Island: lessons learned

• Published in: Malaria Journal
• Main Authors: Carlos A. Guerra, Godwin Fuseini, Olivier Tresor Donfack, Jordan M. Smith, Teresa Ayingono Ondo Mifumu, Gninoussa Akadiri, Delicias Esono Mba Eyang, Consuelo Oki Eburi, Liberato Motobe Vaz, Victor Mba Micha, Leonor Ada Okenve, Christopher R. Janes, Ramona Mba Andeme, Matilde Riloha Rivas, Wonder P. Phiri, Michel A. Slotman, David L. Smith, Guillermo A. García
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2020
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-020-03347-w; https://doaj.org/article/4a7f677042b140799ce062f099bffd13

Abstract At the beginning of 2019, a sudden surge of malaria cases was observed in the district of Riaba, Bioko Island. Between January and April, confirmed malaria cases increased 3.8-fold compared to the same period in 2018. Concurrently, anopheline human biting rate (HBR) increased 2.1-fold. During the outbreak, 82.2% of the district population was tested for malaria with a rapid diagnostic test; 37.2% of those tested had a detectable infection and were treated according to national guidelines. Vector control interventions, including indoor residual spraying and larval source management were scaled-up. After the interventions, the number of confirmed cases decreased by 70% and the overall parasite prevalence in the communities by 43.8%. Observed prevalence in a follow up malaria indicator survey, however, was significantly higher than elsewhere on the island, and higher than in previous years. There was no significant reduction in HBR, which remained high for the rest of the year. The surge was attributed to various factors, chiefly increased rainfall and a large number of anthropogenic anopheline breeding sites created by construction works. This case study highlights the need for sustained vector control interventions and multi-sector participation, particularly in malaria control and elimination settings with persistently high local malaria receptivity.