Risk Factors for Malaria Infection in Central Madagascar: Insights from a Cross-Sectional Population Survey

• Published in: The American journal of tropical medicine and hygiene Vol. 99; no. 4; pp. 995 - 1002
• Main Authors: Howes, Rosalind E, Franchard, Thierry, Rakotomanga, Tovonahary Angelo, Ramiranirina, Brune, Zikursh, Melinda, Cramer, Estee Y, Tisch, Daniel J, Kang, Su Y, Ramboarina, Stéphanie, Ratsimbasoa, Arsène, Zimmerman, Peter A
• Format: Journal Article
• Language: English
• Published: United States Institute of Tropical Medicine 01.01.2018; The American Society of Tropical Medicine and Hygiene
• Subjects: Adolescent; Adult; Asymptomatic Diseases; Child; Child, Preschool; Cross-Sectional Studies; Duffy Blood-Group System - genetics; Female; Gene Expression; Health Surveys; Humans; Infant; Infections; Madagascar - epidemiology; Malaria; Malaria, Falciparum - diagnosis; Malaria, Falciparum - epidemiology; Malaria, Falciparum - parasitology; Malaria, Vivax - diagnosis; Malaria, Vivax - epidemiology; Malaria, Vivax - parasitology; Male; Microscopy; Plasmodium falciparum - classification; Plasmodium falciparum - genetics; Plasmodium falciparum - isolation & purification; Plasmodium vivax - classification; Plasmodium vivax - genetics; Plasmodium vivax - isolation & purification; Polymerase Chain Reaction; Prevalence; Receptors, Cell Surface - deficiency; Receptors, Cell Surface - genetics; Risk Factors; Rural Population; Madagascar
• ISSN: 0002-9637; 1476-1645
• DOI: 10.4269/ajtmh.18-0417

Community prevalence of infection is a widely used, standardized metric for evaluating malaria endemicity. Conventional methods for measuring prevalence include light microscopy and rapid diagnostic tests (RDTs), but their detection thresholds are inadequate for diagnosing low-density infections. The significance of submicroscopic malaria infections is poorly understood in Madagascar, a country of heterogeneous malaria epidemiology. A cross-sectional community survey in the western foothills of Madagascar during the March 2014 transmission season found malaria infection to be predominantly submicroscopic and asymptomatic. Prevalence of infection diagnosed by microscopy, RDT, and molecular diagnosis was 2.4%, 4.1%, and 13.8%, respectively. This diagnostic discordance was greatest for infection, which was 98.5% submicroscopic. Village location, insecticide-treated bednet ownership, and fever were significantly associated with infection outcomes, as was presence of another infected individual in the household. Duffy-negative individuals were diagnosed with , but with reduced odds relative to Duffy-positive hosts. The observation of high proportions of submicroscopic infections calls for a wider assessment of the parasite reservoir in other regions of the island, particularly given the country's current focus on malaria elimination and the poorly documented distribution of the non- parasite species.