Evidence for chikungunya and dengue transmission in Quelimane, Mozambique: Results from an investigation of a potential outbreak of chikungunya virus

• Type of Material: Article
• Authors: Vanio Mugabe, Emory University; Sadia Ali, Instituto Nacional de Saude Maputo; Imelda Chelene, Instituto Nacional de Saude Maputo; Vanessa Onofre Monteiro, Instituto Nacional de Saude Maputo; Onélia Guiliche, Instituto Nacional de Saude Maputo; Argentina Felisbela Muianga, Instituto Nacional de Saude Maputo; Flora Mula, Instituto Nacional de Saude Maputo; Virgílio António, Instituto Nacional de Saude Maputo; Inocêncio Chongo, Instituto Nacional de Saude Maputo; John Oludele, Instituto Nacional de Saude Maputo; Kerstin Falk, Public Health Agency of Sweden; Igor A. Paploski, Universidade Federal da Bahia; Mitermayer G. Reis, Fundacao Oswaldo Cruz; Uriel Kitron, Emory University; Beate M. Kümmerer, Universitat Bonn; Guilherme S. Ribeiro, Universidade Federal da Bahia; Eduardo Samo Gudo, Instituto Nacional de Saude Maputo
• Language: English
• Date: 2018-02-01
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2018 Mugabe et al
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0192110
• Title of Journal or Parent Work: PLoS ONE
• ISSN: 1932-6203
• Volume: 13
• Issue: 2
• Start Page: e0192110
• End Page: e0192110
• Grant/Funding Information: The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.; The views expressed in this written publication do not necessarily reflect the official policies of the U.S. Department of Health and Human Services.; ESG received funds from the European Foundation Initiative into Neglected Tropical Disease (Grant # 91 488) and by the U.S. Centers for Disease Control and Prevention through a cooperative agreement number 5NU14GH001237- 03-00.; VAM, IADP, UK and GSR received scholarships from the Conselho Nacional de Desenvolvimento CientõÂfico e TecnoloÂgico (CNPq), Brazil.
• Keywords: Humans; Female; Disease Outbreaks; Mozambique; Adolescent; Chikungunya Fever; Male; Young Adult; Dengue; Adult
• Research Categories: Environmental Sciences

Abstract

Background In January 2016, health authorities from Zambézia province, Mozambique reported the detection of some patients presenting with fever, arthralgia, and a positive result for chikungunya in an IgM-based Rapid Diagnostic Test (RDT). We initiated a study to investigate a potential chikungunya outbreak in the city of Quelimane. Methods/Principal findings From February to June 2016, we conducted a cross-sectional study enrolling febrile patients attending five outpatient health units in Quelimane. Serum from each patient was tested for CHIKV and DENV, using IgM and IgG ELISA and qRT-PCR. Patients were also tested for malaria by RDT. Entomological surveys were performed around patients’ households, and we calculated the proportion of positive ovitraps and the egg density per trap. A total of 163 patients were recruited, of which 99 (60.7%) were female. The median age was 28 years. IgM and IgG anti-CHIKV antibodies were identified in 17 (10.4%) and 103 (63.2%) patients, respectively. Plaque reduction neutralization assay confirmed the presence of anti-CHIKV antibodies in a subset of 11 tested patients with positive IgG results. IgM anti-DENV antibodies were found in 1 (0.9%) of 104 tested patients. Malaria was diagnosed in 35 (21.5%) patients, 2 of whom were also IgM-positive for CHIKV. Older age and lower education level were independently associated with the prevalence of IgG anti-CHIKV antibodies. Immature forms of Aedes aegypti were collected in 16 (20.3%) of 79 surveyed households. We also found that 25.0% (16/64) of the traps were positive, with an average of 90.8 eggs per pallet. Conclusions Our investigation demonstrated that no CHIKV outbreak was ongoing in Quelimane; rather, endemic transmission of the virus has been ongoing. Aedes aegypti mosquitoes are abundant, but dengue cases occurred only sporadically. Further population-based cohort studies are needed to improve our understanding of aspects related to the dynamics of arboviral transmission in Mozambique, as well as in other parts of Sub-Saharan Africa.