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

Abstract

BackgroundIn 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 findingsFrom 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.ConclusionsOur 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.

Dengue and Chikungunya among Febrile Outpatients in Kinshasa, Democratic Republic of Congo: a cross-sectional study

“…This contradicts the existing paradigm that arbovirus infections are outbreak-driven in Africa and are not endemic, as is the case in Asia and Latin America. Our study adds to mountingbut still scarce -evidence that arboviruses are endemic in large parts of Africa (17).…”

Recent outbreaks of chikungunya virus (CHIKV) in Africa and Asia are driven by a variant carrying mutations associated with increased fitness for Aedes aegypti

“…aegypti adaptive outbreak of 2016, and given this strain’s potential to cause large outbreaks, it is very possible that it is also responsible for this recent occurrence in Mombasa. Furthermore, other simultaneous CHIKV outbreaks have been reported in proximate regions to both Kenya and India, the 2016 outbreak in Mozambique and the 2017 outbreak in Dhaka, Bangladesh (42, 43). The virus from the Dhaka outbreak contained the K211E adaptive mutation, and despite the lack of E2 sequencing, our analyses of the E1 region placed it within the Ae.…”

Third Tofo Advanced Study Week on Emerging and Re-emerging Viruses, 2018

“…A surveillance system was established in 2015 to monitor the occurrence of arboviruses and other emerging viruses as well as building capacity for early detection of these emerging pathogens. Data from the established surveillance for emerging viruses found cases of dengue, chikungunya, Rift Valley fever, hantavirus, and Crimean-Congo hemorrhagic fever across different sentinel sites (Chau et al, 2017;Mugabe et al, 2018;Muianga et al, 2017;Oludele et al, 2017). These results have driven the establishment of diagnostic capacity for early detection of and rapid response to emerging viruses in Mozambique.…”

“…Collaborations initiated at previous TASWs have already led to joint publications among participants [see e.g. (António et al (2018); Mugabe et al (2018))].…”