Seroprevalence of Arbovirus-specific Antibodies in Blood Donors in the Republic of the Congo
Nanikaly Moyen *
Department of Infectious Diseases, Faculty of Health Sciences, Marien Ngouabi University, Brazzaville, Republic of the Congo and Department of Bacteriology-Virology-Immunology, University Hospital Center of Brazzaville, Brazzaville, Republic of the Congo and Aix-Marseille University, French National Research Institute for Sustainable Development, French School of Public Health, Emerging Viral Diseases Unit, Marseille, France.
Laurence Thirion
Aix-Marseille University, French National Research Institute for Sustainable Development, French School of Public Health, Emerging Viral Diseases Unit, Marseille, France.
Joël Bidounga
Department of Cellular and Molecular Biology, Faculty of Science and Technology, Marien Ngouabi University, Brazzaville, Republic of the Congo.
Amelia Dzia-Lepfoundzou
Department of Infectious Diseases, Faculty of Health Sciences, Marien Ngouabi University, Brazzaville, Republic of the Congo andNational Blood Transfusion Center of Brazzaville, Brazzaville, Republic of the Congo.
Petra Emmerich
Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Yannick Dimi
Department of Infectious Diseases, Faculty of Health Sciences, Marien Ngouabi University, Brazzaville, Republic of the Congo.
Rachel Okobo
Department of Cellular and Molecular Biology, Faculty of Science and Technology, Marien Ngouabi University, Brazzaville, Republic of the Congo.
Maria Rosaria Capobianchi
French National Reference Centre for Arboviruses, French Armed Forces Biomedical Research Institute, Brétigny-sur-Orge, France.
Stephan Günther
Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Xavier De Lamballerie
Aix-Marseille University, French National Research Institute for Sustainable Development, French School of Public Health, Emerging Viral Diseases Unit, Marseille, France.
*Author to whom correspondence should be addressed.
Abstract
Background: Evidence on previous exposure to arboviruses in the Republic of the Congo is geographically limited. Serological testing of archived donor specimens can describe historical antibody patterns, although results depend on the assays used.
Objective: To describe IgG reactivity to eight arboviral targets among blood donors sampled at six locations in the Republic of the Congo in 2011.
Methods: In a cross-sectional survey conducted from March to June 2011, sera from 1,009 eligible donors aged 18–65 years were examined by IgG ELISA for seven arboviruses and indirect immunofluorescence for Crimean–Congo hemorrhagic fever virus (CCHFV). ELISA-positive or borderline results for yellow fever virus (YFV), West Nile virus (WNV), Toscana virus (TOSV) and tick-borne encephalitis virus (TBEV) underwent virus neutralization testing (VNT). Frequencies, proportions and Wilson 95% confidence intervals were summarized descriptively.
Results: Of 1,009 donors, 934 (92.6%) were recruited in urban sites and 754 (74.7%) were male. ELISA IgG reactivity was recorded for dengue virus (DENV) in 456 donors (45.2%), chikungunya virus (CHIKV) in 367 (36.4%) and Rift Valley fever virus (RVFV) in 77 (7.6%). VNT-positive results were observed for YFV in 281 (27.8%), WNV in 246 (24.4%), TOSV in six (0.6%) and TBEV in one (0.1%). No CCHFV IgG reactivity was recorded by immunofluorescence. These assay-defined proportions are not directly interchangeable across viruses.
Conclusion: Antibodies reactive with several arboviral targets were detected in this historical donor sample. The findings support geographically broader, contemporary studies using comparable confirmatory assays and vaccination histories, but do not establish recent infections or current transmission intensity.
Keywords: Arboviruses, blood donors, cross-sectional study, immunoglobulin G, Republic of the Congo, seroepidemiology