Community-based sero-prevalence of chikungunya and yellow fever in the South Omo Valley of Southern Ethiopia

Adugna Endale; Daniela Michlmayr; Woldaregay Erku Abegaz; Getahun Asebe; James W Larrick; Girmay Medhin; Mengistu Legesse

doi:10.1371/journal.pntd.0008549

Community-based sero-prevalence of chikungunya and yellow fever in the South Omo Valley of Southern Ethiopia

PLoS Negl Trop Dis. 2020 Sep 3;14(9):e0008549. doi: 10.1371/journal.pntd.0008549. eCollection 2020 Sep.

Authors

Adugna Endale^{1

2}, Daniela Michlmayr³, Woldaregay Erku Abegaz⁴, Getahun Asebe^{5

6}, James W Larrick⁷, Girmay Medhin¹, Mengistu Legesse¹

Affiliations

¹ Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
² School of Medicine, College of Medicine and Health Sciences, Dire Dawa University, Dire Dawa, Ethiopia.
³ Division of Infectious Diseases and Vaccinology, School of Public Health, University of California Berkeley, Berkeley, California, United States of America.
⁴ Department of Microbiology, Immunology & Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
⁵ Department of Veterinary Microbiology, Immunology and Public Health, College of Veterinary Medicine, Addis Ababa University, Bishoftu, Ethiopia.
⁶ College of Agriculture and Natural Resources, Gambella University, Gambella, Ethiopia.
⁷ Panorama Research Institute, Sunnyvale, California, United States of America.

Abstract

Background: Chikungunya (CHIK) and yellow fever (YF) are becoming major public health threats in East African countries including Ethiopia. In Ethiopia, there is no reliable information about the epidemiology of CHIK. This study aimed to assess a community-based sero-prevalence of CHIK and YF in the South Omo Valley, an endemic area for YF.

Methods: Between February and June 2018, blood samples were collected from study participants and screened for IgG antibody against CHIK virus (CHIKV) and YF virus (YFV) infections using ELISA. Data were computerized using Epi Data Software v.3.1 and analyzed using SPSS.

Results: A total of 360 participants (51.7% males, age range from 6 to 80, mean age ± SD = 31.95 ± 14.05 years) participated in this study. The overall sero-prevalence of IgG antibody was 43.6% (157/360) against CHIKV, while it was 49.5% (155/313) against YFV. Out of 155 samples which were positive for IgG antibody to YFV, 93 (60.0%) were positive for IgG antibody to CHIKV. Out of 158 samples which were negative for IgG antibody to YFV, 64(40.5%) were positive for IgG antibody to CHIKV. There was a significant positive correlation between IgG antibodies to CHIKV and YFV (sr = 0.82; P<0.01). Residency in the Debub Ari district (AOR = 8.47; 95% CI: 1.50, 47.74) and travel history to sylvatic areas (AOR = 2.21; 95% CI: 1.02, 4.81) were significantly and positively associated with high sero-prevalence of IgG antibody to CHIKV and YFV, respectively.

Conclusion: High sero-prevalence of IgG antibody to CHIKV shows the circulation of the virus in the present study area. A low sero-prevalence of IgG antibody to YFV in YF vaccine received individuals is highly concerning from a public health point of view as waning of immune response to YFV infection could result in a periodic outbreaks of YF in endemic areas.Nevertheless, the present study has not investigated for possible cross-reactivity of antibody to CHIKV with other alphaviruses like O'nyong-nyong virus and antibody to YFV with other flaviviruses like Dengue fever virus and this warrants further studies in the present study area.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Aged
Aged, 80 and over
Antibodies, Viral / blood*
Chikungunya Fever / blood*
Chikungunya Fever / epidemiology
Chikungunya Fever / virology
Chikungunya virus / immunology
Chikungunya virus / isolation & purification
Child
Cross-Sectional Studies
Ethiopia / epidemiology
Female
Humans
Male
Middle Aged
Residence Characteristics
Seroepidemiologic Studies
Yellow Fever / blood*
Yellow Fever / epidemiology
Yellow Fever / virology
Yellow fever virus / immunology
Yellow fever virus / isolation & purification
Young Adult

Substances

Antibodies, Viral

Grants and funding

The study was financially supported by the Office of Vice President for Research and Technology Transfer, Addis Ababa University (Ref No. RD/PY662/2016). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Dr Mengistu Legesse received the award.