Last modified: 2020-02-25
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) infection using ELISA. Data were computerized using EpiData 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 antibody to CHIKV and YFV (r=0.89; 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 that the virus is circulating in the present study area. In contrast, low rate of sero-positive individuals for IgG antibody to YFV despite vaccination indicates either immunization failure or waning of antibody below the level of detection. Our findings imply the need for further study on the prevalence of acute CHIKV infection in the study area.