Seroprevalence and participatory epidemiology of camelpox in Afar region of Ethiopia

Authors: AREGAWI, WELDEGEBRIAL - Ethiopian Institute Of Agricultural Research; Agga, Getahun; GISHE, JEMAL - Tennessee State University; ABDI, RETA - Long Island University

Submitted to: Preventive Veterinary Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2018
Publication Date: 10/12/2018
Citation: Aregawi, W.G., Agga, G.E., Gishe, J., Abdi, R.D. 2018. Seroprevalence and participatory epidemiology of camelpox in Afar region of Ethiopia. Preventive Veterinary Medicine. 161:25-32. https://doi.org/10.1016/j.prevetmed.2018.10.003.
DOI: https://doi.org/10.1016/j.prevetmed.2018.10.003

Interpretive Summary: Camelpox is a disease of camels that is caused by a pox virus. The disease causes severe economic losses in most pastoral communities who rely on camels for milk, meat, transportation, and as a source of family income. The disease is recently reported from humans in India suggesting its public health risk. Although the disease can be controlled through vaccination of animals, it is not widely practiced in camel rearing regions. Before initiating any disease control measure, understanding the disease situation at a local level is important. A study was conducted in Afar region of Ethiopia to understand the burden of the disease by measuring the presence of specific antibodies circulating in the blood. In addition, camel owners were participated to identify the seasonal occurrence of the disease. The disease was detected in 19% of the camels, and over 80% of the camel herds. The disease mainly occurs during the rainy season and it causes severe illness in young animals. Our findings suggested the widespread occurrence of camelpox in the pastoral communities, and it warrants proper control measures such as vaccination and improved herd management.

Technical Abstract: Camelpox is endemic in most camel rearing regions of the world, causing significant economic losses. However, its epidemiology is not extensively investigated. We conducted a cross sectional seroprevalence study of camelpox in Amibara and Awash Fentale districts in Afar region of Ethiopia from November 2014 to May 2015. In addition, participatory epidemiology (PE) was conducted to identify seasonal occurrence of the disease in the study districts. Blood samples were collected from 384 dromedary camels from 31 herds distributed in five pastoral associations (PAs) in the two districts. Serum samples were separated from the blood samples and tested for the presence of viral antibodies using virus neutralization test. Seroprevalence data were analyzed using multilevel mixed effects logistic regression models accounting for the 4-level hierarchical data structure (camels nested in herds-herds in PA, and PA in district). For the participatory data, Kendall’s coefficient of concordance was used to assess agreements between the informants in identifying seasonal occurrences of the top five camel diseases. Camelpox antibodies were detected in 19.3% of camels (n=384), 81% of herds (n=31), and in all five PAs from the two districts in the Gabi Rasu zone of Afar region, Ethiopia. The seroprevalence did not significantly vary between herds, PAs or districts suggesting the widespread occurrence of the disease. Estimated age stratified basic reproduction number (R0) was 1.25 (95% CI: 0.62 – 2.19). Camelpox was identified as one of the top five common camel diseases in the area. The widespread occurrence of the disease can be attributed mainly to the commingling of camels from many herds during seasonal migration in search of feed and water, a practice very common under pastoral production systems. Although the PE informants indicated the clinical disease to be more common in young animals, seropositivity was higher in older animals. Camelpox commonly occurs during the minor and major rainy seasons. In conclusion, camelpox is found to be endemic in Afar pastoral region with sporadic outbreaks occurring during rainy seasons. Vaccination and improved camel management practices particularly during the high-risk period can be viable strategies to reduce the burden of the disease.