Sero-epidemiological survey of bluetongue disease in one-humped camel (Camelus dromedarius) in Kassala State, Eastern Sudan

Background Bluetongue (BT) is a vector-borne viral disease of ruminant and camelid species which is transmitted by Culicoides spp. The causative agent of BT is bluetongue virus (BTV) that belongs to genus Orbivirus of the family Reoviridae. The clinical disease is seen mainly in sheep but mostly sub-clinical infections of BT are seen in cattle, goats and camelids. The clinical reaction of camels to infection is usually not apparent. The disease is notifiable to the World Organization for Animal Health (OIE), causing great economic losses due to decreased trade and high mortality and morbidity rates associated with bluetongue outbreaks. The objective of this study was to investigate the seroprevalence of BTV in camels in Kassala State, Eastern Sudan and to identify the potential risk factors associated with the infection. A cross sectional study using a structured questionnaire survey was conducted during 2015-2016. A total of 210 serum samples were collected randomly from camels from 8 localities of Kassala State. The serum samples were screened for the presence of BTV specific immunoglobulin (IgG) antibodies using a competitive enzyme-linked immunosorbent assay (cELISA). Results Seropositivity to BTV IgG was detected in 165 of 210 camels' sera accounting for a prevalence of 78.6%. Potential risk factors to BTV infection were associated with sex (OR = 0.061, p-value = 0.001) and seasonal river as water source for drinking (OR = 32.257, p-value = 0.0108). Conclusions Sex and seasonal river as water source for drinking were considered as potential risk factors for seropositivity to BTV in camels. The high prevalence of BTV in camels in Kassala State, Eastern Sudan, necessitates further epidemiological studies of BTV infection in camels and other ruminant species to better be able to control BT disease in this region.

Automated summary

This study investigated the seroprevalence of bluetongue virus (BTV) in camels in Kassala State, Eastern Sudan, finding a high prevalence rate of 78.6%. Potential risk factors for BTV infection in camels were associated with sex and seasonal river as a water source for drinking. Further epidemiological studies are needed to better control bluetongue disease in this region.