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

Abstract

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.

A survey of bluetongue infection in one-humped camels (Camelus Dromedarius); seroprevalence and risk factors analysis

“…According to the findings, BTV sero-prevalence increased significantly during the summer season as compared to other seasons, especially in areas with a high insect population. This is consistent with previous findings of Elmahi et al [ 21 ]. Such findings could be attributed to high density of Culicoides in these areas [ 18 , 40 ], which plays an important role in transmission of BTV and its multiplication increased significantly during summer [ 38 , 41 , 42 ].…”

“…However, the risk assessment found no link between sero-prevalence and the age of the animal or the size of the herd. The findings are directly in line with previous findings reported in camels in Sudan [ 21 , 36 – 38 ].…”

“…The sero-prevalence rate of BTV among camels in this work lie in the same range that reported in previous study in Saudi Arabia (25.7%) by Yousef et al [ 20 ]. Moreover, previous epidemiological studies found higher sero-prevalence for BTV in Sudan (78.6%) [ 21 ], Iran (93.5%) [ 22 ] and Turkey (88%) [ 23 ]. However, the overall prevalence of this study was greater than the previous reported rate in camels in the Kassala region in Sudan, with a prevalence of 4.3% [ 8 ].…”

“…Contrary to the present findings, Abraheem et al [ 36 ] found equal sero-prevalence rate in both sexes with no significant disparity. The disparity in the present work could be related to disparities in male and female sample sizes, as well as variances in husbandry procedures [ 21 , 36 ].…”

Camel viral diseases: Current diagnostic, therapeutic, and preventive strategies

“…It primarily affects ruminant and camelid animals. Symptoms of this infection are more common in sheep, whereas asymptomatic BT infections are more prevalent in cows, goats, and camelids ( 55 ). Twenty-seven variants of BTV have thus far been identified.…”