Seroprevalence of Bluetongue Virus in Dairy Herds with Reproductive Problems in Sudan

The objectives of this cross-sectional study were to determine the seroprevalence of blue tongue virus (BTV) and assess potential risk factors associated with BTV infection in dairy cattle with reproductive problems in Sudan. Serum samples were collected from a total of 784 animals from 37 herds and tested for antibodies against BTV using cELISA. A total of 663 out of 784 (84.57%) sera tested proved positive for BTV antibodies in all farms tested in Khartoum and Gazira States. The prevalence of antibodies was high in both areas being 94.32% in Gazira State and 76.62% in Khartoum State. BTV antibodies prevalence were significantly higher ( ) in older animals than in younger ones. These rates were also significantly higher in the rainy season ( ) and in Gazira State compared to Khartoum State. Sex also showed significant ( ) differences in the seroprevalence, whereby females (74.7%) had higher level than males (9.8%). However, no significant ( ) variations for BTV seroprevalence were observed between breeds. The BTV antibodies prevalence in infertility cases (86.6%) was not significantly different from that found in abortion (74.3%) or neonatal death (66.7%) cases. The high seroprevalence of BTV recorded herein calls for control strategy to be implemented. 1. Introduction Because of the difficulties involved in the diagnosis of the causative agent, bovine fetal loss resulting from abortion and/or infertility can sometimes be challenging to farmers, veterinarian, and diagnostic laboratories [1, 2]. Several bacterial, viral, protozoan, and fungal pathogens had been associated with infertility and abortions in cattle [3]. Viral agents incriminated include bovine herpes-1 (BoHV-1), bovine viral diarrhea virus (BVDV), and bluetongue virus (BTV) [4–6]. Bluetongue virus is the prototype species of the genus Orbivirus, family Reoviridae and occurs almost globally between latitudes 35°S and 50°N. In infected animals, the disease is characterized by various clinical forms, with symptoms ranging from acute to subacute, mild, or inapparent. In addition, this virus is responsible for fetal death, congenital defects, and reproductive failure in cattle [6]. At least 24 immunologically distinct serotypes of the virus are recognized [7–9]. Cattle are readily susceptible to infection with BTV; bovine BTV infections are important because cattle can serve briefly as a source of infection for Culicoides species that biologically transmit BTV to sheep and other ruminants [10]. The sequelae of abortion and the birth of calves with congenital defects like dwarf-like