Introduction
Border disease virus (BDV)is one of viral diseases which affect the animal production. BDV, bovine viral diarrhea virus (BVDV) and classical swine fever virus (CSFV) are classified in the family Flaviviridae.1
BVDV can infect sheep and goats; border disease is known to affect sheep and goat production negatively by losses due to stillbirth, weak offspring.2 Border disease is existing all over the world, Antibodies were reported in different countries; In Iraq, 47% of sheep and 16% of goats tested positive.3 In Turkey 68% of tested sheep were positive.4 Existence of BDV or BVDV antibodies with variable prevalence rates were documented, in India,5 Sudan,6 Austria7 Serbia.8
In Saudi Arabia very scares work was undertaken to investigate the existence of BVDV and/ or BDV in sheep and goats. Antibodies against BDV and/or BVDV were detected in sheep and goats, in Al-Ahsa region 24% of sheep and 3% of goats were found to be positive for BDV antibodies. 9 more recent study reported the presence of pestivirus antibodies in cattle sera in north, east, west and central regions of Saudi Arabia.10
This study was carried out to explore the presence of antibodies against pestivirus in sheep and goats in the northern region of Saudi Arabia.
Materials and Methods
Study area
Two regions in the north of Saudi Arabia were selected for the study, Hail and Rafha (Figure 1).
Collection of samples
Serum samples (n = 624) were collected from sheep (n = 155) and goats (n = 217) in Hail and sheep (n = 144) and goats (n = 108) in Rafha. Sera were collected randomly from clinically healthy animals in the slaughterhouses and some farms. Blood from jugular vein was drawn, centrifuged and sera were kept at -20o C till tested.
Pestivirus antibodies detection using ELISA
Competitive enzymatic immunoassay (blocking ELISA) with pestivirus p80/p125 specific monoclonal antibodies peroxidase conjugate were used to examine collected sera. Kits (Ingezim pestivirus compac) were purchased from Immonologia Y Genetica Aplicada, S.A. C./ Hnos. Garcia Noblejas, 39 28037 – Mardid. Spain. The test was applied as instructed by the manufacturer.
Results
Pestivirus antibodies determination using ELISA in sheep and goat sera
Examined sera (372 from Hail, 252 from Rafha regions) showed antibodies to pestivirus in 115 (18.4%). Sheep showed the highest sero-prevalence (20.7%). Highest sero-positivity was noticed in Rafha region (23.4%), the details are shown in Table 1.
Table 1
Examination of sheep and goat sera for Pestivirus a ntibodies using competitive ELISA
Discussion
Pestivirus including BVDV and BDV are known as significant viral causes of infectious diseases affecting domestic animals leading to great economic losses.2 Border disease in sheep and goats had been extensively reported around the world. In the present study antibodies to pestivirus were found in 18.4 % of 624 examined sheep and goat sera at the north of Saudi Arabia. Unlike a previous work in camel sera,11 highest prevalence rate was found in Rafha which was not expected as Rafha is a small town with very scares animal production facilities.
The detected pestivirus prevalence in sheep (21%) was similar to a previous report (23.7%) in the eastern region of the country9 as well as many countries. It was 23% in 22% in India5 22% in Austria,12 18% in Japan,13 19% in Turkey. 14 Reported prevalence of pestivirus is variable in different countries. The detected prevalence in this study is higher than that presented in may reports, it was only 0.3% and 0.5% in Australia and Denmark,16, 15 5.6% in Ireland17 and USA18 and 7.3% in Turkey.19
However far higher prevalence of pestivirus in sheep were reported, 45% in Turkey,20 68% in Algeria1 as well as in Turkey,21 75% in Turkey.22 This discrepancy is most probably due to the management system, where in USA and Europe strict sanitary and hygienic measures are adopted.
The overall results showed that sheep had higher prevalence rate than goats which is in agreement with the picture reported in different countries, although prevalence in goats was slightly higher than in sheep in Hail region which is unusual and may be due to the collection of samples from highly infected flocks. Existence of antibodies to pestivirus or specifically BDV in sheep and goat sera was confirmed in different countries, in most of the reported cases sheep were found to be highly affected than goats. Pestivirus antibodies were found in% of sheep, 17% of oats in India,5 18.7% in sheep, 6.5% in goats in Chile,23 64% in sheep, 18% in goats in Bulgaria,24 39% in sheep, 15% in goats in Sudan;6 50% in sheep, 3% in goats in Turkey,25 13% in sheep, 12% in goats in Nigeria,26 47% in sheep, 16% in goats in Iraq.3
The results obtained in this study confirmed the high prevalence of pestivirus infection in small ruminants in the country, this raise the need for more detailed study to investigate the prevalence of this viral infection in different areas of the country. Such research beside the molecular characterization of the circulating virus is highly recommended to aid in the control measures of this economically important disease.
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