SMALL RUMINANTS: A SOURCE OF BOVINEHERPES VIRUS 1 (BHV-1) FOR CATTLE

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1 SMALL RUMINANTS: A SOURCE OF BOVINEHERPES VIRUS (BHV) FOR CATTLE YEŞİLBAĞ K. BİLGEDAĞALP S. 2 Uludağ University Faculty of Veterinary Medicine Department of Virology, 6059, Bursa, Turkey, Phone: , Fax: , kyesilbag@uludag.edu.tr,; 2 AnkaraUniversity Faculty of Veterinary Medicine Department of Virology, Ankara Bovine herpesvirus (BHV) is one of the most important agents of cattle, causing reproductive, respiratory and neurological disorders world wide. Although the agent is originally known as a cattle virus, studies have showed that it may also infect small ruminants in natural and experimental conditions. In goats, but not in sheep yet, latency and reactivation of the virus in infected individuals have been previously demonstrated. In this presentation, infection situation of sheep and goats from different regions of Turkey is explained. Our studies (Yesilbag, K., BilgeDağalp,S., OkurGümüşova, S., Güngör, B.: Revue de Medecine Veterinaire 2003; 54 (2):772774) which subjected 65 adult goats from 5 provinces of Turkey, showed that 5.52% of goats tested have neutralizing antibodies against BHV. On the other side, harmonious to this study, 024 sheep sera from 4 provinces located in eastern, western and central regions of Turkey were tested against BHV by virus neutralisation assay. The mean prevalence of BHV antibodies among tested animals was 2.44%. The prevalence values for eastern, central and western regions were 5.9%,.4% and 3.3%, respectively. There was no positive sheep detected in eight provinces. Pozitivity rates in 6 provinces where positive animals have been detected were ranged from.04% to 22.72%. In comparison with previous studies, it was concluded that small ruminants may act as a source of the virus for cattle population. This situation may interfere to control and eradication attempts designated for BHV. INTRODUCTION Herpesvirus infections of domestic ruminants are about economic losses due to respiratory and reproductive problems. Bovine herpesvirus (BHV) is a major pathogen of bovines world wide and causes different clinical manifestations including infectious bovine rhinotracheitis (IBR), infectious pustular vulvovaginitis (IPV) / balanopostitis (IPB) and meningoencephalitis (Barnard and Collet, 994). These conditions are related to strains of BHV subtype, subtype 2 and subtype 3, respectively (Six et., 200). BHV subtype 3 was later classified as BHV5 (Roizman et al., 992). Recently, it has been demonstrated that both BHV and BHV5 are causative agents of bovine encephalomyelitis (Meyers et al., 2000; Roels et al., 2000). The agent is an enveloped dsdna virus which is classified in the Alphaherpesvirinae subfamily of the family Herpesviridae. As a characteristics of this subfamily, BHV has capability to produce latent infection after primary (acute) infections. The latency of herpesviruses means presence of viral genome in trigeminal or sacral ganglions without replication. The virus could be reactivated by stress factors such as pregnancy, transportation and corticosteroid applications. There are some studies which have been demonstrated that cross transmission of ruminant herpesviruses among ruminant species is possible. On the other hand latency of BHV in goats was successfully demonstrated (Wafula et al, 985). Although the status of latency in sheep has not been demonstrated yet, it is highly possible to occur. Our studies (Yeşilbağ et al., 2003) showed that goats breed in

2 2 Turkey have neutralizing antibodies against BHV with a prevalence of 5.52%. In the light of this knowledge, the data obtained from studies on BHV in sheep and goats are presented here. MATERIALS & METODS Samples Results from a total of 639 randomly selected animals (65 goats and 024 sheep) were subjected. Goats were from 5 provinces (Edirne, Çanakkale, Balikesir, Denizli, and Isparta), and sheep were from 4 provinces of Turkey (see Table). The age of sampled animals was over one year old. Genders were not kept in view. Samples were heat inactivated (56 C for 30 min) before testing and stored at (20) C until serological applications. It is known that vaccination against BHV is not applied to small ruminants in Turkey. Virus and Cell Line Colorado strain of BHV was used as test virus. Madin Darby Bovine Kidney (MDBK) cell line was used in serum neutralisation test and for propagation of the virus. The cells were grown in Eagle s Minimal Essential Medium (EMEM), enriched with 0% foetal calf serum. Titre of the virus, calculated by SpearmannKaarber method was 0 5,25 ml. Serological Examinations Detection of neutralising antibodies specific to BHV was performed by serum neutralisation test as described elsewhere (Frey and Liess, 97). For this purpose, 50µl serum was placed into microtitreplate wells as duplicates and mixed with 50µl volume of the test virus (00TCID 50 ). After one hour of incubation at 37 C 5% CO 2 atmosphere, MDBK cells were shared to plates in a concentration of cells per well. Results were evaluated after 3 days of incubation at 37 C in a 5% CO 2 atmosphere. Total inhibition of the virus growth was accepted as criteria for samples which was positive for BHV antibodies. RESULTS Fifty nine animals (3.59%), 34 goats and 25 sheep, out of 639 were positive for BHV neutralizing antibodies (see Table). Antibody prevalence detected in goats (5.52%) was a little higher than the prevalence in sheep (2.44%). There were seropositive goats in all of provinces subjected, but 8 provinces had no sheep that positive for BHV antibodies. Positivity rates were ranged from 2.0% to 3.57% for goats, and 0 % to 22.72% for sheep.

3 3 Table : Distribution of samples to locations and prevalance of BHV antibodies Location Number of Samples Number of Positives % Prevalance by Species (%) Goat Samples * Balıkesir Çanakkale Edirne Denizli Isparta S h e e p S a m p l e s Batman e Elazığ e Konya c Sivas c Ankara c Amasya c Eskisehir c Kocaeli w Sakarya w Isparta w Aydin w Kırklareli w Tekirdağ w Denizli w TOTAL *Data were adapted from Yeşilbağ et al.(2003); e : eastern, c: central, and w: western regions of Turkey DISCUSSION Herpesvirus infections of domestic ruminants have an increasing interest in veterinary virology and clinical sciences. Although some investigators (Akça, 98; Burgu et al., 984; Bechmann, 997; Brako et al., 984) failed to detect BHV antibodies in sheep, Goyal et al. (988) and Elazhary et al (984) reported a seroprevalance of 0.5% and 2.9% respectively. In a study including 5 sheep, Yavru et al. (999) found that seroprevalance of the infection is 9.6% in 2 intensively managed farms in central Turkey. Interestingly, Singh et al.(200) reported that infection rate in Indian sheep population is 67.9%. Similar results are also consistent for goats. For example, seroprevalance values were 6.9% in Quebec, Canada (Elazhary et al., 984), 3.9% in Luisiana, USA (Fulton et al., 982), and.2 in Nigeria (Taylor et al., 977). Data presented here show that the prevalence of infection is 2.44% in sheep and 5.52 % in goat population in Turkey. In overall, it seems that the prevalence of BHV in goats is a little bit higher than in sheep. It may be due to the species susceptibility. Up to date, latency and recurrence of the virus in goats were successfully explained (Wafula et al., 985) as well as transmission to the cattle. It is though to be the case also for sheep. In rural conditions small and large ruminants are pastured together. Moreover, in small capacity family farms, it is common to harbour these species in the same unit. Hence, this model of breeding may allow cross transmission of the agent among the species. This

4 4 risk may reduce the efficiency of BHV control activities. On the other hand it will not be forgiven that newly purchased sheep and goats that if latently infected, can introduce the virus to BHV free cattle populations. REFERENCES Akça Y.: Türkiye de sığır ve koyunlarda enfeksiyöz bovine rhinotracheitisenfeksiyöz pustular vulvovaginitis (IBRIPV) üzerine serolojik araştırmalar. PhD thesis, Ankara Un.Vet Fak., Ankara, 98. Barnard B.J.H. and Collett M.G.: Infectious bovine rhinotracheitis/infectious pustular volvovaginitis. In : J.A.W. Coetzer, G.R. Thompson, R.C. Tustin (Ed) : Infectious disease of livestock. Oxford University Press, 994, Bechmann G., Serological investigations in the diagnosis of viral infections derived from cattle in sheep. Dtsch Tierarztl Wochenschr. 997, 04 :324. Brako EE, Fulton RW, Nickolson SS, Amborski GF, Prevalence of bovine herpesvirus, bovine viral diarrhea, parainfluenza3, goat respiratory syncitial, bovine leukemia, and bluetongue viral antibodies in sheep. Am J Vet Res, 984, 45: Burgu I., Ozturk F., Akça, Y.: Tahirova devlet üretme çiftliği koyunlarında viral enfeksiyonlar üzerine serolojik araştırmalar. Ankara Univ Vet Fak Derg, 984, 3: Elazhary M.A.S.Y., Silim A. and Dea S. : Prevalence of antibodies to bovine respiratory syncitial virus, bovine viral diarrhoea virus, bovine herpesvirus, and bovine parainfluenza3 virus in sheep and goats in Quebec. Am. J. Vet. Res., 984, 45, Frey H.R. and Liess B. : Vermehrungskinetik und verwendbarkeit eines stark zytopatogenen VDMD virusstamnes für diagnostische untersuchungen mit der 3mikrotiter method. Zbl. Vet.Med. B, 97, 8, 67. Fulton R.W., Downing M.R. and Hagstad H.V : Prevalance of bovine herpesvirus, bovine viral diarrhoea, parainfluenza3, bovine adenoviruses3 and 7, and goat respiratory syncytial viral antibodies in goats. Am. J. Vet. Res., 982, 43, Goyal S M, Khan M A, McPherson S W, Robinson R A and Boylan W J. (988): Prevalance of antibodies to seven viruses in a flock of ewes in Minnesota. Am. J. Vet. Res 49 : Meyers G., Döffay J. and Thiry E. : Les encephalitis a herpesvirus bovines. Le Point Vet.,2000, 3, Roels S., Charlier G., Letellier C., Meyer G., Schynts F., Kerkhofs C., Thiry E. and Vanopdenbosch E. : Natural case of bovine herpesvirus meningoencephalitis in and adult cow. Vet. Rec., 2000, 46, Roizman B., Desrosiers.C., Flenkenstein B., Lopez C., Minson A.C. and Studdert M.J. : The family herpesviridae: An update. Arch Virol., 992, 23, Singh, RP., Bhat MN., Sastry KNN. Studies on the prevalence of antibodies to BHV in sheep. Ind Vet J, 200, 78 : Six A., Banks M., Engels S M., Ros Basconana C. and Ackermann M. : Latency and reactivation of bovine herpesvirus (BHV) in goats and of caprine herpesvirus (CapHV) in calves. Arch. Virol., 200, 46, Taylor W P, Okeke A N C and Shidalin N.: Prevalence of bovine viral diarrhea and infectious bovine rhinotracheitis antibodies in Nigerian sheep and goats. Trop. Anim. Health Prod., 977, 9, 775.

5 5 Wafula, J.S., Mushi, E.Z. and Wamwayi, H. : Reaction of goats to infection with infectious bovine rhinotracheitis virus. Res. Vet. Sci., 985, 39, Yavru, S., Ozturk, F., Gürhan, I., Şimşek, A., Ünver, G., Duman, R., Yapkıç, O.: Koyunlarda sonlunum yolu viruslarının serolojik olarak araştırılması. Hayvancılık Aaştırma Derg. 999, 9: Yesilbag, K., BilgeDağalp, S., OkurGümüşova, S., Güngör, B.: Revue de Medecine Veterinaire 2003; 54 (2):772774