Prevalence of antibodies to bovine viral diarrhoea virus in Namibian wildlife

Abstract

Pestivirus infection in domestic ruminants has been reported in several parts of southern Africa (Theodoridis and Boshoff, 1974). In'wildlife naturally occurring bovine viral diarrhoea virus (BVDV) infection has only rarely been reported (Plowright, 1969). It was the purpose of this investigation to record the antibody levels to BVDV in 535 sera from the following 9 Namibian wildlife species: roan antelope The sera originated either from wildlife cropping operations in southern Namibia or from the Etosha National Park in northern Namibia. Neither age nor sex of the sampled animals were known. All sera were stored at -20~ until testing.For the determination of antibody levels, a direct neutralising peroxidase-linked antibody (NPLA) assay using the 0712/Han/80 strain of BVDV was performed (Hyera et aL, 1987). Neutralising antibody titres greater than 1:5 were considered positive.The percentage of seropositive animals within a species, as well as the titre range, is given in Table I. Six out of 9 species were shown to have antibodies to BVDV. The prevalence in seropositive species ranged from 5 to 67 per cent. Giraffe and roan antelope sera showed titres 1 : 1,000; the highest antibody titres were found in 2 giraffe with 1:56,234 and 1:28,184. Oryx, kudu, sable antelope and blue wildebeest had titres of about 1:100 (Table I). All sera originating from red hartebeest, black wildebeest and springbok were free of detectable antibodies against BVDV.The data presented showed that BVDV infection is widespread in Namibian wildlife. Hamblin and Hedger (1979) demonstrated antibodies to BVDV in the sera of 17 out of 45 wildlife species from various African regions. Among these were sera from kudu, oryx, wildebeest, springbok and giraffe sampled in Namibia. In addition, we demonstrated antibodies in sera from roan and sable antelope but failed to detect antibodies in springbok sera.The very high antibody titres in giraffe and roan antelope suggest that these animals could have experienced a recent infection and that the BVDV strain which was used throughout the test is antigenetically similar to field virus strains which infected these animals. The isolation of a cytopathogenic pestivirus from a diseased giraffe in Kenya (Plowright, 1969) and the high titres measured in our survey indicate that giraffe are highly susceptible to pestivirus infection. No significance is attributed to the absence of antibodies in sera from red hartebeest and black wildebeest due to the low number of samples.Unless BVDV persistence and its perpetuation in wildlife species is proven, their role in the epidemiology of BVDV infection in livestock remains obscure.

Serologic Surveillance for Selected Viral Agents in Captive and Free-Ranging Populations of Arabian Oryx (Oryx Leucoryx) From Saudi Arabia and the United Arab Emirates

“…Infection of wild ruminants can result in either acute disease or a subclinical infection (Van Campen et al, 2001). A high prevalence of antibodies against the NADL strain has been recorded in three other related species of Hippotraginae: gemsbok and sable and roan antelope (Hamblin and Hedger, 1979;Soine et al, 1992). Ours is the first study to demonstrate exposure of Arabian oryx to BVDV.…”

Seroepidemiology of Bovine Viral Diarrhoea Virus (BVDV) in the Adamawa Region of Cameroon and Use of the SPOT Test to Identify Herds with PI Calves

“…Their identification and removal is considered key to control efforts [5]. Several studies have demonstrated significant seroprevalence in African wildlife, although the role of sheep and wildlife in BVDV transmission is yet to be fully elucidated[6]–[8]. Once a PI animal enters a herd, it has been assumed that the herd is likely to remain infected due to the ongoing production of PI animals as naïve cows are infected during pregnancy, however, recent evidence suggests that herds may self-clear [9].…”

Serosurvey for Selected Infectious Disease Agents in Free-Ranging Black and White Rhinoceros in Africa

“…Atang and Plowright (1969) reported the isolation of BVD virus from a captive giraffe (Giraffa camelopardalis) in Kenya and also cited the isolation of BVD from a sick buffalo (Syncerus caffer) shot in the Central African Republic, which was apparently involved in an outbreak of disease that affected warthog (Phacocoerus aethiopicus) and eland (Taurotragus oryx). Antibody against BVD virus has been shown to be widespread in domestic and wild species throughout Africa (Hamblin and Hedger, 1979;Nettleton, 1990), although the prevalence of antibody appears to vary for different countries, particularly for wildlife species (Hamblin and Hedger, 1979;Soine et al, 1992). In cattle, a high prevalence of antibody often correlates with the presence of persistently infected animals within the herd and spread is most successfully achieved by close contact with these persistently infected animals (Roeder and Drew, 1984).…”