Gareth F. Bath

Schmallenberg virus – Is it present in South Africa?

In July 2006, a case of two out of three lambs born to one ewe in a flock of 45 had signs that, in retrospect, were possibly consistent with Schmallenberg virus infection. This occurred in the Onderstepoort area (Gauteng Province) but a definitive diagnosis was not made. Then, in May 2008, a farmer in the Delmas area (Mpumalanga Province) reported that deformed lambs had been born to several ewes in the flock. Six of the approximately 50 mated ewes gave birth to lambs showing varying degrees of arthrogryposis, torticollis, kyphosis, mandibular brachygnathia and hydrocephalus. Of these, only two were born alive but they died within a few hours. Blood was collected from the ewes with deformed lambs, a random sample of ewes that had given birth to normal lambs and a lamb that was normal but had a twin that was deformed. The samples were tested for Wesselsbron and Akabane antibodies using a complement fixation test and a haemagglutination/haemagglutination inhibition test that were available at that time. Bluetongue virus antibodies were also tested for using a commercial Enzyme-linked immunosorbent assay (ELISA) test. All samples showed negative results for all diseases tested. At the time Rift Valley fever virus had not been diagnosed in that region for many years and so it was not included in the testing. It is unlikely that this was the cause as no liver pathology was detected on postmortem examination of the lambs and no adult ewes had died. The farmer reported that another farm just a few kilometres away experienced the same deformities in some of their lambs but this farm was not investigated. During investigation it was thought that the cause was possibly a new strain of Akabane virus, although there was no way to confirm it. However, with the recent discovery of the Schmallenberg virus, it is possible that this virus has been present in South Africa for at least the last four years without being identified.

Non-pharmaceutical Control of Endoparasitic Infections in Sheep

The need for sustainable, holistic, and integrated parasite management against sheep worms is emphasized. This article describes approaches for worm management, including lowering the rate and amount of contamination of pastures, identifying and protecting the most vulnerable animals, reducing the selection pressure for anthelmintic resistance, monitoring of parasite infections, and increasing the resistance and resilience of sheep. Control measures under development also are discussed.

Rumenolith formation in a Bapedi ram.

During a routine flock visit, a farmer observed that one of the eight tooth Bapedi rams had been losing body condition despite being separated from the flock and fed supplementary feed. The rams body condition score was assessed as 2 out of 5 (one point less than the average of the rest of the rams) and the teeth appeared normal with no excessive wear. The rumen was assessed by auscultation, palpation and ballottement where a foreign body (approximately 20 cm × 5 cm - 10 cm) was clearly palpated and ballotted. A rumenotomy was performed and a large mass of tightly compacted foreign matter and plant material was removed. The mass consisted of synthetic fibre, plant material and calcium phosphate (50.5%). It appeared to have formed as the result of the ingestion of a synthetic fibre which formed the nidus of a concretion. This was probably the result of deficient nutrition, with the rams eating the synthetic fibre in an attempt to increase feed intake. The ram recovered uneventfully after the rumenotomy was performed and supplementary feeding.

Abortions in sheep associated with Arcobacter skirrowii infection

The history, circumstances, clinical signs, post mortem lesions, morbidity, mortality and laboratory findings are described in an abortion storm in sheep that occurred in Mpumalanga, South Africa, associated with infection with Arcobacter skirrowii. Altogether, about 200 Suffolk Down ewes lost 60 lambs in late pregnancy or at term. Although only three foetuses were submitted for investigation, two had signs consistent with a diagnosis of A. skirrowii infection and the organism was isolated from the placentas of both specimens. No abortions had occurred in previous years, or have subsequently. There were no animal introductions prior to the outbreak that could have indicated a source of infection. One stillborn lamb submitted subsequently had lesions consistent with dystocia, and the history and circumstantial evidence indicated that dystocia had been a factor in several more losses. No ewes or rams had shown signs of diarrhoea or other diseases associated with A. skirrowii infection. Twenty-two faecal, preputial and vaginal swab specimens taken from six rams and 13 ewes after the abortion event were all negative for A. skirrowii. This is the first report of abortions in sheep associated with A. skirrowiiin South Africa. Because the genus Arcobacter is similar to Campylobacter, it is possible that infection has gone unrecognised in the past. Veterinarians and laboratories should take note and include this genus in the list of potential abortifacient organisms. The possible role of Arcobacter species in other diseases like enteritis and mastitis, as well as the potential role as a zoonosis, must be borne in mind.

A questionnaire survey on diseases and problems affecting sheep and goats in communal farming regions of the Eastern Cape province, South Africa

A questionnaire of 15 questions was completed by four categories of respondents with the aim of establishing the experience and opinions of these groups on the constraints including animal health problems for communal, small-scale sheep and goat farming in the Eastern Cape province of South Africa. The questionnaires were completed independently and categories were representative of the areas investigated. Analysis of responses was done by means, ranges, votes and clusters of responses. Comparisons between the responses of the four categories were made to identify similarities or contrasts. The results revealed that of non-veterinary concerns, stock theft was the major problem for these farms. Nutrition was a further major constraint. A third area of significant concern was the provision or availability of facilities like fences, water troughs, dips and sheds. Lack of marketing and business skills were also seen as important deficiencies to be rectified so as to promote profitable farming. Of the most important veterinary problems identified, the provision, availability, cost and care of drugs and vaccines were seen as major stumbling blocks to effective disease control, as well as lack of access to veterinary services. The most important diseases that constrain small-ruminant livestock farming in the farming systems investigated were sheep scab and other ectoparasites, heart water, enterotoxaemia, internal parasites and bluetongue. A lack of knowledge in key areas of small-stock farming was revealed and should be rectified by an effective training and support programme to improve the contribution of small-ruminant farming to livelihoods in these communities.

Incomplete reduction of branchial clefts in Mutton Merino lambs.

Congenital malformations of the branchial arches, clefts and grooves have not been previously reported in sheep. These defects may be due to infectious agents (especially viruses), toxins or genetic abnormalities. Defects were reported in two of a set of quadruplet lambs born prematurely to an eight-tooth Mutton Merino ewe. The lambs weighed between 2.0 kg and 2.5 kg; this is below the normal expected birth weight of 3.5 kg for quadruplet lambs, below which viability is compromised. The firstborn lamb was severely affected by bilateral oroauricular fistulae. The second lamb was unilaterally affected on the right, less severely than the first. The third lamb was normal and the fourth was mummified. The occurrence of another case in this small flock almost a decade earlier indicates that there could be genetic involvement.