Protozoa species were identified in rumen contents of four domestic sheep (Ovis aries) from South Africa. All animals were fed a forage diet which consisted of 50% lucerne and 50% teff hay. Ten new host records were identified, bringing the total number of species and forms observed in sheep in South Africa to 30. The occurrence and geographic distribution of ciliate protozoa in both domestic and wild sheep from around the world are summarised. It was found that 15 genera and 131 species occur in domestic sheep globally.

The dairy industry is a large and important business in Saudi Arabia. Although farms are administered to high international standards, some reproduction problems, of uncertain aetiology, are encountered. The most frequently seen are conception failures, abortions, stillbirths and the birth of weak or malformed calves. These conditions are suggestive of bovine viral diarrhoea virus (BVDV) infection. Unfortunately, very little published information is available regarding the impact of this disease on cattle populations in Saudi Arabia. As a consequence, the present study was carried out and is the first of its kind in Saudi Arabia and the Gulf region. The aim of the study was to elucidate the role of in utero BVDV infection leading to the birth of weak or malformed calves on a large dairy farm in Saudi Arabia. The study was divided into two parts. Firstly, apparently healthy neonatal calves were sampled for the detection of pre-colostral serum antibodies to BVDV. The presence of these antibodies indicates exposure of the foetus to BVDV during the last two trimesters of gestation. Secondly, tissue samples from malformed neonatal calves were examined for the presence of BVDV antigens. Detection of such antigens confirms exposure of the foetus to the virus during the first trimester of gestation. The results of the investigation indicated that 36.1% of the neonatal calves were exposed to BVDV infection in utero. This is higher than what has been reported in the literature and suggests that dairy farmers in the Arabian Peninsula need to be made aware of the dangers of BVDV infections in their herds. The epidemiological significance of the results is discussed.

Despite its important role as vector for African horse sickness virus (AHSV), very little information is available on the dissemination of this virus in Culicoides (Avaritia) imicola Kieffer (Diptera: Ceratopogonidae). This study reports on the applicability of a real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) to detect AHSV in dissected midges. A total of 96 midges were fed on AHSV-infected blood, after which one test group was dissected into head/thorax and abdomen segments immediately after feeding and the other only after 10 days of incubation. The majority of the midges (96%) ingested the virus successfully and there was no significant difference between the virus concentration in the heads/thoraxes and the abdomens immediately after feeding. After incubation, virus was detected in 51% of the midges and it was confined to the abdomen in the majority of these. The fact that virus was detected only in the heads/thoraxes of four Culicoides midges after incubation suggests the presence of a mesenteronal escape barrier. Replication in the salivary glands was not shown. An increase of the mean virus concentration in the abdomen after incubation indicates localised viral replication. The real-time RT-qPCR is recommended for further studies investigating the replication and dissemination of AHSV in Culicoides midges.

Bluetongue (BT), a disease that affects mainly sheep, causes economic losses owing to not only its deleterious effects on animals but also its associated impact on the restriction of movement of livestock and livestock germplasm. The causative agent, bluetongue virus (BTV), can occur in the semen of rams and bulls at the time of peak viraemia and be transferred to a developing foetus. The risk of the transmission of BTV by bovine embryos is negligible if the embryos are washed according to the International Embryo Transfer Society (IETS) protocol. Two experiments were undertaken to determine whether this holds for ovine embryos that had been exposed to BTV. Firstly, the oestrus cycles of 12 ewes were synchronised and the 59 embryos that were obtained were exposed in vitro to BTV-2 and BTV-4 at a dilution of 1 x 102.88 and 1 x 103.5 respectively. In the second experiment, embryos were recovered from sheep at the peak of viraemia. A total of 96 embryos were collected from BTV-infected sheep 21 days after infection. In both experiments half the embryos were washed and treated with trypsin according to the IETS protocol while the remaining embryos were neither washed nor treated. All were tested for the presence of BTV using cell culture techniques. The virus was detected after three passages in BHK-21 cells only in one wash bath in the first experiment and two unwashed embryos exposed to BTV-4 at a titre of 1 x 103.5. No embryos or uterine flush fluids obtained from viraemic donors used in the second experiment were positive for BTV after the standard washing procedure had been followed. The washing procedure of the IETS protocol can thus clear sheep embryos infected with BTV either in vitro or in vivo.

Ticks, as vectors of disease and damage agents, impact directly and indirectly on the economy of the livestock industry in southern Africa. This study surveyed the occurrence and distribution of ticks infesting livestock across the North West province, South Africa. During three phases in consecutive years, officers of the provincial Veterinary Department collected specimens monthly from livestock hosts at specified sites across the province. Data analysis constituted the fourth phase of the study. A total of 1090 collections from 265 sites yielded 42 566 tick specimens, comprising 22 different tick species (18 ixodids, 4 argasids). The specimens represent all of the major tick vectors of disease that occur in South Africa. The major tick-borne diseases (i.e. heartwater, both African and Asiatic bovine babesiosis and anaplasmosis) were found to be prevalent mainly in the north-eastern region of the province, which also displayed the highest tick species diversity. The central region appears transitory to some of the major vectors. Although some tick species were contained within specific regions, others were widespread across the province. Associated serology data show that most herds sampled in areas endemic for babesiosis and anaplasmosis in the north-eastern region are endemically unstable and at risk to these tick-borne diseases should vector control measures become ineffective.

National audience

Conventional methods of detecting Corynebacterium pseudotuberculosis, a bacterium that causes caseous lymphadenitis (CLA) in sheeps and goats focused on several serodiagnostic tests such as ELISA, Western blotting and various inhibition and precipitation techniques. This paper described a Surface Plasmon Resonance (SPR) protocol for the direct detection of polyclonal
antibodies against Corynebacterium pseudotuberculosis with immobilisation of the antigen on unmodified transducer surface. The lower limit of detection was determined to be 2 μg mL-1 of immobilised antigen (Ag). Sufficient binding interaction was monitored on unmodified transducer; and saturation of the binding interaction was observed at 80 μg mL-1 of interacted antibody.

A monitoring program for melamine in milk and feed was conducted in response to global melamine alertness in the year 2008. Two screening methods were adopted i.e., a liquid chromatography triple quadrupole tandem mass spectrometry (LC-MS/MS) and enzyme-linked
immunosorbent assay (ELISA). The liquid chromatography method developed by several international research centers was adapted. This method consisted of an initial extraction with 10%trichloroacetic acid (TCA) for milk samples or 60% methanol/water for feed samples, followed by a series of centrifugation, dilution and filtration steps. Melamine was analysed in the chromatographic program using a zwitterionic HILIC LC column. Electrospray ionisation in positive ion mode was used. The quantity of melamine
present was determined with a calibration curve consisting of sample extracts from milk or feed fortified from 25 to 50 ppb that were taken through the extraction procedure. The ranges of recovery from
fortified raw milk samples (n=20) and feed samples (n=21) was 70–80% and 68%, respectively. The limit of detection was estimated at 10 ppb for both matrixes. Milk samples were found negative for melamine,
however 4.5% of feed samples were found to contain the compound at concentrations between 1 to 5 ppm.

The ameliorative effect of salts, ascorbic acid olyphosphate and zinc oxide supplementation on heat stress was studied in adult buffaloes of either sex which were randomly divided into two groups of four animals each. Group I served as control and Group II was supplemented with sodium bicarbonate, potassium carbonate, ascorbic acid polyphosphate and zinc oxide. All the animals were exposed to two conditions of temperature and humidity: hot-dry and hot-humid in psychrometric chamber for 4 hours daily for 10 days. Blood was collected on days 1, 5 and 10 of treatment. The activities of enzymes catalase, superoxide dismutase (SOD) and concentrations of reduced glutathione (GSH), hormone cortisol and thiobarbituric acid (TBA) binding substances (lipid peroxidation) were estimated in serum. Significant decreasewas observed in activities of serum catalase and SOD. Serum GSH concentration decreased while serum concentrations of TBA binding substances and cortisol significantly increased in both groups which were subjected to heat stress. Dietary supplementation of ascorbate, zinc and electrolytes resulted in further decrease in the enzymes' activities where as the serum GSH increased at par to normal values. Serum concentrations ofTBA binding substances and cortisol were comparatively lower in supplemented group in both types of stress. Thus, supplementation of ascorbate and zinc in addition to electrolytes relieved the animals of oxidative stress.