Scielo RSS <![CDATA[Onderstepoort Journal of Veterinary Research]]> vol. 87 num. 1 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>An assessment of bovine herpes virus 4 as a causative agent in abortions and neonatal death</b>]]> Numerous viruses, including bovine viral diarrhoea virus (BVDV), bovine herpes virus 1 (BoHV-1) and bovine herpes virus 4 (BoHV-4), and other pathogens are the most common causes of reproductive disorders and are responsible for huge economic losses in livestock production. This study investigates the aetiological role of BoHV-4 in fertility problems such as abortions, stillbirth and birth with unviable calves. Retrospective samples from 38 animals, including 17 aborting cows, 17 aborted foetuses, three stillborn calves and one unviable newborn calf were analysed. The BoHV-4 genome was detected in 25 (65.7%) animals by polymerase chain reaction. In 14 of these infected animals, we detected co-infection with BVDV, while the co-presence of BoHV-1 was also detected in one animal. In addition to the high prevalence of BoHV-4 genome in materials related to fertility problems, isolation of BoHV-4 from the brain of one stillborn calf indicated a causal link between BoHV-4 and fertility problems, such as abortion, stillbirths or birth with unviable calves. <![CDATA[<b>Validating a non-invasive technique for monitoring physiological stress in the samango monkey</b>]]> The non-invasive monitoring of physiological stress can provide conservation and wildlife managers with an invaluable tool for assessing animal welfare and psychological health of captive and free-ranging populations. A significant decrease in free-ranging primate populations globally and an increase in captive-housed primates have led to a need to monitor the stress and general welfare of these animals. We examined the suitability of three enzyme immunoassays (EIAs) for monitoring stress-related physiological responses in the samango monkey, Cercopithecus albogularis erythrarchus. We conducted an adrenocorticotropic hormone (ACTH) challenge on a male and female at the National Zoological Garden, Pretoria, South Africa. Individual faecal samples were collected 8 days pre- and post-ACTH administration and subsequently analysed for faecal glucocorticoid metabolite (fGCM) concentrations. During the study, biological stressors occurred for both the male and female. Two of the three EIAs tested (11-oxoetiocholanolone I and II) were able to reliably monitor fGCM alterations throughout the study period in both sexes. The 11-oxoetiocholanolone I EIA, however, had the lowest mean deviation from the calculated baseline value and was thus chosen as the preferred assay. Both the physiological activation of the stress response and the biological response to a stressor could be monitored with the chosen assay. The successful establishment of a reliable, non-invasive method for monitoring adrenocortical activity in C. albogularis erythrarchus will now allow conservationists, scientific researchers and wildlife managers to evaluate the level of stress experienced, and general welfare, by animals in captivity as well as free-ranging populations. <![CDATA[<b>Investigating selective media for optimal isolation of <i>Brucella</i> spp. in South Africa</b>]]> Bovine brucellosis in South Africa is caused mainly by Brucella abortus biovar (bv.) 1 and less frequently by B. abortus bv. 2. Bacterial isolation is regarded as the gold standard for diagnosis of Brucella species; however, it is not very sensitive. The aim of this study was to determine the selective medium with optimum antibiotic composition that will allow the growth of Brucella species (spp.) while inhibiting moulds, yeast and most, if not all, Gram-negative contaminants in South Africa. In the controlled experiment, modified Agrifood Research and Technology Center of Aragon (CITA) medium (mCITA) seemed to be the optimum selective medium for isolation of Brucella spp. as compared with Farrell's medium (FM) and modified Thayer Martin (mTM), while FM inhibited the growth of most fungal and bacterial contaminants. Mean comparison between the three media used to culture B. abortus resulted in lower mean difference ranging from 0 to 2.33. In case of Brucella ovis, high mean difference was obtained when comparing FM with mCITA (10.33) and mTM (12). However, the mean differences of 0.67 and 1.67 were obtained when comparing mCITA and mTM media used to, respectively, culture pasteurised and raw milk spiked with B. ovis. Further optimisation at the Agricultural Research Council - Onderstepoort Veterinary Research Institute resulted in a comparable performance between FM and mCITA; however, mCITA allowed optimal growth of the fastidious B. ovis, which is generally inhibited on FM. Generally, mCITA seemed to be the optimum selective medium for isolation of Brucella spp., while FM inhibits the growth of most fungal and bacterial contaminants. Thus, veterinary laboratories can use mCITA and/or FM but should take into consideration the detection of factious Brucella isolated in the country or region. <![CDATA[<b>Failure of diplodiatoxin to induce diplodiosis in juvenile goats</b>]]> Diplodiosis is an important neuromycotoxicosis of ruminants in South Africa when grazing on harvested maize fields in winter. It is believed to be caused by mycotoxin(s) synthesised by Stenocarpella (Diplodia) maydis. Although several metabolites have been isolated from S. maydis culture material, none of these have been administered to ruminants to reproduce the disease. The objectives of this study were to isolate diplodiatoxin and to administer it to juvenile goats. Diplodiatoxin, considered as a major metabolite, was purified from S. maydis-infected maize cultures (Coligny 2007 isolate). Following intravenous administration of 2 mg and 4 mg diplodiatoxin/kg body weight for five consecutive days to two juvenile goats, no clinical signs reminiscent of diplodiosis were observed. Based on previous experimental results and if diplodiatoxin was the causative compound, the dosage regimen employed was seemingly appropriate to induce diplodiosis. In addition, intraruminal administration of 2 mg/kg diplodiatoxin to one goat for three consecutive days also did not induce clinical signs. It appears as if diplodiatoxin alone is not the causative compound. Other metabolites and/or mixtures of diplodiatoxin and other mycotoxins, when available in sufficient quantities, should also be evaluated. <![CDATA[<b>Challenges for controlling bovine tuberculosis in South Africa</b>]]> All effects taken together, bovine tuberculosis (bTB) has a long-term detrimental effect on bovine herds and many wildlife species in South Africa. The disease is not only found in domestic cattle but also in African buffaloes and has to date been diagnosed in 21 wildlife species, including several rare and endangered species, thus having a potentially serious effect on conservation and biodiversity. In cattle, bTB is mostly characterised by sporadic outbreaks, but bovine herds chronically infected with the clinical disease are not uncommon. Presently, the recognised bTB control strategy in South Africa is based on 'test and slaughter', using the intradermal tuberculin test, followed by the slaughter of animals that have tested positive. Affected herds are placed under veterinary quarantine with movement restrictions until the outbreak is eradicated; this can take several years or last indefinitely if the outbreak cannot be eradicated. The same measures apply to infected buffalo populations, often with no prospect of ever being eradicated. This strategy is neither practical nor viable in the context of a communal farming system and becomes unethical when dealing with valuable wildlife reservoir hosts. Transmission of bTB between wildlife and cattle has been demonstrated and emphasises the need for an effective, affordable and culturally acceptable control strategy to curb the spread of bTB in South Africa. In countries with similar challenges, vaccination has been used and found to be promising for treating wild and domestic reservoir species and may hence be of value as a complementary tool for bTB control in South Africa.