Several outbreaks of Rift Valley fever (RVF) have been documented in South Africa since it first occurred in the country in 1950. However, there is no comprehensive account of the timing, location and extent of all known outbreaks. As part of a study investigating the epidemiology of RVF in South Africa, a full history of outbreaks was compiled using references to the disease in South Africa from scientific literature, annual reports, disease reports and animal disease databases. The geographic location and temporal occurrence of each outbreak were recorded as accurately as allowed by the available records. The result was a better and more complete picture than has hitherto been available of the spatial and temporal distribution of RVF in South Africa for the period between 1950 and 2011. Several smaller outbreaks which had not been described previously in literature were documented. Extensive outbreaks occurred in the central interior of the country (Free State, Eastern Cape and Northern Cape provinces), interspersed with smaller outbreaks or long intervening periods of absence, whilst smaller outbreaks occurred in the eastern part of the country (KwaZulu-Natal, Mpumalanga and Gauteng).

Several lyssavirus species occur in Africa (Rabies virus, Lagos bat virus, Mokola virus, Duvenhage virus, Shimoni bat virus and Ikoma lyssavirus), displaying a high sequence diversity between isolates belonging to the same species. There is limited information about comparative pathogenesis of these African lyssaviruses and this precludes authoritative opinion on the potential public and veterinary health impact. In this study, an analysis of representative African lyssaviruses attempted to correlate viral genomic sequence similarities and differences with the corresponding pathogenic profiles observed in mice. The study demonstrated that the virus isolates evaluated could be lethal to mice when introduced intramuscularly and that different isolates of the same lyssavirus species differ in their virulence. Using real-time polymerase chain reaction (PCR), viral RNA was detected in brain tissue, but no viral RNA was detected in the salivary glands or blood of mice that succumbed to infection. Comparison of known pathogenic domains indicated that pathogenicity is likely to be dependent on multiple domains. Cumulatively, our results re-emphasised the realisation that the pathogenicity of a lyssavirus species cannot be deduced based on studies of only a single isolate of the species or a single pathogenic domain.

In 2004, a new concept was introduced for simplifying identification of larvae of the common I nematodes of cattle, sheep and goats that comprises estimates of the lengths of the sheath tail extensions of infective third-stage larvae (L3) of each genus and/or species to that of I: Trichostrongylus spp., instead of having to be dependent only on measurements in micrometre. For example, if the mean length of the sheath tail extension (the extension of the sheath caudad, beyond the caudal tip of the larva) of Trichostrongylus colubriformis and Trichostrongylus axei is assumed to be 'X', then that of Haemonchus contortus is 2.0-2.7 'X' - a difference that is I not difficult to estimate. An additional new approach suggested now, particularly for L3 of species and/or genera difficult to differentiate (such as Chabertia ovina and Oesophagostomum II: columbianum), is to estimate the proportion of the larval sheath tail extension comprising a terminal thin, whip-like filament. For the experienced person, it is seldom necessary to measure I: more than one or two sheath tail extensions of L3 in a mixed culture, because the identity of most of the remaining L3 can thereafter be estimated in relation to those measured, without having to take further measurements. The aim of this article was to present the novel approach in the form of a working guide for routine use in the laboratory. To facilitate identification, figures and a separate organogram for each of small ruminants and cattle have been added to I: illustrate the distinguishing features of the common L3.

A cross-sectional study was conducted to determine the prevalence of sub-clinical and clinical mastitis and the associated factors in cows from selected smallholder dairy farms in Zimbabwe. Physical examinations were conducted on all lactating cows for evidence of signs of clinical mastitis. Composite milk samples were collected from all lactating cows for bacterial culture and somatic cell counting. Cows were categorised as clinical if they exhibited clinical features of mastitis, or sub-clinical if no apparent signs were present but they had a positive bacterial isolation and a somatic cell count of at least 300 x 10³ cells/mL. Farm-level factors were obtained through a structured questionnaire. The association of mastitis and animal-and herd-level factors were analysed using logistic regression. A total of 584 animals from 73 farms were tested. Overall, 21.1% (123/584) had mastitis, 16.3% (95/584) had sub-clinical mastitis and 4.8% (28/584) had clinical mastitis. Herd-level prevalence was 49.3%. Coagulase-negative staphylococci (27.6%), Escherichia coli (25.2%), Staphylococcus aureus (16.3%), Klebsiella spp. (15.5%) and Streptococcus spp. (1.6%) were the most common isolates. In individual cows, pure dairy herds (OR = 6.3) and dairy crosses (OR = 3.1) were more likely to have mastitis compared to Mashona cows. Farms that used pre-milking teat dipping were I: associated with reduced mastitis prevalence. Further research is needed on the prevalence of mastitis and a comparison of data for both smallholder and commercial dairy farms in all regions of Zimbabwe should be undertaken.

A study of the prevalence of African horse sickness in horses was conducted, using records | from two private equine practices in Harare for the period 1998-2004. Results indicated a higher prevalence of the disease in horses in Zimbabwe in the late rainy season (March - May). Age of the horse was found to be a significant risk factor, with foals or yearlings appearing to be 1.80 times more likely to contract the disease compared with horses older than two years. The case fatality rate in foals or yearlings was also higher than in older age groups, but this difference was not significant. The vaccination status was an important risk factor, with vaccinated horses 0.12 times less likely to die from the disease compared with unvaccinated horses. Young, unvaccinated horses therefore seem to be the most susceptible to the disease I and have greater chances of fatality. This study highlights the importance of adequately protecting horses against African horse sickness by providing immunisation through vaccination and discusses the need to review current vaccination strategies being practiced in Zimbabwe.

The study aimed to determine the prevalence of peste des petits ruminants in the arid zone (Niamey, Tillabéry and Tahoua) of the Republic of Niger. A serological survey was conducted and 519 serum samples were collected from 253 unvaccinated sheep and 266 unvaccinated goats. The sample included 340 female animals (168 sheep and 172 goats) and 160 kids and lambs (78 lambs and 82 kids). A competitive enzyme-linked immunosorbent assay yielded an overall seroprevalence of 45.0%. The prevalence in sheep was 42.0% compared with 47.9% in goats. The seroprevalence observed amongst small ruminants in Tahoua (49.8%) and Tillabéry (46.6%) was significantly higher (p = 0.001) than that observed in animals from Niamey (25.1%). It was also higher (p = 0.04) in sheep younger than two years (51.8%) than in adults (37.6%). Conversely, the seroprevalence showed no significant difference between male animals (35.8% in sheep; 50.1% in goats) and female animals (45.1% in sheep; 46.4% in goats). The prevalence of the disease observed amongst the sheep and goat populations confirms the continued danger of this disease in the areas studied. It is therefore necessary to develop strategies such as improving livestock services, providing effective vaccines and implementing a vaccination programme for an effective control of the disease in sub-Saharan Africa.

The use of haematological techniques to assess fish health is generally accepted. The aim of the current study was to determine selected haematological changes that occur in Clarias gariepinus (Burchell, 1822). infected with trypanosomes. Blood films were prepared according to standard techniques to confirm trypanosome infections and whole blood was collected, the serum and plasma separated, and prepared for albumin and total protein concentration analysis. Plasma albumin levels were significantly higher in infected wild caught fish than in uninfected wild caught fish and uninfected breeding stock. Serum albumin levels were significantly lower in infected wild caught fish when compared to uninfected breeding stock. The total plasma and serum protein levels were within the normal range for C. gariepinus, that is, 3 g - 6 g/100 mL. The total plasma protein levels varied significantly between the three groups. However, the total serum protein levels were only significantly different between uninfected breeding stock and uninfected wild caught fish, as well as uninfected breeding stock and infected wild caught fish. The total protein levels were significantly higher in infected wild caught fish than in the other groups, a possible indication of an infection or inflammatory host response.

The metacercarial (larval) stages of diplostomid digeneans are known to inhabit freshwater fish, causing tissue damage in the process. Due to their widespread diversity, little is known about their life cycle. The classification of these parasitic stages to the species level using only the morphology is very challenging due to the lack of genitalia; they are regarded to be the most important structures in the identification of these organisms. In this study, additional morphological information through light and scanning electron microscopy is given for two different diplostomids found in the cranial cavity of Clarias gariepinus and the vitreous chambers of Tilapia sparrmanii and Pseudocrenilabrus philander. The diplostomid metacercaria inhabiting the cranial cavity of Clarias gariepinus was morphologically identified as Diplostomulum (Tylodelphys) mashonense and an unknown metacercaria of the genus Diplostomum was found in the vitreous chambers of Pseudocrenilabrus philander and Tilapia sparrmanii. Both parasitic species' 28S recombinant deoxyribonucleic acid genomic regions were successfully amplified using Dig 125/1500R primer pairs. The assay yielded a product of approximately 1300 base pairs as seen on the gel images. There were 14 nucleotide differences over the entire analysed sequences resulting in a 1.1% (14/1273) nucleotide difference. In line with the morphological characteristics of these parasites, there seemed to be a slight difference in their genetic makeup. The application of molecular techniques on digenetic trematodes seems very promising and may yield great potential in future descriptions of morphologically similar parasitic species.

Objective-To evaluate the effect of underwater treadmill exercise on static postural sway in horses with experimentally induced carpal joint osteoarthritis under various stance conditions. Animals-16 horses. Procedures-On day 0, osteoarthritis was induced arthroscopically in 1 randomly selected middle carpal joint of each horse. Beginning on day 15, horses were assigned to either underwater or overground (without water) treadmill exercise at the same speed, frequency, and duration. Two serial force platforms were used to collect postural sway data from each horse on study days −7, 14, 42, and 70. Horses were made to stand stationary on the force platforms under 3 stance conditions: normal square stance, base-narrow placement of the thoracic limbs, and removal of visual cues (blindfolded) during a normal square stance. The mean of 3 consecutive, 10-second trials in each condition was calculated and used for analysis. Results-Displacement of the center of pressure differed significantly depending on the stance condition. Among horses exercised on the underwater treadmill, postural stability in both the base-narrow and blindfolded stance conditions improved, compared with findings for horses exercised on the overground treadmill. Horses exercised on the overground treadmill were only successful at maintaining a stable center of pressure during the normal square stance position. Conclusions and Clinical Relevance-Variations in stance position had profound effects on the mechanics of standing balance in horses with experimentally induced carpal joint osteoarthritis. Underwater treadmill exercise significantly improved the horses’ postural stability, which is fundamental in providing evidence-based support for equine aquatic exercise.

This study was carried out to evaluate the diagnosis of acute clinical mastitis (ACM) which was based on the vital signs and complete blood count (CBC) tests in dairy cows. Twenty eight dairy cows diagnosed with ACM, were selected for the study between Jan 2003 and July 2006 in the National Institute of Animal Science. Based on their vital signs (rectal temperature, depression, rumen contraction and, dehydration status), ACM was divided into three different classes; mild, moderate and severe forms. In addition, ACM cows were subjected to CBC tests for further diagnosis of ACM. Of the 27 dairy cows diagnosed with ACM, 3 cows were determined to have a mild form, while moderate and sever forms were each observed in twelve cows. Among of them, 4 cows died, 5 cows were culled and 18 cows were recovered. In the mild form, all haematological parameters were comparable with normal values. However, leukopenia, due to neutropenia and lymphocytopenia, appeared characteristically in the moderate and severe forms. Using the observation of vital signs in conjunction with CBC tests, the diagnosis of ACM is more accurate, and is helpful in making decisions of whether treatment or culling of dairy cows infected with ACM is most appropriate.