Survey of canine babesiosis in South Africa

A questionnaire, designed to obtain qualitative information on a number of variables concerning canine babesiosis (biliary fever) in South Africa, was sent to 510 veterinary practices in late 1993. Of the 157 practices that responded, all were presented with cases of babesiosis and most were situated in Gauteng, the Western Cape and KwaZulu-Natal. Apart from the Western Cape, a winter-rainfall region, the prevalence of babesiosis cases in dogs was highest in summer. Most of the respondent practices treated between 1,000 and 5,000 sick dogs that included 100 to 500 babesiosis cases each year. Respondents identified cerebral babesiosis, enterorrhagia, 'red' or haemoconcentrated babesiosis, acute renal failure and pulmonary babesiosis or 'shock lung', amongst others, as the most prevalent forms of complicated ('atypical') babesiosis. Diminazene, imidocarb and trypan blue were the most popular antibabesials. Trypan blue was most often used in shocked patients, whereas diminazene and imidocarb were preferred when there was a high parasitaemia in the absence of shock. At least 19 antibabesial treatment regimens were used in practices. These comprised the use of single doses of antibabesial drugs; split doses with repeat injections, and combined drug variations, some of which are undesirable due to possible sterilisation of Babesia infection or potential toxicity. Side-effects were most commonly associated with imidocarb use. Ninety-six percent of respondents used supportive treatment (e.g. corticosteroids, vitamins and 'liver support') in all cases of babesiosis. The use of blood transfusion as supportive treatment varied according to practice and severity of the case. Most practices never cross-matched blood to be transfused, and transfusion reactions were rare. Diminazene was most frequently incriminated in cases where drug 'resistance' or relapses occurred. Cerebral and 'red' cases resulted in high mortality. Treatment of babesiosis costs the dog-owning public in South Africa more than R20 million each year. Information on the distribution and possible complicating role of Ehrlichia canis was obtained. Development of a vaccine was the first research priority identified.     

Campylobacter fetus fetus abortions in vaccinated ewes

AIMS: To investigate the cause of an outbreak of ovine abortion in 1996 in a flock of 300 two-tooth (rising 2-year-old) ewes vaccinated against Campylobacter fetus fetus infection and to subsequently characterise the strain of C. fetus fetus isolated from aborted foetuses. METHODS: Standard bacteriological methods were used to identify C. fetus fetus isolates which were then antigenically typed and subjected to pulsed-field gel electrophoresis (PFGE) and compared to the vaccine strain. RESULTS: C. fetus fetus was identified as the causal agent of the abortions despite the ewes having been vaccinated before ram introduction and at the time of ram removal. Four isolates cultured from aborted material were indistinguishable when compared using antigenic typing and PFGE, but all differed from the vaccine strain. CONCLUSIONS: Within the limitations of the available typing systems, it is proposed that PFGE may be a useful tool to establish the distribution and strain variation of C. fetus fetus. CLINICAL RELEVANCE: This field case indicates the need for further study of non-vaccine C. fetus fetus strains which cause abortion in vaccinated ewes, and of the importance of these strains to the New Zealand sheep industry.     

Husbandry Factors and the Resumption of Luteal Activity in Open and Zero‐Grazed Dairy Cows in Urban and Peri‐Urban Kampala,Uganda

The study investigated the influence of selected husbandry factors on interval to resumption of post‐partum cyclicity among dairy cows in urban and peri‐urban Kampala. A prospective study of 85 day post‐partum period of 59 dairy cows in open (n = 38) and zero grazing (n = 21) systems was conducted on 24 farms. Cows of parity 1–6 were recruited starting 15–30 days post‐partum. Progesterone (P4) content in milk taken at 10–12 day intervals was analysed using ELISA. The cow P4 profiles were classified into ‘normal’ (< 56 days), ‘delayed’ (> 56 days), ‘ceased’ or ‘prolonged’ (if started < 56 days but with abnormal P4 displays) resumption of luteal activity and tested for association with husbandry and cow factors. Of the 59 cows, luteal activity in 81.4% resumed normally and in 18.6%, delayed. Only 23.7% maintained regular luteal activity, while the others had ceased (10.2%), prolonged (37.3%) or unclear luteal activity (20.3%). There were no differences between open and zero‐grazed cows. Milk production was higher (p < 0.05) in zero than open grazing, in urban than peri‐urban and in cows fed on brew waste (p < 0.001) compared with mill products and banana peels. Results suggest that luteal activity resumes normally in a majority of cows, although only a minority experienced continued normal cyclicity once ovulation had occurred, in the two farming systems irrespective of feed supplements or water, and that supplementing with brew waste is beneficial for milk production.     

Adatom pairing structures for Ge on si(100): the initial stage of island formation

With the use of scanning tunneling microscopy, it is shown that germanium atoms adsorbed on the (100) surface of silicon near room temperature form chainlike structures that are tilted from the substrate dimer bond direction and that consist of two-atom units arranged in adjoining substrate troughs. These units are distinctly different from surface dimers. They may provide the link missing in our understanding of the elementary processes in epitaxial film growth: the step between monomer adsorption and the initial formation of two-dimensional growth islands.     

Atomistic Processes in the Early Stages of Thin-Film Growth

Growth of thin films from atoms deposited from the gas phase is intrinsically a nonequilibrium phenomenon governed by a competition between kinetics and thermodynamics. Precise control of the growth and thus of the properties of deposited films becomes possible only after an understanding of this competition is achieved. Here, the atomic nature of the most important kinetic mechanisms of film growth is explored. These mechanisms include adatom diffusion on terraces, along steps, and around island corners; nucleation and dynamics of the stable nucleus; atom attachment to and detachment from terraces and islands; and interlayer mass transport. Ways to manipulate the growth kinetics in order to select a desired growth mode are briefly addressed.     

A national serological survey to verify Australia's freedom from porcine reproductive and respiratory syndrome

Objective To provide serological data to support Australia's claim of freedom from porcine reproductive and respiratory syndrome.
Design A national serological survey was designed to provide 99% confidence of detecting at least one infected pig herd in Australia, assuming that at least 5% of herds would have been exposed to porcine reproductive and respiratory syndrome virus and that at least 25% of the 'finisher' pigs in these herds would have antibodies to the virus.
Procedure A two-stage testing regime was used. All samples were tested with a commercially available enzyme-linked immunosorbent assay. If assay reactions were found, all samples from the herd were to be tested using the indirect immunofluorescence antibody assay.
Results Of the 875 samples from 163 herds from all States in Australia, there was some evidence of reactivity in only four samples from four herds on the enzyme-linked immunosorbent assay. Further testing using the indirect immunofluorescence antibody assay according to the study protocol demonstrated that the reactions were not due to the presence of specific porcine reproductive and respiratory syndrome virus antibodies in the sera.
Conclusion The results of this study support the view that Australian pigs are free of porcine reproductive and respiratory syndrome virus.     

Ovine hepatogenous photosensitivity caused by the plant Nidorella foetida (Thunb.) DC. (Asteraceae)

Following a field outbreak of hepatogenous photosensitivity in sheep, an identical condition was reproduced experimentally by dosing 2 sheep with green, homogenized, Nidorella foetida material, collected from the camp where the outbreak occurred. This is a rare, unpalatable, aromatic shrub found in swampy places in the south-western Cape Province. The main lesion was a hepatosis, characterized by peripheral coagulative necrosis and midzonal degeneration in the 2 acute cases and mild bile duct proliferation and hepatic regeneration in the more chronic field case. Botanical, toxicological, clinical and pathological data are given.