During the mid 1990s a potentially serious, chronic syndrome was reported in well-managed beef and dairy herds from unrelated parts of South Africa. Farmers reported that it manifested as various combinations of decreased production, decreased weaning masses, apparent immune breakdown in previously immunocompetent animals, increased reproductive disorders, various mineral imbalances in non-deficient areas and goitre, noticeable as enlarged thyroid glands. The farmers associated this syndrome with certain batches of sugar cane molasses and molasses-based products. The syndrome was reminiscent of an "endocrine disruptive syndrome". The objective of this study was to evaluate the suspected endocrine disruptive effect of molasses included in cattle feed. Using existing in vitro assays, four batches of molasses syrup were screened for possible inclusion in a calf feeding trial. Two batches were selected for the trial. Thirty-two, 4- to 6-week-old, weaned Holstein bull calves were included in the single phase, three treatment, parallel design experiment. In two of the groups of calves, two different batches of molasses were included in their rations respectively. The control group was fed a ration to which no molasses was added, but which was balanced for energy and mineral content. The mass gain of the calves was recorded over the 6-month study period. The calves were clinically examined every week and clinical pathology parameters, immune responses and endocrine effects were regularly evaluated. Even though endocrine disrupting effects were detected with the in vitro screening assays, these could not be reproduced in the calves in the experiment. The two batches of molasses utilized in the calf feeding trial did not induce major differences in any of the parameters measured, with the exception of a lower mass gain in one of the molasses-fed groups (Group 1), which tended towards significance. The results of the study indicate that the two batches of molasses had no endocrine disruptive or immunosuppressive effects in calves.

A rapid immunodiagnostic test kit was evaluated against a selection of isolates of lyssavirus genotypes occurring in Africa. The test was carried out in parallel comparison with the fluorescent antibody test (FAT) and isolates representing previously established phylogenetic groups from each genotype were included. The specificity of the rapid immunodiagnostic test compared favourably with the FAT and was found to detect all representatives of genotypes 1, 2, 3 and 4 in brain samples of either field cases or suckling mouse brain inoculates.

In 2007 Nevill, Venter, Meiswinkel & Nevill demonstrated that the pupae of five Culicoides species belonging to the Imicola complex of the subgenus Avaritia could readily be differentiated from one another using various morphological characters. Three of the described species, Culicoides bolitinos Meiswinkel 1989; Culicoides loxodontis Meiswinkel 1992 and Culicoides sp. # 107 (= C. kwagga, Meiswinkel, unpublished thesis 1995), were reared from the dung of large herbivores, which included buffaloes, elephants, white and black rhinoceroses and zebras. However, during that study a further two Avaritia species, neither of which belonged to the Imicola complex, were reared from dung and these are the subject of the present study. For the past 20 years the adults of these two new closely related species have been known as Culicoides sp. # 54 pale form (p.f.) Meiswinkel and Culicoides sp. # 54 dark form (d.f.) Meiswinkel. The taxonomic description and formal naming of the adults of these two species has yet to be done. The present description and comparison of their pupae show that they are two clearly distinct species; that there is no group of morphological characters that can be used to differentiate these two species from the previously described five species of the Imicola complex; and finally that there was no difference between the pupae of C. sp. # 54 d.f. nor C. sp. # 54 p.f. reared from the dung of different host animals.

Different species of trypanosomes may infect their mammalian hosts both singly or in combination. This study was undertaken to determine the trypanosome species that may be afflicting pigs in Uganda. Blood was collected from pigs of all ages and sexes from two districts, Kasese in Western and Jinja in Central Uganda. Of the 133 pig blood samples from Kasese that were tested for trypanosomes using the microhaematocrit centrifugation technique (MHCT), none was found to be infected. However, of the 253 pigs from Jinja district, nine were infected with trypanosomes of which three had T. vivax as determined by MHCT. However, application of the ITS1 rDNA PCR test revealed that eight pigs had T. vivax in mixed infections and one pig had T. vivax monolithic infection. These observations show that under certain circumstances, pigs may be important reservoirs for, as well as hosts to, T. vivax, contrary to earlier reports.

The present study was performed in order to evaluate the effects of lower than usual industry levels of dietary trace minerals on plasma levels, faecal excretion, performance, mortality and morbidity in growing-finishing pigs in a hot African climate. Group 1 (n =100 pigs) received a diet with common industry levels of trace minerals. Group 2 (n =100 pigs) received reduced dietary trace mineral levels but were fed the same basic diet as Group 1. Mortality, morbidity, pig performance and carcass measurements were evaluated. Two pigs in Group 1 and three pigs in Group 2 died. Thirteen pigs in Group 1 and 27 pigs in Group 2 were medically treated (P < 0.05). Carcass masses, back fat depth, loin depth, and lean percent were not significantly different between the groups. However, the carcasses when evaluated revealed a non-significant higher back fat thickness, lower loin eye area and percentage of fat-free lean in barrows compared to gilts within each group. Despite lower initial masses, pigs fed diets containing industry levels of trace minerals were heavier (P < 0.05) and had a higher (P< 0.05) than average daily gains compared to those that received a diet containing lower levels of trace minerals. Faecal zinc excretion was significantly lower (P < 0.05) in pigs fed with lower dietary zinc levels. Copper, manganese and iron excretion were not affected (P &gt; 0.05) by the dietary levels of these trace minerals. Plasma trace mineral concentrations were not affected by the dietary treatment.

The present study was designed to assess and compare three different formulations of the new Onderstepoort infectious coryza (IC) quadrivalent vaccine, which contain an NAD-independent strain of Avibacterium paragallinarum (previously known as Haemophilus paragallinarum), and a commercial IC vaccine, not containing an NAD-independent strain, for their safety and ability to protect chickens of varying ages against virulent challenges with four different serovars of A. paragallinarum, including the NAD-independent strain of the C-3 serovar. Four groups of 140 chickens each were vaccinated at the age of 17 weeks and revaccinated at the age of 19 weeks with each of the four vaccine formulations. A similar sized group of non-vaccinated chickens was used as control. Two rounds of challenge were conducted: a group of chicken in each vaccination group was challenged between 31 and 35 weeks of age, while another group was challenged between 51 and 55 weeks of age. The "in-contact" challenge model was used in this experiment. For each vaccination group, the four challenge strains representing four local serovars were used in each challenge round. The efficacy of the vaccines was compared based on overall protection levels obtained and the duration of protection. The safety of the different vaccines was determined by the severity of post-vaccination reactions. The need for the incorporation of the NAD-independent strain in the vaccine was evidenced by the low protection level against NAD-independent challenge recorded in the group of birds vaccinated with the commercial vaccine. The results obtained confirmed not only the variation in virulence of different South African serovars, with serovar C-3 being the most virulent and serovar B having almost no virulence but also the age related increase in susceptibility. The importance of a suitable formulation of the vaccine is discussed.

When large numbers of crocodile skins were downgraded because of the presence of small pin pricklike holes, collapsed epidermal cysts were found deep in the dermis of juvenile crocodiles while forming cysts were observed in hatchlings. Histopathology of these forming cysts showed the presence of intracytoplasmic inclusions in proliferating and ballooning epidermal cells. Pox virions were seen in electron microscope preparations made from the scabs of such early lesions. The partial sequencing of virus material from scrapings of these lesions and comparison of it with the published sequence of crocodile poxvirus showed the virus associated with the deep lesions to be closely related, but different. To differentiate between the two forms of crocodile pox infection it is suggested that the previously known form should be called "classical crocodile pox" and the newly discovered form "atypical crocodile pox". The application of strict hygiene measures brought about a decline in the percentage of downgraded skins.

The QRS response of the electrocardiogram to bleeding has been a source of interest to the physiologist for more than a century. Studies in the dog, cat and chicken have shown a reduction in QRS amplitude in response to bleeding. This effect has been explained by the so-called Brody effect, in which the intraventricular mass of blood acts as a conducting medium, augmenting radial conduction, thus resulting in the subsequent reduction in QRS amplitude in conditions where the intraventricular mass of blood is reduced. The aim of this study was to evaluate whether the Brody effect will be present in the ovine heart and, furthermore, to evaluate if the right and left ventricles will demonstrate the same QRS change if the Brody effect is indeed present. This study clearly demonstrated that the Brody effect is present in the ovine heart. Furthermore, two unique aspects emanating from this study are firstly the fact that this is the first study to show that premature ventricular complexes are able to induce the Brody effect and, secondly that there is a very clear difference in the response of the right and the left ventricles when the Brody effect is induced in the ovine heart.

The best technical package for the future comprises trypanocidal drugs for temporary relief and the use of insecticide-treated cattle, artificial baits and aerial spraying to attack the vector, to so give more lasting security. Whether this can speed the previously slow progress will depend on overcoming past hindrances to tsetse control: sporadic support, disputes over its desirability, difficulties of sustaining international operations, and poor planning in some instances. The Pan-African Tsetse and Trypanosomiasis Campaign intends to speed the progress but will fail unless it improves its image by breaking its association with the sterile insect technique and quickly executing some cheap and effective operations in large areas. Even then, there could be severe brakes due to Africa's political and financial instability. Overall, the pace of control is likely to increase, but perhaps only a little.