The infection of Yankassa rams with three important trypanosome species affecting livestock, namely, Trypanosoma congolense, T. vivaxand T. bruceiproduced both acute and chronic fatal conditions. Chronic infections were induced in the three infections by the application of subcurative doses of diaminazene aceturate (Berenil®). Pathological changes in the infected animals included splenomegaly and hepatomegaly which were more pronounced in acute than in chronic T. congolense infection. However, these changes were more severe in chronic than in acute T. vivax infection. While splenomegaly was more pronounced in chronic T. brucei infection than in acute, hepatomegaly and lymphadenopathy were more severe in acute than in the chronic condition. The increases in size of the spleen, lymph nodes and liver were associated with congestion, increases in cell density related to increased immunological reactions in the spleen and lymph nodes as well as increase in numbers, size and activity of the phagocytic cells in these organs.

A questionnaire survey was carried out to document traditional remedies used in the treatment of cattle wounds and myiasis in Amatola Basin. Eighty-three cattle farmers from nine villages were interviewed. The majority of respondents (67.9 %) use traditional remedies for treatment of these conditions. However, 25.9 % of them use a combination of traditional remedies with conventional medicines. The survey revealed that 13 medicinal plants belonging to 11 families were used. Aloe ferox, Prunus persica and Phytolacca heptandra were, however, the most commonly used. Leaves are the most frequently used plant part, often prepared as an infusion. Other non-plant remedies used include disinfectants, antiseptics as well as diesel and petrol. Manual removal of maggots from wounds was also practise and treatment is usually continued until the wound heals.

The first detailed description of the pathology of tuberculosis, caused by Mycobacterium tuberculosis, in springbok is reported. The springbok were part of a semi-free-ranging herd kept on the grounds of iThemba Laboratory for Accelerator Based Science (LABS) in the Kuils River district of the Western Cape Province, South Africa. Mycobacterium tuberculosis was isolated from three animals out of a total of 33 sampled, with two animals showing tuberculosis lesions. The index case was an adult ewe that showed advanced miliary tuberculosis with marked macroscopic and microscopic lesions in the lungs, pleura and respiratory lymph nodes, and numerous acid-fast bacilli. Six healthy rams were sampled nine months later and a pilot study indicated miliary tuberculosis lesions in one ram, which again were macroscopically most prominent in the lungs, pleura and respiratory lymph nodes. Macroscopic lesions were also noted in the sternal, iliac, prefemoral and retropharyngeal lymph nodes. Microscopy in this animal revealed lesions in the macroscopically affected organs as well as numerous other lymph nodes, and suspected lesions occurred in the testicle and colon. Acid-fast bacilli were scarce to moderate in affected organs. Because of the miliary nature of the lesions in both affected animals, the route of infection could not be established conclusively. The lesions in most affected organs of both animals resembled classical tuberculous granulomas. A main study conducted on healthy animals 19 months after the pilot study failed to find any animal with tuberculosis lesions in the group of 25 sampled, and all were negative for mycobacteria via mycobacterial culture.

Although Theiler became internationally known for his pioneering veterinary research a distant century ago, there are probably few veterinary researchers today who have not heard of him. Onderstepoort, the research institute he created, is equally well, if not even better, known. Moreover, the name Onderstepoort is not only associated with his institute but also with the only South African faculty of veterinary science, another Theiler 'baby'. The purpose of this presentation is to determine why this was so, and to what extent the fame was justified. Was it due to the 'Spirit of Onderstepoort' sometimes referred to by Theiler in the early as well as later stages of his career, or was there perhaps more to it, and what was Theiler's share in the development of that spirit, that fame?

Finding appropriate ways of dealing with the problem of tsetse and trypanosomosis will be an important component of efforts to alleviate poverty in Africa. This article reviews the history of economic analyses of the problem, starting with the use of cost to guide choice of technique for tsetse control in the 1950s, followed by work in the 1970s and 1980s linking these to the impact of the disease on livestock productivity, and in the 1990s to its wider impact. In the current situation, with limited resources and a range of techniques for controlling or eliminating tsetse, the cost implications of choosing one technique or another are important and a recent study reviewed these costs. A novel approach to assessing the potential benefits from removing trypanosomosis by creating 'money maps' showed that high losses from animal trypanosomosis currently occur in areas with high cattle population densities on the margins of the tsetse distribution and where animal traction is an important component of farming systems. Given the importance of the decisions to be made in the next decade, when prioritising and choosing techniques for dealing with tsetse and trypanosomosis, more work needs to be done underpinning such mapping exercises and estimating the true cost and likely impact of planned interventions.

Tsetse-fly and the disease it transmits, trypanosomosis, remain an enormous disease challenge in the 37 countries of sub-Saharan Africa where the impact continues to be manifest in disease burden, increased level of poverty and decreased agricultural productivity. The impact also extends over an estimated 10 million km² (a third of the African continent) of land area, a third of which contains some well-watered part of the continent, thus denying humans and livestock of potentially rich arable and pastureland. The disease is a threat to an estimated 50 million people and 48 million cattle with estimated annual losses in cattle production alone of 1-1.2 billion US$. These losses are due to stock mortality and depressed productivity, which may be of meat, milk, reproduction or traction. Beyond its direct effects on humans and livestock is its impact on African agriculture and the livelihood of the rural population in the affected countries: the fly and the disease influence where people decide to live, how they manage their livestock, and the intensity and the mix of crop agriculture. The combined effects result in changes in land use and environment which may, in turn, affect human welfare and increase the vulnerability of agricultural activity. Trypanosomosis is, therefore, both a public health and an agricultural development constraint. The challenges that the elimination or control of tsetse fly and trypanosomosis pose as well as the opportunities to develop appropriate intervention technologies are discussed in this presentation.

Heartwater is an economically serious tick-borne disease of ruminants caused by the intracellular bacterium Ehrlichia ruminantium. The disease has traditionally been controlled by four different approaches: controlling the tick vector by dipping, establishing endemic stability, performing immunisation by infection and treatment, and preventing the disease by regular administration of prophylactic antibiotics. The first three of these methods are subject to failure for various epidemiological reasons, and serious disease outbreaks can occur. Prophylaxis is effective, but very expensive, and the logistics are daunting when large herds of animals are involved. The development of a safe, cheap and effective vaccine is the only likely way in which heartwater can be economically controlled, and over the past 15 years three new types of experimental vaccine have been developed: inactivated, attenuated, and recombinant vaccines. These new vaccines have shown varying degrees of promise, but none is as yet sufficiently successful to be marketable. We describe the experimental products, and the various technical and biological difficulties which are being encountered, and report on ways in which new technologies are being used to improve vaccine effectiveness.