Research on this economically important disease of ruminants, especially sheep, which had been named bluetongue by farmers in the 19th century, has been part and parcel of the activities at Onderstepoort ever since its establishment in 1908 and therefore covers a full century of the OVI's existence. In view of Onderstepoort's centenary celebration a brief overview of this research is given in terms of the historic milestones which influenced and guided global research on this and other viral diseases of animals.

Investment in disease control should be targeted to critical points that provide the greatest benefit to the livelihoods of livestock-dependent stakeholders. Risk-based targeting should balance the impacts of diseases against the feasibility of their control. This requires sensitive and specific surveillance systems that provide representative overviews of the animal health situation for accurate assessment of disease impact and transmission patterns. Assessment of impact should include household and market effects. The key in surveillance is involving livestock owners using active methods that ensure their disease priorities are addressed. Epidemiological targeting of interventions to critical points in disease transmission cycles should be done to obtain maximal disease reduction. Interventions should be delivered in full partnership with both private and community-based stakeholders to assure high uptake and sustainability. In developing countries, approaches such as participatory disease surveillance and community-based animal health programs have been effective and comply with international animal health standards.

Sir Arnold Theiler's research in 1908/09 led to the discovery of the first rickettsial pathogen, Anaplasma marginale, and set the stage for his development and implementation of an effective live vaccine based on a less virulent strain, A. marginale ss. centrale. His 1910 report, describing A. marginale, is among the classic monographs in infectious disease research, presenting not only observations in exacting detail but also highlighting the deductive reasoning leading to association of a new pathogen with a specific disease. With a centennial perspective and both conceptual frameworks and molecular tools unimaginable in Theiler's time, the significance of several observations in the original report - cyclic bacteremia, strain superinfection, and taxonomic position - is now clear and highlight the broad applicability of key principles of pathogen biology.

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.

Contagious bovine pleuropneumonia (CBPP) or lung sickness, is an insidious pneumonic disease of cattle caused by Mycoplasma mycoides subspecies mycoides small colony variant (MmmSC) and it is one of the major diseases affecting cattle in Africa. With the imminent eradication of rinderpest from Africa (Somali ecosystem) CBPP has become the disease of prime concern in terms of epizootics that affect cattle on the continent. The control and/or eradication of the disease have suffered from unsustained control actions due to lack of operational funds to support such actions and deterioration in the quality of veterinary services in many countries affected by the disease. Stamping out procedures which were adopted by Botswana to control the disease (1995-1997) cannot be carried out by many countries currently affected by CBPP due to the high financial cost, the widespread nature of disease, animal welfare considerations and the potential loss of a valuable genetic resource base. The current scenario of CBPP disease epidemiology in sub-Saharan Africa requires that proactive measures are taken to safeguard countries in southern Africa which are currently free from CBPP from being contaminated by the disease thus affecting the beef industry and people's livelihoods ; and to progressively control the disease in endemic zones of Western and Central Africa.

The studies were carried out on 32 rams of the ossimi breed (270 days of age). Sixteen rams (group 1) received a ration containing 0.2 ppm. Se , and 30 mg vit.E, the other 16 rams (group 2) received 0.5 ppm. Se, and 50 mg vit.E/kg feed mixture .The feeding test was conducted from 270 days until 360 days of age. During the experiment the rams were subjected to live evaluations, i.e. testes circumference, libido level, semen characteristics, as well as selenium concentration and glutathione peroxidase (GSH-Px) activity in blood serum and seminal plasma. Routine macroscopic and microscopic analyses of semen quality were accompanied by measurement of Se content and GSH-Px activity in blood and semen. The Se concentration in blood plasma, seminal fluid and spermatozoa was measured by fluorometric method, while the GSH-Px activity by method based on NADPH - coupled reaction .Comparing the results in animals of both groups , it was clear that the all were in good health conditions as ascertained by clinical examination. No significant variation was detected in body weight of animals of both groups. Significant elevation (p<0.05) in the values of semen conc., semen conc./ ejac , semen motion , sperm motility / ejac.as well as total sperms count were observed in animals of group 2 as compared to those of group 1 .

Forty five, 21-day-old balady chick were used in this experiment. Chicks were divided into three equal groups. The 1st group used as control. The 2nd and 3rd groups were supplemented with lead (Pb) acetate (1500 ppm) in drinking water but the latter group received ration containing 20% barley. Blood samples were collected from the wing vein after 1, 2 and 3 weeks. RBCs count Hb concentration and PCV were significantly decreased in group II during the experimental period. RBCs indices showed a significant decrease in MCH and MCHC in group II after 2 and 3 week of experiment. Leukogram showed heteropenia and moncytopenia. Total protein values showed significant decrease in group II due to decrease in serum albumin level after 2 and 3 week of experiment. Significant increase in activity of liver enzymes AST & ALT and serum uric acid were observed in group II after 3 weeks of experiment. Measurement of serum level of malondialhyde (MDA) revealed a significant increase in group II after 2 weeks of experiment while the total antioxidant capacity (TAO) showed significant decrease in group II after 2 and 3 weeks of experiment. Results of the lead residues in the experimental groups revealed that lead residue in muscle, liver and kidney were rise in group II compared with groups I and III.

Twenty tails of buffaloes were used in this study from apparently healthy adult animals. They are dissected to reveal their arteries and veins. Fourteen photographs illustrated the results in the study. The study revealed that the arterial supply of the tail comes from the median caudal, superficial caudal, deep caudal, dorsolateral caudal arteries and the tail is drained by five caudal veins; median caudal, two ventrolateral caudal and two lateral caudal veins.

Ten tails of buffaloes were used in this study from apparently healthy adult animals. They were dissected to reveal their nerve supply. Eight photographs illustrated the results in the study. The study revealed that there are five pairs of caudal nerves, sympathetic and parasympathetic innervations of the tail are demonstrated.