Considerable difficulties are associated with the isolation of Yersinia enterocolitica from food particularly milk and milk products. Most methods are time consuming require enrichment steps and are unable to differentiate pathogenic isolates from non pathogenic ones. The purpose of this study was to evaluate the detection of Yersinia enterocolitica in milk by both polymerase chain reaction (PCR) and conventional culturing methods. Fifty milk samples were collected from Shami goats in North Sinai governorate. Two primers (DG26 and DG63) were used in PCR and the size of the PCR-product was 440bp. The results obtained by PCR technique were in good agreement with that obtained by conventional culturing method. Five samples (10%) were positive by PCR while 4 samples were positive by conventional culturing method. Interestingly, PCR results are obtained within few hours. Moreover, it solved the problem of interpretation of classical biochemical and serological typing in one step without necessity of using additional examinations. This makes diagnosis in food control laboratories much faster and more efficient.

The challenge virus standard (CVS-11) strain of fixed rabies virus was propagated in weaning mice brains and in suckling mice brains. It was also propagated on baby hamster kidney cell line (BHK-21) with use of diethylaminoethyl-dextran (DEAEDextran). These passages were titerated in 3-4 weeks old white Swiss mice using mouse inoculation test (MIT). The virus harvest was concentrated using zinc acetate method , inactivated by beta-propiolactone (BPL) and adjuvanted with combination of vitamin E and selenium. The prepared adjuvanted inactivated tissue culture rabies vaccine was subjected to quality control tests as safety, sterility and potency using National Institute of Health (NIH) test against reference vaccine.

Peroxidase labeled immunoglobulins to camelpox virus (CPV) were prepared for use in various techniques of ELISA. Ten rabbits and three goats were inoculated with a mixture of camelpox virusand Freund’s adjuvant. Sera were pooled separately on the 10th day post the last inoculation and immunoglobulins were precipitated using saturated ammonium sulphate. The globulins were 2.8 g/dl and 2.5 g/dl for rabbits and goats respectively and used for peroxidase conjugation. The peroxidase labeled immunoglobulins were titrated and evaluated using direct solid phase ELISA, double antibody sandwich ELISA and dot immunoblot ELISA. The prepared conjugates gave specific and clear positive reactions till the dilution of 2000 and 1500 for rabbits and goats immunoglobulins respectively. The prepared labeled immunoglobulins could be successfully used in detection of camel pox viral antigen of local virulent and standard vaccinal strain of the virus using various ELISA techniques.

Poisoning with cardiac glycoside-containing plants is collectively the most important plant-associated poisoning of livestock in southern Africa. As a diagnosis of this significant poisoning is currently based on circumstantial evidence, a practical chemical procedure indicating the presence of cardiac glycosides in plants and animal specimens would be of considerable benefit. The fluorescence polarization immunoassay (FPIA) method, used to determine digoxin plasma levels in humans and dogs, was adapted to estimate cardiac glycoside levels in known cardiac-glycoside- containing plants as well as in the rumen and organs of dosed sheep. Positive FPIA values were obtained with bufadienolide-containing plants, while negative results were obtained with plants not known to contain cardiac glycosides. The FPIA has aided in the diagnosis of cardiac glycoside poisoning in livestock and game in 30 outbreaks examined at the Division of Toxicology, Onderstepoort Veterinary Institute. Each outbreak is briefly described. As a result of this assay, a better understanding of cardiac glycoside poisoning has been reached.

Psittacine beak and feather disease (PBFD) is a common viral disease of wild and captive psittacine birds characterized by symmetric feather loss and beak deformities. The causative agent, beak and feather disease virus (BFDV), is a small, circular single-stranded DNA virus that belongs to the genus Circovirus. BFDV can be detected by PCR or the use of haemagglutination (HA) and haemagglutination inhibition (HI) assays that detect antigen and antibodies respectively. Erythrocytes from a limited number of psittacine species of Australian origin can be used in these tests. In South Africa, the high cost of these birds makes them difficult to obtain for experimental purposes. Investigation into the use of erythrocytes from African Grey parrots and Brown-headed parrots yielded positive results showing the haemagglutinating activity of their erythrocytes with purified BFDV obtained from confirmed clinical cases of the disease. The HA activity was further confirmed by the demonstration of HI using BFDV antiserum from three different African Grey parrots previously exposed to the virus and not showing clinical signs of the disease.

Seasonal surveys were conducted at the Vaal Dam between April 2000 and January 2001. Twenty smallmouth yellowfish (Labeobarbus aeneus) and 20 largemouth yellowfish (Labeobarbus kimberleyensis) were collected with the aid of gill nets. Surface water quality variables were included. The cestodes were identified as either Bothriocephalus acheilognathi Yamaguti, 1934 or "other cestode spp.". The majority (99.8 %) of the cestodes found in both yellowfish species were identified as B. acheilognathi (Asian tapeworm). The prevalence, mean intensity and abundance of B. acheilognathi in both yellowfish species were calculated. Ecological parameters including species specificity, seasonality, gender specificity and relationships between fish size and the Asian tapeworm prevalence were also included. In this study, B. acheilognathi preferred L. kimberleyensis over L. aeneus although a low intensity was observed in smallmouth yellowfish. Furthermore, the infection (in terms of prevalence, abundance and mean intensity) in largemouth yellowfish was markedly higher. Seasonal patterns observed in the Asian tapeworm's infection of smallmouth yellowfish are attributed to breeding and subsequent feeding patterns of this fish species with relatively high infections recorded in winter and spring. For L. kimberleyensis no explanation can be given regarding the seasonal patterns observed for the mean intensity and abundance of B. acheilognathi. The maximum and minimum mean intensity and abundance values in largemouth yellowfish were recorded in autumn and spring, respectively. In addition, the prevalence of B. acheilognathi was consistently high in all four seasons.

Ingestion of the plant Nolletia gariepina was confirmed as the cause of acute mortalities in cattle in the Kuruman area of the Northern Cape Province of South Africa. The aim of this trial was to investigate the toxic effects of this plant with respect to clinical signs, pathophysiology and pathology using the sheep as a model. At dosages of 1.5 g dried, milled plant material/kg body mass there were no detectable abnormal findings, while at dosages of 2.8-3.0 g/kg most of the animals died acutely. In subacutely affected sheep, depression, inappetance, teeth grinding, tachycardia, weak ruminal movements and recumbency were noticed. The most prominent pathophysiological changes observed, included a sharp rise in non-protein nitrogen substances in the plasma, remarkable decline in glomerular filtration rate, increase in sodium and potassium excretion, and a rise in urine gamma glutamyltransferase activity. Macroscopically a severe nephrosis was present in all the animals. The most important findings detected histologically were necrosis of the proximal convoluted tubular epithelium and large numbers of protein casts in the lumens.

Resistance to trypanocidal drugs has been detected in various African countries and is a serious impediment to the control of livestock trypanosomosis. To determine whether drug resistant trypanosome strains are present in the Zambézia Province of Mozambique a study was initiated. To assess the effect of the farming system and the drug-use regimen on the development of drug resistance, trypanosome isolates were collected from cattle from subsistence and commercial livestock production systems. The susceptibility of seven isolates against isometamidium chloride, diminazene aceturate and homidium chloride was tested in mice using a multiple-dose test. In four of the seven isolates high levels of drug resistance to diminazene aceturate and isometamidium chloride were detected. In most cases the observed levels of drug resistance correlated with the drug-use practices in the particular livestock production system.

In an assessment of cell mediated immunity against Salmonefl g_'p_h_i antigen in Guinea pigs following their intraperitoneal injection with sensitized spleen cells. The results were revealed a high level of cell mediated immunity against Salmonella typh_i_ antigen in the Guinea pigs intraperitonealy received the sensitized spleen cells (5x1 08/1111). The level of cell mediated immunity was detected using delayed type hypersensitivity test. Macrophages migration inhibition test and Erythrocytes rosette test. The nonnal (nonsensitized) spleen cell recipient group (control group) was showed no level ofcell mediated immunity using these tests.

A case control study was conducted in Busrah at the period from March to September 2002 . The population included in this study was divided into two groups . The first group was included patents with G6pD deficiency and the second group was included normal individuals as a control group . Stool samples were collected from both groups for bacteriological e.'amination . This study revealed that ; there was an association between G6pD deficiency and Salmonella typhi carrier state and this association was statistically significant in urban rather than rural area .