Nasopharyngeal swabs and pnuemonic lung autopsies collected from diseased or slaughtered sheep and goats suffering from respiratory manifestation were subjected to microbiological sreening. In addition, serum samples were collected from all animals were investigated. P. hemolytica was the most prevalent recovered bacterial isolates followed by S. aureus and E. coli. On the other hand, Aspergillus fumigatus was the most prevalent fungus. Aspergillus species and Candida albicans were also isolated. Most of the isolated bacterial strains were found sensitive to spectrama and chloramphenicol. Serodiagnosis of P. hemolytica by ELISA using the whole cell antigen gave positive results in 18.3 and 22.5% of diseased sheep and goats respectively and 52% and 42.1% of slaughtered pneumonic sheep and goats respectively. Also serodiagnosis of Aspergillus fumigatus by indirect haemagglutination test revealed positive results in18.3and 17.5% of diseased sheep and goats respectively and 24% and 21% in sera of slaughtered pneumonic sheep and goats respectively. Histopathological changes due to P. haemolytica and Aspergillus fumigatus were recorded.

The taxonomic status of some nippostrongyline nematodes deposited in the National Collection ofAnimal Helminths, Onderstepoort, is revised. Heligmonina boomkeri n. sp. is described from Aethomys chrysophilus from South Africa. The most closely related species by the body measurementsand the pattern of the caudal bursa is Heligmonina bignonensis Diouf, Bâ & Durette-Desset, 1997, a parasite of Mastomys erythroleucus from Senegal. It differs from the new species mainly in thenumber of ventral cuticular ridges at mid-body (four versus five) and the left ala in the male is shorterthan the body diameter. The systematic position of Heligmonina spira (Ortlepp, 1939) and Neoheligmonella capensis (Ortlepp, 1939) is confirmed here through their synlophe, which was not previously studied.

A wild strain of Eimeria tenella was isolated and utilized for immunization studies. Its optimal sporulation was attained at room temperature 24-25 °C after 24-48 h. Two groups of chicks were immunized by dosing a graded dose of five oocysts/chick/day for 6 days followed by 50 oocysts/chick/day for 7 days. A third group was not immunized and served as a negative control. Immunized chicks gained mass at the same rate as unimmunized ones, but when challenged with 200 000 oocysts/chick, mass gains declined in the unimmunized group. The growth rate of immunized chicks was not affected by challenge (P > 0.05). Upon challenge, unimmunized chicks produced significantly more oocysts than immunized chicks (P < 0.005). Immunized chicks withstood a challenged with 200 000 oocysts/chick without developing any clinical signs whereas the unimmunized chicks developed typical clinical signs of coccidiosis. Unimmunized chicks had significantly more severe lesions in the caecum than any other group (P > 0.005) and also produced significantly more oocysts than any other group (P > 0.005).

During December/January 1996/97 typical summer syndrome (hyperthermia and a 30 % drop in milk yield) occurred in succession in two Holstein dairy herds (n = 240 and n = 150 milking cows, respectively) on the South African Highveld. These farms are situated in the midst of the prime maize and dairy farming areas of South Africa where this condition had never been diagnosed before. The individual components of the concentrate on both farms were negative for ergot alkaloids. Endophytic fungi and/or ergot infestation of teff and other grasses fed to the cows were then suspected of being involved, but neither endophytes nor ergot alkaloids could be implicated from these sources. By measuring the serum prolactin levels of groups of sheep (n = 5) fed the first farm's total mixed ration (TMR) or its three individual fibre components for a period of 11 days, the source of the ergot alkaloids was identified. A statistically significant decrease in the level of this hormone occurred only in the group on maize silage (which constituted 28 % on dry matter base of the TMR). The involvement of the maize silage was further chemically confirmed by the high levels of total ergot alkaloids, predominantly ergocryptine, found by LC-MS in the silage as well as in the TMR (115-975 ppb and 65-300 ppb, respectively). The ergot alkaloid content (mainly ergocryptine) of the maize silage on the second affected farm was 875 ppb. Withdrawal of contaminated silage resulted in gradual recovery of stock on both farms. Nut sedge (Cyperus esculentus and Cyperus rotundus of the family Cyperaceae) has a world-wide distribution and is a common weed in annual crops, and can be parasitized by Claviceps cyperi. Careful examination of the maize silage from both farms revealed that it was heavily contaminated with nut sedge and that it contained minute sclerotia, identified as those of Claviceps cyperi, originating from the latter. Nut sedge was abundant on both farms and it is believed that late seasonal rain had resulted in mature, heavily ergotised nut sedge being cut with the silage. Claviceps cyperi sclerotia, collected on the affected fields in the following autumn contained 3 600-4 000 ppm ergocryptine. That the dominant alkaloid produced by this particular fungus was indeed ergocryptine, was confirmed by negative ion chemical ionization MS/MS. In one further outbreak in another Holstein herd, teff hay contaminated with ergotised nut sedge and containing 1 200 ppb alkaloids, was incriminated as the cause of the condition. This is the first report of bovine ergotism not associated with the Poaceae infected with Claviceps purpureum or endophytes but with the family Cyperaceae and this particular fungal phytopathogen.

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.

Merino sheep in Thornveld, Dorper sheep and Angora goats in inland Valley Bushveld, Angora goats and Boer goats in Valley Bushveld on the coastal plateau, and springbok, Antidorcas marsupialis, and black wildebeest, Connochaetes gnou, in Karroid Mountainveld, all in the Eastern Cape Province, were examined for the larvae of nasal bot flies. The sheep and goats were infested with the larvae of Oestrus ovis, and Dorper sheep and Boer goats harboured more larvae than Angora goats on the same farms. Most infestation was present from November to May in Merino sheep in Thornveld, from February to June in Dorper sheep in inland Valley Bushveld, and from May to September in Angora and Boer goats in Valley Bushveld on the coastal plateau. These patterns of seasonality appeared to be regulated by the severity of the summer temperatures at the various localities. The springbok were infested with the larvae of Rhinoestrus antidorcitis, most of which seemed to mature from June to August. All larval sages of Oestrus variolosus and Gedoelstia hässleri were present in the black wildebeest, and large numbers of 1st instar larvae of G. hässleri appeared to accumulate on the dura of the wildebeest from June to August.

Two hundred and twenty-five small mammals belonging to 16 species were examined for ticks in Free State, Mpumalanga and Limpopo Provinces, South Africa, and 18 ixodid tick species, of which two could only be identified to genus level, were recovered. Scrub hares, Lepus saxatilis, and Cape hares, Lepus capensis, harboured the largest number of tick species. In Free State Province Namaqua rock mice, Aethomys namaquensis, and four-striped grass mice, Rhabdomys pumilio, were good hosts of the immature stages of Haemaphysalis leachi and Rhipicephalus gertrudae, while in Mpumalanga and Limpopo Provinces red veld rats, Aethomys chrysophilus, Namaqua rock mice and Natal multimammate mice, Mastomys natalensis were good hosts of H. leachi and Rhipicephalus simus. Haemaphysalis leachi was the only tick recovered from animals in all three provinces.

Forty-eight pathogen free New Zealand rabbits were divided into two groups, the first group contained eighteen rabbits served as normal control and the second group of thirty rabbits were received 1 ml bovine herpesvirus-1 (BHV-1) virus suspension (107 TCID 50) by intraperitoneal route. Rabbits both groups were subjected to hematological, serum biochemical, different serological and histopathological examination 3,7,10,14,21 and 28 days post infection. Clinical observation of infected rabbits showed febrile response and mild conjunctivitis after 24 and 48h. of inoculation, respectively. The hemogram revealed no significant alteration in the erythrogram while leucogram showed leucocytosis accompanied with heterophilia, lymphopenia and monocytopenia at the 3rd and 7th days post infection. Serum biochemical analysis showed significant elevation in the activity of AST, ALT and AP and in blood urea nitrogen and creatinine concentration along the experimental period. Serum total proteins, albumin, :, ; and < globulin significantly increased at different periods of the experiment. BHV-1 antibodies were detected in the sera of infected rabbits by Dot ELISA and ELISA from the first week until the forth week post infection. Histopathological examination revealed that the most affected organs were the trachea, lungs and liver while adrenals, kidneys, and spleen showed mild pathological alterations.

Samples from medial retropharyngeal, superficial cervical and deep femoral lymph nodes of four camels were fixed in neutral buffered formalin and prepared for light and electron microscopic examination. The camel lymph nodes were formed of stroma and parenchyma. A dense collagenous capsule and trabeculae beside fine reticular framework represented the stroma. The parenchyma was formed of follicular and non-follicular forms of lymphoreticular tissue. The lymphoid follicles were mainly secondary in nature formed of germinal center and outer corona. Afferent and efferent lymph vessels were noticed at the same area of the capsule. Capsular, subcapsular, trabecular, peritrabecular and parenchymal lymph sinuses were noticed in camel lymph nodes.

Fifteen outbreaks with clinical picture and post- mortem lesions similar to that of rabbit haemorrhagic viral disease (RHVD) were investigated in vaccinated flocks during the period between February and July 2005 at Kafr El-Sheikh Governorate. Twelve representative liver homogenate were positive in haemagglutination test (HA) using human type (O) washed RBCs, with titer more than 1/160. Detection of virus particles by electron microscopy, histopathological findings as well as pathogenicity test , confirmed that the outbreaks were RHVD. The possible role of field rats for the transmission and spread of RHVD among rabbitaries was studied. Cross reactivity and cross protection tests were conducted. These tests proved that the newly emerged RHVD isolates were not closely related to classical local vaccinal strain of RHVD and may be a variant strain.