Bolo disease: a specific, localised skin disease of woolled sheep.

Bolo disease is limited to Merino and Döhne merino sheep in the Stutterheim and Cathcart districts of the eastern Cape Province. It occurs under natural grazing conditions regardless of the season of the year and the condition of the natural grazing. Ewes and wethers are most frequently affected. Skin lesions are well-defined, and the corresponding fleece has dark-grey to almost black spots, patches or bands varying in number, size and distribution between individual sheep. The wool in the affected areas is visibly shorter, less dense and tender, and the tips of the staples are spiky. In freshly-shorn sheep, the affected areas appear chalky white. Chronic and superimposed acute lesions are present in the same specimen histologically. Skin lesions include superficial and follicular hyperkeratosis, acanthosis, and sebaceous gland hyperplasia and hypertrophy. These changes are accompanied by dilatation of some of the follicles in the midshaft area, and collapse of the subepidermal tissue with only a few remaining collagen fibres separating the follicles and the sebaceous glands from the thickened epidermis. Corynebacterium spp. is the most consistent bacterium isolated from the lesions. Lesions produced by suspensions of this organism simulated both clinical signs and histopathological findings of the natural condition.

Bolo disease: a bacteriological survey.

A total of 718 sheep, 381 severely and 190 mildly affected with Bolo disease as well as 147 visibly unaffected animals emanating from 15 farms in the Stutterheim and Cathcart districts in the eastern Cape were subjected to bacteriological examination of skin surfaces and wool specimens. Altogether, 1,168 specimens were examined. These included skin swabs, skin scrapings and wool samples. Corynebacterium spp represented 94.4% of the primary isolates in cultures prepared from all specimens and 97.2% in those derived from skin swabs only, while a variety of other bacteria collectively constituted the remainder of primary isolates. In all, Corynebacterium spp was isolated from specimens of 94.2% of sheep severely affected with Bolo disease and from 83.7% of those mildly affected, whereas it could only be isolated from 1.36% clinically unaffected sheep. In a comparative study, swabs taken directly from the skin surface, proved to be the method of choice for the collection of specimens for bacteriological examination of Bolo disease. Using this method, Corynebacterium spp. was isolated from 98.7% of severely, and 85.3% of mildly affected sheep as well as 4% of sheep apparently unaffected by Bolo disease. The isolation of Corynebacterium spp. from skin scrapings collected from the 3 categories of affection (73.3%, 57.3% and 4% respectively) and from wool samples (52%, 41.3% and 1.3% respectively) proved these 2 methods of sampling to be less reliable. A close association has been established between the incidence of Corynebacterium spp. and the occurrence of clinical Bolo disease.

Arthropod-borne virus zoonosis surveillance in the Cape Province: 1. Prospective serological investigations for virus activity in the Beaufort West and Middelburg Districts during 1981.

In addition to the routine sero-epidemiological surveillance for arthropod-borne viral zoonoses in the Cape Province carried out by the Department of Medical Microbiology and State Health Department of Virology laboratory, we conducted a prospective serological investigation for virus activity during 1981 in two districts of the Province, namely the Beaufort West and Middelburg districts, which experienced heavy rainfall during the first two months of that year. The approach used was to obtain paired serum samples from identified domestic stock representative of several species from 2-5 months apart and to test them for haemagglutination inhibition antibodies to Rift Valley fever, Wesselsbron and Middelburg virus antigen preparations in order to ascertain, as an indication of viral activity, whether changes in antibody levels occurred between the collection dates. The results indicated that there was probable activity of Rift Valley fever virus and activity of Wesselsbron virus (or related flaviviruses) and Middelburg virus (or related alphaviruses) in the Karoo between the middle of February and the end of July 1981. Despite this activity and heavy rainfall registered at meteorological stations in both the Beaufort West and Middelburg districts as well as general reports of heavy rainfall and considerable mosquito activity over widespread areas of the Karoo, Eastern and S.W. Cape Province, there were no epizootics or epidemics of overt arthropod-borne zoonotic viral disease in the province during 1981.

A report on the consumption, composition and nutritional adequacy of a mixture of lush green perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata) fed ad libitum to Thoroughbred mares.

Non-pregnant Thoroughbred mares were stabled and subjected to 2 trials, each 24 h in duration, to establish their total consumption of a mixture of freshly cut, lush green perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata) in approximately equal proportions; and to compare the total intake of crude protein, calcium, phosphorus and mass of the grass mixture on a dry matter basis with their daily nutritional requirements. The body mass of each mare was calculated at the commencement of each trial. In the first trial 2 lactating mares with foals at foot, 65 days and 8 days of age, and one mature non-lactating mare, consumed 75,5 kg, 61,0 kg and 39,5 kg of the grass mixture, cut in the early vegetative stage, respectively. The perennial ryegrasss (L. perenne) contained 79,63% moisture, 1,67% crude protein, 0,75% calcium, 0.057% phosphorus and 20.37% dry matter. The cocksfoot (D. glomerata) contained 79,52% moisture, 2,27% crude protein, 0,051% calcium, 0,061% phosphorus and 20,48% dry matter. The younger foal did not eat the grass mixture. The mass of grass mixture consumed by the older foal was not determined. In the second trial conducted 3 weeks later, when oat straw (Avena sativa) was also fed ad lib itum, the same lactating mares, but a different mature non-lactating mare, consumed 54.5 kg, 56.0 kg and 40.5 kg of the grass mixture, cut in the mid bloom stage, respectively. The perennial ryegrass (L. perenne) contained 70,03% moisture, 2,37% crude protein, 0,086% calcium 0,068% phosphorus and 29,97 dry matter.(ABSTRACT TRUNCATED AT 250 WORDS)

Cretinism in Angora goats.

An outbreak of goitre and hypothyroidism in newborn Angora kids is described. the does had been grazing on lucerne from the time of mating and received a free-choice lick, which included iodine. Investigations revealed that the condition was iodine-responsive, and was probably caused by a goitrogen like thiocyanate.

Actinobacillus seminis infection in sheep in the Republic of South Africa. III. Growth and cultural characteristics of A. seminis.

Bacteriological tests were done on a large number of different strains of Actinobacillus seminis and also, repeatedly, on the same culture or on different cultures taken periodically from the same donor animal. These tests were also applied to strains of A. seminis representing different serological types, which in turn were compared with strains of Brucella ovis. The tests as applied proved that A. seminis strains have defined, morphological, staining, cultural and biochemical properties, although they can generally be regarded as biochemically inactive. Growth was greatly enhanced on media enriched with blood or serum and also more luxuriant when incubated in a carboxophilic atmosphere. Nitrate reduction was found to be a variable characteristic, as it was more often negative, while weakly positive and negative reactions for hydrogen sulphide production were encountered with equal frequency. On the basis of their bacteriological properties, the strains representing the different serological types can be divided into 2 groups. Strains belonging to the first of these groups conform to the earlier description of A. seminis by Baynes & Simmons (1960) and are usually catalase positive and oxidase negative, while those in the second group more closely resemble Histophilus ovis described by Roberts (1956), and produce variable reactions on the catalase and oxidase tests. Although growth did occur aerobically and was more luxuriant in a carboxyophilic atmosphere in all strains, it was always much slower for strains resembling H. ovis. Similarly, the growth produced by these strains was poorer and more irregular on ordinary nutrient media and, although greatly enhanced and more regular in all strains on enriched media, it was again much slower for these strains. In all stages of development, the colonies of strains similar to H. ovis were always slower and more transparent in appearance, and tended to remain low convex and undifferentiated. Packed organisms of these strains were light yellow (lemon) in colour in contrast to strains resembling A. seminis, which had a greyish-white appearance. A. seminis and B. ovis can clearly be distinguished on their morphology, Stamp staining reaction on both semen and culture smears, colonial morphology, the delayed colony development of B. ovis and sensitivity to dyes and antibiotics.

Actinobacillus seminis infection in sheep in the Republic of South Africa. I. Identification of the problem.

A clinical palpation and semen smear examination of 647 rams submitted to the Regional Veterinary Laboratory during 1967 revealed that 42 (6,5%) of these animals had clinical epididymitis or orchitis, 6 (0,9%) showed other types of genital lesions and 98 (15,1%) suffered from subclinical genital infection. A. seminis and A. seminis-like organisms were isolated from semen specimens of 18 out of 35 rams with clinical epididymitis or orchitis, 25 out of 33 rams with subclinical infection and none out of 13 rams which showed no neutrophils in their semen. On 4 stud farms where Elberg Rev. 1 vaccine was meticulously applied and the complete absence of Brucella ovis infection was established, of a total of 327 rams examined, 10 (3,6%) were found to be clinically and 72 (22,0%) subclinically affected. A. seminis was isolated from 5 out of 6 of these rams with clinical lesions and 10 out of 15 of those which showed evidence of subclinical infection.

Actinobacillus seminis infection in sheep in the Republic of South Africa. II. Incidence and geographical distribution.

To obtain information on the incidence and distribution of Actinobacillus seminis infection in the Republic of South Africa, a clinical and serological survey was carried out on 409 farms situated in 29 districts. All rams submitted for certification to the Regional Laboratory from 1/1/69 to 31/1/74 were included in a separate investigation. These particular rams represented different breeds and originated from farms in over 48 districts. Examinations were also carried out on all rams on 11 stud farms in the Middelburg and adjacent districts with a high incidence of epididymitis, despite regular immunization with Elberg Rev. 1 vaccine. These investigations confirmed that genital infection of rams still presents a major problem in the main sheep breeds and the main sheep farming areas of South Africa. A high incidence of infection with A. seminis, an organism which appear to be the most important one associated with genital infection in this country, was also established. Genital infection due to A. seminis is geographically also very widespread.

Geeldikkop: preservation of toxic material.

Wilted Tribulus terrestris plants were harvested from a camp in which geeldikkop had just previously broken out. The plants were treated in various ways in an attempt to preserve their toxicity. The only successful method of preservation found was rapid freezing of harvested material. Three kg of plants were kept frozen for six weeks and then dosed via rumen fistula to a sheep which subsequently developed characteristic symptoms and lesions of geeldikkop.

Discolouration of wool: 1 green discolouration.

Since 1974 green bacterial discolouration of Merino wool was frequently encountered in the Karoo and Eastern Cape areas. The occurrence of this condition coincided with the extraordinary wet conditions that prevailed during this period. Pseudomonas aeruginosa was recovered in almost pure culture from affected wool of 24 out of 25 different sheep. The role played by this particular organism was fonfirmed by the successful reproduction of this condition after exposure of unaffected sheep to cultures of Ps. aeruginosa isolated from green wool.

An outbreak of diphtheria in Boergoat kids.

During an outbreak of diphtheria or ulcerative stomatitis in young Boergoat kids Fusobacterium necrophorum was consistently isolated under anaerobic cultural conditions from material taken from the edges of the ulcerative lesions from all of the cases examined. Corynebacterium pyogenes, Staphylococcus aureus, Actinobacillus lignieresi, Moraxella spp. and Lactobacillus spp. were also isolated anaerobically and/or aerobically. The typical symptoms and lesions were confirmed to the mouth, tongue and throat regions.