Bovine farcy: a clinico-pathological study of the disease and its aetiological agent.

An extensive survey for bovine farcy covering 14,192 animals was conducted in the Sudan. The incidence of the disease was 31.9 per cent in Western Sudan which is regarded as an endemic area. Animals were examined clinically and at post-mortem. The lesions involved the prescapular, femoral, parotid, retropharyngeal, submaxillary, inguinal and mediastinal lymph nodes. Some animals had farcy lesions in the udder and some developed the pulmonary form of the disease. The disease is slow, but progressive in nature and was more prevalent among adult cattle than calves. Mycobacterium farcinogenes was found to be the cause of bovine farcy in the Sudan. The morphological and biochemical characteristics, and the mycolic acid content of the isolated strains were found to be identical to the reference strains of M. farcinogenes and were quite different from reference strains of Nocardia farcinica from which they were easily distinguished by the presence of alpha-mycolate, alpha'-mycolate and epoxymycolate in M. farcinogenes. Hydrolysis of mycolic acids with tetrabutylammonium hydroxide and the precipitation with toluene and acetonitrile gave good results comparable with acid methonalysis and alkaline hydrolysis. Precipitin lines were detected in the sera of some farcy-infected cattle. Histopathological examination of farcy lesions revealed a severe granulomatous reaction characterized by lymphocyte, macrophage, epithelioid and giant cell infiltration as well as marked fibrous proliferation. These changes were indicative of a progressive disease of the delayed tuberculin hypersensitivity type.

First report of infectious necrotic hepatitis (black disease) among Nubian goats in Sudan.

In a flock of 425 female and male Nubian goats in the Khartoum Province, an outbreak of a disease causing sudden death of 18 apparently healthy goats occurred (11 females and 7 males, 3-6 years old). Adult Fasciola gigantica were found in the livers of all goats and in seven of them Cysticercus tenuicollis cysts. These organs showed necrotic and severe histopathological changes. Clostridium novyi type B was isolated from necrotic areas of all livers and found to be highly pathogenic and toxigenic to laboratory animals. The disease was diagnosed as infectious necrotic hepatitis (black disease). Faecal examination revealed the presence of F. gigantica eggs. Lymnaea natalensis snails were found to be prevalent in the water canals. As the Khartoum Province is regarded as an endemic area for black disease, routine vaccination is highly recommended for its control in goats and sheep.

Cutaneous habronemiasis in horses and domestic donkeys (Equus asinus asinus).

Cutaneous habronemiasis in 15 horses and 5 donkeys is described. The lesions were distributed in many parts of the body involving the medial canthus, shoulder and pectoral regions, knee and fetlock joints, abdominal wall and prepuce. Some animals had more than one lesion. The lesions were ulcerative and filled with soft light red granulation tissue. When curretted, the deeper layers revealed a dense fibrous tissue with calcified foci. Close examination of the lesions showed that the superficial layer of this dense fibrous tissue contained small caseated and necrotic foci. The same features prevailed in lesions involving the muscular areas, but the deeper layers consisted of a dense granuloma with no evidence of cicatrization. Curretted material digested in potassium hydroxide revealed fragments of larvae of the nematode suggestive of Draschia or Habronema. The histopathological changes were severe and comprised: necrotic foci in a dense fibrous stroma infiltrated with eosinophils, macrophages and few giant cells. Sections of the larvae surrounded by eosinophils were encountered in lesions of the muscular areas. Curretting and excision of the lesion were effective and produced complete healing of the wound by scar tissue formation.

Studies on gangrenous mastitis in goats.

One hundred and fifty goats were diagnosed as having proven gangrenous mastitis. The disease was categorized into early, intermediate and late stages. Gangrenous mastitis in goats is typified by a sudden onset, dark hyperemia, and edema with progressive discoloration of the distal part of the udder. The disease affected lactating goats but not the dry ones. Coagulase positive Staphylococcus aureus was isolated from 60% of composite and half milk samples obtained from the diseased goats. The histopathological changes mainly comprised proliferation of connective tissue, thrombosis and necrosis involving a group of lobules. Treatment of the early and intermediate stages of the disease was successful through the administration of systemic and intramammary terramycin together with diuretics and topical antiseptic cream. The late stage of the disease was successfully treated only through surgery.

Experimental transmission of a goat strain of Sarcoptes scabiei to desert sheep and its treatment with ivermectin.

Desert sheep were experimentally infected with a goat strain of Sarcoptes scabiei, proving that this mite is not completely host specific. More severe lesions were produced on sheep when the mites were applied to lacerated than when applied to scarified or non-scarified areas. Lesions were more pronounced on moistened areas than dry areas and lesions produced on dry scarified areas resembled those produced on non-scarified moistened ones. Skin scrapings from the experimental lesions in the sheep contained numerous mites of all stages, proving the goat mites had become well established and were reproducing actively in the experimental lesions. Severe histopathological changes were observed in skin sections, comprising mainly thick crust formation, mites beneath the keratin and severe degenerative and necrotic changes. Treatment of sheep with ivermectin at a dose rate of 200 micrograms kg-1 body weight produced rapid and excellent cure.

Experimental infection of the one-humped camel (Camelus dromedarius) with Sarcoptes scabiei var. cameli and S. scabiei var. ovis.

Camels were experimentally infected with Sarcoptes scabiei var. cameli and S. scabiei var. ovis. The lesions produced by both mites were progressive and similar in extent and severity. The lesions produced by the mites spread mechanically through gnawing and scratching, and eventually covered most of the body of the host. Skin scrapings from the experimental lesions contained many mites of all stages, proving that S. scabiei var. cameli and S. scabiei var. ovis became equally well established, reproducing actively in the experimental lesions in their 'natural' and 'wrong' host respectively. The histopathological changes produced by S. scabiei var. cameli and S. scabiei var. ovis were similar. The lesions comprised thick scab and keratin formation, with mites beneath the scab and keratin, marked haemorrhages and severe degenerative and necrotic changes. Excellent clinical recovery occurred following the application of HCH (BHC) after removal of crusts and detritus with salicylic acid. The incomplete host specificity of Sarcoptes necessitates the complete isolation of healthy from infected animals regardless of the host species.

The effect of niclofolan on desert sheep experimentally infected with immature Fasciola gigantica.

Eight desert sheep were each infected orally with 500 metacercariae of Fasciola gigantica and, after 4 weeks, four of the animals were given niclofolan orally at the recommended therapeutic dose rate of 7 mg/kg, the other four remaining as controls. One week later, the animals were slaughtered and the fasciocidal effect of the drug was evaluated on the basis of worm burden, haemogram, some plasma constituents, and gross and histopathological lesions of the liver, as indicators of efficacy. The treatment was found to be ineffective, the degree of infection remaining the same as in the untreated control group. The experiment was repeated using eight infected sheep: four were given the drug orally at a dose rate of 10.5 mg/kg, i.e., 1.5 times the recommended dose; and the same parameters were measured as described above. The drug failed to cure the infected sheep, and caused depression, anorexia and weakness. In a third experiment six sheep were infected as before and three were treated with niclofolan by deep i.m. injection at the recommended therapeutic dose of 2 mg/kg. A week later the animals were killed and examined as before. The drug was effective in treating the infection and produced no untoward effects except for transient signs of pain at the site of injection. It seems possible that the oral dose, unlike the i.m. dose, of niclofolan is not absorbed and/or metabolized sufficiently to prevent elimination of the infection.

Experimental infection of the domestic donkey (Equus asinus asinus) with a goat strain of Sarcoptes scabiei, and treatment with ivermectin.

Donkeys were experimentally infected with Sarcoptes scabiei from goats, proving that this mite is not completely host specific. The lesions produced on the donkeys were characterized by extensive areas of alopecia, covered with thin crusts and bran-like scales. The skin had many excoriations but showed no cracks or fissures. Skin scrapings from the experimental lesions in donkeys contained numerous mites of all stages and skin sections showed severe histopathological changes, proving that the goat mites had become well established and were reproducing actively in experimental lesions. Treatment of the donkeys with ivermectin produced excellent and rapid cure.

A new technique for the isolation of Demodex bovis from preserved infected material.

A technique for the preservation of infected material from lesions of bovine demodicosis is described, together with a simple method for the isolation and permanent mounting of individual Demodex bovis mites. The technique is based on the fact that the mites float up from pus and cell debris, from which they can easily be collected.

Experimental infection of goats with Sarcoptes scabiei var. ovis.

Goats were experimentally infected with Sarcoptes scabiei var. ovis from sheep, proving that this mite is not completely host specific. More severe lesions were produced on goats when the mites were applied to lacerated than when applied to scarified or non-scarified areas. Lesions were more pronounced on moistened areas than dry areas, and lesions produced on dry scarified areas resembled those produced on non-scarified moistened ones. Skin scrapings from the experimental lesions in the goats contained numerous mites of all stages, proving that the sheep mites had become well established and were reproducing actively in the experimental lesions. Sever histopathological changes were observed in skin sections, which showed mainly thick scab formation, mites beneath the keratin and severe degenerative and necrotic changes. Treatment of the experimental lesions with Lorexane cream (hexachlorocyclohexane) produced rapid and excellent cure.

Goat pox in the Sudan.

Out outbreak of goat pox occurred among 60 adult and young goats in the Sudan. Among the findings of special interest was the extensive and wide distribution of pox lesions on the bodies of the animals. The severe involvement of the mucous membranes of the muzzle, eyes and nostrils gave rise to acute respiratory distress and systemic reaction. The suppression of secondary bacterial infection with local and systemic terramycin in addition to supportive therapy of affected animals alleviated the condition and none of the animals died. Typical pox lesions were produced experimentally on goats and sheep using infected material from goats. Human infections were not encountered.