Leptospirosis
By Dr Mackie Hobson BSc(Agric),BVSc

1. Diseases

Leptospirosis has not been diagnosed in Angora goats in South Africa.

The dry and hot conditions in the Karroo, where most Angora goats occur, are very unfavourable to leptospirosis. Leptospirosis in South Africa has mostly been reported from areas with relatively high rainfall such as Mpumalanga, KwaZulu Natal and the coastal area of the Eastern Cape provinces. However, it has also been diagnosed in the drier Limpopo and North West provinces.

What is the prevalence of Leptospirosis in South Africa?

A few serological surveys have been carried out in South Africa. One such recent serological survey was conducted in cattle originating from rural communities of the province of KwaZulu-Natal (KZN) in South Africa and revealed a prevalence of 19.4%

In South Africa serological investigation to detect maintenance hosts a few reedbuck, bushpig, black wildbeest, nyala and rhinoceroses had positive antibody titres against a few serovars.

These bacteria have been reported to survive for at least 183 days in wet soil. In contrast they may survive for less than 30 minutes in air dried soil. Spring, autumn and early winter are associated with highest prevalence in temperate climates.

What clinical signs does Leptospirosis cause?

Leptospirosis is rare in sheep and goats but possible clinical signs include:

• Acute death
• Redwater resulting from infection with Leptospira pomona .
• Septicemia
• Leptospira hardjo - abortion may be the only sign,
• Milk drop syndrome similar to one observed in cattle can be seen in lactating ewes

The severity of clinical signs is associated with the serovar and species of animal affected. Clinical signs can therefore vary after an incubation period of 2-16 days.

• Fever and anorexia
• Reduced reproductive efficiency and milk production
• Abortions, stillbirths and weak calves.
• Haemoglobinuria

How is Leptospirosis transmitted?

Transmission is usually via urine contamination of feed and water. Transmission may also take place transplancentally, venereally, during coitus and artificial insemination.

Following on indirect transmission, usually by water or mud contaminated with infected urine, particularly on abraded skin, or skin softened by prolonged immersion in water, leptospires enter the blood stream.

Treatment

• Antibiotics (oxytetracyclines and penicillin) - in the early stages of infection.
• Vaccination is carried out in certain countries.

Post Mortem findings

• icterus, anaemia,
• Discoloured urine ‘redwater’ (haemaglobinuria)
• splenomegaly,
• widespread haemorrhages (mucosal and subcutaneous),
• hepatomegaly,
• pulmonary oedema and acute or chronic interstitial nephritis.
• Foetal pathology is non-specific and foetuses may be fresh or autolysed. No significant lesions are seen in the placenta.

REFERENCES

• Leptospirosis in cattle in South Africa Dr. J.H. Vorster, BVSc, MMedVet (Path) Vetdiagnostix Veterinary Pathology Services

Dr. P.H. Mapham, BVSc (Hon) Veterinary House Hospital 339 Prince Alfred Road,

• Leptospirosis in cattle, pigs, sheep, goats, horses and humans

Note Number: AG0455
Piotr Fabijanski, Ellinbank