Leptospirosis - Pigs

Description

Leptospirosis is an infective disease caused by the bacteria Leptospira. There are a number of serovars of the bacteria which vary in their pathogenesis and host specificity. L.bratislava and L.pomona are both host adapted to swine and are the most common cause of clinical leptospirosis in pigs. Other serovars whih are host adapted to other species can also cause disease in pigs: L.icterohaemorrhagiae transmitted by rats, L.canicola by dogs, L.grippotyphosa by wildlife and rarely L.hardjo by cattle. Transmission is via urine of infected animals, persistence in the environment relies on soil moisture and water ways. Venereal transmission from carrier boars and sows is also responsible for infection and maintenence of the disease

Signalment

Leptospirosis has a worldwide distribution; it is more prevalent in warm wet climates. The incidence of disease depends on the serovar involved.

Diagnosis

Clinical Signs

The most common clinical presentation is abortion 2-4 weeks before term, still births and weak piglets which die shortly after birth are also seen.

• Late term abortion
• Still birth

An acute syndrome has been described in piglets but is very rare, clinical signs are outlined below:

• Pyrexia
• Dyspnoea
• Haemoglobinuria
• Anorexia
• Icterus
• Anaemia

Some serovars can become endemic in a herd causing minimal disease but presenting a major zoonotic concern.

Treatment

Treatment with antibiotics such as oxytetracycline, enrofloxacin and ampicillin are effective for chronic cases. Early treatment fo acute cases with antibiotics may be successful, a blood transfusion may also be needed if the anaemia is severe.

A vaccine exists in the USA but is not available in the UK; the protection provided is short lived, it minimises but does not eliminate clinical disease in all cases.

References

• • Pigs
    • The rodent-adapted serovars icterohaemorrhagica and copenhagenii cause acute disease in pigs
    • Severe disease in young pigs
    • Serovar pomona is the host-adapted species, and may be shed in the urine
    • Infections may cause abortions and stillbirths
    • Pigs are maintenance hosts for serovars tarassovi and bratislava, which may cause reproductive failure