Leptospirosis

Leptospirosis is a disease caused by a bacterium that has a predilection for kidneys and can also cause reproductive problems.

Alternative names: Leptospira interrogans, Leptospira borgpetersenii, pomona, icterohaemorrhagiae, canicola, bratislava, serjoe, tarassovi

Information

Leptospira are bacteria with a long and slender spiral shape, present in most mammalian species. Over 260 serotypes are known, usually called serovars, and some species cause cross-infections. Each serotype has one or more host (usually only two or three) that multiply the type and keep them. A serotype can remain infective all its life in its host reservoir.

In pigs, the important leptospires includes 2 species and serotypes virus. They are Leptospira interrogans (serotypes pomona, icterohaemorrhagiae, canicola, and Bratislava) and Leptospira borgpetersenii (Serjoe and tarassovi serotypes). It can be infected by other serotypes from urine of other animals, for example L. canicola of dogs and L. hardjo from cows but infections are subclinical and do not cause the disease. The pig is then a fortuitous host, it is to say, it does not perpetuates the infection and is only responsible for a minimum dissemination. It is believed that some wild animals act as reservoir hosts.

Once these organisms are introduced into pig farms they become carriers and produce kidney infections and intermittent excretion of the organism in urine. The disease is rare in nursing piglets and infects only individual animals.

Remember that this disease can be transmitted to humans. 

 

Symptoms

Sows

In acute outbreaks:

  • Loss of appetite.
  • Fever.
  • Depression.
  • Abortions during third quarter.
  • Stillbirths.
  • Increment of  mummified piglets.
  • Increase of weak, nonviable piglets.
  • Increment of premature piglets.
  • Increment of stillbirths.
  • Increment of returns in breeding sows.

Lactating piglets

  • Not as frequent.
  • Loss of appetite.
  • Jaundice.
  • Blood in urine.
  • Seriously ill pigs die.

Nursery and fattening

  • Acute jaundice.
  • Hemorrhage.
  • Sudden death.
  • Pale animals.

 

Causes / Contributing Factors

The infection can enter the farm in one of the following three ways:

  1. Introduction of infected gilts and boars.
  2. The infection can be introduced into the farm by other animals; rats, mice and dogs that can serve as reservoirs of the infection.
  3. The farm has been exposed to indirect sources of contamination, for example contaminated water, dirty floors and in bad shape that allow urine to puddle. It is transmitted through urine.

 

Diagnosis

It is not an easy task but it could be very useful to:

  • Study the percentage of abortions, returns, stillbirths, weak piglets and age when it takes place in sows and gilts.
  • Take blood samples from suspect animals and repeat 2-3 weeks later.
  • Vaccines produce low antibodies.

 

Control/Prevention

  • Medicated feed with tetracycline, oxytetracycline or chlortetracycline. Medicate during three weeks and repeat the treatment after six weeks. Medicate again every six weeks four more times.
  • Strategic Medication. Where there is a history of periodic infertility, medicines may be administered in feed just before the time when the disease is expected to start.
  • Inject the sows at weaning with 25mg / kg of streptomycin. The boars should be treated with this antibiotic once every six weeks. Alternatively use semi-synthetic penicillins.
  • Give vaccines to the reproductive herd at least once every six months with vaccines of multiple strains.
  • Use potable, uncontaminated water.