Leptospirosis - a work health safety issue

In the past wet season a significant number of NT stock workers have been affected by Leptospira Pomona.  Confirmed cases of leptospirosis in humans are reported by the NT Department of Health Centre for Disease Control. Leptospirosis is a notifiable disease in humans, commonly referred to as ‘Lepto’, poses a serious threat to staff working on cattle stations, particularly in the flood plain and rural Darwin/Katherine regions. Leptospirosis is caused by a number of strains of the Leptospira bacteria, which have the ability to infect both animals and also cause serious disease in humans. Animals infected include cattle, pigs, sheep, goats, horses, dogs and rats in addition to native wildlife including kangaroos.

Leptospirosis is highly contagious because of the many ways it can be spread from animal to animal, or from animals to humans. The disease can be spread through urine, or at birth or abortion, resulting in the contamination of water, feed, pastures and soil. Once in the environment, the bacteria are able to infect animals and humans through damaged skin or the membranes lining the nose, eyes or mouth. Stock workers are most likely to contract the disease when working in cattle yards or abattoirs with infected cattle. Infection can result from both direct exposure to urine when handling or slaughtering cattle and working in yards where the water, mud, soil or vegetation have been infected. ‘Bang tailing’ and cleaning of water troughs are two key activities which can pose a risk to stockpersons. Handling the foetus of an aborted calf, or assisting with calving can be a further source of infection for humans. Recreational activities that may pose a risk include camping, bushwalking, gardening and hunting.

The clinical signs in cattle will vary depending upon the strain of the disease. In general, animal signs associated with leptospirosis include weak newborns, fever, infertility, mastitis, jaundice, depression and anorexia. Abortion ‘storms’ may also be seen in cows that are greater than five months pregnant. Abortions may occur weeks after initial symptoms, or even in the absence of symptoms.  These signs are rarely recognised in the NT.

Symptoms in humans have been found to occur within 10 days; however can range from 4 to 19 days. The length of illness varies, with people being sick for a few days, or as long as three weeks or more. Relapses are common however it is rare for person to person transmission to occur. Symptoms can include any of the following:

Sudden onset of fever
Severe headaches
Chills
Severe muscle pain (especially in the legs)
Reddened eyes
Cough
Diarrhoea
Vomiting

Occasionally, people with Leptospirosis will develop Weil’s disease, symptoms include jaundice, bleeding, breathing difficulties and confusion. Although extreme cases can prove to be fatal, most cases involve people with mild symptoms that resolve themselves with little to no complications, or cases where there are no symptoms at all.  It is important to reach a diagnosis for proper treatment and to exclude more serious diseases such as melioidosis.

As there is no vaccination against leptospirosis for humans, employers and staff members need to be aware of the disease, take precautions to avoid exposure and know what to do if a staff member suspects that they may have leptospirosis or displays symptoms consistent with the disease. Precautions to take against leptospirosis include:

  • avoiding unnecessary contact with water that may be contaminated
  • wearing gloves and eye protection when handling the tail end of animals to minimise urine contact (pregnancy testing, bang tailing etc.)
  • covering all cuts or wounds with waterproof dressing
  • washing hands and arms  thoroughly after handling animals, carcasses or other contaminated materials
  • avoiding hand to mouth (i.e. smoking), nose and eye contact when handling animals that may be infected
  • washing and drying hands thoroughly before smoking or drinking
  • controlling rodent populations
  • instituting wild pig management programs
  • vaccinating livestock with ‘7 in 1’ vaccine against Lepto Pomona and Hardjo strains.

For further information regarding leptospirosis visit nt.gov.au.

If you believe that you, or a staff member has leptospirosis contact your local doctor for testing.  It is important to mention your risk factors or possible exposure to Lepto.

If you think that your livestock have leptospirosis please contact your DPIR Regional Veterinary Officer.

Darwin - (08) 8999 2035
Katherine - (08) 8973 9716
Alice Springs - (08) 8951 8181

Last updated: 08 June 2017