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Six cases of leptospirosis reported in the greater Darwin region in the past 6 weeks have highlighted hunting as a risk activity for contracting this potentially fatal disease.

Leptospirosis is a bacterial disease that can be mild or severe and can cause death. The disease presents with a variety of symptoms but most commonly with fever, sudden-onset headache, chills, aches and conjunctivitis. Kidney and liver failure can occur as well as bleeding (e.g. into the lungs) and mental confusion. Prompt and specific treatment for the disease as early as possible is essential.

Leptospirosis is an occupational hazard to those working on the land or with animals and a recreational hazard to bathers, campers and sportsmen in infected areas. Contact of the skin (especially abraded skin) with water, wet soil or vegetation that is contaminated with urine of infected animals (notably rats, pigs, cattle and dogs) constitutes the main mode of transmission of leptospirosis.

Of the recent 6 cases, 2 men (and a possible 3rd suspect male case) were duck hunters at the Harrison Dam/Fogg Dam area during the time consistent with them acquiring their disease. All were hunting in bare feet. The third male case lives on a rural block where there are many animals and he is most often barefoot.

The 3 female cases were turtle hunting around Oenpelli - also in bare feet.

The Fogg Dam/Harrison Dam area is home to a very large and dense population of the 'dusky rat' (Rattus colletti), a native rat. Rats are considered the most significant reservoirs of leptospirosis worldwide.

Earlier in the year a male abattoir worker from Katherine was notified with leptospirosis making him the 7th reported case to date this year. All 7 cases have been hospitalised and 2 have required intensive care treatment.

From 1992 to 1999 there had been 9 cases of leptospirosis notified in the Northern Territory. Of note, all had been males aged 26 to 60 years, all were non-Aboriginal (the ethnicity of one 1993 case was unknown). Six cases were from the Katherine area with the remaining 3 from the Darwin area. Occupation or 'risk activity' for acquisition of the disease had not been systematically collected, however anecdotally, several Katherine cases were involved in activities around the Katherine Gorge - as tourists or guides.

The need for those dealing with animals and this environment to wear protective footwear and clothing is highlighted. Health practitioners need to be aware of the disease. Parks and Wildlife and Environmental Health are aware of the cases and health alerts will be distributed to hunters, tourists and workers in the area.

Contact Officer: Dr Vicki Krause, Director, Centre for Disease Control, Territory Health Service. Telephone: +61 8 922 8044.

Footnotes
1. Media Release. Darwin: Territory Health Service; 15 December 2000.

This article was published in Communicable Diseases Intelligence Volume 24, No 12, December 2000.