The national rat population is increasing, and approximately 50% of rats in Ireland carry and excrete the organism Leptospira Ictero-Haemorrhagiae in their urine. Infection of humans with this organism can cause an illness called Leptospirosis which is also commonly known as Weil's Disease.

Leptospirosis has been known to result in death in 9% of cases. Formerly the disease occurred mainly among sewage or abattoir workers, farm workers and miners, but more recent records show that the majority of deaths are now related to water activities. In Ireland, the number of reported cases to the Department of Health has risen over the last few years; 8 cases in 1997, 12 in 1998, and 15 cases in 1999.

The disease is curable if recognised in time, but many doctors in urban areas will never have encountered it. If you have any reason to suspect that you may have been infected, you may need to draw your doctor's attention to the possibility that the symptoms could be Weil's Disease.

LEPTOSPIRA ORGANISM

Rats commonly live near water and in areas where there are sources of food such as animal feed, grain, or food residues from human habitation or other animals: farms, stables, around canteens, in such places as quarries and along river and canal banks. The leptospira organism is passed in the rats' urine and, while it does not live long in dry conditions, can survive some time in water. Salt water soon kills off the organism but there is a significant risk in tidal waters and other rivers. The risk increases upstream and is greatest in canals, ponds or areas of slowly draining water. For rat infestations in domestc gardens, minimise the risks of infection by washing and cleaning all garden furniture, childrens toys, etc.

ABOUT THE ILLNESS

The organism enters the body through breaks in the skin such as cuts, blisters and abrasions, or via the lining of the nose, throat or alimentary tract. The incubation period is 7-13 days and the disease starts with a fever, muscular aches and pains, loss of appetite and vomiting with prostration. Subsequent bruising of the skin, sore eyes, nosebleeds and jaundice may occur. The fever lasts about five days and may be followed by significant deterioration. It is vital that the doctor be told that the patient may have been in contact with a source of infection. The symptoms can easily be mistaken for those of flu and, if the patient has a clean occupation, the possibility of Weil's disease may be overlooked in the early stages. Laboratory testing of blood will confirm the diagnosis but this may take undue time in an ordinary hospital lab. Treatment is usually by Penicillin Antibiotic.

SOME USEFUL PREVENTION TIPS

Any skin wound or blister, old or new, may be infected if immersed in water polluted by the organism. So, when dealing with an infestation, wearing gloves probably provides the most effective protection since waterproof plasters on their own are unlikely to stay in place.

Clean, fresh water should be used to wash wounds as soon as possible.

All rats need water to survive, and the leptospira organism lasts much longer in water. So, empty any water containers in the garden, and turn any empty flowerpots or containers upside down, so as they will not fill if it rains.

If you have a rat infestation in your garden, ensure that all childrens toys and garden furniture are thoroughly washed and cleaned before reusing.