Written by the NWCRO Medical Officer for informational purposes only. No liability accepted. This guide is based on current medical opinion and is not guaranteed accurate in all specific cases.
Weil's Disease is a bacterial infection, caused by the Leptospirosis bacterium, and is spread by the urine of rats. Cave water draining from farmland or areas of human habitation is usually infected with leptospirosis to varying degrees. Whether you will catch Weil's Disease depends on the levels of infection, what you do with the water, and how susceptible you are.
The bacteria usually enters your body via cuts to the skin, or via the nose, mouth or alimentary tract (for those with a limited medical vocabulary, the alimentary tract sees the food on the way out, the mouth sees it on the way in..) Thus, anyone coming into contact with infected water or swallowing any of it is at risk of infection.
Note that infected water does not have to look and smell like raw sewage to be dangerous. The cave does not have to be infested with rats if the run-off comes from an infested surface area. However, water which does appear polluted, or the sight of some of our furry friends, is Warning Number One that the water is to be avoided.
To minimise the risks of infection, the only truly effective way is to avoid contact with the water. Thus, avoid immersion, especially the head, and cover any cuts with waterproof dressings. Wear oversuits and gloves, and divers, who are particularly at risk, should opt for drysuits and try as much as possible to avoid swallowing any water when purging or changing regs.
An attack of Weil's resembles a cold or flu in the initial stages. The incubation period is from 3 to 19 days. Early symptoms are:
Later symptoms may include :
The fever lasts for approximately five days, then a significant deterioration follows.
If untreated, Weil's Disease is serious and often FATAL
If you become ill a few days after a caving trip, and you have any of the above symptoms, it is extremely important to contact your doctor as soon as possible. You must tell your doctor that you suspect Weil's Disease, as many of them do not associate it with influenza symptoms without a helpful hint. Treatment with antibiotics is only effective if started rapidly after symptoms develop. A blood test is conducted to determine the presence of Weil's Disease, the public health laboratory receiving the test should perform an ELISA test for leptospirosis. If in the United Kingdom, and the local PHL cannot perform and ELISA test, the sample should be sent to: The Leptospirosis Reference Unit, Public Health Laboratory, County Hospital, Hereford HR1 2ER. Telephone 01432 277707. This contact is for UK use only, by the doctor or PHL staff only.
Weil's Disease is a notifiable illness in the UK and it is essential to disclose a confirmed case to the local Public Health office, who will need to know where you believe it was caught.
Weil's disease information centre