Weil’s Disease is very rare but something swimmers, rowers & SUP users need to know about
[NB This feature was written in 2010, and contains data from that time].
Weil’s is not peculiarly a disease of water users and it’s not – counter to the popular urban myth – particularly associated with rats.
Weil’s has traditionally been an occupational disease – affecting animal handlers, livestock farmers, people who work in the waste management and fishing industries, and anyone who works around the back end of a cow. Anyone who develops and builds property near standing water will be aware of it. One recent case involved a street cleaner using a jet wash to clean up after a street market. Another involved a rugby player, thought to have contracted it by drinking from a beer bottle that was contaminated in a pub cellar. Anecdotal stories include a fisherman who cooled his beer in a river.
There is less than a 1 in 10 million chance of contracting Weil’s, and most cases are successfully treated with antibiotics.
‘Weil’s Disease is actually not a disease, but a development of a waterborne bacterial infection called leptospirosis,’ says Dr Robert Smith, a clinical scientist from the Health Protection Agency who specializes in this area.
‘Around 50 people a year in England and Wales become infected with leptospirosis, and only 10% of those go on to develop Weil’s.’
According to Smith (who analyses infections for the HPA), of the 2,009 cases of leptospirosis in England and Wales 14 were from travelling abroad (it’s very much a tropical and subtropical disease, rare in temperate climates), 11 were occupational (farmers, vets), seven recreational (canoeing, fishing, sailing, windsurfing, swimming), six acquired it residentially (from rats and mice around the house, cleaning out ditches, streams or drains), and two from accidental immersion. In previous years it has even been acquired at Glastonbury Festival.
While rats are oddly prevalent in all literature about Weil’s, this does not reflect their importance as a source. The bacteria is actually harboured in the kidneys of a wide variety of animals – cattle, deer, pigs, sheep, horses, dogs and rodents. Pee from any of these animals, carried into water, could carry the bacteria.
Weil’s Disease is a secondary phase of a bacterial infection called leptospirosis. ‘It is one of the most widespread zoonosis (disease spread from animals to humans) in the world, where it is most common in tropical and subtropical environments,’ says RoSPA.
‘Leptospirosis is no more common in urban than rural watercourses,’ says Smith, ‘and it doesn’t correlate with water purity generally.’ You can find it in crystal clear and clean salmon and trout streams as well as urban docks or Camden Lock.
Even where leptospirosis is present in a water body, it is very hard to be infected. You cannot be infected by swallowing water, and ‘there is little or no risk of transmission through intact skin,’ says Smith. The most common route of infection with leptospirosis is through a cut or abrasion, although the mucous membranes in the eyes or mouth could provide an entry point, particularly if there are cuts, bleeding gums, or de-roofed blisters.
In terms of avoiding higher risk areas, the bacteria is likely to be concentrated at the edge of water bodies, where animal pee runs into the water, and the water runs slower, so the bacteria are less dispersed. Floods may flush more infection into the water, raising risk. Water carries infection, but something like cutting a foot in the mud beside a river and lakeside, could lead to bacteria in a wound.
Water users who are worried about infection are advised to apply waterproof plasters to any cuts or abrasions, and shower and handwash afterwards – particularly if there are cuts and abrasions, which should be cleared of any bacterial crud.
‘Weil’s disease is the secret weapon of whatever dark forces are opposed to wild swimming,’ wrote Roger Deakin, author of Waterlog. Previous generations have always had things to scare them away from the water, with folklore about selkies and river hags like Jenny Greenteeth pulling unsuspecting folk to their deaths, but in the 21st century we have other names for our deep water fear – blue green algae and Weil’s Disease.
If there’s a logical heart to our paranoia about Weil’s, it’s the severity of illness when it does hit. Symptoms of leptospirosis usually develop within seven to 14 days after contact with infection, but can take as little as three, or as many as 30. The initial symptoms are so like common flu that telling a doctor that you have been associated with water (or stuck a fork through your boot while cleaning a ditch)and getting a blood test are key. The symptoms are fever, severe joint pain (particularly in joint muscles), headache and chills, much like flu. Less common are nausea and vomiting.
Symptoms generally pass within four to nine days, without treatment. But in around 10% of people, a second more serious phase occurs, and it is not fully understood why. This is the result of the bacteria infecting organs such as the brain, kidneys, liver, eyes and lung. It is treated with antibiotics, and the earlier the better as it can lead to fatal complications such as liver, lung or kidney failure.
London swimmers, triathletes, rowers and canoeists need have no greater fear of Weil’s than those in the provinces, or in any range of working environments. Water bodies like the Serpentine are tested and reach EU bathing standards but neither the EU standards or Environment Agency data test for this rare bacteria.
Symptoms can occur between 3 and 21 days from the time of infection. If you have these symptoms after swimming see a doctor ASAP – early diagnosis and treatment of leptospirosis can prevent more severe cases of infection. There can be two distinct phases of leptospirosis.