Rhubarb - thanks for alerting us - I found this for anyone who is worried....
The Weils Disease Information Center
Transmission methods
Aquiring a leptospira infection is not as easy as some people would like you to believe. Thousands of sport cavers and underground workers are exposed to the bacterium every day of the year and the incidences of infection are low. Typically, 8 people contract the infection in the UK due to watersports, caving and similar activities. However, those entering high risk areas do need to be aware of the infection and how to minimise their exposure. The disease is spread by direct water or urine contact and is not usually transmitted from person to person.Ingestion of infected animal tissue can also cause the illness.
Areas of high risk
As we have already said, the Leptospira bacterium is predominantly spread by the urine of animals. Most cases result from rats, though farm animals can also carry the infection and wild or domestic livestock can also present a risk. The bacteria can survive for up to one month if the urine is transferred into water immediately, though dies rapidly if dried out. For this reason farm animals and wild/domestic livestock presents less of a risk than rats as the exposure must be to the urine directly. Rat populations exist near water and the urine from the colony easily passes into the system. The bacterium can only survive for this length of time in fresh water. In saltwater the organism is killed within a few hours.
The bacteria is endemic to rat populations of numerous species across the world and it is a sensible policy to assume all rats, wherever they are found, harbour the infection unless proved otherwise. Note that infected water does not have to look and smell like raw sewage to be dangerous. Sewers are obviously high risk sites, but as can be testified by cavers and mine explorers who have contracted the infection, apparently clean water in other underground sites can be a source of exposure if the water originates from an infected surface source. In the UK farming and caving areas are closely associated and it is likely that the water entering these caves has passed through areas of rat habitation or is contaminated by urine from farm stock. The (illegal) practice of dumping carcasses and domestic effluent into caves and mine workings has led to dramatically increased risks in very specific sites though in the UK rats do not normally inhabit caves or abandoned mine workings.
Surface sites are also possible sources of infection. Anglers,windsurfers, canoeists or those who swim in freshwater sites can be exposed to infection. If rats are sighted in or near a body of water then exposure to that water should be avoided. Rivers in urban areas are particularly high risk as the policy of dumping anything and everything into the river and it's runoff areas leads to food sources and shelter for rats.Remember that the bacterium only survives in fresh water - marine watersports have never resulted in an infection from these bacteria.
Transmission methods
The bacteria enters your body via cuts to the skin, or via the nose,mouth or other mucous membranes. Exposure requires contact with the water or the animals' urine directly, or the consumption of infected tissue. Bacteria are not particularly good at surviving in the outside world and unless there is a large amount of water vapour in the air (for instance near a waterfall) the organism is not airborne. Thus, anyone coming into contact with infected water either by skin exposure or ingestion is at risk of infection. Those with cuts to the skin are more at risk than others.It is rare to pass the infection person- to-person, though contact with an infected person's urine is obviously as risky as the original source. Vegetables grown in areas likely to be contaminated with animal urine should be washed and well cooked.