The illness

The usual incubation is 2 to 12 days. Usually a flu like illness occurs which resolves in 2 - 3 weeks. There may be fever, severe headache, pains in the back and calf and prostration. A few cases develop jaundice, when the condition is known as Weils disease.

Although death may occur in 15% of the jaundiced patients, death without jaundice is virtually unknown. Antibiotics during the first few days help in limiting infection. Many cases recover without specific treatment.

Prevention

          1   Cover all cuts and abrasions with waterproof plasters.

2. Always wear footwear to avoid cutting feet.

3. Avoid capsize drill or rolling practice in suspect waters.

4. Where possible, shower soon after canoeing.

5.  If in doubt contact your doctor early.

The level of risk

Each year, on average, 9 watersports people contract Leptospirosis, among which 3 on average are canoeists.

Leptospirosis is very rare, and its deterioration into Weil's Disease even more rare. Weil's Disease is, however a very serious illness, and must be swiftly diagnosed and treated.

We all know about hypothermia, anyone immersed in cold water is likely to develop hypothermia; but rescuers need to be aware that:

Casualties who have been submerged to the point of drowning need urgent application of CPR techniques to protect against damage to the brain. Even if a casualty appears to have the signs of being dead (duration of immersion; absence of signs of circulation; fixed dilated pupils) every attempt must be made to resuscitate. It is only after medical intervention that death can be confirmed. Indeed, if effective life support measures have been taken, casualties will often recover after medical support has been given.

The results of the team's research indicates that it is impaired swimming efficiency and the body's responses to being immersed in water which are more likely to produce a fatal outcome, rather than the effects of hypothermia.

Some people retain a mammalian diving response, so that upon submersion the need to breathe is diminished. This response causes the airway to seal, preventing water from being inhaled. The circulatory system then re-distributes the proportion of oxygen to the heart and brain. The effect of this is that the heart slows significantly and the condition of the brain is maintained, albeit at a lower level of activity than in normal circumstances.

Casualties who attempt to swim when immersed will chill at a faster rate than those who act to conserve core body heat. The effects of chilling and activity are more likely to contribute to a fatality than hypothermia, which may actually contribute towards the ultimate survival of a casualty. This is because the rate at which the major organs of the body use energy (and thus, oxygen) is slowed dramatically in hypothermia cases, enabling the oxygen that is available to be concentrated in the brain. Activity demands a higher level of output by the heart, which becomes severely stressed in these circumstances and often fails.

When children are immersed in cold water the chilling effect is rapid because they have a large surface area in proportion to their weight. The body core will chill quicker than that of an adult.

People immersed in cold water do better when wearing clothing which insulates the limbs as efficiently as the trunk. Movement of the limbs contributes to the overall loss of body temperature even if the trunk is well clothed and insulated.

Ultimately the results of this research project confirms what we, as lifesavers, already know: