I would love to know exactly how common Weill's disease is,

Very rare, only a real danger to people like cavers and sewer workers.

It is also a danger to anyone who comes into contact with water features
such as rivers, canals, docks, ponds, etc. I used to work on the river
Thames and my employer's Chief Medical Officer provided me (and my
colleagues) with a card (which I had to carry with me) warning of the
dangers of leptospirosis. I have also known of a couple of deaths from
leptospirosis, contracted after contact with water in the Thames (this is
what brought about the card).

There is also a danger to farm workers as leptospirosis is known to be
carried in some livestock. In fact it is believed that this is where
leptospirosis started and was then caught by rats who carried it into the
towns and cities.

Yes, it is very rare but the real danger is to think "it will never happen
to me". Leptospirosis kills (through liver and kidney damage) when
untreated. A simple blood test will identify it and doctors tell me it
responds extremely well to antibiotics.

In other words, awareness of leptospirosis can save a life. Yes, it may only
be one life but that life may be you or someone close to you. If you may
have been contaminated (through ingestion or cut in the skin) and develop
flu-like symptoms, check with your doctor before retiring to bed.

Regards

Howard Neil