The disease leptospirosis is caused by leptospira bacteria. It is transmitted to humans by contact with the urine of rats, cattle, foxes, rodents and other wild animals, usually by contact with contaminated soil or water. There are many different types of leptospirabacteria, each tends to be associated with a specific animal species. The most common bacteria in the UK is Leptospira hardjo, which is found in cattle and Leptospira icterohaemorrhagiae, which is associated with rats.
The bacteria enters the body via cuts to the skin, or via the nose, mouth or other mucous membranes.In most cases the infection causes a flu-like illness and severe headaches. The severe form of the disease (Weil's disease) causes jaundice and liver damagedamage and carries a reported death rate anywhere between 4-40%. Only about 10-15% of affected people suffer this more dangerous form.
Salmonella is a type of bacteria and is one of the most common causes of food poisoning worldwide.
There are more than 2,000 different types of salmonella, but only two types are responsible for most outbreaks of food poisoning in humans. It is thought that there may be one million cases of food poisoning in humans in the UK each year.
Salmonella infections occur in all farm animals, notably chickens, and in most wild animals. Studies in 1990 showed that about 50% of frozen and fresh chicken contain the bacteria.
In addition, salmonella infections in dairy herds may lead to contamination of milk, which if not adequately pasteurised may cause infection.
Credited with having one of the highest mortality rates of any infectious bacterial disease amongst pigeons, salmonella can remain infective in the environment for 1 year or more, given the right conditions.
Salmonella bacteria passes out of the body in the droppings thus spreading contamination if the birds come into contact with food taken by other birds.
The transmission of salmonella is enhanced by large gatherings of birds at communal roosts or bird tables, and poor hygiene at feeding stations can fuel a local outbreak.
Once salmonella passes onto a human, the bacteria multiply in the intestines and within 12-36 hours usually cause diarrhoea, stomach cramps and sometimes vomiting and fever. The symptoms continue for several days and then, in most people, they cease.
If a case of salmonella is suspected, it may be worthwhile to consider a cull on the local population of pigeons to reduce the likelyhood of a major outbreak
