A recent warning from the Food Safety Authority has highlighted the presence of a rare, but potentially fatal, disease in the Republic. Six people have contracted Weil's disease here in the past 18 months.
There have been four cases in Dublin, one in Carlow and one in Tipperary. Leptospirosis is the proper name for the disease; Weil's syndrome describes the severe and sometimes fatal version.
Leptospirae are a distinct family of microbes called spirochaetes which live in several species of mammals. Rats are the most likely source of human infection but leptospirae also live in dogs, birds and fish.
Doctors refer to leptospirosis as a zoonosis, a term used to describe a disease which is transmitted to humans via animals. The spirochaete establishes a symbiotic relationship in its animal host - often living unobtrusively in the kidneys of the rat or dog without causing any disease. Only when it is passed to humans does the leptospira cause illness.
The bugs are excreted in animal urine and are able to survive in water for many months. It is this characteristic which has led to most cases of recreational exposure. Swimming in rivers and lakes, as well as canoeing, windsurfing and water-skiing, are all associated with leptospirosis.
There has been at least one case in the Republic involving a golfer retrieving a lost ball from a water-filled ditch. The microbe entered his system through a skin cut and he went on to develop the full-blown Weil's syndrome.
Leptospirae multiply in the blood and tissue of the infected person. They cause most damage in the liver and kidneys and can lead to a severe illness in five to 10 per cent of cases.
A mild infection may result in no symptoms at all but most people will experience a flu-like illness with fever, chills, severe headache, nausea and vomiting. Muscle pain, which is a particular feature of leptospirosis, characteristically affects the calves, the back and the abdomen.
The illness usually subsides after a week, although in some people the fever re-occurs after about three days. This is a sign that the person's immune system has developed antibodies to the spirochaete. A chronic eye infection will sometimes persist following this second phase.
Weil's syndrome, or severe leptospirosis, is a far more serious illness, with sufferers requiring intensive hospital care. It has a high mortality rate. Jaundice indicates liver failure and there are also signs and symptoms of kidney failure. Involvement of the lungs causes shortness of breath, chest pain and blood-stained sputum. The unfortunate patient may then go on to develop bleeding from the nose and gut while the skin will develop severe bruising.
The incubation period for the infection is up to 26 days, although seven to 14 days is the usual delay between exposure to leptospira and the development of symptoms.
The Food Safety Authority has become concerned about the possibility - even more rare than the water-borne route - of transmitting the infection via poorly prepared and poorly stored food. The main vector for such an occurrence is the rat and the authority has issued a statement warning pubs and restaurant owners to ensure adequate standards of food storage. Areas where foodstuffs are stored should be structurally sound, with no broken air bricks, gaps under doors or piles of unattended rubbish, all of which could attract rodents, according to Ray Ellard, chief specialist environmental health officer with the authority.
The severe form of leptospirosis is treated with antibiotics, usually intravenous penicillin. Early treatment is an important element in preventing mortality from the disease.
Thanks to all of you who responded to the column on the health risks of flying (The Irish Times, August 14th). The face masks from the Aviation Health Institute have attracted a lot of interest; here is the telephone number again - 0044-800 3896066.
Positive feedback on the air purifier and humidifier comes from a Dublin reader who reports that it helped her considerably on a recent long-haul flight. A Kinsale reader e-mailed with details of a device to help prevent ear problems while flying. Ear Planes'
are a form of ear plugs containing a gadget which slowly equalises ear pressure despite the sudden pressurisation of aircraft cabins. She bought these devices, which she found very helpful, in the US, but she kindly supplied a UK contact telephone number: 0044-1304-620199. Ear Planes' are available through the Boots chemists chain here at £4.49.
Finally, the UK government has just announced an official inquiry into air quality aboard aircraft following recent concerns. It is a subject this column will return to again.
Contact Dr Houston at mhouston@irish-times.ie or leave messages on tel 01-6707711, ext 8511.