Pest-control companies are reporting a major rise in the incidence of cockroach infestations in apartment blocks and other urban accommodation.

The insects, which have been linked to the spread of salmonella and gastroenteritis in humans, are thought to be coming into Ireland in foreign foodstuffs, cargo and luggage.

"Ten years ago we were getting two to three calls a year for cockroaches, now we're getting two or three a week," says Danny Proctor, of Cannon Pest Control.

"The calls are mainly to apartment blocks in the cities where the infestations can spread rapidly from floor to floor because of the structure of the buildings."

The primary cause, Proctor believes, is the increased level of foreign foodstuffs, such as bags of rice, cereals and oils, being brought into the country.

But he is also convinced that it is a result of people travelling farther afield and to more exotic locations and bringing the insects back in their luggage.

Because the insects feed on such a wide range of food and rubbish, they have been linked to the spread of a number of disease-causing bacteria, most notably those associated with salmonella and gastroenteritis.

Their droppings and carcasses have also been associated with respiratory-related allergies.

Proctor tells of a recent case in an apartment in Dublin where the occupant had complained about her child having constant stomach bugs.

"When we removed the fridge and oven, we found the place was alive with cockroaches," he said.

"Obviously we can't prove the child was being getting ill as a result of the cockroaches but they are a particularly filthy insect which can transmit disease and contaminate food."

The most common species of the insect in Ireland is the German cockroach, which often clusters in kitchens and bathrooms near plumbing fixtures or cracks or crevices in cupboards and sinks. It feeds on almost any food, and can even survive on soap, glue and toothpaste.

Ireland is also home to the larger Oriental cockroach, or water bug, so called because of its preference for dark, damp and cool areas. It is commonly found near drains, leaky water pipes and under refrigerators, sinks, washing machines and floors.

Rentokil Ireland's technical manager Dr Colm Moore says there are now personnel in city centres dedicated solely to cockroach control.

"We have also witnessed a significant rise in the number of cases involving public buildings, such as hospitals, restaurants and hotels."

In terms of prevention, Dr Moore says, people living in apartment blocks should insist on their property management companies employing pest control firms to carry out regular inspections.

But people also need to maintain a certain level of hygiene in their kitchens and bathrooms, in terms of keeping surfaces clean and cleaning up spills, he says.