Cockroaches present one of the most significant public health risks, carrying diseases such as dysentery, gastroenteritis, diarrhoea, typhoid, poliomyelitis and salmonella. They are most commonly found in commercial premises in which food is produced or handled, such as restaurants and catering establishments. However, they are not uncommon in domestic situations where they live in kitchens and drains.
The three most important species are the Oriental cockroach, the German cockroach and the American cockroach.
The Oriental cockroach reaches 20-24mm in length in its adult stages, is almost black in colour and is largely found in cooler, less humid areas than its German counterpart, which, at 9-14mm long is markedly smaller, yellowy-brown in colour, is a better climber than the Oriental cockroach and thrives particularly well in kitchens and canteens. The largest of the species, the American cockroach, is red-brown in colour and can reach 30-35mm in length. This species survives well in drains and sewers.
Cockroaches are nocturnal creatures, which spend the daytime hours hiding in cracks and crevices around sources of food and water such as cookers and sinks. Complex pipe work systems and underground ducts in larger buildings can make their control all the more difficult. Food contamination occurs when the cockroach moves from refuse to food preparation areas. Cockroaches will eat practically anything from human food to leather, wallpaper and even other cockroaches.
Control and eradication of cockroaches is a complicated procedure. This is best carried out by a suitably qualified person.