Because cockroaches eat a wide range of food, including rotting garbage, it is believed that they spread a number of diseases to humans including salmonella and gastroenteritis. Recent studies have indicated cockroaches can also cause allergies.A cockroach infestation can be treated with a combination of good hygiene practices and insecticide.It is believed that the cockroach may be a reservoir for a range of bacteria including salmonella, staphylococcus and streptococcus. The cockroach can also harbour viruses such as the polio virus.Like the household fly, the cockroach will eat virtually anything ranging from food spills on a kitchen floor to faecal matter. Ingested bacteria can survive in the cockroach's digestive system, sometimes for months or even years, and are passed in its droppings. It is thought that disease is then transmitted to humans when humans eat cockroach droppings, perhaps on contaminated food.Recent research suggests that the cockroach may also be associated with human allergies.The life cycle of a cockroachA female cockroach lays between 10 and 40 eggs at a time. On average, the female can lay around 30 batches of eggs in her lifetime. The hatched young look the same as adult cockroaches, but smaller and without wings. Depending on the conditions and type, a cockroach can live for up to 12 months. These insects are cold-blooded and thrive in warm, humid conditions. This is why buildings in the northern parts of Australia are particularly prone to infestations.