Cockroaches are synonymous with filth and poor hygiene. Their feeding and nesting habits mean they can easily pick up a range of disease-causing microorganisms on their bodies and ingest them from the rotting and foul materials they crawl and feed on. The German cockroach, in particular, is a common indoor pest where food is handled, in homes, restaurants, commercial kitchens and hospitals.
For businesses handling food, cockroaches are a sign of poor food hygiene practices and could result in a breach in food safety regulations and standards. They feed on anything that is suitable for human consumption and in addition many other natural products such as cardboard, leather, faeces and even fingernails and toenails of sleeping people
Diseases from cockroaches
Cockroaches do not transmit diseases directly to humans through bites, like mosquitoes, ticks, and fleas, but indirectly, from you consuming contaminated food or touching contaminated surfaces.
According to the World Health Organization (WHO): “Cockroaches are one of the most significant pests found in apartments, homes, food-handling establishments, hospitals and healthcare facilities worldwide.”
There are over 60 pathogenic bacteria, fungi, moulds, parasitic worms and viruses that have been found in cockroaches, including:
- E. coli
- Straphylococcus aureus
- Straphylococcus faecalis
- Shigella dysenteriae
Many of the Salmonella samples that were collected in one study reported by WHO were resistant to antibacterial drugs, which would make infection control more difficult.
Cockroaches and asthma
Cockroach allergy was first reported in 1943. It was discovered when patients developed a rash after cockroaches crawled on their skin.
Cockroaches can trigger asthma because some proteins in their faeces and body parts produce an allergic reaction in certain people. Tiny particles from the dried faeces and body parts can be spread through the air in dust in buildings and expose the residents to the allergens.
The American College of Allergy, Asthma & Immunology reports that the saliva, faeces and shed body parts of cockroaches can trigger both asthma and other allergic responses.
Many studies worldwide have found high levels of exposure to cockroach allergens in people living in urban areas, showing the extent of cockroach infestations in people’s homes:
- The US National Pest Management Association found that around 63% of homes in the US contained cockroach allergens, but in urban areas, the proportion rose to between 78% and 98%
- In the US 60-80% of inner-city children with asthma had been exposed to cockroach allergens.
- In Poland, around 25% of children with asthma had been exposed to them.
- In Taiwan, 58% of all people with asthma had been exposed to them.
- In China, 11-98% of dust samples from nine cities contained cockroach allergens.
How do cockroaches spread diseases?
As they are reservoirs of organisms which cause disease and not vectors, cockroaches use other means to spread diseases.
Cockroaches can spread diseases through:
- Saliva and vomit
- Physical contact with food and surfaces
Due to their unsanitary eating habits, cockroaches can pass harmful pathogens through their droppings. When a cockroach feasts on something contaminated, such as a raw piece of chicken or animal faeces, the microorganisms present will enter and may lay dormant or multiply in its digestive system. The pathogen can then be excreted in cockroach droppings and will contaminate surfaces and food where they crawl.
Cockroach saliva and vomit
Cockroach saliva and vomit are also responsible for spreading microorganisms. Cockroaches sometimes excrete saliva onto food before ingesting it and they also periodically disgorge partially digested food. These can both spread pathogens acquired from eating contaminated food materials.
Cockroaches can be found in many filthy environments that provide them with food, shelter and a suitable environment to survive. These include sewers, cesspits, drains and garbage bins, where they come into contact with a range of microorganisms, such as bacteria, viruses and fungi. These become attached to cockroaches’ bodies in the dust and liquid materials found there.
The legs of a cockroach, for example, have spines that are sensitive to touch and provide a very large surface area to pick up pathogens. Anything a cockroach touches or rubs past may then become contaminated.
How can you catch a disease from a cockroach?
You can catch a disease from a cockroach in a range of different ways. However, for the most part, cockroach diseases are caught by eating or coming into contact with items that a cockroach has contaminated.
Eating and drinking contaminated food
The most common form of transmission of a disease from a cockroach is from eating or drinking anything it has contaminated. This can either be through consuming food or drink contaminated by cockroaches, or by eating or drinking something that has been made using contaminated cooking utensils, cutlery or crockery, or touched contaminated surfaces.
Inhaling contaminated air
If the air supply is contaminated with dust containing particles of cockroach faeces, dried saliva, vomit or shed skin and this is inhaled by people suffering from asthma, the allergens can trigger an asthma attack.
Touching contaminated items
Touching items contaminated with a microorganism deposited by cockroaches is also a route through which transmission can occur. Touching an item which has been contaminated then touching your eyes, nose, mouth or an open wound can result in the pathogen entering the body and infection setting in.
How to prevent cockroaches spreading diseases
The most effective way to prevent cockroaches spreading diseases in your home or business is to practice general food hygiene. This will remove any food sources — including tiny spills and food particles — that will attract them into your property and reduce to possibility of these crawling insects entering your property.
These methods include:
- Eliminate food sources for cockroaches
- Thorough cleaning where food is stored, prepared, cooked and eaten
- Building maintenance to seal cracks and gaps that they can enter through
- Following proper hand hygiene practices to prevent you catching an infection from contaminated objects surfaces