Bed bugs are a challenging pest to deal with – here’s everything pest managers (and customers) need to know them.
Bed bug bites are normally the first sign that a customer has a bed bug problem. Making a medical diagnosis is the role of a medical professional, but pest managers need to understand bed bug biting behaviour and the risks around bed bugs to be able to advise their customers on the importance of preventing bed bug infestations.
How do bed bugs bite?
Bed bugs are attracted to carbon dioxide and body heat to find a potential host. Bed bugs bite at night and probe multiple times trying to find a suitable capillary, which can result in multiple bites. Their bite fluids include at least 46 different proteins (some of which are the cause of allergic reaction) and components to numb the skin and prevent the blood from clotting. Once they have found a successful feeding site, they will feed for 5-10 minutes, until full. They will then disengage and return to their harbourage.
What do bed bug bites look like?
Whilst some people will have no reaction to a bed bug bite, most bites will appear as a small, raised, itchy red spot (pictured above). Often there will be numerous bites in one area, sometimes in a line – the result of a bed bug trying to find a suitable capillary. So lots of bites doesn’t necessarily mean there are lots of bed bugs, although there could be.
Bed bug bite treatments
Victims should consult a medical professional for diagnosis and treatment. With the exception of cases of severe allergic reaction, normally the only treatment that’s required is medication to relieve the itching.
Do bed bugs carry and transmit diseases?
To date, there is no definitive proof that bed bugs transmit disease. But there’s a big ‘but’! Scientific literature lists at least 45 diseases that bed bugs carry (including bacteria, viruses and fungi) and at least theoretically, there is the potential for these to be transferred to humans when bitten. This could occur directly through fluids entering during the biting process or through bed bug faeces which could enter the body when the victims scratch their bites.
To be a vector for disease transmission, bed bugs need to demonstrate vector competence – can they acquire the infectious agent, maintain or amplify it within their body and subsequently transmit it to another animal?
Although bed bugs are known to carry 45 or more diseases, actual transmission has not been proven for any of these diseases. Bed bugs have a reflex faeces excretion after a blood meal, which will often been seen as spots on bed sheets and mattresses. One microbe considered more likely to be transferred is the parasitic protozoa Trypanosoma cruzi, which causes Chagas disease. This parasite is known to be transmitted by kissing bugs, which have many similarities to bed bugs. T. cruzi has been found in wild bed bugs, and in laboratory studies the bed bugs were shown to acquire the parasite after feeding. The parasite was subsequently detected in their faeces and their salivary glands – meaning it could potentially be transmitted during biting.
Like bed bugs, kissing bugs have a reflex faeces excretion after feeding and scratching bites is known to facilitate the entry of parasites through the broken skin. So, there is good evidence to show such transmission is possible, but it has yet to be proven. One of the other leading candidates for likely transmission by bed bugs is the Hepatitis B virus.
Allergic reactions to bed bugs
Although the concern about potential disease transmission is valid, the issues around allergic reactions to bed bugs is both known and serious. Individuals can have differing reactions to their first bed bug bites – some have no reaction, some have a bigger allergic reaction – with the bites developing into an extremely itchy wheal up to 5 cm in diameter and some even developing a blister. More of a concern is that people who have regular bed bug bites can develop sensitivity to their bite components, and can develop a life-threatening anaphylactic shock even after one or two bites.
This allergic reaction is not just confined to bed bug bites; in rooms and apartments which have seen significant, ongoing bed bug infestations, histamines (which can cause allergic reactions) have been found at greatly elevated levels. These histamines are present in bed bug faeces and spent skins. Unless a comprehensive clean is carried out, these histamines remain for an extended period, even after the bed bugs have been eliminated.
