About bed bugs

Bed bugs are parasites that preferentially feed on humans but will feed on most warm blooded animals if available. Although they are not considered to be a major pest or health hazard they can be highly unpleasant to live with and can cause a severe lack of sleep, anemia and serious mental fatigue.

Adult bed bugs are brown to reddish-brown, oval-shaped, dorsoventrally flattened and about 2-5 mm long. Their flat shape enables them to readily hide in cracks and crevices. In some cases colonies have been found in places where it is difficult to insert a sheet of paper.

Bed bugs are typical cimicids. They are secondarily wingless in that they have evolved to loose their functioning wings. In contrast, primitive insects such as psocids have yet to develop the ability of flight. The short rudimentary wing is still clearly visible in adult specimens.  They have a broad head and well developed eyes. When not feeding the mouth parts are stored, tucked under the head and thorax. During feeding the mouth parts are swung forward to bring them perpendicular to the insects’ body

Mating in bed bugs is very unusual. The male has a curved aedeagus at the tip of the eleventh abdominal segment. On the ventral side of the females’ fourth abdominal segment is the opening of the ribaga. The male penetrates the cuticle of the female in a process aptly called traumatic insemination. Sperm is deposited in the ribaga along with a nutrient rich substance to improve the viability of the eggs. The sperm migrates through the haemolymph to the base of the oviducts, which they ascend to fertilise the descending eggs.

Females migrate away from the main aggregations after mating to avoid repeat matings. This post mating migration is key in the spread of an infestation through a building. Female bed bugs lay between one and ten eggs per day depending on the availability of food. The eggs are cemented to rough surfaces or in cracks and crevices using a protein “glue”. The eggs are usually affixed in areas that adults congregate or harbour between feeding trips. 

Eggs hatch in around 10 days, but their development rate is governed by the ambient temperature. In common with most Hemimetabolous blood feeding insects all nymphal stages and adults of both sexes feed on blood. However newly hatched first instar nymphs cannot immediately begin to feed. They first need to acquire vital gut flora, this is acquired in aggregations where the newly hatched nymph is exposed to previous generations fecal matter.

These bacteria provide supplementary nutrition of compounds not present in the feed and not formed by the bug. These symbiotic bacteria are found in the mycetome in the abdomen. Unusually bed bugs need two symbiotes, one pleiomorphic and one bacilli.  
They require a blood meal in order to molt and develop into the next stage. Bed bugs reach maturity after five molts each nymphal stage requires one or two blood meals. The nymphal period is greatly prolonged when food is scarce.

Bed bugs are well known for their ability to survive prolonged periods of starvation. In laboratory tests they have been seen to survive 18 months without a feed. Under favourable conditions development from egg to adult can be as short as five weeks, however this can be protracted by a lack of food or a reduced ambient temperature

International travel and commerce are thought to facilitate the spread. Young and adult bed bugs are readily transported in luggage, clothing, bedding and furniture. Bed bugs can infest aircraft, ships, trains and buses. However local exposure and natural migration appear to be an increasing source of infestation. In many cases the neighbouring dwelling may be the source of the infestation and unless treated will act as an offsite population reservoir. Negotiation with neighbours can be a very delicate matter and needs to be treated with the utmost care and discretion.

Bed bugs are most frequently found in dwellings with a high rate of occupant turnover, such as hotels, hostels, dormitories, shelters, prisons and multi occupancy buildings. Such infestations are not usually a reflection of poor hygiene or bad housekeeping but that a previous occupant had come into contact with them at some stage

Bed bugs are relatively fast moving insects that are predominantly nocturnal blood-feeders. They are however opportunistic, becoming diurnal if the host is only present during daylight e.g. shift workers. They will also feed on awake hosts with lots of disturbance, as seen in some infestations on public transport or in public buildings.

Early nymphs may become engorged with blood within three minutes, whereas a full-grown bed bug usually feeds for ten to fifteen minutes depending on apyrase levels injected at the time. Apyrase levels are dependant on the duration since the last feed. A starved bug will inject lower levels so will need a more protracted feed. They then crawl away to a hiding place to digest the meal, which may take 3 or 4 days.

Bed bugs hide during the day in dark protected sites, preferring fabric, wood, and paper surfaces. They usually occur in fairly close proximity to the host, although they can travel further if necessary. Bed bugs have only 56 antennal receptors. So true klinotaxis only occurs at very close range. Primary location of the host is predominantly by luck, the foraging bugs blunder around in a random search pattern, waving their antennae in the air trying to pick up on a stimulus that will help locate the host. For this reason bed bugs try where possible to harbour very close to the host.

Bed bugs can often be found in tufts, seams, and folds of mattresses, later spreading to crevices in the bedstead or divan base. In heavier infestations they also may occupy hiding places further from the bed. Such as window and door frames, floor cracks, skirting boards, furniture, and under gripper rods of fitted carpets. Bed bugs move through three dimensions to feed and harbour, often crawling upward to hide in pictures, wall hangings, shelves, loosened wallpaper, cracks in plaster and ceiling moldings. They also migrate under floorboards and behind skirting to locate favourable micro climate to congregate, mate and lay eggs.

If disturbed bed bugs excrete an alarm pheromone causing congregations to disperse quickly. This pheromone is suspected to also be emitted if the host wakes, triggering feeding bugs to abandon the feed and return to the refuge

The bite is painless at the time but will typically cause the skin to become irritated and inflamed. Individuals differ greatly in both the extent and timing of their response to a bite. A small hard swollen white welt may develop at the site of each bite, which can occur in rows or batches of three or four. This is accompanied by severe itching that lasts for several hours to several days. In rare cases an allergic reaction may follow. The morphology of bites is highly variable and bed bugs are almost impossible to diagnose on bites alone.

It is believed that 1 in 10 people show no signs of biting, often leading to the myth that they only attack certain people. Cases of extreme reaction seem to be on the increase.
Some individuals respond to bed bug infestations with anxiety, stress, and insomnia.
If an infestation is heavy or prolonged anemia or iron deficiency can develop.

If the client is feeling tired and lethargic it is advisable for them to go to their doctor for an iron test. Iron supplements prescribed by the doctor can help significantly. The doctor may also prescribe an anti-histamine. This can help reduce the effects of the bites, reduce itching and consequentially the risk of secondary infection.

It is vital that the doctor is advised that the bites are bed bugs as they have been misdiagnosed in the past as scabies, chicken pox and on one occasion small pox!
Mentally the toll on the client can be considerably worse.

The bedroom is a safe haven, it is seen as the safest place in the home. Bed bugs by their nature violate this space and attack the host when they are at their most vulnerable. To many clients this violation has been akin to burglary. Most clients will suffer some form of mental response. Commonly in the form of lost sleep, fatigue and depression. In some cases the response is more acute.

Some clients have been admitted to hospital to assist their recovery or have required medicating to control their symptoms. It is therefore vital that all communications with the client are sympathetic and diplomatic. The approach should be to offer the solution and not to comment on the extent of the problem possibly inflaming the situation. Do not however give unduly high expectations or false hope