Bed Bug Basics in Nairobi

Bed bugs were nearly wiped out after World War II thanks to applications of now-prohibited pesticides like DDT.

But in the early 2000s, bed bug populations surged in North America. It was the first time many pest management professionals had ever encountered the pest, which hadn’t been studied in decades. Industry knowledge on how to control bed bugs was lacking.

Over the past 20 years, we’ve learned a lot about this pest. And today, bed bug extermination services account for 49.5 percent of the pest management industry’s revenue, according to a report by a global industry research firm.

The industry continues to deepen its knowledge of cryptic pests and hone techniques and products to control them.

What do Bed Bugs Look Like

The adult common bed bug, Cimex lectularius, is about a quarter-inch long. It is flat, wingless, and reddish brown. It is similar in size, shape, and color to an apple seed. Juvenile bed bugs (nymphs) are smaller and pale, making them difficult to see. As nymphs grow, they become darker and larger.

“Many people out there think that bed bugs are microscopic and they’re impossible to see, and that’s why they’re so difficult to get rid of. But in actuality, if you know what you’re looking for, then you are going to be able to more easily find the signs of bed bugs and find those bed bugs themselves,” says Jairus.

Customers often mistake juvenile cockroaches and carpet beetles for bed bugs.

The Bed Bug Life Cycle

Bed bugs hatch from eggs. They then progress through five stages, or instars, on their way to adulthood. Bed bugs must have a blood meal to molt and progress to the next instar. Bed bugs only feed on blood. As well, female bed bugs need a blood meal to develop eggs. After mating, female bed bugs lay one to five eggs a day.

According to the Mallis Handbook of Pest Control (10th edition), the entire bed bug lifecycle (egg to egg) typically takes four to five weeks under optimal conditions (70 to 80 percent relative humidity and 28 to 32 degrees Celsius). Up to four generations of bed bugs may occur in a year. Adult bed bugs can live up to 316 days or longer in ideal conditions.

When Were Bed Bugs Introduced?

Customers often want to know how long bed bugs have been present in their homes.

“Clients want to make assumptions on when they’ve been introduced, but it’s really impossible to tell,” says Collins.

Here’s why: Environmental conditions affect how fast bed bug eggs hatch. In warm weather, eggs may hatch in two weeks. In cold weather, this may take two months. It is difficult to know how many bed bugs were introduced in the first place.

“If only five-bed bugs were introduced to start out, that might take two months to achieve 100-bed bugs,” explains Collins. But if 50-bed bugs were introduced, such as by bringing in an infested piece of furniture, it might only take two weeks for 100 or more bed bugs to develop, he says.

How Bed Bugs find a Host

Three cues help bed bugs find a human host. The first is carbon dioxide, which we exhale. Bed bugs sense carbon dioxide and use it to zero in on a blood meal.

The second cue is body heat. Bed bugs sense body heat, allowing them to move closer to the host.

The third cue is body odour or the chemicals emitted by human skin.

In addition to humans, bed bugs will feed on the blood of animals in the home, such as dogs, cats, rabbits, and birds. The pests feed every few days to once a week.

How People React to Bed Bug Bites

Bed bugs typically bite at night when the host is still and sleeping soundly. While the actual biting is painless, the resulting bite marks may be red and itchy. Bites tend to occur in rows and clusters on exposed skin surfaces, often on the upper torso, arms, and neck.

Everyone reacts differently to bed bug bites. A 2009 study by the University of Sheffield found almost 15 percent of participants had a seven- to 11-day delayed reaction to repeated bed bug bites, and 54 percent didn’t react at all to the initial bite.

Similarly, 30 percent of people said they did not react to bed bug bites in a 2009 University of Kentucky (UKY) survey. And elderly people were less sensitive to bed bug bites, found a survey conducted by UKY and the Lexington (Kentucky) Health Department.

“We never want to use bites to definitively identify a problem,” says Collins. If someone complains about bites, this is a reason to conduct an inspection. “It is not a reason to say, ‘Okay, you absolutely have bedbugs; we need to do that bedbug treatment right away,’” he cautions.

While bed bugs aren’t known to transmit disease through bites, they do cause emotional distress. Bed bugs cause people to lose sleep, which leads to issues like lack of concentration, irritability, and anxiety.

Signs of Bed Bug Activity

A common clue to bed bug activity is fecal spotting, which looks like black dots made with a fine-point marker. Bed bugs typically defecate near their hiding spots, which can help target your treatment efforts.

“That fecal spotting tells me maybe there are eggs in this area. Maybe there’s a crack that I just can’t see into, but I can see fecal spotting, so I am fairly certain that bed bugs are present in this area,” says Michael.

Also be on the lookout for live bugs and cast skins, or the molted skins of bed bug nymphs. Eggs and first- and second-instar nymphs, which are nearly translucent, are more difficult to see with the naked eye.

Where are Bed Bugs Found?

Bed bugs and bed bug eggs are predictable in that they’re typically found where people spend time resting. This may be the bed, recliner, or sofa. Wheelchairs and motorized carts often harbor bed bugs and often are overlooked during inspection and treatment.

Bed bugs gather or aggregate in tiny cracks and crevices. On a bed, they’re most likely found in the box spring, which is disrupted less than the mattress when sheets are changed. Also inspect screw holes and joints of wood furniture like side tables and headboards, behind baseboards and wall hangings, and along mattress seams.

John has noticed a bed bug distribution pattern over the years: About 70 percent of apartments and single-family homes have low-level bed bug infestations with 20 or fewer live bed bugs. About 20 percent get moderate infestations with 20 to 100 live bed bugs, and 10 percent are high-level infestations with 100 or more live bed bugs.

How Mating Behaviour Influences Location

Bed bugs mate by a process called traumatic insemination, where the male bed bug pushes his reproductive organ directly into the female’s abdomen, not into the female reproductive tract. On average, females may endure five of these stabbings per feeding. Males are attracted to female bed bugs that recently had a blood meal, which enables them to produce eggs.

“This gives rise to some of the theories about why females move so much, why we might find female bed bugs or eggs or nymphs away from the bed bug aggregation sites because those females might be leaving those aggregation sites to lay eggs and to try and heal their abdomens up,” says Thomas.

How Bed Bugs Move

Bed bugs move to different locations in two ways. The first is by hitchhiking. Bed bugs can hitch a ride on luggage, purses, backpacks, or clothing during a hotel stay, while riding public transportation, visiting a friend’s house, or even moving from room to room.

Bed bugs also are very mobile and travel extensively on their own, according to a 2015 Rutgers University study. The researchers collected bed bugs, marked them with different coloured dots of paint in the lab, and then released them into six apartments. Using pitfall-style monitors, they found the marked bed bugs traveled extensively throughout those apartments and within two weeks were moving into neighboring units.

“This is why, if you’re not already doing them, surrounding-unit inspections are so important,” says Collins.

Why Monitoring for Bed Bugs is Essential

A visual inspection may not catch a low-level infestation of bed bugs. That is why it is important to use monitoring devices. Knowing the severity of the problem influences the treatment regimen because how you handle two-bed bugs will differ from how you control 200 or 2,000-bed bugs.

Place pitfall traps or monitors under the feet of furniture and beds. They intercept bed bugs leaving or trying to access these resting places. The bed bugs crawl up the textured side of the trap and fall into the slippery valley, where they can’t climb out. Studies conducted in 2011 and 2016 by Rutgers University researchers found pitfall traps were more effective at detecting low-level bed bug infestations than visual inspections. However, the devices cannot replace visual inspection, because they do not gather information like evidence of fecal spotting.

Ongoing monitoring helps gauge the effectiveness of treatment. The number of bed bugs trapped in monitoring devices should decrease until the population is eliminated. In addition to monitoring devices and visual inspection, some professionals use canine scent detection to inspect for bed bugs before treatment and to ensure no bed bugs or eggs are living post-treatment.

“We always want to make sure we’re not just relying upon one method,” says Michael.

How Much Site Preparation is Necessary?

Many bed bug treatment protocols just don’t hold up anymore, and “one of those things is traditional prep for bed bugs,” says Gerald.

It once was standard practice to require residents to strip the bed, empty closets and dressers, launder all bed linens and clothes, bag items that could not be washed, move items out of the affected rooms, and more. But this approach can make the infestation harder to treat and is not always necessary.

Only the most severe infestations may require prep. “Ninety-five percent of bed bug infestations do not need traditional prep to get rid of that infestation prior to treatment,” says Gerald. “And five percent, that’s when we’re going to need a whole lot of cooperation. We’re going to be putting in a whole lot more work for those infestations. Why are we treating the 95 percent like they are that five percent?”

A no-prep approach doesn’t mean no cooperation. “It just means we’re taking an assessment-based approach” and making site-specific recommendations — I need you to launder this, empty that — without the resident disrupting the entire environment, he says.

How to Choose the Right Bed Bug Treatment

An integrated pest management approach that relies on multiple tools is the most effective way to control bed bugs. Tools may include structural heat treatment, fumigation, vacuuming, steam cleaning (which kills eggs), freezing, and the application of natural, biological, or synthetic insecticides.

To combat bed bug resistance, regularly rotate classes of chemicals — choosing different modes of action and active ingredients — in your treatment protocol.

Bed bugs develop pesticide resistance in three ways. First, they can develop reduced cuticular penetration or thicker exoskeletons, meaning insecticides don’t easily penetrate the cuticle layer like they do in thinner-skinned bed bugs.

Second, they develop a more robust mixed-function oxidase system, where the bug’s enzymes attach to the insecticide entering its body and rendering it useless.

Third, the nervous systems of some bed bugs adapt so the alpha subunit on the nerve — the place where a pyrethroid molecule would lock in — no longer fits the pyrethroid key. This renders the insecticide ineffective.

It only takes a few bed bugs with these mutations to survive treatment and breed for a new generation of resistant pests to develop.

Be judicious in your use of dust and glue boards to prevent behavioral resistance. This is when a pest learns to avoid certain substances.

Use mattress encasements, which “allow us to take that complicated box spring out of the equation and help protect our clients’ bedding and help make our treatment methods easier,” says Thomas.

“Lastly, it’s not what you’re using, but how you are using it. You can use the best product on the market, but if it’s not being used with the biology and the behavior of the bed bug in mind, then it’s not going to have a whole lot of effect,” he says.