Bed Bugs: Perfect Parasites

Bed bugs have enjoyed a close relationship with humanity for as long as we have been able to keep records. Archeologists have even discovered bed bugs preserved among the artifacts of ancient Egyptians. Bed bugs have evolved to feed on humans ever since they discovered that cave-person blood was tastier than bat blood. For the most part, they have escaped our notice. If bed bugs wielded an immediately painful bite or were easier to find and squish, we probably would have exterminated them long ago. 

A perfect parasite cannot be too harmful to its host if it wants to stay around for the long haul. For this reason, bed bugs painlessly suck our blood while we are sleeping and creep away immediately after they are finished with their meal. Even the saliva that they spit into us while they feed contains a cocktail of around 100 different secreted proteins. These biological drugs prevent clotting, increase blood flow and prevent us from feeling the bite until long after the bed bug has scurried to a safe refuge.

Allergic responses to the saliva in bed bug bites usually take more than an hour and often take more than a day to appear, but they may persist for several days.  Since people have such diversity in their immune systems, symptoms will vary enormously. About 50 percent of people do not react to bed bug bites at all, while others may suffer an itchy and persistent rash. Serious whole-body reactions are very rare but can occur. A computer search will reveal horrific images of bed bug bites. Just remember, not everything you see on the inter-tube is real!

Bed bugs get all of their nutrition from blood, though they need a little help from friendly bacteria that convert nutrients in our blood into B vitamins for them. Unlike mosquitoes where only the ladies exsanguinate us, both male and female bed bugs need to sip our blood. They typically visit the sleeping snack bar about once a week. With unlimited access to blood, bedbugs typically live for about five months. Recent research has shown that starved bedbugs only survive for a few months. The commonly cited “fact” that bed bugs persist for more than a year without feeding has not withstood close scrutiny. Well-fed, laboratory-reared female bed bugs have been shown to lay an average of about 113 eggs during their lifetimes, which is also less than most sources state.

Bed bugs are practically two dimensional, which makes them ideally suited to hiding in unseen spaces. Some of their favorite hideouts are box springs and cracks in furniture and walls. The seams and crevices on a suitcase will do just fine. The female bed bug only needs to mate once in her life. If a newlywed hitches a ride in a person’s luggage she'll be able to continue to produce offspring for the rest of her life without needing to find a new partner.   

Bed bugs have never been shown to transmit any human diseases. Although bed bugs might suck up bacteria or viruses from an infected person, the pathogens do not multiply or survive in the bed bug’s digestive system. Another reason that bed bugs are not known for transmitting diseases is that they vastly prefer humans over other animals as a food source. Local vector borne diseases are typically transferred from animals to people. For example, the bacteria that cause Lyme disease are generally transferred from small rodents to people by a deer tick.  West Nile Virus can be transferred from birds to people by a few species of mosquito.

Bed bugs are not the only thing that cause itchy rashes. The New York Times recently reported on an interesting case of mistaken identity. A person spent $3,500 on an exterminator, who had detected bed bugs with a bug-sniffing dog.  She threw out an expensive bed and 40 garbage bags filled with baby toys and clothing. Eventually, she found that her skin irritation was the result of rodent mites, and not bed bugs.

By the way, it is never necessary to discard clothing or beds that have been in contact with bed bugs! Clothes can be spun in the dryer on the high setting for just 30 minutes. The heat will kill bed bugs very effectively. Mattresses and box springs can be covered with the same inexpensive covers that are used by allergy sufferers to control dust mites. They are breathable and are 100 percent effective against the bed bugs that might be hiding in the mattress or box spring. Of course, mattress covers can’t stop the bed bugs that are hiding elsewhere. There are several other practical approaches for detecting and safely exterminating bed bugs that go beyond the scope of this blog.

I have been fortunate that I have not had to deal with bed bugs in my home.  However, I like to travel, shop at malls, go to the movies and generally interact with other people. I cannot live in a state of perpetual vigilance against bed bugs. I should not be shocked if these sneaky vampires show up. 

When I have to deal with a bed bug infestation, I am going to enlist the help of a professional exterminator who has had experience with treating homes for bed bugs. I will probably need to interview a few before I find one who is up to the task. I will only hire someone who is willing to explore common-sense physical strategies in addition to the chemical arsenal. 

One approach that I promise I will not try, is to deal with my bed bugs all by myself! I am going to need some professional help with this challenge. However, even the most effective and responsible exterminator is not going to be able to get the job done without my help, patience and cooperation. I will need to take their advice seriously, even if it is inconvenient.

The admirable trait of self-sufficiency, combined with the typically high cost of professional bed bug management, leads many people to take the law into their own hands. While understandable, it is very unfortunate. Each year more than 150,000 calls are made to poison centers with concerns about exposure to common household insecticides. It is estimated that 80 percent of most people’s exposure to pesticides occurs indoors. Only one death has been reported as the direct result of misuse of insecticide for bed bugs, and this was an extreme case. Still, the long-term consequences of improperly applied insecticides are greater than the health hazard posed by bed bugs. When I choose a bed bug exterminator, I will look for one who considers chemicals to be one arrow in the quiver, and not the only line of defense.

One explanation for the recent resurgence of bed bugs is that our indoor living spaces are not as contaminated with insecticide as they were just a few decades ago! Few people want to stay in a motel room that smells like bug spray. I tried it once in Washington, PA. It was awful! Upscale hotel rooms no longer have the aroma of stale cigarette smoke to mask the odor of their insect control efforts.  Over time, many public spaces have become more hospitable to bed bugs, but they have also become safer for their human occupants. Something to celebrate!

When DDT was introduced as an insecticide in the 1940s, it was considered to be a miracle. It killed bugs almost immediately on contact. It is not very toxic to people, especially when compared to existing options, like arsenic and mercury compounds or cyanide gas. It was also very cheap. From the 1950s to 1972, DDT was everywhere and bed bugs were on the run. 

By the 1960s, it became apparent that the rampant overuse of DDT was causing serious environmental problems. By the time it was banned in the United States in 1972, many agricultural pests had already evolved DDT resistance. More effective insect control strategies were already replacing the largely obsolete powder.

While bed bugs became rare in in the United States around the 1950s, they continued to thrive in other parts of the world. Meanwhile, globetrotting bed bugs evolved resistance to many insecticides, including DDT. It’s past time to retire the urban legend that bed bugs could be eliminated in the United States if DDT could be sold in the local hardware store. That myth had already been busted back in 1958.

The ability of insects to evolve resistance to insecticides seems a bit strange at first blush. We like to think of bug spray as something that we humans invented all by ourselves. How did bugs get to be so good at finding ways to escape their effects? Actually, plants were synthesizing potent insecticides, such as pyrethrum, caffeine, nicotine and cocaine, long before chemists figured how to do it! From the six-legged perspective, our modern insecticides were nothing new.

The bug killing elixirs that are available at the local hardware store are generally ineffective against bed bugs. Bed bugs are already resistant to many of them.  Other products might kill bed bugs, but are long-lasting and toxic to humans, so they should never be used indoors, especially in a bedroom where you will be in direct contact with them. Even the insecticides that are approved for professional use do not kill bed bug eggs, so repeated visits from an exterminator are often required.

Insecticide foggers (“bug bombs”) are totally useless for banishing bed bugs. In addition to being toxic to people and not reaching the places where bed bugs hide, they have been known to cause houses to explode.  

Perhaps the most convincing argument against the DIY approach to bed bugs is that some insecticides will stimulate bed bugs to flee to previously bug-free parts of the home! This can make the original problem much worse than anything the sorcerer’s apprentice had to cope with. Some insecticides probably smell as bad to bed bugs as they do to people.

One factor in our local resurgence of worldly and chemically-resistant bed bugs is that air travel is less expensive than it used to be. Back in the 1950s, air travelers enjoyed wonderful food and luxurious , but paid for it.  A round-trip flight from New York to Europe would have cost the 2012 equivalent of about $5,000. Bed bugs have celebrated our relatively affordable airfares by hitchhiking in the crevices of our luggage. 

For most of human history, bed bugs were just another annoying part of life, along with stubbed toes, sunburns and poison ivy reactions. The psychological trauma that bed bugs inflict on many people today is real and needs to be taken seriously. The very thought of bed bugs can cause people to lose sleep. Sleep deprivation is a known health hazard. In some cases, the anxiety caused by bed bugs is more dangerous than their actual bites. 

An understanding that bed bugs are really nothing new and are probably here to stay will not provide any comfort. Let’s take solace in the knowledge that with perseverance, patience and professional expertise, local bed bug infestations can be eliminated.