Don’t Let the Bedbugs Bite — Chromatography to the Rescue

Bedbugs are small blood-sucking insects that live in our beds. They are attracted by body heat, smell and the carbon dioxide we breathe out. They feed on human blood leaving small bites similar to a mosquito bite. Although not particularly dangerous, bedbugs can cause an unpleasant itchy skin reaction along with stressful emotional and psychological problems in some people.

By the end of the twentieth century, the amount of bedbugs had been reduced in many countries — insecticides and hygiene methods had largely eradicated the problem. However, in the last fifteen years there has been an increase in reports of bedbugs to public health bodies — both in numbers and areas of infestation. The increase has been attributed to several things including increased travel, re-use of furnishings and a development of insecticide resistance.

Spying on the bedbugs

Due to their impact on humans it is important to detect bedbugs quickly before an infestation takes hold. And this is not easy. Routine surveillance using current methods is expensive and technically challenging. The techniques rely on mimicking the presence of a human host using carbon dioxide, heat and smell. Over $500 million per year is spent on bedbug management in the USA. Now a team at the Simon Fraser University in British Columbia, Canada has discovered some chemical triggers that may well lead to a cheap and simple detection system for bedbugs — and chromatography played its part in the story.

Hunting pheromones

The story began eight years ago when Gerhard and Regine Gries started a search for bedbug pheromones. Pheromones are simply chemicals that are released by animals and insects to affect the behaviour of other animals of a similar species — chemical signals. Pheromones can be used to trigger many different kinds of behaviour: alarm, sexual arousal or to indicate a food trail for example.

Using gas chromatography and mass spectrometry (see this article for information on GC-MS) they were able to find some pheromones that attracted bedbugs — but only in lab experiments, not in infested rooms. They tried to find the missing pieces by teaming up with chemist Robert Britton. He used NMR to study the tiny amounts of chemicals that had been isolated from bedbug skin shed in places they find safe. After a further two years of study the team found that the chemical histamine signals safety to bedbugs, and once in contact with histamine bedbugs stay where they are.

The answer was in the poo

Unfortunately, histamine with the previously identified pheromones still didn’t attract bedbugs in infested apartments. Something was still missing. Regine Gries started looking at bedbug faeces, and eventually found three new volatile compounds that had never been associated with bedbugs before. When the new and old pheromones were combined — the lure worked and the research has been published in Angewandte Chemie.

So the next time you wake up in the morning with no red bedbug bites — thank chromatography for your pleasant night’s sleep. Hope the bedbugs don’t bite.

Image Source: Bedbugs