Our first survey

Resistance against bed bugs is getting more and more organized. The war’s nerve is awareness. So, we launched our first public survey on Sunday, April 7th. It involves analyzing the population’s relationship with bed bugs, its level of awareness on the subject and its expectations.

Our Human practices team began its journey scouting at the St Charles train station – A busy transit point – with a concern for plurality of sources. The team had two forms at its disposal: a first one for bed bugs victims, and a second one for the lucky non-victims. Twenty-six people aged between 15 and 62 were interviewed. Although the number of people is not large enough to be significant, a beginning of trend seems to emerge from the results. Other polling campaigns will therefore be necessary. In the meantime, we will divulge some results of our research for you.

We learned that 17% were already infested by bed bugs, revealing the extent of the plague. Thus, only 1 in 2 people knows these small invaders. This paradoxically demonstrates the lack of prevention and awareness on the subject. Moreover, respondents agree that the scourge is not sufficiently broadcasted and covered, in comparison with its expansion.

People from all over France, but also from very scattered origins, told us about their meeting, or that of their relatives, with bed bugs. The result is a great diversity of concerns: the psychological fear of sharing your living space with small creatures, the price of bedding losses (which can range up to 2000 €), the duration and difficulty of current disinfection techniques…

Overall, the provided solutions by pest control specialists seem to be effective, but require leaving your place for extended time periods, to throw infested furniture … However, performing the procedure by yourself does not appear to be an option for the respondents. In parallel, it seems that the majority public interest is efficiency (71%) although ecology is not left behind (19%).

Throughout this campaign, we wanted to know the general opinion of the population on the use of GMOs (Genetically Modified Organisms) as a mean of fight against bed bugs. The survey has shown that 1 out of 3 people are in favor of the use of GMOs but insisted that they should be radically more effective. This highlights some “GMOphobia” within the population. It is not clearly justified, as all the interviewees said that they do not know what a GMO is. This points out a significant lack of awareness on biotechnology and its use.

This first database will allow our research team to target more precisely the expectations to which Breaking Bugs will have to answer. The survey also clarified and highlighted the topics of our future information and communication campaigns. Finally, we got in touch with the public and the bed bugs’ victims, confirming our will to win this fight!

Infested locations collected during the survey.

(Should extend after a few more surveys).

Interview with Mr Jean Michel Bérenger

On the 30th of March, we had the chance to meet Mr. Jean Michel Bérenger, a bed bugs specialist. This passionate and recognized entomologist has given us his time to answer a lot of our questions in his laboratory at the IHU (Institut Hospitalo-Universitaire Méditerranée Infection).

What are the main bed bugs species, and what differences can we spot?

The two main species of bed bugs are Cimex hemipterus and Cimex lectularius. These two species are the most studied and most likely to be the cause of infestation. There are no morphological differences (at least not with the naked eye), nor any metabolic differences between them. Thus, a basic bug trap can attract both.
It is already known that Cimex hemipterus is originally found in Russia and Sweden. The same goes for Cimex lectularius. It is assumed that the first individuals of these species appeared in these countries.

What do bed bugs feed on?

Like mosquitoes, bed bugs are exclusively hematophagous insects. Even though humans are the first victims, they can survive by feeding on the blood of other animals, such as cats, dogs, birds and even the gecko. It has been shown that with bed bugs feeding on non-human blood, the number of females’ spawning decreased and that the different stages of their development cycle were longer.

What are the essential nutrients for their survival and how are they assimilated?

Bed bugs draw vitamins A and B from their blood meals, essential for their survival. The blood digestion will be done thanks to symbionts that they carry in them at the intestine in the mycetoma. These symbionts will draw essential nutrients from the blood.
The insect’s body is at room temperature (22/24°C). A hematophagous insect should instantly die by thermal shock with a 37°C meal (Humans’ blood). An adaptive temperature regulation system is set up: specific to each hematophagous insect. For bed bugs, this mechanism is maintained by a ‘’Heat Shock Protein’’ (HSP) that sucks in the occurring thermal shock, protecting its environment.

We know that bed bugs have a carapace, what is it made of?

The bed bug shell consists of chitin and hydrocarbons at all stages of its development cycle. Moreover, one of the major phenomena of resistance in bed bugs is the thickening of the cuticle. The treatment used to eradicate them will have more difficulty to penetrate, and therefore will be less efficient.

What about the phenomenon of resistance?

The bed bugs’ resistance phenomenon is mainly caused by humans. If you use a lambda insecticide on a wild bug, it dies instantly, which is not the case with some bed bugs. This is because most people use products with molecules to which the bug resists, which maintains its resistance somehow. So, from the outset it must be known with which individual we are dealing. Thanks to their strong sense of smell, some dogs can spot bed bugs’ larvae and adults, even through a double wall.

What are bed bugs attracted to?

Bed bugs are guided to us by 3 main factors: CO2, temperature and odors. In addition, recent studies have revealed their attraction to colors, such as red and black as well as contrasts (juxtaposed black and white). This attraction would be explained by a camouflage behavior.

Finally, the pheromones are very important. The black spots that can often be found around the areas where they are, are made of their own droppings. It is digested blood, containing pheromones that are very detectable particles by bed bugs. This detection can be done in a very wide area around the point of emission. After a series of meal hunting, they use the pheromones released by their droppings to guide themselves back and find their dark den. They capture the pheromones via their antennas.

What are the optimal conditions for bed bugs’ development cycle?

Bed bugs live at room temperature (about 25°C). Some people think that lighting is a very important parameter, while others feel that it is not, since originally these insects live in dark caves with bats.

When are bed bugs the most vulnerable in their life cycle?

Bed bugs are the most vulnerable in their first stages of life. It is at this point that individuals exhibit a high metabolic activity that decreases as one goes through the life cycle. It is therefore easier to target metabolic pathways essential to the individual during these life stages.

Which microorganisms are bed bugs sensitive to?

They are not sensitive to viruses, but a recent study has been conducted on their contamination by bacteria and especially by pathogenic fungi, for example Beauveria bassiana.

Do they Interact with other insects? Do they have any predators?

Bed bugs live inside our houses; thus, they don’t interact much with other insects. The House Centipede (Scutigera coleoptrata) is one of its natural predators, but I do not think anyone agrees with the idea of ​​bringing them inside their home to get rid of bed bugs.

What about their evolution cycle?

Bed bugs are insects that have become simpler over time. They have no more wings, no more complex eyes but compound eyes, compared to their wild counterparts. Set over against triatoma (wild hematophagous bugs in the Amazon jungle), they only have about fifty pheromone sensors. Their wild counterpart has more than 3000. This is a good example of simplification; bed bugs are no longer in need for wings and many sensors since their prey, us humans, is a few steps away.

Are bed bugs pathology vectors?

To date, no pathogen can be transmitted by the bite of a bed bug, since there is none in the salivary glands. Pathogens are only found in their droppings and intestines.

What are the limits of the solutions?

The use of gas is misguided, because bed bugs can also hide behind a piece of furniture against the wall, where the gas does not reach. Individuals will not all be affected.
There is already a passive trap that puts together an odorant tube (coriander odor) and an adhesive tape. It’s an interesting solution for the bugs that have just arrived in the room and have not yet installed. Otherwise, the use of an active trap (CO2, temperature, odor) is more efficient. These traps already exist (heat and smell) but are more or less effective. On the other hand, there is not yet a trap putting together the three attraction factors of bed bugs.

 

A mighty warrior, bedbug is his name

Did you ever wake up with red stings and found blood stains in your bed? It looks like you were invaded, not by aliens but bedbugs: that’s even worse! Here is the culprit.

Fig. 1 – There is your culprit

Bedbugs are a hematophagous arthropod of the family Cimicidae within the order of Hemiptera. The 2 genuses and species implicated in human infestations are Cimex lectularius and Cimex hemipterus. C. lectularius is spread worldwide, but C. hemipterus lives in tropical environments. The only way to distinguish both species is by the color. In fact, C. lectularius is lighter than C. hemipterus.

Former parasite of the bat at the time of cavemen, bedbugs have been attacking humans for over 40 000 years. It’s no joke when we tell you that bedbugs are smaller than dracula (about 5 mm), and in larger numbers. They crawl around while you’re sleeping to suck your blood. A phenomenon that causes dermatological and allergy problems.

Lifestyle

Bed bugs are expert hitchhikers, passively transported by humans via luggage, boats, trains, etc. They are found in areas with frequent human attendance, and ideal for their development and life cycle.

Being nocturnal insects, they hide during the day inside the bedding and any dark places available in the room. It is only at night that they dare to come out of their shelter to eat. They can move within a radius of 10 meters. They can also climb up floors via the ventilation ducts. Real sports in sum! After a series of meal hunting, they use the pheromones released by their droppings to guide themselves back and find their dark den.

Reproduction and life cycle

Fig. 2 – Traumatic sexual reproduction From « Les punaises de lit Cimex lectularius et Cimex hemipterus – Biologie, Lutte et Santé publique », 2 ème édition. CNEV, 2015, p. 24.

Their sexual reproduction is said to be “traumatic”. Reproduction occurs via insemination of the female by a male through numerous violent perforations of her abdomen. This phenomenon gives rise to a high mortality rate of the partner during reproduction. If the female survives, she will be exposed to numerous infections that might kill her. Nonetheless, throughout their adult lives, females can lay up to ten eggs a day, or about 300 to 500 eggs in their lifetime. From an evolutionary point of view, this fertility is an offset to the high mortality induced by reproduction.

The life cycle of bedbugs is very slow: it is between 40 and 70 days. This explains the one-month delay between the actual infestation and the discovery of invasion sites. Unfortunately, when these sites are visible, the bedbug colony is already too big.

Fig. 3 – Bedbugs development cycle From « Les punaises de lit Cimex lectularius et Cimex hemipterus – Biologie, Lutte et Santé publique », 2 ème édition. CNEV, 2015, p. 24

Their development cycle breaks down into 5 stages.

 

Each of them lasts from 3 to 15 days. Fun fact, the essential condition to move to the next stage is a blood supply. Once an adult, a bedbug will be able to survive without blood meals for approximately 2 years in ideal conditions.

 

Treatment

While exterminating bedbugs, no residual threshold is acceptable, otherwise the invasion will start again. Therefore, it is a matter of setting up an efficient fighting strategy.

Current treatment strategies are limited and highly invasive. They require specialized exterminators. They master the art of using very toxic materials and gaseous pesticides. But their skills are limited in activity. The fumigation saves the recesses of bedsteads, mattresses, cracks and more. Thus, sorting the furniture prior the extermination is essential.

The following steps will be necessary:
1. A partial removal of the furniture.
2. A total restoration of the premises (taking off the wallpaper, the carpet…).
3. A decontamination of personal effects that is done either:
– At very high temperatures: 60 ° C and above to target adults, 110 ° C and above to tackle all the bedbug stages.
– At very low temperature: at least -20 C ° for 4 days (for clothes…).
4. Chemical control by powerful pesticides.
5. Awareness! It is the key to understanding the origin of bedbugs’ infestations and preventing future upsurges.

Afterwards, we can create traps to attract bedbugs (with carbon dioxide or specific pheromones, repellent bed covers, diatomaceous earth…).

Conclusion

To sum up, bedbugs are very invasive pests. They have a remarkable impact on our hygiene and public health. An entire population can be affected. Therefore, replacing current extermination methods is a must.

Our iGEM team from Aix-Marseille is here to explore new, innovative and cheaper alternatives.

 

References
1. Delaunay P, Berenger JM, Izri A, Jourdain F, Perrin Y, Robert V. , « Les punaises de lit Cimex lectularius et Cimex hemipterus – Biologie, Lutte et Santé publique », 2 ème édition. CNEV, 2015, p. 24
2. Anastay M. ,Blanc V. , Del Giudice P. , Marty P. , Delaunay P. , « La punaise de lit : un ectoparasite émergent », La Lettre de l’Infectiologue, Tome XXVI – n° 1, janvier-février 2011, p. 18