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In the latest years bedbugs (Cimex Lectularius L.) have increased their annoying presence everywhere: in hotels, bed and breakfast, pensions and even in means of public transport.
Bedbugs have been common in many European nations since the 50’s. They have always been associated to poor sanitary conditions and, in fact, their presence had seemed to reduce thanks to a controlled use of effective and residual insecticides, like DDT for example, and thanks to the progressive improvement of structural and health conditions as well.
However, during the last 6-8 years we have viewed a reappearance of these insects even in highly industrialized nations. Italy makes no exception and must face the comeback of this parasite (which is an hematophage organism). The fact that bedbugs have spread in tourist sites in particular is not surprising, as they are the favourite destinations of thousands of tourists.
Some researchers couldn’t avoid noticing this ‘comeback’. As a matter of fact at the 15th European Sove, that took place in Greece last April, they have presented a report about this fastidious parasite.
Mr. Clive Boase has tried to analyze the reasons behind bedbugs comeback and here are his conclusions: the Cimex Lectularius’ presence must be connected to the increasement of international journeys combined with the modification of use of pesticides for civil usage- In particular in order to control the presence of cockroaches and ants is now preferred to use gel and inviting decoy when common pesticide do not sort any effect ( Fletcher, Axtell, 1993).
Speaking the truth at this very moment is not possible to draw attention to a single factor as the principal cause of this problem yet. In fact researches show a totality of factors in which we can underline the difficulty met by disinfestors in controlling fastly and efficaciously bedbugs presence.
This difficulty may be due to the poor knowledge we have of this bug whose biology is still not completely know by everybody.
If we take a closer look to bedbugs we can see that the Cimex Lectularius is a relatively small insect with its 5 mm of length and 3 mm of width. It has an oval and flat shape with a reddish-brown colour and feelers composed by four segments.
Bedbugs are nocturnal insects and feed themselves on any mammal. Although even birds can be source of infestation. They develop through a gradual metamorphosis ( egg- nymph- adult insect), live in small groups and usually find their favourite spot into cracks or other small hiding places. Every male can fertilize more than one female over the range of 24 hours. Every female can lay from 200 up to 500 eggs over a lifetime: from a minim of 1 to a maximum of 5 eggs per day,
Eggs usually take 6-10 days to hatch and the young nymphs reach the adult stage through 5 phases. In order to pass from a stage to another bedbugs must eat, and their meal consists in blood, of course.
This blood meal takes up to 12 minutes to be completed (these insects usually sting around the eyes and other parts of the face). Usually thir bite is not painful therefore most of the times it is not even perceived.
Usually when optimal conditions persist (75%-80% of relative humidity and 28-30 degrees) within 4-5 weeks the vital cycle is completed. There can be more than 4 generations over the range of a year.
However the period necessary to the development of a bedbugs population could be extended in case of a change of environmental conditions like, for example, in case temperature reduces or if bedbugs cannot assume blood due to the lack of hosting organisms. Adult bedbugs can also live quite a few months without food and nymphs do as well even if for a shorter period of time.
Bedbugs tend to live united due to the emission of a uniting pherormone. They usually choose to live in cracks and ravins close to the hosting organisms like bed heads, bedsides, furniture, skirting boards. Bedbugs’ stings can lead to painful inflammations although, to date, cases of pathogen agents transmission to humans have not been found.
However it is also important to underline the fact that specific researches have isolated numerous micro organisms detrimental to human health from these insects.
It is mostly important that the battle against bedbugs is led by professional disinfestors. In fact is very common that an early success turns into a more problematic and persistent situation afterwards if it has not been looked after more than well.
Advices for disinfestors that battle against bedbugs can be summed up in few points:
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