Risks associated with Arthropods

Mosquitoes are vectors of numerous viruses and parasites, and are also responsible for significant nuisance. It is therefore recommended to protect yourself from their bites with appropriate protection. Individual measures to prevent mosquito breeding (such as eliminating stagnant water sources at home) are complementary.

Mosquitoes of the genera Anopheles et Culex They bite mostly at night. These mosquitoes are found worldwide but are disease vectors primarily in tropical areas of Africa, America, and Asia, and to a lesser extent in more temperate zones. They can transmit malaria parasites (Anopheles only), arboviruses (West Nile virus, American encephalitis virus or Japanese encephalitis virus) and filarial worms.

Mosquitoes of the genus Aedes They usually bite during the day, with peak activity at the beginning and end of the day. They can transmit arboviruses (such as those that cause dengue, yellow fever, chikungunya, and Zika): see pages for related diseasesand microfilariae responsible for lymphatic filariasis. The nuisance caused by large and aggressive populations of certain mosquitoes exists in every country in the world, from the equator to the Arctic Circle. Mosquitoes in Nordic countries can also be very aggressive during the short summer season.

Bed bugs are small, ubiquitous, nocturnal insects. They can be easily transported by hiding in clothing, luggage, and other personal belongings, meaning that international travelers can spread this nuisance back to their home countries (through passive transport).

The places where travellers run the greatest risk of exposure are those with the highest turnover of people: buses, trains, planes but especially hotels (regardless of their price range), tourist resorts, cruise ships…

To date, no transmission of pathogens by these bedbugs has been described. Bacterial superinfections, particularly from scratching with dirty hands, are possible, as with any pruritic dermatosis.

The recommendations to avoid bed bug infestations in your home upon your return are as follows:

• during the trip:

Inspect your room upon arrival to ensure there are no bed bugs (look under the sheets, under the mattress cover, the bed base, the baseboards, etc.).

If bedbugs are observed, it is best to change your place of stay.

If this is not possible, avoid placing your luggage and personal belongings on the bed, sofa, in the wardrobe or any other spaces likely to harbor bedbugs (for example, isolate all luggage and personal effects – hairbrush, makeup bag, etc. – on a tiled surface);

• Upon returning, if you suspect an infestation:

Carry out physical treatment of clothing and luggage (washing clothes at 60°C or steam cleaning at 120°C) which destroys bed bugs at all stages, or freezing at -20°C for a minimum of 48 hours depending on the size of the object.

Clean what cannot be physically treated with a vacuum cleaner (don't forget to clean the vacuum cleaner hose as bed bugs can come out of it, and throw the tightly sealed bag in an outdoor bin).

If this fails, additional chemical treatment is necessary: ​​contact the town hall or a professional specializing in pest control (holder of a "biocide certificate").

Ticks, which are differentiated into soft ticks and hard ticks, have a worldwide distribution and occupy varied biotopes.

Hard ticks bite during the day, and their blood meal lasts for several days. Transmission of pathogens occurs within 12 to 24 hours after the bite for bacteria and parasites, but can occur immediately for viruses (hence the importance of prevention). In soft ticks, blood meals are rapid and occur at night, with immediate transmission of infectious agents.

Preventing tick bites involves wearing covering clothing (preferably light-colored to make ticks easier to spot) tight at the ankles and wristsSkin repellents applied to exposed areas have limited effectiveness.

Preventing the risk of transmission of infectious agents after tick bites relies on the following methods:

• A thorough body examination, including the scalp, navel and genitals after potential exposure (on returning from a walk in a risk area, etc.).

Most hard tick bites are painless and occur mainly (but not exclusively) on the lower body parts in adults – because ticks lie in wait on vegetation – but they are frequently found on the scalp in children.

• Using a tick remover or fine tweezers to extract a tick.

Grasp the tick as close to the skin as possible and remove it slowly but firmly. Do not apply any product to the tick beforehand. Disinfect the bite site and wash your hands.

The persistence of tick bites in the skin following extraction should not lead to medical or surgical intervention, but to disinfection and regular monitoring of the bite site.

• No antibiotic therapy or request for further tests is justified at this stage.

Monitoring the bite site (for the appearance of erythema or eschar) for several weeks is necessary. Further investigations are warranted if even a mild fever or fatigue develops a few days after the bite.

• A vaccination exists to prevent infection by the tick-borne encephalitis virus (see disease page).

Microscopic mites, such as chiggers, can infest the skin during walks in natural environments, particularly in tropical areas, and cause intense itching. To protect yourself, it is recommended to use skin repellents. After a bite, benzyl benzoate can be applied once or twice to the scratched areas using a cotton swab to reduce the itching.

In Asia, one of these microscopic mites of the genus Leptotrombidium transmits scrub typhus.

Scabies is a common cause of widespread itching after returning from travel. The mite responsible (Sarcopts scabiei) does not transmit any pathogens.

Other stinging arthropods such as spiders, centipedes, scorpions and certain social insects (wasps, hornets, bees…) can cause envenomation (local or general manifestations, induced by the penetration into the body of venom which is more or less toxic depending on its composition).

Any bite or sting that causes marked local symptoms or general symptoms (sharp pain, swelling, malaise, low blood pressure, vision problems, nausea, fever, etc.) requires a consultation.

In the case of bivouacking, to avoid the passive transport of arthropods or the colonization of personal belongings (clothing, shoes, etc.), it is recommended to store them in a sealed and well-closed plastic bag or container.