Flies, botflies, and horseflies abroad and while traveling: are they dangerous, where do you encounter them, where can you see them?
What are flies, horseflies, and botflies?
- Flies are insects with two wings, related to mosquitoes, of which there are very many species. A very small proportion of these fly species feed on animal blood, and very occasionally that animal is a human.
- Horse flies are also known as deer flies. Female horse flies bite humans and can even bite through thin clothing. Horse flies are usually quite large fly species that bite quickly and painfully after landing. Because they cannot fly away immediately after biting, you can swat them dead quite effectively.
- Botflies are fly species that cannot bite or sting. botfly larvae often live in living mammals but rarely in humans.
Are flies dangerous?
- Of the hundreds of thousands of fly species, there are a few species/groups that can be called dangerous.
- Deadly fly: the tsetse fly is notorious for the sleeping sickness that a bite can cause. An infected tsetse fly can transmit a single-celled parasite during the bite and thus transmit the potentially fatal sleeping sickness.
- Sandflies: these small flies cause enough misery for their own chapter
- Horseflies: the bite of a horsefly is usually painful and causes severe itching but is otherwise fairly harmless. Sometimes a nasty bite can cause a bacterial infection, for example rabbit fever. In West and Central Africa, horseflies can transmit the parasite Loa loa, known by the telling name 'eyeworm'
- Botflies: There is only 1 species of botfly that regularly parasitizes humans; this species lives in Latin America. This is not a botfly that lands on you, but mosquitoes, ticks, and flies that spread the eggs of this fly, after which the larvae can crawl into a human's skin. This Dermantobia hominis gained some notoriety when Freek Vonk allowed the larvae to continue living in his skin after discovery. These larvae are normally not dangerous if removed carefully.
- Food poisoning: flies can cause food poisoning by flying from a dirty, contaminated piece of meat or feces to, for example, a market stall with uncooled food.
Where do dangerous fly species occur?
- The tsetse fly, or actually the more than 30 species of tsetse fly, are found in tropical Africa in savannas and in the forest.
- Horseflies can be encountered worldwide; they are active during the day and rarely enter houses. Horseflies mainly bite large mammals and are therefore common around livestock farms and in nature reserves with, for example, wild horses, deer, or other large grazers.
- The botfly species, whose larvae like to grow up in human skin, is found in South and Central America, but the chance of infection is quite small.
How can you prevent a fly or horsefly bite?
- Depending on the fly species, insect repellents, with and without DEET, are quite effective. You can prevent horsefly bites by wearing thicker clothing with high coverage and then swatting every one that chases you to death.
- If you are staying for an extended period in a place with many horseflies, such as on a farm, setting up a horsefly trap can be a solution. The animals on the farm will also be grateful to you.
What can you do after a horsefly bite?
- If the wound is still open and you have Betadine or alcohol at hand, disinfect the wound to prevent a bacterial infection.
- Try to cool the skin after a bite.
- Do not scratch; this will enlarge the bump and worsen the itching.
- Keep an eye on the bite site. If inflammation occurs, antibiotics may be necessary.
