A limited number of insect species directly transmit diseases to humans. Some of these insects live on or beneath human skin as parasites. The most problematic among them are flies and insects that bite. Flies, in particular, can transfer harmful microorganisms from human or animal waste to food or open wounds through their feet or legs.
Several severe illnesses are transmitted by insect bites. This list includes malaria and filariasis (carried by mosquitoes), sleeping sickness (from tsetse flies), leishmaniasis (from sandflies), epidemic typhus (from lice), and the plague (from rat fleas). Additionally, mosquitoes, sandflies, and ticks can transmit other diseases like yellow fever, dengue, Lyme disease, and certain forms of viral encephalitis. When these insects consume blood from an infected individual or animal, they can harbor or multiply the disease-causing organisms inside them. These pathogens can then be passed to a new human host either through the insect’s saliva during a bite or through their feces close to the bite area.
The majority of diseases transmitted by insects are found in tropical and subtropical regions. However, Lyme disease, which is spread by ticks, is also present in certain areas of the UK.
Preventing insect-borne diseases primarily involves ensuring flies don’t land on food, wearing appropriate clothing to deter insect bites, using insect repellents, and in regions with malaria, employing mosquito nets, screens, pesticides, and taking antimalarial tablets.