Bugs that Live on the Human Body: Bed Bugs, Triatomine and Lice

Whilst you are sleeping these little critters are out to lunch. Bed bugs have been making a huge comeback, and domestic infestations of Cimex lectularius are being reported in increasing numbers. When bed bugs bite they dine on human blood, and the first signs that they have been enjoying you are usually blood splats on bed linen or you may notice a skin irritation at the sites of the puncture marks where they have pierced the skin. The irritation is an allergic reaction to a chemical in bed bug saliva.

As annoying as these blood suckers are, they do not spread disease. Their comeback is due in part to their resistance to some of the insecticides that we throw at them. Research teams are now actively studying the bed bug genome to find out how to break down bed bug defences.

Triatomines are the blood-sucking bugs that harbor Trypanosama cruzi the human parasite that causes Chagas disease. The condition was named after the Brazilian doctor, Carlos Chagas who discovered it in 1909, and it's more common in Latin America. When an infected insect bites, it is usually on the face (hence its nickname as the "kissing" bug) and it leaves behind infected feces. An infection usually starts when this waste material is rubbed into the eyes or the into the wound that the insect has created. If treated early the symptoms of Chagas disease will go away. If left untreated the disease can cause intestinal and heart problems in later life.

Lice are blood-sucking bugs that feast exclusively on human blood. When separated from a human host they die within a couple of days, as they need your involuntary blood donation to survive. There are two lice species that keep us company and infest human skin - Pediculus hominis, and its two subspecies of head and body lice - and then there's Phthrius pubis - the pubian hair louse. To drink human blood the lice pierce the skin, and chemicals in their saliva prevent the blood from clotting. Lice can be removed using specially formulated shampoos and products.