#31 Tsetse Flies
Tsetse flies are extremely deadly because of a specific sickness they cause known as “sleeping sickness“. The flies transmit the disease through the injection of toxins, which they provide when they feed on blood.
Once the toxin, called trypanosome, is injected, proper treatment is needed to avoid fatalities. Estimates state that these flies could be responsible for a whopping half a million lost lives in the continent of Africa alone.