Mosquitos
Mosquitos are not only a nuisance but also quite a killer. There are over 3,000 types of mosquitos in the world and various ones carry deadly viruses like malaria, encephalitis, elephantiasis, yellow fever, dengue fever, West Nile virus, and the Zika virus. According to the Conde Nast Traveler these diseases from mosquitos harm 700 million and kill roughly 725,000 people each year.