> Est. annual deaths: 17,400
About 4.5 million Americans are bitten by dogs each year, resulting in thousands of hospitalizations and 30 to 50 deaths. Pitbulls and Rottweilers are responsible for the majority of fatal attacks, with German Shepherds a distant third. Although the global number is impossible to know with any accuracy, the World Health Organization estimates that 60,000 people die from rabies transmitted through dog bites annually.
> Est. annual deaths: 24,200
Sandflies can transmit a number of diseases, including the deadly chandipura virus, which is similar to rabies. Even deadlier is leishmaniasis, caused by a parasite transmitted by sandfly bites, predominantly in poorer countries. There are estimated to 700,000 to 1 million new cases of leishmaniasis each year, and, while actual counts are not available, Doctors Without Borders states that the affliction is second only to malaria in parasitic-caused deaths.
> Est. annual deaths: 60,000
An estimated 4.5 million people, mainly agricultural workers and children in Africa, Asia, and South America, suffer snake bites each year. About half of the bites are venomous, with between 80,000 and 130,000 resulting in death. Survivors often suffer other health impacts, from liver disease to amputations.
> Est. annual deaths: 580,000
Gates arrives at his number by adding human deaths by homicide (409,000) and deaths by war (approximately 172,000), making homo sapiens the second deadliest animal in the world.
> Est. annual deaths: 830,000
An estimated 700 million people contract diseases from mosquito bites each year, and about a million die as a result. The highest numbers of mosquito-driven deaths are 25,000 from dengue fever, 30,000 from yellow fever, and hundreds of thousands from malaria. (Mosquitos carrying malaria, Gates notes, kill a child every minute.) Mosquitos are also responsible for untold numbers of other debilitating but less deadly diseases such as lymphatic filariasis, chikungunya, zika virus, and West Nile virus.