What wild animal kills the most people?
I would have disagree with Nick Nicholas' answer. Although flying insects like the mosquito and Tsetse fly play a essentially important part in causing disease, they do not cause the disease themselves. They are the zoonotic vector - carrying microbial disease itself - most often viruses (malaria, yellow fever, dengue, small pox), protozoan (African sleeping sickness), bacteria (less common -the plague - eradicated now).
From the NIH:
"Vector-borne and zoonotic diseases (VBZD) are infectious diseases whose transmission involves animal hosts or vectors. Vectorborne diseases, such as malaria, are those in which an organism, typically insects, ticks, or mites, carry a pathogen from one host to another, generally with increased harmfulness (virulence) of the pathogen in the vector. Zoonoses, such as Avian Flu, are diseases that can be transmitted from animals to humans by either contact with the animals or through vectors that carry zoonotic pathogens to from animals to humans. While many VBZD, such as malaria, yellow fever, dengue, and murine typhus, are rarely seen in the United States, we are directly susceptible to VBZD that are found in warmer climates and vulnerable due to global trade and travel. Many VBZD are climate sensitive and ecological shifts associated with climate change are expected to impact the distribution and incidences of these diseases."
From the CDC:
"Some animals can carry harmful germs that can be shared with people and cause illness – these are known as zoonotic diseases or zoonoses. Zoonotic diseases are caused by harmful germs like viruses, bacterial, parasites, and fungi. These germs can cause many different types of illnesses in people and animals ranging from mild to serious illness and even death. Some animals can appear healthy even when they are carrying germs that can make people sick.
Zoonotic diseases are very common, both in the United States and around the world. Scientists estimate that more than 6 out of every 10 known infectious diseases in people are spread from animals, and 3 out of every 4 new or emerging infectious diseases in people are spread from animals. Every year, tens of thousands of Americans will get sick from harmful germs spread between animals and people. Because of this, CDC works 24/7 to protect people from zoonotic diseases."