The overwhelming majority of illnesses contracted by humans are “zoonotic,” which means that they come from animals, a new study reports.

Approximately 60 percent of all infectious diseases are zoonotic, and 75 percent of emerging diseases are zoonotic, accounting for about 2.4 billion human illnesses and 2.2 million human deaths worldwide annually. Even more surprisingly, it is a select 13 that currently cause the most harm.

The study analyzed data from various illnesses. High priorities on the list were “endemic zoonoses,” like brucellosis; “epidemic zoonoses,” like anthrax; and “emerging zoonoses,” like HIV/AIDS, which can spread to become global disasters.

The majority of these illnesses come not from wild animals, but from cultivated ones, particularly livestock.

The damage is particularly prevalent in low- to middle-income countries, where poor people depend on most of their income from livestock. The devastating threat of a milking animal’s loss, or worse yet, a relative’s, from zoonoses always hangs over their heads.

Despite the threat of zoonoses, with the increased demand for meats and dairy, livestock are an increasingly lucrative commodity.

In fact, the International Livestock Research Institute notes that regional and global meat markets, created out of a need for increased demand for their products, could present a way for such farmers to move out of poverty. Zoonoses are throwing a wrench in their efforts, however. One in eight livestock in developing countries, for example, are infected with brucellosis, which lowers meat and dairy production by 8 percent.

The study provides a list of Top 20 “hot spots” affected by such illnesses. There are just a handful of countries in which these diseases are concentrated, like India, Ethiopia, and Nigeria. However, the northeastern United States, western Europe, and Brazil are also considered “hot spots” for emerging diseases.

The study was a joint effort conducted by the International Livestock Research Institute, the United Kingdom’s Institute of Zoology, and Vietnam’s Hanoi School of Public Health.

The study was published in Nature.