Livestock, pets and other domesticated animals could provide new clues into the emergence of infections that can spread between humans and other animals.

image expired

The study showed that the longer an animal had been domesticated, the more parasites and pathogens it shared with humans.

The findings suggest that although wild animals may be important for the transmission of new diseases to humans, humanity's oldest companions – livestock and pets such as cattle and dogs provide the vital link in the emergence of new diseases.

Researchers from the University of Liverpool analysed data from existing studies and information collected in the Liverpool ENHanCEd Infectious Diseases (EID2) database, the researchers cross-referenced all known cases of parasites and pathogens in domestic animals with the length of time they have been domesticated by people.

In dogs, which have been domesticated for over 17,000 years, there were 71 shared parasites and pathogens, and in the 11,000 year association between humans and cattle, 34 have accumulated.

Epidemiologist, Dr Marie McIntyre was part of the study team.  She said, "We don't have enough knowledge of how new diseases get from wildlife into humans.

"This study shows that domesticated animals can play an important role in that process and that diseases have been shared in this way for thousands of years."

The research also examined 'centrality', to determine which domestic animals are in the middle of a web of shared infections.  These animals are most active in spreading disease to other domesticated species.  This 'centrality' linked directly with the length of time since domestication.