During the past century the world's population ballooned from 1 billion to 6 billion, its people became frequent international travelers and traders, and its food supply was globalized. These are just a few of the factors that have led to a dramatic increase in new and emerging zoonotic diseases -- ailments like hantavirus, anthrax and cat-scratch disease that are naturally transmitted between animals and humans, according to a UC Davis infectious-disease researcher.

"To effectively prevent and control zoonotic diseases, the scientific and health communities need to develop a discovery-to-control continuum, ranging from recognition and identification of these diseases to diagnosis training and communication," says Bruno Chomel, a veterinary microbiologist and an authority on the epidemiology of zoonotic diseases.

Chomel, a professor in the UC Davis School of Veterinary Medicine, recently published an overview of emerging zoonotic diseases in the summer issue of the Journal of Veterinary Medical Education.

During the past 20 years, Chomel notes, major progress has been made in identifying disease-causing agents that are transmitted by insects and ticks, especially bacteria that are carried by ticks and cause diseases like cat-scratch disease and Lyme disease. The rate of discovery on viral zoonotic diseases has been even greater, with several rodent-borne viruses like the hantaviruses and arenaviruses identified in North and South America during the past decade.

Part of this success is due to the availability of new tools and procedures in the field of microbiology that help scientists accurately identify pathogens and the diseases they cause. But Chomel points out that, with the rise in the number of outbreaks of zoonotic diseases as well as the new and looming threat of zoonotic agents being used as biological weapons, there is an acute need for developing a comprehensive approach to preventing and controlling zoonotic diseases.

He suggests that such an approach should include improved capabilities in recognizing emerging zoonotic diseases; collaborative, multidisciplinary research; international partnerships for disease diagnosis and surveillance; improved education and training for professionals who may be the first to see cases of human and animal disease; and new strategies for disseminating information about emerging diseases.

Chomel has studied Bartonella infections, cat-scratch disease, hantavirus, rabies and plague and conducted many infectious-disease surveys of wildlife. A new species of bacteria was recently named Bartonella chomelii in honor of Chomel, who was the first to experimentally demonstrate the transmission of another Bartonella species by fleas in cats and to isolate a Bartonella species from domestic cattle.