A high-level centralized animal health authority is needed for the United States to confront a growing threat of illnesses like avian flu and mad cow disease that can spread from animals to humans, the National Research Council recommended in a study released Monday.

Dozens of local, state and federal agencies and private companies have responsibilities for animal health. A new authority is needed to encourage communication and cooperation between these groups, according to the council, an arm of the National Academy of Sciences.

Diseases in animals can critically affect the worldwide food supply, the study said. In recent years several illnesses originating in animals have spread, including causing deadly infections in humans:

—Severe acute respiratory syndrome appeared in 2003, infecting nearly 8,000 people in 30 countries and causing $8 billion in economic disruption.

—Mad cow disease, or bovine spongiform encephalopathy, became a major problem in Britain and spread to other countries. It caused economic disruption when borders were closed to American beef after a single case was discovered in Washington state in 2003. A second U.S. has since occurred.

—West Nile virus arrived in New York in 1999 and has since traveled across the continent carried by birds and mosquitoes. Last year alone there were 2,250 cases in 40 states.

—A new strain of deadly avian flu is threatening several countries in Asia. Millions of birds and dozens of humans have been infected, and authorities fear a global spread.

The nation's animal health system lacks ways to analyze risks and plan for outbreaks, the report said.

In addition to establishing a central system to coordinate animal health activities, the report called on the departments of Agriculture and Homeland Security to support rapid development of new technology to detect, diagnose and prevent the spread of animal diseases.

A second Research Council report, also released Monday, called for stronger efforts to recruit more veterinarians and other scientists into veterinary research.

Both reports said it is becoming more difficult to handle the increasing problems in animal health because of a growing shortage of veterinary pathologists, lab animal scientists and other veterinary researchers, especially those involved in public health.

The council also called for stronger links between public and private labs that test for and diagnose animal diseases.

It said the Agriculture Department made a good start by forming the National Animal Health Laboratory Network, but it added that network lacks the capacity to deal with multiple outbreaks and is only prepared to detect a narrow list of diseases.

In addition, that network needs better connections to the public health systems that detect and diagnose human disease, the report said.