After Leonard Eldridge graduated from Washington State University’s veterinary college in 1965, he was known as the folksy, country-type vet who drove gravel roads at dark to treat sick farm animals – a role similar to the James Herriot character made famous in the book "All Creatures Great and Small.”

Today, Eldridge is more like the scientist played by Dustin Hoffman in the 1995 film, "Outbreak.” Hoffman is the hero, and the villain is a pathogen that jumped from animals to humans.

Global travel, changing weather patterns and growing populations contribute to the advance of harmful diseases that spread between animals and humans or are transmitted from animal to animal. Eldridge’s job as Washington state’s chief veterinarian and assistant director of the Animal Services Division of the state’s Department of Agriculture is to keep the pathogens that cause those diseases in check.

Eldridge, who wore a crimson Cougar pin on his lapel, traveled from Olympia to WSU recently to address third-year veterinary students in a class that didn’t exist until this academic year: Emerging and Exotic Diseases of Animals. The course replaced the Foreign Animal Diseases class.

"It’s a different world now,” Eldridge told the lecture hall gathering. "You as veterinarians will be on the first line of defense against infectious agents that can have deadly and economically devastating consequences.”

Eldridge went through a roster of diseases that can threaten agriculture, animal and public health, including avian influenza, Q fever, West Nile virus, rabies and foot-and-mouth disease. Because dangerous microbes lurking in a faraway land one week can launch widespread disease on U.S. soil the next, "We must safeguard the people of Washington by identifying and limiting their exposure,” he said.

Nothing is foreign

Last month in Atlanta, veterinarians sat alongside doctors, biologists and virologists at the U.S. Centers for Disease Control’s (CDC) Eighth International Conference on Emerging Infectious Diseases. Increasingly, veterinarians are experts in disease surveillance and prevention and in diagnosing and reporting unusual illnesses before they become epidemics, said WSU associate professor Mushtaq Memon, who teaches Emerging and Exotic Diseases of Animals and invited Eldridge to speak to his class.

These days, all it takes is a slip in agricultural sanitation or a traveler from another country with a microbe on the bottom of his shoe to set off an outbreak, Memon said.

"Nothing is foreign anymore, which means we’re all in this together,” he said. "By the time our students become veterinarians, we want them to be able to identify emerging diseases and know how to respond to them.”

Q fever, for example, is caused by a bacterium that can pass to humans mostly from goats, cattle and sheep. In animals, it can go unnoticed until pregnant females abort or deliver stillborns.

But in humans, it causes flu-like symptoms and, in rare cases, can be fatal, Eldridge told the students.

First recognized in Australia in the mid-1930s, Q fever appeared in the U.S. just a few years later. Last spring, seven ill people in Washington state were diagnosed with it.

"It’s here, folks,” said Eldridge, while holding his index finger in the air. "All it takes is one organism to make an animal or person sick.”

Working closely with the CDC and WSU, Eldridge traced the outbreak’s source to a Grant County ranch that breeds and sells goats; he then moved quickly to quarantine the animals at the 13 farms where they were sold. The people infected were treated with antibiotics and recovered.

Influenza in flight

So far, no birds in North America have tested positive for the deadly form of avian influenza, A-H5N1, but milder strains are showing up in migratory birds such as the northern pintail, Eldridge told the class. Though not dangerous, the virus is being closely monitored in case it mutates into something more virulent.

"We know from studying their migration patterns that our birds, namely pintails, associate with wild birds in Eurasia,” where H5N1 is most prevalent, he said.

Since 2003, H5N1has killed more than 50 percent of the 602 people infected with it in Asia, Europe and Africa, according to the World Health Organization.

Eldridge made it clear to students that when it comes to disease-causing pathogens, veterinarians can’t play chicken.

"Always remember,” he said, "Early identification; quick containment.”