Influenza is one of the most common cross-species disease threats. That’s why many experts – including those at the Defense Health Agency’s Public Health Division – are increasingly integrating human medicine, animal health and environmental science to prevent and treat the flu, as well as other serious public health threats.

Known as the One Health concept, this multi-disciplinary approach aims to solve critical health challenges in an increasingly interconnected world.

Many animal species carry and spread influenza.  The influenza virus also mutates quickly, said Capt. Michael Cooper of the U.S. Public Health Service and chief of respiratory disease surveillance in the Global Emerging Infections Surveillance section in the Public Health Division’s Armed Forces Health Surveillance Branch. Of the four flu virus types – A, B, C and D – three (A, B and C) are known to infect and cause illness in humans. Flu viruses can change over time, and the emergence of a new and different influenza virus can cause a global pandemic.

“Influenza A and B viruses cause seasonal epidemics in humans almost every winter,” said Cooper, a recent panelist at a webinar called “One Health: Influenza and Prevention in Humans and Animals.” “Given its nature and the potential for pandemics, flu is of particular concern regarding Force Health Protection and global health. In the Department of Defense, military members are stationed around the world, often in close quarters, or in locations with heavy animal-human interaction such as farming or herding. We have a vested interest in the detection of emerging pathogens.”

Birds are the main animal reservoir for influenza, and a current strain of circulating H5N1 bird flu has raised both public health standpoint and economic.

“Sometimes the only way to stop the spread of these diseases is through a “stamping out” strategy – birds that aren’t killed by the disease get killed by humans trying to stop the spread of disease. That can lead to a tremendous loss of income, as well as a vital food source, especially in poorer areas of the world,” said U.S. Army Lt. Col. Paul Hollier, another panelist and chief of global veterinary engagement at the DHA Public Health Division’s Veterinary Services Branch.

Sometimes animals can be impacted even when they have nothing to do with the spread of a disease. For example, Hollier cited the 2009 pandemic and the financial losses pork producers suffered when the misnomer “swine flu” was used in public health messaging instead of the correct term, H1N1 influenza. He said that communication and collaboration barriers between health and agriculture industries resulted in an estimated $400 million loss to the U.S. economy. Some estimate the global impact in billions of dollars.

The best way for humans, and some animals, to protect themselves from the flu is through an annual immunization. Flu shots need to be given annually because virus types always change and cross-protection between circulating strains from one year to the next is unlikely.

Catherine Skerrett, a webinar panelist and family nurse practitioner at DHA Public Health Division’s Immunization Healthcare Branch Regional Office at Wilford Hall Ambulatory Surgical Center in San Antonio, discussed the benefits of influenza vaccination.

“Yearly flu vaccination can keep you from getting sick, and can also reduce the risk of serious complications from infection,” she said. “If you get immunized while you’re pregnant, you will transfer some protection to your unborn child. And, getting immunized protects those around you who cannot receive the vaccine.”

The encroachment on forests by humans causes animals and humans to interact more. The ease of international travel make the spread of disease more likely today than in the past, Cooper said. But, he added, surveillance of these diseases has never been better, and the technological advances of the past 20 years have aided significantly in reducing the overall burden of disease.

Hollier said the best way to contain disease in an animal population is to keep it from being introduced, because after it infects animals and spreads, slaughter of animals might be the only way to contain it. Animal slaughter is dangerous, he said, both for the spread of the disease to humans and the contamination of the environment.

“We need an interdisciplinary approach to tackle these complex issues,” Hollier said. “I’m encouraged by recent movement in the public health education community to include animal health and ecosystem health as foundational knowledge for the accreditation of public health schools and programs.”

The One Health concept has been endorsed by more than 850 prominent scientists, physicians and veterinarians worldwide with the hope of helping to protect and save millions of lives from emerging and endemic infectious diseases around the world.