VMRCVM's Center for Public and Corporate Veterinary Medicine presents Avian Influenza Program
July 6, 2005
About 50 people from state and federal agencies and veterinary practitioners recently gathered at the Virginia-Maryland Regional College of Veterinary Medicine’s (VMRCVM) College Park Campus for a four-hour seminar on Avian Influenza recently.
Experts took a comprehensive look at the influenza virus in general and the troublesome H5N1 strain that has plagued Asia and is increasingly viewed with alarm as an agent that could cause a global pandemic of human influenza.
Presentations were shared on the molecular biology of the virus, bio-security, public health, and emergency response planning.
After opening remarks from Center for Public and Corporate Veterinary Medicine Assistant Director Dr. Katherine Feldman, Dr. Daniel R. Perez, one of the nation’s leading experts on avian influenza, made a presentation entitled “Jumping influenza viruses from ducks to humans.”
Perez joined the VMRCVM’s Maryland Campus at the University of Maryland at College Park in 2003 after working with Robert Webster, one of the world’s leading influenza researchers, at the St. Jude’s Children’s Research Hospital in Memphis, Tenn. Perez recently received a $5 million grant from the USDA, the largest ever awarded by the agency to study a single disease, to lead a multi-university consortium on a major project to study avian influenza.
Influenza is considered a non-eradicable disease because there is an extensive pool of viruses in migratory waterfowl, said Perez, whose principal research interests lie in the interspecies transmission and pathogenesis.
There is a constant gene exchange across species caused by “antigenic drift” and “antigenic shift” and relatively minor changes can help the virus evade the immune system.
“What is worrisome about these viruses is that they have human-like receptor specificity,’ said Perez, who also indicated that many of the influenza viruses seem to emanate from southeast Asia.
The three great human influenza pandemics of the 20th century, including the 1918 “Spanish Flu” that killed more than 20 million people, the 1957 Asian flu, and the 1968 Hong Kong Flu were all believed to be caused by flu viruses that contained both human and avian flu genes, Perez said.
In recent history, there have been several events where influenza A virus from domestic poultry have caused disease in humans. In 1997, an outbreak of H5N1 virus in chickens was transmitted to 18 humans and resulted in six deaths. An outbreak of H9N2 virus in domestic poultry in Hong Kong and southern China also caused human disease and a 2003 outbreak of H7N7 in the Netherlands resulted in 89 human infections.
But scientists and officials from the World Health Organization to the Centers for Disease Control and prevention in Atlanta remain very concerned that the H5N1 strain circulating in southeast Asia could pose a major public health risk to humans.
So far, 100 human cases have been reported in Cambodia, Thailand, and Vietnam, and 54 victims have died.
Perez said greater cooperation between the animal and human health communities as well as surveillance and bio-security are the first lines of defense against pandemic influenza. Developing vaccines to immunize potential human victims is crucial and it is important to learn more about the molecular basis of interspecies transmission and pathogenesis.
Perez also discussed his research that is investigating the role quail may play as intermediate hosts responsible for the generation of influenza A strains with pandemic potential.
Next, Dr. Nathaniel L. Tablante, associate professor and extension poultry veterinarian at the University of Maryland at College Park, presented a talk entitled “Clinical Presentation and Pathology of Avian Influenza.” During his talk, Tablante outlined how the disease is spread in avian populations and discussed the low pathogenic and highly pathogenic types that affect poultry.
Tablante said stepped up bio-security protocols with special emphasis on isolation, traffic control, sanitation, surveillance, and education and outreach were key to preventing and containing outbreaks.
The significance of the threat that Avian influenza H5N1 presents to agriculture was presented by Dr. Tracy S. DuVernoy, an emergency management official with USDA’s Animal and Plant Health Inspection Service (APHIS). Total U.S. poultry production is estimated at $23.3 billion, she said, and the U.S. also is the world’s largest exporter of broilers and turkeys.
DuVernoy said the USDA views H5N1 as a continued threat to U.S. agriculture, is participating in inter-agency and multi-national working groups designed to mitigate the threat, and is committed to protecting U.S. agriculture.
Dr. Daniel Bautista of the Maryland Department of Agriculture discussed the 2004 “low-path” outbreak of avian influenza on Maryland’s Eastern shore during a presentation entitled “Avian influenza and emergency response in Maryland.” Bautista stressed the importance of bio-security, surveillance and appropriate disposal of poultry carcasses.
During a talk entitled “Pandemic influenza planning in Maryland,” Dr. Jean Taylor of the Maryland Department of Health and Mental Hygiene emphasized that the threat of pandemic flu is likely and that strategic planning is crucial because of the enormous impact such an outbreak would have in the United States and throughout the world.
The conference was organized by the VMRCVM’s Center for Public and Corporate Veterinary Medicine, located on the college’s Maryland Campus at the University of Maryland at College Park.