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Review of Public Health Response to Influenza H1N1

May 13, 2009

Editor's note: Listen here to a recording of the two-hour influenza H1N1 symposium. (right click to download mp3 file)

May 13

The School of Veterinary Medicine brought the CA Department of Public Health, flu researchers, physicians, veterinarians and health sciences students together Tuesday, May 12 for an influenza symposium focusing on the H1N1 influenza virus. 

Bonita Sorensen, chief deputy director of the California Department of Public Health, who reviewed the state's outbreak response, explained that a physician surveillance program in California was responsible for collecting the samples that the CDC confirmed as influenza A H1N1, "which had never been seen before in the world."

The novel influenza strain is spread from person to person, not swine, as several symposium participants reminded the audience. The misnomer of swine flu, stated Bennie Osburn, dean of the School of Veterinary Medicine, may have been responsible for an 82% decline in the consumption of pork in recent weeks in Mexico. In the U.S., the pork industry reported that profits have dropped 16%, said Sharon Hietala, professor of clinical diagnostic immunology in the School of Veterinary Medicine's California Animal Health and Food Safety Laboratory. Osburn and Hietala emphasized that the H1N1 flu is not a food safety issue.

Sorensen described the state's plan for responding to a major health emergency and explained how the department scaled its response through April and May as the state realized that the event was not reaching pandemic proportions. About $10 million was spent on outbreak response. She said, "California is probably better prepared than any other state with investment and surge capacity" in regard to preparedness for a pandemic. The state, however, requires more preparation for a worst-case scenario, and planning does need to involve veterinary expertise. "We fully realize that over two-thirds of emerging infections are beginning in animals," Sorensen stated, so the veterinary profession is integral to public health discusssions about infectious diseases. 

On the clinical side, Christian Sandrock, an assistant professor of pulmonary and critical care medicine in the UC Davis Health System, discussed the decisionmaking processes in hospitals, private practices and public health agencies (he is also a public health officer for Yolo County) during infectious disease outbreaks for the vaccination and treatment of health care workers and patients. He also reviewed some of the factors involved in preparation for large numbers of cases and alternative sites for mass vaccinations and treatment. Sandrock mentioned one teaching center in the School of Veterinary Medicine that could be temporarily turned into a treatment facility for people if the need arose.  

"Alphabet Soup"

Nicole Baumgarth, an associate professor of immunology and an influenza researcher in the School of Veterinary Medicine, used the term "alphabet soup" as an analogy to explain how influenza viruses mix with
components from birds, swine and human influenza virus types and subtypes. Because of its constant reassortment, influenza viruses are among the most rapidly changing of the viruses.

Baumgarth, who conducts research on the immune response to influenza in mice, stated, "Eradication of flu virus is impossible with so many potential hosts that can replicate the virus and spread it through water" or, in the case of wild birds, migrating to new locations. Baumgarth said, "Its nature makes it successful. Ten percent of the virus is dedicated to suppression of the immune response, so it is already infecting you before you feel sick, and by Day 3 it is on its way to spread elsewhere." Vaccination, to prevent the virus from attacking a person's immune system, is the only way to stop the virus. Baumgarth's veterinary research uses infectious disease models to identify and characterize the most basic mechanisms of the immune response in an attempt to develop new designs for vaccines.

Regarding the H1N1, Sorensen noted that the novelty of the flu strain meant that people have no antibodies built up against it, yet so far many illnesses have been mild. Interestingly, Baumgarth pointed out that the cases were affecting younger patients. She commented that people born before 1957, when another influenza epidemic occurred, may have some protection from the current flu due to previous exposure to what may have been a similar strain.

Animal Testing Services in California

Because of influenza and other diseases that are zoonotic in nature--spread from animals to humans or humans to animals--the CA Animal Health and Food Safety Laboratory system manages ongoing monitoring programs to detect infectious disease in poultry, wild birds, swine and many other species. Swine testing for H1N1 has already occurred, Hietala explained. "We 'pinged' our data April 24 that no pigs were found with influenza," she said. "We are amping up testing at fairs and exhibitions for signs of flu and other diseases--and that's to protect the swine," she added. Backyard animals as well as larger production units are part of the laboratory's surveillance program. The laboratory is also a member of several national networks that can gear up for response to animal emergencies involving large numbers of samples to be tested throughout the state.

As flu season begins in the Southern Hemisphere, symposium speakers expressed intentions to observe how influenza might affect other countries in case there are lessons to be learned. Participants took a wait-and-see attitude about potential actions, saying that events would be impossible to predict and the production of vaccine for 2009 would not change. However, whether in public health offices, hospital emergency rooms, diagnostic laboratories or veterinary research facilities, all agreed that they were ready to cooperate in a joint battle against any upcoming influenza epidemics.

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