In the air we breathe
New PHHP scientists study agents that cause respiratory illness
By Jill Pease
It was October 2009 with the swine flu pandemic in full swing, when the USDA announced the first case of the pandemic flu virus had been detected in U.S. pigs. Secretary of Agriculture Tom Vilsack rushed to reassure the public that pork products were safe to eat.
The researcher behind the discovery was Gregory Gray, M.D., M.P.H., chair of the College of Public Health and Health Professions’ department of environmental and global health. His team, along with collaborators at the University of Minnesota, and the Centers for Disease Control and Prevention, identified the pandemic H1N1 virus, the same strain that had sickened thousands of humans, in show pigs at the Minnesota State Fair.
Gray is one of several researchers in the recently-established department of environmental and global health who are studying the properties and transmission of respiratory pathogens like flu viruses and nanoparticles.
Flu viruses can move from domestic to wild animals to humans and back again, and in the process mutate and swap genes to generate new strains, Gray said.
“The fear is that as with other pandemic viruses, the pandemic H1N1 influenza virus of 2009 could become established in North American pigs, mix with other influenza viruses which are common in pigs, and cause another pandemic,” Gray said. “We need to study various animal populations and the workers in these facilities so that if new viruses emerge we can detect them quickly and develop vaccines.”
Gray is currently conducting a national study of agricultural workers who work with swine, turkeys, geese or ducks. The study will monitor the workers and their household members for flu infections that can be transmitted by animals and humans.
John Lednicky, Ph.D., an associate professor in the department, is studying another flu virus that moves through animal and human populations, H5N1, or avian influenza.
“Hundreds of millions of birds have been killed by avian flu, but the virus still hasn’t spread easily between people. We’re trying to understand why,” Lednicky said.
There have only been about 500 confirmed human cases of avian flu in hotspots like Indonesia and Vietnam, but with a 60 percent mortality rate, the consequences of contracting avian flu are very serious.
Lednicky has created a unique lab chamber to study nasal inhalation of avian flu virus in ferrets. He can safely aerosolize the virus and control both the size of the resulting airborne particles and the rate of airflow to produce conditions that closely mimic how humans may come in contact with the virus. The model he developed could be used in future studies of other viruses, bacteria and fungi.
Tara Sabo-Attwood, Ph.D., who will join the faculty in December from the University of South Carolina, researches how synthetic respiratory pathogens can lead to the development of lung disease. She is investigating the pulmonary effects of inhaled nanoparticles, teeny bits of matter used in hundreds of household and industrial products. Sabo-Attwood specifically studies carbon nanotubes, microscopic cylinder-like structures which are found in items like sports equipment and electronics. Research on the possible toxicity of nanoparticles, particularly in occupational settings, has lagged behind their use, Sabo-Attwood said.
“Carbon nanotubes resemble asbestos fibers — long tubes that can link end to end. There is concern that exposure to carbon nanotubes could do the same thing that asbestos does to the lungs,” she said.
She is working with Gray and Lednicky to examine the interaction between carbon nanotubes and viral agents.
“We know that nanoparticles and flu viruses both produce lung injury,” Sabo-Attwood said. “What happens when you put the two together? Can nanoparticle exposure make you more susceptible to viruses? Or could having a virus make you more susceptible to nanoparticle damage?”
Faculty members in the environmental and global health department regularly collaborate with other researchers at the Emerging Pathogens Institute as well as the Center for Environmental and Human Toxicology and the Southeastern National Tuberculosis Center. Working with partners from the Malcom Randall Veterans Affairs Medical Center, department researchers are studying the best ways to prevent the spread of infectious disease among hospital workers and patients. Research collaborations with the UF College of Veterinary Medicine include the study of canine and bovine viruses that have the potential to spread to humans.
“What a privilege it is to work with the talented group of researchers and the outstanding research facilities we have here at the University of Florida,” Gray said.