Dr. Ronaldean Pawlisch, a retired Brodhead veterinarian, knows firsthand about the notorious Type A influenza virus, H1N1, because he partnered with the nation’s top researchers on the subject at the University of Wisconsin-Madison in the 1960s and 1970s.
Dr. B.C. (Barney) Easterday of the University of Wisconsin-Madison School of Veterinary Medicine was the first on the research team to work with practicing veterinarians, one of which was Dr. Dean Pawlisch. Dr. Robert Hanson and Dr. Easterday pioneered the project, which has become recognized and esteemed internationally. As early as 1965, Dr. Pawlisch observed swine influenza in Green County swine herds and became interested in exploring the possibility that the disease might be transmitted to people who worked with pigs. Dr. Pawlisch knew that Dr. Easterday and his team were looking for a possible connection between people and pigs because of those who had considered that such a link was possible during the pandemic of the Spanish Flu of 1918.
H1N1 is not a new threat; it was responsible for the Spanish Flu of 1918, which caused the death of 20 to 50 million worldwide, 675,000 nationwide. Some believe the Spanish Flu hastened the end of World War I because 80 percent of the deaths in the United States Army were due to the influenza. Only 20 percent of the deaths were attributed to combat injuries.
Knowing of this research, Dr. Easterday was the first person Dr. Pawlisch called when he discovered a sick hired man on a farm with sick pigs at Thanksgiving time in 1976. Dr. Easterday was in Brodhead within two hours of receiving the call. An already hectic schedule turned into a frenzy of activity. One of Dr. Pawlisch’s business partners, Dr. John Carson, was at a convention in California. Dr. Pawlisch tried to get a hold of the county nurse, but of course, she had already left for the holiday. He and Dr. Easterday collected duplicate samples for laboratory testing from the sick pigs and sick man. Half of the samples were tested in Dr. Easterday’s laboratory, and half were taken to the State Laboratory of Hygiene for testing. The laboratory testing demonstrated that the viruses from the pigs and the man were identical. This was the first documented conclusive evidence that the swine influenza virus could be transmitted from pigs to a human being.
Dr. Pawlisch’s discovery, which was extremely important then, is still recognized as significant by researchers today as shown by mention of his name in a lecture recorded on April 17, 2009, given by Dr. Christopher Olsen, Associate Dean for Academic Affairs and a Professor of Public Health at the School of Veterinary Medicine at the University of Wisconsin-Madison. This lecture was released to the media on May 4, 2009. Dr. Olsen studies the transmission of disease between animals to human beings. (For those wishing to see the entire lecture, log on to http://www.wpt.org/universityplace/UP298_olsen.cfm.)
Today, many are concerned about the current “Swine Flu,” that is circulating in human beings, which Dr. Pawlisch noted should not be called that. Dr. Olsen also noted when discussing the “Bird Flu” that the next pandemic has not been hatched yet. It is true that the influenza discussed in the media today is a type A influenza virus, H1N1. There are Type B and Type C influenza viruses, but only influenza Type A viruses have been transmitted between human beings and animals. It is also true that Type A viruses affect a wide range of animals and have been responsible for epidemics and pandemics. An epidemic is an outbreak of a disease that affects an abnormally large number of individuals in a given population or region. A pandemic is a number of epidemics happening around the world at the same time.
Besides the Spanish Flu of 1918, two other pandemics occurred in the modern age, according to Dr. Olsen. In 1957, the Asian Flu (H2N2) was weaker, with ten times fewer deaths than in 1918. In the U.S., there were 69,800 deaths. In 1968, the Hong Kong Flu (H3N3) struck which was even less severe, with 33,800 deaths in the U.S. One must keep in mind that during a normal flu season in the United States, there are 36,000 to 50,000 deaths due to the flu or flu complications. The last pandemic in 1968 had numbers in this range. It was a pandemic, though, because it was occurring simultaneously worldwide.
There are two large proteins on the influenza virus particle, Hemagglutinin (H or HA) and Neuraminidase (N or NA), that scientists look at when studying the influenza virus. The former (H) has 16 subtypes of the virus, the latter (N) 9. The genetic material of these viruses is segmented into eight different pieces. When a person or animal is infected with two or more influenza viruses having different genes, those genes may be reassorted resulting in new variations of the virus. Changes in the H are key to the pandemics. The 1918 virus was mixed with a duck virus to give us the 1957 flu. The 1968 virus is a mixture of a human virus and two duck viruses.
For the most part, animals are not transmitting viruses to humans. Viruses are caught differently for each. For example, birds shed the virus from their intestines, spreading it that way; people catch a virus through respiratory means. Scientists have discovered some interesting links, though. All 16 H’s (Hemagglutinins) have been found in avian species. Waterfowl can have all of those 16 H’s in various combinations, transmitting the virus to other fowl during migration. Studies show that waters of far northern lakes contain the flu virus when sampled during fowl migration. Pigs may be a mixing vessel for the emergence of newly reassorted viruses since pigs may become infected with both avian viruses and human viruses.
Those studying influenza and influenza viruses continue to strive to provide the knowledge about the disease and the virus that will provide better tools for the prevention and the control of this devastating disease. Meanwhile, one of the best ways to defend yourself is common sense: wash your hands well and often. If you are ill, stay home so you do not infect others.
By Michelle R. Welsh
Originally published in the Brodhead Free Press, May 15, 2009.