Feb 12, 2020 10:59 AM

SCHROCK: Flu Virology 101

Posted Feb 12, 2020 10:59 AM
<i>John Richard Schrock</i>
John Richard Schrock

    “How many bodies can you store in the cold rooms?”  We faced this question over two decades ago as university personnel charged with disaster planning. I was in a biology department and one of the HAZMAT team. We were drafting a plan for handling a repeat of the influenza of 1918, a pandemic that took more lives on a daily basis than any other disease.

    This specific question revealed that our local hospital would not have enough space in the morgue to accommodate the number of deaths. Our walk-in temperature-controlled rooms could take some of the overflow. The university would also close down. Students living nearby would be sent home. International and more distant domestic students would stay in the dorms and be supplied with food. 

    Our animal care and use committee would have to decide whether we would euthanize our laboratory mice or whether a staff member would take on the duty of caring for the animals. Otherwise, we would cease operating and “stand in place” in an attempt to prevent the spread of this flu virus strain if it returned.

    Why are some types of flu mild while some are far more virulent? That takes learning some flu science and what the letters and numbers, such as AH5N1 and BH1N1, mean. 

    Influenza A viruses occur in other animals such as ducks, seals, chickens, pigs, whales, horses and cats. But influenza B viruses circulate only among humans. (There is a C virus that causes mild flu cases, and a D influenza only found in cattle.) 

    Influenza A viruses are then grouped in subtypes based on differences in “H” and “N” proteins on the surface of the virus: hemagglutinin and neuraminidase. According to the CDC, “there are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes. All known subtypes of influenza A viruses have been found among birds, except subtype H17N10 and H18N11 which have only been found in bats. While it is unusual for people to get influenza infections directly from animals, sporadic human infections and outbreaks caused by certain avian influenza A viruses have been reported.”

    The 1918 flu pandemic was caused by an AH1N1 virus of avian origin. Despite the common name “Spanish flu,” it was first identified in soldiers at Fort Riley in Kansas. The CDC estimates “...about 500 million people or one-third of the world’s population became infected with this virus. The number of deaths was estimated to be at least 50 million worldwide with about 675,000 occurring in the United States.” Our crowded troop ships carried soldiers with this flu to Europe. At this time there were no anti-viral drugs—indeed viruses were not yet understood and a bacterium was suspected.

    Antibiotics would not be developed until World War II, and antibiotics are useless against viruses. The main defense against viruses are vaccines that stimulate our immune systems to form antibodies. If the virus does not rapidly evolve differences, as in the case of smallpox and polio, we can eliminate a virus by vaccination (successful with smallpox, still pending with polio). 

    Unfortunately, influenza evolves rapidly and especially in highly populated cities. Each year there is an educated guess on which new influenza strains have arisen that will spread the following year. Again the CDC explains: “One influenza A(H1N1, one influenza A(H3N2, and one or two influenza B viruses (depending on the vaccine) are included in each season’s influenza vaccines. Getting a flu vaccine can protect against flu viruses that are like the viruses used to make vaccine.”

     While everyone is focused on the Wuhan coronavirus, China’s Ministry of Agriculture just reported (February 1) an outbreak of the highly pathogenic H5N1 bird flu at a farm in Hunan. 4,500 of the 7,850 chickens died of the bird flu. The remainder were destroyed and no humans contracted the flu. In 2013, another avian influenza A(H7N9) virus arose in China and caused 1,568 human infections. Approximately 39 percent of those who contracted it died, but it does not spread easily between people. The CDC states: “If it did, experts believe it could result in a pandemic with severity comparable to the 1918 pandemic.” The danger from a coronavirus or flu virus depends on how pathogenic it is (case-fatality rate, how easily it is spread human-to-human, how long a carrier is contagious, and whether carriers always present symptoms.    

    The willingness of the highly-crowded Chinese population to stay-in-place to control the spread of potentially pandemic viral diseases is simply not recognized by the Western people or press.  Americans focus more on rights than responsibility. And American science education—and therefore public understanding—is abysmal by international standards. 

    Returning to the planning of a university shutdown in the face of a return of the 1918 flu strain, I asked about quarantine roadblocks. The answer was “no.”  

    Americans want their freedom of movement. In this case: a freedom to die.     

John Richard Schrock has trained biology teachers for more than 30 years in Kansas. He also has lectured at 27 universities in 20 trips to China. He holds the distinction of “Faculty Emeritus” at Emporia State University.