Lisa Moore, University of Southern Maine
Originally published in the Bangor Daily News on February 3, 2015.
This past fall, we saw a response to the Ebola virus in the U.S. dominated by fear, not knowledge, with one of the most disturbing stories unfolding right here in Maine.
Nurse Kaci Hickox had no Ebola symptoms, yet she was forced to live in a tent in New Jersey after returning from West Africa before she was allowed to travel to Fort Kent, where Gov. Paul LePage attempted to quarantine her in her home.
Ebola isn’t contagious until its symptoms, primarily fever, are apparent; and Ebola doesn’t spread through the air, but through contact with infected blood or other bodily fluids. This discriminatory and anti-democratic reaction to Ebola is reminiscent of the reaction to AIDS in the 1980s before it was known that AIDS was caused by a virus that spreads only through contact with bodily fluids, regardless of a person’s social status or sexual orientation.
Every winter, influenza sweeps through the U.S., killing thousands of people. And cases of measles are spreading rapidly right now in California. Unlike AIDS and Ebola, both of these viruses spread through the air when people cough or sneeze.
Viruses that cause disease can be scary and deadly. But knowledge is power, and a basic understanding of viruses can help alleviate fear, prevent panic, and help us respond more appropriately to minimize the spread and severity of viral diseases.
Viruses are the smallest of organisms. They contain genetic material that codes for making new virus particles.
One characteristic is that viruses require a host cell to make new virus particles because viruses themselves don’t have all the molecules needed for this process. Once enough virus particles are made, they are released from the host cell, usually killing the host cell in the process. Some viruses, called retroviruses, actually insert their genetic material into their host genome and stay there until some environmental signal causes it to come out of the host genome, make new particles, and leave the cell. Human Immunodeficiency Virus, or HIV, which causes Acquired Immunodeficiency Syndrome, or AIDS, is an example of a retrovirus.
Specific viruses depend on specific host cells in order to produce new virus particles. They identify and attach to those cells with the help of proteins. For example, influenza has the proteins hemagglutinin (H) and neuroaminidase (N) on the surface of its the virus particles. Influenza A H5N1 is the influenza virus that caused epidemics among birds in 2004 and Influenza A H1N1 is the one responsible for the 1918 and 2008 flu epidemics.
The specific proteins also allow the host immune system to detect and eliminate the virus. However, viruses can mutate quickly sometimes resulting in changes to the proteins, which, in turn, may allow them to infect a different host cell (such as jumping from bird to human hosts) and-or evade detection by the host immune system.
How does knowing all this help? Preventing and treating illness due to viruses is most effective when one understands viruses’ basic biology. You can lower your chances of getting sick from viruses by minimizing your exposure: avoid touching contaminated surfaces or fluids and wash your hands frequently. You can minimize spreading disease by covering your mouth and nose when sneezing and frequently washing your hands.
One of the best ways to prevent sickness from viruses is to get vaccinated. Vaccines contain some or all of the proteins for a specific virus, called antigens, such as the H and N proteins found in influenza virus. The vaccine allows a person’s immune system to make molecules (called antibodies) that target the antigens.
Vaccines vary in effectiveness. Some, like the vaccine used against measles, have proven to be highly effective; the Measles H protein hasn’t changed much. But some viruses can mutate their proteins rapidly. So, vaccines made to a set of proteins are not always effective against the mutated proteins. This is why new flu vaccines are made every year in an attempt to target the rapidly evolving seasonal flu.
Many believe taking antibiotics is the best way to deal with colds or flu-like illness. But antibiotics specifically target bacteria and, because bacteria are fundamentally different kinds of organisms than viruses, are not effective against viruses. Antiviral drugs are an option, however. They don’t actually kill viruses but prevent them from multiplying, which can reduce the symptoms.
Every year, we understand more and more about the biology of viruses, which has led to the development of more sophisticated and effective antiviral vaccines and drugs. Understanding some basic information about viruses, including their amazing diversity and how they spread, helps put pathogens in perspective. Politicians charged with leading and protecting our democratic society also need to understand basic biology — how disease spreads and how to confront them with knowledge rather than fear.
Lisa Moore is a professor in the Department of Biological Sciences at the University of Southern Maine. She is a member of the Maine chapter of the national Scholars Strategy Network, which brings together scholars across the country to address public challenges and their policy implications.