University of Arizona
On March 11, the COVID-19 outbreak was characterized as a pandemic by the World Health Organization (WHO). The same month Jay C. Butler, MD (CAPT, USPHS, RET), Deputy Director for Infectious Diseases, Centers for Disease Control and Prevention (CDC) stated “As of March 2020, the international outbreak of COVID-19 poses a serious public health threat.”
According to the CDC, this is the first global outbreak of a disease caused by the emergence of a novel (new) coronavirus. SARS-CoV-2 is the virus that causes the COVID-19 disease. The virus is transmitted from person-to-person, and community spread is occurring in many locations. The federal government is working with state, local, tribal, and territorial partners, as well as public health partners, to respond.
The basics about SARS-CoV-2 and the disease COVID-19
What residents and communities can do to prevent the spread of SARS-CoV-2
The CDC has produced excellent guidance materials https://www.cdc.gov/coronavirus/2019-ncov/index.html, focused on many different situations (Fig. 2).
Another important measure to help slow down the spread of disease is social distancing. Social distancing is the deliberate increase of physical space between people to avoid spreading a disease-causing pathogen. Cancelling events that are likely to draw crowds, such as sporting events, festivals, and cultural gatherings are all examples of social distancing.
There are other examples of social distancing that avoid people congregating in enclosed spaces, these include working from home, closing schools and switching to online classes, postponing meetings, and visiting with loved ones using telephone or video connections instead of in-person.
Coughs and sneezes play a key role in transferring respiratory disease-causing pathogens between infected people and susceptible people. Contaminated articles and surfaces generally play a secondary but important role in virus transmission.
What’s a Cough?
Coughing is an important reflex as it clears the airways of foreign particles including irritants, microbes, mucus and allergens from the throat. We cough when sensory receptors in the upper respiratory tract send a signal to the brain indicating that there is something irritating in the airway. The part of the brain that receives and interprets messages is called the “cough center.” The cough center then triggers muscles in the throat and chest resulting in a cough, and here’s what happens step-by-step:
What’s a Sneeze?
Sneezing is a reflex triggered by irritants in the nose. Hundreds of receptors line the nasal cavity and if irritated send a signal to the brain initiating a sneeze. Here’s what happens:
As many as 40,000 droplets of fluid shoot out from the face at speeds greater than 100 miles per hour (Fig. 3). Most of the droplets are less than 100 microns in diameter (the same thickness as a piece of standard printer paper). Many droplets are so small they are invisible. Larger, heavier droplets fall onto surfaces or the ground quite rapidly, but smaller droplets can stay airborne and be moved around on air currents. Sneezing spreads droplets as far as eight meters!
A single cough or sneeze can contain hundreds of millions of virus particles (Fig.4). Social distancing in all forms simply aims at reducing the number of people exposed to people coughing and sneezing, as well as contaminated surfaces and articles.
Unfortunately, an infectious person can distribute droplets carrying viral pathogens into the air even when breathing or talking normally (but to a far lesser extent).
SARS-CoV-2 persistence in indoor environments
Researchers are studying how long SARS-CoV-2 can persist in the air and on surfaces in an infectious form. In all cases lots of environmental factors will influence persistence. However, scientists in Germany (Kampf et al., 2020) analyzed 22 published studies covering human coronaviruses such as Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and endemic human coronaviruses (HCoV), and find that the viruses can persist on inanimate surfaces like metal, glass or plastic for up to 9 days, but can be destroyed with commonly used disinfectants including 62-71% ethanol, 0.5% hydrogen peroxide, and 0.1% sodium hypochlorite.
Early research indicates SARS-CoV-2 can persist in an infectious form in indoor air for minutes to hours.
To help reduce the spread of SARS-CoV-2, cleaning and disinfection of homes, schools, and other indoor environments is an important part of infection control. This is a two-step process:
The application of a disinfectant on a dirty surface will not be very effective.
The power of soap and warm water
Each SARS-CoV-2 particle consists of genetic material (RNA) enveloped in a lipid (fat) and protein layer (Fig. 5). Soapy warm water acts to break down the lipid layer coating, helping to breakdown and destroy the virus. Soap also provides the added benefit of removing dirt, grease and grime from a surface.
The CDC states routine cleaning and disinfection procedures are appropriate, and the EPA has produced a list of disinfectants for use against SARS-CoV-2 https://www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2. Disinfectants are antimicrobial pesticides. Make sure the products you are using are appropriate for the intended use. Please read the label and follow all instructions.
Antimicrobial pesticides are products intended to be used to:
Disinfect, sanitize, reduce or mitigate growth or development of microbial organisms. They are also used to protect inanimate objects, industrial processes or systems, surfaces, water or other chemical substances from contamination, fouling or deterioration caused by bacteria, viruses, fungi, protozoa, algae or slime.
Antimicrobial pesticides come in a wide variety of forms and can be used to treat surfaces, air, and water to prevent, reduce or kill dangerous harmful and non-harmful bacteria, fungi, algae, and viruses. Antimicrobial pesticides are categorized based on the type of microbial pest they are designed to reduce or eliminate. Some products are intended to kill certain algae and odor-causing bacteria that are generally not a threat to human health.
Other antimicrobials are designed to sanitize, disinfect or sterilize surfaces against microbes that are harmful to human health.
The three types of antimicrobial pesticides used to protect public health are:
Best practice reminders
Handle disinfectants with care. Many commonly used chemicals can cause severe eye and vision damage if the product is splashed into the eyes; skin injury if the skin is exposed; and/or respiratory problems after inhaling fumes.
Labels on bleach products that are not registered as disinfectants lack necessary use instructions for achieving adequate disinfection and additional precautionary measures for protecting users, other people and the environment.
For disinfection, use only bleach products and other disinfectants that are registered by the U.S. EPA.
Never mix ammonium (quats) with hypochlorite (bleach) - toxic gases will be produced.
If a medical emergency occurs call 911.
If an exposure occurs call the poison help line.
The National Pesticide Information Center can offer guidance 1.800.858.7378 email@example.com. Open 8:00AM to 12:00PM Pacific Time, Monday-Friday
SARS-CoV-2 is not just another “flu”. We gain a better understanding of the virus and the disease COVID-19 with each passing day. However, based on the available data so far scientists affirm that SARS-CoV-2 is more infectious than an average influenza virus, and has the potential to kill a higher percentage of those infected. The death rate from a typical flu is about 0.1%, with the very young and the elderly the most vulnerable to fatal disease. The death rate from COVID-19 is estimated at about 3.4%, and although it can be severe or even fatal for young people. The elderly population over the age of 80 years are by far the most vulnerable to fatal disease.
The CDC leads a One Health initiative that is a collaborative, multisectoral, and transdisciplinary approach, working at local, regional, national, and global levels with the goal of achieving optimal health outcomes recognizing the interconnection between people, animals, plants, and their shared environment (Fig. 6).
CDC Coronavirus (COVID-19) https://www.cdc.gov/coronavirus/2019-ncov/index.html
Disinfecting Wipes: Not for Kids! http://healthyschools.org/data/files/Disenfectant_Wipes_Guide.pdf
EPA Coronavirus Main Page: https://www.epa.gov/coronavirus
NPIC has newly-updated fact sheets on disinfectants and sanitizers at http://npic.orst.edu/factsheets/antimicrobials.html, COVID-19 virus information http://npic.orst.edu/ingred/ptype/amicrob/covid19.html, and a video at https://www.youtube.com/watch?v=rfkzHv40Pz0.
Kampf, G., D. Todt, S. Pfaender, E. Steinmann. 2020 Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. Journal of Hospital Infection 104: 246-251.
Information in the newsletter was compiled from CDC, EPA, NPIC, the American Institute of Physics Science News, and Journal of Hospital Infection.
Save the Date: April 28th, 2020, Tuesday, 7:30am - 5:00 pm. 3rd Arizona School IPM Conference. Online, information to follow.
Check out upcoming Integrated Pest Management Webinars at https://www.epa.gov/managing-pests-schools/upcoming-integrated-pest-management-webinars
For more information about the EPA Schools program, visit: http://www.epa.gov/schools/
To view all our previous newsletters, visit: https://acis.cals.arizona.edu/community-ipm/home-and-school-ipm-newsletters
This material is in part funded by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2017-70006-27145 that provides Extension IPM funding to the University of Arizona. Information regarding this document is within the guidelines of the Border 2020 Program funded by the U.S. Environmental Agency (EPA) and administered by NADB. Additional support is provided by the U.A. – Arizona Pest Management Center.