Why Hand-Washing Really Is as Important as Doctors Say
Prevention becomes essential to stopping the spread of the virus because there is no vaccine to prevent it and no anti-virals to treat it.
How can such a simple, low-tech solution make a difference?
Remember – coronavirus spreads easily by droplets from breathing, coughing and sneezing. As our hands touch many surfaces, they can pick up microbes, including viruses. Then by touching contaminated hands to your eyes, nose or mouth, the pathogens can infect the body.
As a microbiologist, I think a lot about the differences between microbes, such as bacteria and viruses, and how they interact with animal hosts to drive health or disease. I was shocked to read a study that indicated that 93.2 percent of 2,800 survey respondents did not wash their hands after coughing or sneezing.
Let me explain how washing your hands decreases the number of microbes on your hands and helps prevent the spread of infectious diseases.
Bacteria and viruses are different in a number of ways. Bacteria are single-celled organisms that can reproduce on their own, while viruses constitute a core of genetic material encapsulated by a protein coat and can only reproduce by attaching themselves to host cells. Because viruses don't have the organelles to reproduce, they "hijack" the cellular machinery of host cells to make multitudes of new viruses.
These differences are why antibiotics cannot kill viruses, which typically target specific structures in the cellular components of bacteria that are absent in viruses.
Despite their differences, however, the best way to prevent the disease of bacterial and viral pathogens alike is to effectively wash your hands.
There are two strategies to decreasing the amount of microbes on your hands.
The first is to decrease the overall biomass of microbes – that is, decrease the amount of bacteria, viruses and other types of microorganisms. We do this by lathering with soap and rinsing with water. Soap's chemistry helps remove microorganisms from our hands by accentuating the slippery properties of our own skin.
The second strategy is to kill the microbes. We do this by using products with an antibacterial agent such as alcohols, chlorine, peroxides, chlorhexidine or triclosan. However, the efficacy on these agents can be variable depending on a given microbe.
Are soap and water enough?
Some academic work has shown that antibacterial soaps are more effective at reducing certain bacteria on soiled hands than soaps without them.
However, there's a problem. Some bacterial cells on our hands may have genes that enable them to be resistant to a given antibacterial agent. This means that after the antibacterial agent kills some bacteria, the resistant strains remaining on the hands can flourish.
Further, the genes that allowed the bacteria to be resistant could pass along to other bacteria, causing more resistant strains. Even more important with respect to coronavirus, antibacterial agents, such as oral antibiotics, don't kill viruses.
With this in mind, you may want to stick with plain old soap and water.
Going Back to Grade School
To clean our hands, the CDC recommends that we:
- Wet hands with clean water
- Apply soap and lather/scrub every nook and cranny of your hands for 20-30 seconds (about the time to sing "Happy Birthday" twice)
- Rinse well with clean running water
- Dry hands with a clean paper towel or air-dry.
During the 20-30 seconds of lathering the World Health Organization recommends incorporating six maneuvers to cover all parts of your hands.
If soap and water are not unavailable, the CDC recommends using an alcohol-based hand sanitizer that contains at least 60 percent ethanol. Alcohols have a broad-spectrum of antimicrobial activity and are less selective for resistance compared to other antibacterial chemicals. Although alcohol-based hand sanitizers may not work on all classes of germs, the WHO recommends the use of an alcohol-based hand rub to kill viruses that may be on your hands.
Not All Microbes Are Germs
The presence of some microbes isn't necessarily a bad thing. In fact many of the microbes that live on or within us are essential for our health.
We live in a microbial world: Trillions of different microbes colonize our skin, gut and orifices. Collectively, this consortium of bacteria, archaea, fungi and viruses are called our microbiota. A plethora of exciting research suggests that the associations of animal hosts with their microbiota are fundamentally important for the host's biology.
Our microbiota can protect us from germs by training our immune system and by colonization resistance – the characteristic of the intestinal microbiota to block colonization of pathogens. There is ample evidence suggesting that commensal bacteria regulate invading viruses, and in some cases have a suppressive role in their infections. For example, bacteria can prevent influenza virus infection by binding or trapping them directly or by producing metabolites that decrease the stability of influenza virions.
Although more research needs to be done to understand the intricate interactions between microbial communities with host cells, consistent work illustrates that a diverse population of microbes and a balance of this community is important for our health.
So what is the take-home message?
There is no doubt that washing our hands with liquid soap and water is effective in reducing the spread of infectious microorganisms, including those that are resistant to antimicrobial agents.
When you don't have the opportunity to wash your hands after touching questionable surfaces, use an alcohol-based hand sanitizer. Limit the touching of your hands to your mouth, nose and eyes.
Furthermore, maintain a healthy microbiota by limiting stress, getting enough sleep and "fertilizing" your gut microbes with a diversity of plant-based foods. It's not only a small world, but a dirty one as well.
Editor's note: This article contains updated information from an article that was published originally Dec. 17, 2017.
Michelle Sconce Massaquoi is a doctoral student in the Institute of Molecular Biology under the mentorship of biology professor Karen Guillemin.
Reposted with permission from The Conversation.
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When hurricanes and other extreme storms unleash downpours like Tropical Storm Beta has been doing in the South, the floodwater doesn't always stay within the government's flood risk zones.
New research suggests that nearly twice as many properties are at risk from a 100-year flood today than the Federal Emergency Management Agency's flood maps indicate.
Flooding Outside the Zones<p>About <a href="https://furmancenter.org/files/Floodplain_PopulationBrief_12DEC2017.pdf" target="_blank">15 million</a> Americans live in FEMA's current 100-year flood zones. The designation warns them that their properties face a 1% risk of flooding in any given year. They must obtain flood insurance if they want a federally ensured loan – insurance that helps them recover from flooding.</p><p>In Greater Houston, however, <a href="https://doi.org/10.1111/j.1539-6924.2012.01840.x" target="_blank">47% of claims</a> made to FEMA across three decades before Hurricane Harvey were outside of the 100-year flood zones. Harris County, recognizing that FEMA flood maps don't capture the full risk, now <a href="https://www.hcfcd.org/floodinsurance" target="_blank" rel="noopener noreferrer">recommends that every household</a> in Houston and the rest of the county have flood insurance.</p><p>New risk models point to a similar conclusion: Flood risk in these areas outstrips expectations in the current FEMA flood maps.</p><p>One of those models, from the <a href="https://firststreet.org/flood-lab/research/2020-national-flood-risk-assessment-highlights/" target="_blank">First Street Foundation</a>, estimates that the number of properties at risk in a 100-year storm is 1.7 times higher than the FEMA maps suggest. Other <a href="https://doi.org/10.1088/1748-9326/aaac65" target="_blank" rel="noopener noreferrer">researchers</a> find an even higher margin, with 2.6 to 3.1 times more people exposed to serious flooding in a 100-year storm than FEMA estimates.</p>
What FEMA’s Flood Maps Miss<p>Understanding why areas outside the 100-year flood zones are flooding more often than the FEMA maps suggest involves larger social and environmental issues. Three reasons stand out.</p><p>First, some places rely on relatively old FEMA maps that don't account for recent urbanization.</p><p>Urbanization matters because impervious surfaces – think pavement and buildings – are not effective sponges like natural landscapes can be. Moreover, the process for updating floodplain maps is locally variable and can take years to complete. Famously, New York City was updating its maps when Hurricane Sandy hit in 2012 but hadn't finished, meaning flood maps in effect <a href="https://projects.propublica.org/nyc-flood/" target="_blank">were from 1983</a>. FEMA is required to assess whether updates are needed every five years, but the <a href="https://www.fema.gov/cis/nation.html" target="_blank" rel="noopener noreferrer">majority of maps</a> <a href="https://www.oig.dhs.gov/sites/default/files/assets/2017/OIG-17-110-Sep17.pdf" target="_blank" rel="noopener noreferrer">are older</a>.</p><p>Second, binary thinking can lead people to an underaccounting of risk, and that can mean communities fail to take steps that could protect a neighborhood from flooding. The logic goes: if I'm not in the 100-year floodplain, then I'm not at risk. Risk perception <a href="https://doi.org/10.1088/1748-9326/ab195a" target="_blank" rel="noopener noreferrer">research</a> backs this up. FEMA-delineated flood zones are the major factor shaping flood mitigation behaviors.</p><p>Third, the era of climate change scuttles conventional assumptions.</p><p>As the planet warms, extreme storms are becoming <a href="https://nca2018.globalchange.gov/" target="_blank">more common and severe</a>. If greenhouse gas emissions continue to increase at a high rate, computer models suggest that the chances of a severe storm dropping 20 inches of rain on Texas in any given year will increase from about 1% at the end of the last century to 18% at the end of this one, a chance of <a href="https://doi.org/10.1073/pnas.1716222114" target="_blank" rel="noopener noreferrer">once every 5.5 years</a>. So far, <a href="https://www.rstreet.org/wp-content/uploads/2020/02/195.pdf" target="_blank" rel="noopener noreferrer">FEMA hasn't taken into account the impact climate change is having</a> on extreme weather and sea level rise.</p>
Racial Disparities in Flooding Outside the Zones<p>So, who is at risk?</p><p>Years of research and evidence from storms have highlighted social inequalities in areas with a high risk of flooding. But most local governments have less understanding of the social and demographic composition of communities that experience flood impacts outside of flood zones.</p><p>In analyzing the damage from Hurricane Harvey in the Houston area, I found that <a href="https://doi.org/10.1088/1748-9326/aba0fe" target="_blank">Black and Hispanic residents disproportionately experienced flooding</a> in areas beyond FEMA's 100-year flood zones.</p><p>With the majority of flooding from Hurricane Harvey occurring outside of 100-year flood zones, this meant that the overall impact of Harvey was racially unequal too.</p><p>Research into where flooding occurs in Baltimore, Chicago and Phoenix points to some of the potential causes. <a href="https://www.nap.edu/read/25381/chapter/4#16" target="_blank" rel="noopener noreferrer">In Baltimore and Chicago</a>, for example, aging storm and sewer infrastructure, poor construction and insufficient efforts to mitigate flooding are part of the flooding problem in some predominantly Black neighborhoods.</p>
What Can Be Done About It<p>Better accounting for those three reasons could substantively improve risk assessments and help cities prioritize infrastructure improvements and flood mitigation projects in these at-risk neighborhoods.</p><p>For example, First Street Foundation's risk maps account for <a href="https://firststreet.org/flood-lab/research/flood-model-methodology_overview/" target="_blank">climate change</a> and present <a href="https://floodfactor.com/" target="_blank" rel="noopener noreferrer">ratings</a> on a scale from 1 to 10. FEMA, which works with communities to update flood maps, is <a href="https://www.fema.gov/media-library-data/1521054297905-ca85d066dddb84c975b165db653c9049/TMAC_2017_Annual_Report_Final508(v8)_03-12-2018.pdf" target="_blank" rel="noopener noreferrer">exploring rating systems</a>. And the National Academies of Sciences, Engineering and Medicine recently <a href="https://www.nationalacademies.org/news/2019/03/new-report-calls-for-different-approaches-to-predict-and-understand-urban-flooding" target="_blank" rel="noopener noreferrer">called for a new generation of flood maps</a> that takes climate change into account.</p><p>Including recent urbanization in those assessments will matter too, especially in fast-growing cities like Houston, where <a href="https://authors.elsevier.com/a/1boBRyDvMFW6W" target="_blank" rel="noopener noreferrer">386 new square miles</a> of impervious surfaces were created in the last 20 years. That's greater than the land area of New York City. New construction in one area can also <a href="https://scalawagmagazine.org/2018/01/city-in-a-swamp-as-houston-booms-its-flood-problems-are-only-getting-worse/" target="_blank" rel="noopener noreferrer">impact older neighborhoods downhill</a> during a flood, as some Houston communities discovered in Hurricane Harvey.</p><p>Improving risk assessments is needed not just to better prepare communities for major flood events, but also to prevent racial inequalities – in housing and beyond – from <a href="https://www.npr.org/2019/03/05/688786177/how-federal-disaster-money-favors-the-rich" target="_blank" rel="noopener noreferrer">growing</a> after the unequal impacts of disasters.</p>
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