Transmission, impact of viral outbreaks

Times like these remind us how scientifically unaware many people can be. That Corona beer or a Chinese conspiracy are at the root of the Coronavirus may be the most outlandish of the absurd notions surrounding the epidemic. With such crazy ideas in mind, let’s try to get a better grip on some of the facts, especially those related to transmission and origins of the disease.

Disease transmission — transmission from person to person is always a great concern. This has led to a worldwide campaign to encourage frequent hand washing and avoiding places where the virus might be more widespread.

It’s also prompted unprecedented cancellations of all sorts of events and public gatherings, as transmission risks increase greatly in large crowds. Millions voluntarily avoided crowded places, even before the rash of cancellations.

Much as returning soldiers from World War I helped carry the Spanish Flu around the world in 1918, 21st Century air travel has accelerated the spread of the Coronavirus. Many have advocated for more thorough fever screening for those travelling by air, but few countries have typically done such testing.

Viruses cannot reproduce outside biological hosts but they can survive on inanimate objects. The staying power of viruses can vary a great deal from one to another.

Some relatives of the new COVID-19 can live for a week on hard surfaces. This durability has led to another intense worldwide campaign — sanitization of surfaces that might harbor the virus.

Many viruses can also be transmitted through unsanitized water. Most pathogens, including viruses, are unable to survive in chlorinated water or water exposed to ultraviolet light.

Unfortunately, many water supplies throughout the world are not chlorinated.

Water treatment systems are not the only source of ultraviolet light, as the natural ultraviolet light from sunlight can also kill viruses.

The specific staying power of COVID-19 is still uncertain. But as an “enveloped” virus it is much more susceptible to environmental influences and chemicals, even things like detergents.

Consequently, COVID-19 is deactivated at even low levels of chlorination and is killed by proper chlorination of water.

Viruses also generally do not like warmer and more humid conditions. They do best in drier air around 40 degrees Fahrenheit. That’s one of the reasons they are typically more of a problem in the wintertime.

Origins of Viral Outbreaks — Epidemiologists, those that study epidemics and their causes, try to determine the origin of disease outbreaks of all kinds. They are particularly interested in figuring out where epidemics begin in the hope that we might avoid future outbreaks or minimize their effects.

COVID-19 is one strain of the family of coronaviruses, which includes several that are responsible for the common cold. Coronaviruses can be transmitted between animals and people.

Like a number of other nasty viruses of the last quarter century, they have originated in animals that are eaten or come in contact with humans. Bats, civet cats and dromedary camels have all been linked to serious epidemics.

Especially when released into densely populated urban areas, as are so prevalent in China, the spread of such diseases are difficult to slow.

Though we are still, thankfully, far from a pandemic like the Spanish Flu of 1918, some sensible precautions would clearly be in our best interests.

John Frederick (wwwjohnjfrederick.com) writes on scientific and environmental issues.


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