ChesterCountyMedicineSpring2020 - 8

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A Plague for
the Ages
BY MIAN A. JAN, M.D., F.A.C.C., F.S.C.A.I, AND
SEAMUS WINTERS, MHS, PA-C

We wrote this article on May 1st, 2020 and updated it on May 18th, 2020.
Data and information on COVID-19 is rapidly changing day to day and even
hour to hour, thus this is a brief presentation of what we know at this time.

n late 2019, a novel coronavirus was identified as the cause of
pneumonia cases in Wuhan, China. This virus, now known as
coronavirus 2019 (COVID-19), is a severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) and its structure is depicted
below in Figure 1. Understanding and management of this virus has
been rapidly evolving since it has led to a global pandemic.

2 is an image from a Chinese market). Previously, only animals
could transfer it to each other. Within about 2 weeks, the virus
mutated and gained the ability to spread from human to human.

Genome sequencing and analysis indicated that the coronavirus
that causes COVID-19 is a betacoronavirus in the same subgenus
as the severe acute respiratory syndrome (SARS) virus (as well as
several bat coronaviruses), but in a different clade.

Figure 2: A wild meat market in Shanghai in Feb. 2020 seen
in a USA Today article on April 8, 2020.

Figure 1: Diagram of coronavirus virion structure showing
spikes that form a "crown" like the solar corona, hence the name.
One hypothesis about the origin of COVID-19 is that in
December 2019, in a wild meat market in Wuhan, China the virus
made the jump from animals to humans (pictured at right in Figure

8 CHESTER COUNT Y Medicine | SPRING 2020

The virus enters the target cell through the angiotensinconverting enzyme 2 (ACE2). ACE2 is mainly expressed in
vascular endothelial cells, the renal tubular endothelium, and in
Leydis cells in the testes. It is also expressed in lungs, kidneys, and
GI tract.
Person to person spread through droplets is thought to be the
cause of spread of the virus. This has led to easy transmission from
person to person when an infected person touches a surface, talks,
sneezes, or coughs, especially because there can be asymptomatic
carriers of the virus. One person can infect 432 people in one

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ChesterCountyMedicineSpring2020

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