viruses – watercress words by Dr Aletha

” In a very short period, health care and society have been severely challenged by yet another emerging virus. Preventing transmission and slowing the rate of new infections are the primary goals.
However, the concern of COVID-19 causing critical illness and death is at the core of public anxiety.”
JAMA, March 11, 2020 “Care for Critically Ill Patients with COVID-19”

“just a virus”

You’ve probably visited your doctor or your child’s doctor for an acute illness that started suddenly or over a few days. Likely the symptoms included some combination of

fever and/or chills
sore throat, runny nose, and/or sneezing
cough
joint and/or muscle aches
vomiting with or without diarrhea
rash
redness with or without drainage from the eyes
headache and a general miserable feeling

This illustration depicted a 3D computer-generated rendering of a whole influenza (flu) virus with a light grey surface membrane, set against a white background. The virus’ surface proteins, hemagglutinin (HA) and neuraminidase (NA), were depicted in light and dark blue, respectively. HA is a trimer, which is comprised of three subunits, while NA is a tetramer, which is comprised of four subunits, with a head region resembling a 4-leaf clover. CDC/ Douglas Jordan, public domain

And you were probably told that you or your child had “a virus”,or viral infection, followed by one or more of the following phrases-

there is no treatment but it will go away
the treatment will not cure it, but it will help the symptoms
it has to run it’s course
it resolves without treatment
you caught it from someone else
it is contagious
the symptoms will go away, but it stays in your body
you may get it again
you won’t get it again
there is a vaccine to prevent this
there is no vaccine to prevent this

This image depicted a Centers for Disease Control and Prevention (CDC) scientist interacting with her Caliper LifeSciences’ Zephyr Molecular Biology Workstation, working with samples to be tested using a real-time PCR machine, known as a themocycler (see PHIL 22904), in order to identify the various types of poliovirus contained therein. The data from this analysis is stored in a computer, while the software further analyzes the data before being reviewed by a scientist. The themocycler can vary the temperature, which is important, for PCR requires multiple test rounds at different temperatures. In the instrument, viral RNA is copied into DNA and then the DNA is amplified. Specific probes bind to the DNA, in order to determine what type of polio present. One hundred ten labs around the world can run this assay, and can tell if an isolate contains polio, or not, and if so, what kind.CDC/ Holly Patrick, MS, MPH

And finally, you may have heard a phrase I hope you never hear, and I hope we doctors never use again-

“It’s JUST a virus.”

Why it’s never “just a virus”

The quote at the beginning of this post is from an article in the Journal of the AMA . Unless you haven’t listened to any news for the past 8 weeks, you are well aware of the “challenge” the whole world has been confronting over what some do call “just a virus”; and you know that it has caused much critical illness and death, leading to “public” and private anxiety.

But we shouldn’t have been surprised. Viruses have been around probably as long as humans have, we just didn’t know much about them until the past century or so. After all, viruses are made of genetic material DNA or RNA, like us and animals; when viral DNA/RNA invades our bodies and enters our cells, they start reproducing (replicating), causing disease. (This is a simplified explanation of what viruses do.)

Transmission electron microscopic image of an isolate from the first U.S. case of COVID-19, formerly known as 2019-nCoV. The spherical viral particles, colorized blue, contain cross-sections through the viral genome, seen as black dots.CDC/ Hannah A Bullock; Azaibi Tamin

How do doctors know it’s a virus?

Until fairly recently, viral infections were diagnosed by typical symptoms and characteristic physical exam findings, especially fever and rash, and many are still diagnosed that way. Then laboratory scientists developed tests for some viruses, which help confirm the diagnosis , important when a treatment is available. The tests can also be used to know if someone is or is not already immune to a disease, if a vaccine is available.

So what infections are caused by viruses?

Lots of them are, but fortunately most are not nearly as serious as the novel coronavirus that causes COVID-19, or the 2 previous coronavirus outbreaks, SARS and MERS. You’re probably quite familiar with some of them. Here’s what I think is an easy to understand way to categorize them.

This illustration provides a 3-dimensional (3D) graphical representation of a tightly packed, icosahedral, poliovirus particle that consists of 60-copies each of capsid polypeptides, designated as pink VP1 (viral protein1), green VP2, purple VP3, and though not shown here, VP4. This particle was composed of units of four capsid polypeptides, which interact in groups of five, resulting in a viral particle that has, what is referred to as 5-fold (pentameric), and 12-fold symmetry. Note the deep canyon on the capsid’s surface surrounding the apex of each pentamer of the virus. The canyon, together with the pentamer apex, is used as the site for capsid binding to cellular receptors.CDC/ Sarah Poser

categories of viral infections

This is how they behave without previous vaccination or treatment (when available) .This is not an exhaustive list, just some of the most common. These all spread person to person.

Short duration, followed by life-long immunity

measles
mumps
rubella
polio
hepatitis A

Short duration, followed by short-lived immunity

RSV- respiratory syncytial virus
influenza
rhinovirus (common cold)
coronavirus

Persistent infection, life-long carrier of virus, virus inactive at times, not always passed to other people

HSV-herpes simplex virus
VZ-varicella/zoster (chicken pox-shingles)

Persistent infection, life-long carrier of virus, virus always active and can be passed to other people

HIV/AIDS-human immunodeficiency virus
Hepatitis B
Hepatitis C
HPV-human papilloma virus

Viruses that spread from animals to humans

Avian influenza
Rabies
West Nile virus

Viruses that spread from animals to humans-and sometimes then to other humans

yellow fever
coronavirus
Ebola

Centers for Disease Control and Prevention (CDC) activated its Emergency Operations Center (EOC) to assist public health partners in responding to the coronavirus disease 2019 (COVID-19) outbreak first identified in Wuhan, China.

How serious are viral infections?

How serious a viral infection is depends on how you want to define “serious”. Even a “mild” illness can be a major problem if it’s you or your family that is sick. With a mild illness, you still may feel too sick to work or go to school, which you should not do anyway, so not to transmit it to other people.

The above classification is quite simplified, a framework for looking at infections that you’ve probably heard of. They range from the common cold, with no risk of death, to HIV/AIDS and rabies, which are always fatal without treatment.

People with the short duration infections usually recover but some carry risk of progressing into life threatening respiratory events, due to RSV, influenza, and now the coronaviruses. Polio frequently left its victims paralyzed for life and measles can cause permanent deafness.

The herpes virus and VZ virus cause recurrent outbreaks of painful skin sores. . Hepatitis B and C viruses can lead to chronic liver disease and liver cancer. HPV causes benign warts but also cancer of the cervix.

This illustration, created at the Centers for Disease Control and Prevention (CDC), reveals ultrastructural morphology exhibited by coronaviruses. Note the spikes that adorn the outer surface of the virus, which impart the look of a corona surrounding the virion, when viewed electron microscopically. In this view, the protein particles E, S, and M, also located on the outer surface of the particle, have all been labeled as well. A novel coronavirus, named Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), was identified as the cause of an outbreak of respiratory illness first detected in Wuhan, China in 2019. The illness caused by this virus has been named coronavirus disease 2019 (COVID-19).CDC/ Alissa Eckert, MS; Dan Higgins, MAMS

“the challenge of emerging virus”

I hope that we all learn from this pandemic. I hope both physicians and patients take viral infections more seriously and appreciate the complexity and challenge they represent. We share something important with them-DNA, the genetic material that creates health as well as disease. Viruses aren’t static; like us they change and adapt.

We have vaccines that can dramatically reduce our risk of getting several of these diseases and I hope more people will use them. We have a few drugs which combat these diseases; fortunately some have been life saving, like those for HIV/AIDs.

Healthy lifestyles offer protection against infections of all kinds but we frequently overlook their value. You may be tired of hearing them but they include

hand washing- often and thoroughly
cleaning and disinfecting frequently touched surfaces
water and sanitation facilities
safe food handling and cooking practices
wise sexual practices
staying home when sick
limiting contact with animals and preventing insect bites
immunization

sharing the HEART of health

For this post I reviewed sections of the textbook Fenner and White’s Medical Virology, Fifth Edition , made available online free at ScienceDirect.com specifically to help medical professionals navigate the COVID-19 challenge.

You might want to check out some less technical references at these links.

Overview of Viral Infection s

Viral Infectio n

Except for the cover photo, the pictures in the post are from the Centers for Disease Control and Prevention website, and are in the public domain.

Virus vs Bacteria

One major difference between bacterial and viral infections is the treatment. We have many more effective antibiotics (drugs which fight bacteria) than we do antiviral drugs.

And antibiotics do not affect viruses. Despite that fact, patients often expect and even demand their physicians prescribe antibiotics for viral infections such as influenza, colds and bronchitis- and unfortunately too often we physicians do it anyway.

Influenza- the vaccine is given annually and targeted to the strains of virus predicted to be active in any given year.

Measles (rubeola), Mumps, Rubella (German measles) -I am grouping these together since their vaccines are usually given together as the MMR. Recent outbreaks of measles have been attributed to the decline in vaccination rates.

Polio, a disease parents feared when I was a child, due to to risk of permanent paralysis, now essentially eradicated in the United States

Rotavirus, in infants and small children, a common cause of gastroenteritis- vomiting and diarrhea, with or without fever and abdominal pain

HPV, the human papilloma virus, causes warts of all kinds, but the vaccine is targeted to the strains that cause genital warts and can lead to cervical cancer

The cousin viruses, Hepatitis A and Hepatitis B.

Hepatitis is an infection of the liver, which can range from a mild disease to life threatening. Hepatitis A is spread through contaminated food or water. Hepatitis B is spread through contact with infected blood or other body fluids.

Another set of cousins, Varicella Zoster (VZ) virus causes two different infections and thus has two vaccines. The original infection is varicella or chickenpox, formerly a common childhood illness but not seen often now due to the vaccine. When it reactivates, usually years later in adulthood, it is known as zoster or shingles.

There are also several vaccines usually reserved for travel to specific areas of the world, occupational exposure, military service or other special circumstances. These include vaccines for anthrax, typhoid, cholera, (bacteria) and yellow fever, smallpox,and rabies (viruses).

Diseases for which there is no vaccine

One of the most serious is malaria, caused by a parasite transmitted by infected mosquitos. Malaria is rarely a risk in northern or extreme southern areas of the world, but for the tropics, especially sub-Saharan Africa it is a major health problem.

Otherwise we all are at risk of other serious infections that we cannot yet prevent with immunization. These include

HIV-human immunodeficiency virus ,and most other sexually transmitted diseases including HSV- herpes simplex virus, gonorrhea, syphilis, and chlamydia.

HCV- Hepatitis C

Most respiratory viruses, including rhinovirus, cause of the common cold; RSV-respiratory syncytial virus and infectious mononucleosis

The Ebola virus

Borrelia, not really a bacteria, it’s a spirochete, which causes Lyme (not lime) disease

And the bacteria Staphylococcus, which causes “staph” (not staff) infections of the skin and Streptococcus, which causes “strep throat”.

If you have any questions or concerns about which vaccines you might need to protect yourself against infections, please consult your own personal physician.

Detailed information about vaccines and infectious disease is available from the Centers for Disease Control and Prevention

Preventing bacterial infections

Prevention is a focus in healthcare now and immunization has been one of the most effective ways to prevent disease ever developed. The list of diseases that are “vaccine preventable” is long and continues to grow. Vaccine recommendations may be based on a person’s Vaccine administration may vary by Immunization protocols have become so complex…

February 16, 2015January 19, 2023