Treating Novel vs. Known Viruses

Mankind is a long way from winning the fight against viral infection. In fact, it’s arguably a battle we won’t ever win, rather one that we will continue to revisit over and over again as new strains of known viruses arise. In recent decades, several viruses have jumped from animals to humans creating new strains, known as novel viruses – which occur when a known virus mutates; triggering sizable outbreaks; and claiming thousands of lives, such as the 2014-2016 Ebola outbreak. 

What are the differences between known and novel viruses, how must we adapt our response to different kinds of outbreaks, and what must be done to prevent pandemics? 

What is a Virus and What Makes it Novel?

For years the scientific community has been locked into what has become known as the zombie debate. At the heart of this debate is the question: are viruses alive or not? Initially, viruses were seen as poisons and were named according to this belief, then they were understood to be life-forms, then biological chemicals. 

Today, the debate wears on, with viruses being thought of as existing in a gray area between the living and nonliving: they cannot replicate on their own, but can do so in living cells of a host, sometimes even co-opting the host to such a degree that behavior is affected. For example, rabies causes the host to become wildly aggressive and toxoplasmosis can make a pet owner fall more deeply in love with their feline friend.

Although this debate is long from over, at this point a virus is seen more as an event than anything else. A virus can not last long outside of the body, it is only when it enters a living cell of a host that it “comes alive”. This entails hijacking the cell, and using the mechanisms within the cell, to feed and replicate itself, eventually destroying the host cell and spewing the replicated virus out into the rest of the body. A virus is technically a tiny infectious particle or parasite, much smaller than bacteria or an individual cell.

In medical terms, “novel” refers to a virus that has not yet been identified or studied in humans, due to a mutation – whether the strain is entirely new to the human population or not. In fact, “novel” originated from the Latin word “novus” meaning “new,” and because of the unknown nature of these viruses, it is particularly challenging for healthcare professionals to predict how they may spread as there are no data on infection rates, infectious periods, or long term effects on the body. These factors are very difficult to determine at the onset of an outbreak, when time is of the utmost importance. 

Why are Novel Viruses so Dangerous?

A novel virus must be treated differently than a seasonal one, as the human body does not have an adaptive immune response to new viruses. Before an adaptive response can happen, the body must first produce an innate immune response.

An innate immune response is a general defense mechanism that is triggered when a viral intruder is detected, regardless of whether or not the virus is known or novel. This built-in “alarm system” causes a host cell to release a protein that tries to interfere with the virus’s replication, or prompts the immune system to shut down the compromised cells. 

An adaptive immune response, on the other hand, is a much more specific line of defense, and therefore also more complex, as the body will have now created a memory of this specific viral invader. The immune system can not produce an immediate response to a virus if the system first has to recognize the foreign invader before mounting a specialized attack. The adaptive immune response is responsible for creating specific antibodies to combat the disease. 

If a cut on the skin comes into contact with a viral intruder, the body will automatically, through the innate response, attempt to eliminate the virus on the surface of the skin. However, the body will need time to create an adaptive response to any microscopic parasites that make it past the surface.

What are Some of the Deadliest Known Viruses?

There have been viruses throughout history that have claimed millions of lives and left a sizable impact on the healthcare system, some of which remain active all over the world, today. A few of the most deadly viruses known to mankind are:

• Ebola: Spread through contact with blood, bodily fluids, or infected tissue. Ebola first struck humans in 1976. Ebola has several strains, two strains of Ebola have fatality rates of up to 71% and one as high as 90%. 
• HIV: Also known as Human Immunodeficiency Virus, HIV has claimed the lives of 32 million people since it first entered the human population in the 1980’s. 
• Smallpox: While smallpox has been eradicated since 1980, humans battled the deadly disease for thousands of years. Smallpox killed one-in-three people that became infected, and left survivors with permanent scars and oftentimes blindness. 
• Dengue Fever: Often carried by mosquitoes, the dengue virus infects 50 to 100 million people a year. First appearing in the 1950’s, dengue has spread through the Philippines, Thailand, and now continues to spread through tropical regions of the world. Today, 40% of the world’s population lives in areas where dengue is endemic. 
• Severe Acute Respiratory Syndrome (SARS): This virus first appeared in 2002 in southern China. First emerging in bats then spreading to humans, SARS later infected more than 8,000 people across 26 countries. 

What are Some Recurring Known Viruses?

Overtime, vaccines and medications aid in recovery and help to limit the spread of a virus, but this is generally only after years of research following an initial outbreak. Understanding current Centers for Disease Control and Prevention(CDC) guidelines and outcomes of other novel outbreaks can be helpful in determining how to address any new viruses that enter the population.

Some known viruses are both evolving and recurring, making them difficult for healthcare professionals to combat. One of the most notorious recurring epidemics of known and novel viruses is influenza. Because viruses are not a single strain, they are a group of constantly changing strains, our knowledge of how a virus will behave evolves year after year. The more contagious a virus, the more mutations it will likely exhibit.

Influenza type A and type B spread through the population causing seasonal epidemics. Between 5% and 15% of the population will become infected each year, specifically impacting vulnerable age groups. Up to 500,000 people will die from influenza, annually.

Humans have built immunity from repeated exposure to influenza. However, because influenza mutates every year, it is virtually impossible to eradicate it entirely. The individual influenza strains in the seasonal flu vaccine are selected each year based on surveillance data indicating which viruses are currently circulating and forecasting which ones are the most likely to circulate during the coming season. Because of this, the vaccine is around 40-60% effective. 

While not guaranteed to stymie the spread of influenza, the scientific community and the CDC still promote the use of the flu vaccine to help mitigate the spread of the virus. Because the flu vaccine is adapted to target the strains most likely to affect the population, it is important to receive a new vaccination every year.  

What is a Pandemic and What are the CDC Guidelines?

An outbreak is a greater than expected increase in cases of a disease, even if it’s only a single unexpected case, on the other hand, an epidemic occurs when a disease affects a large population of people within a community. A pandemic is then categorized by that same disease traveling outside of the affected community and infecting a large number of people internationally. 

In the event of a pandemic, the CDC, has developed an action plan that includes guidelines and strategies to combat it. The intent of the CDC’s guidelines are to stop, slow, or otherwise limit the spread of a pandemic in the United States. The six stages of CDC activity during a novel pandemic are: 

1. Investigation: Initial research is done on the virus and the reported cases in humans are investigated.  
2. Recognition: Discussions regarding the potential for ongoing transmission of the virus take place. 
3. Initiation: As the pandemic begins, public health officials and healthcare professionals must take the necessary steps to prepare. 
4. Acceleration: The “speeding up” of the virus means actions such as school and child-care closures and social distancing may need to be implemented. 
5. Deceleration: When cases begin to decrease in the United States actions include vaccinations and strict monitoring of the virus. 
6. Preparation: In this stage, public health takes preventative actions in the case of a second pandemic wave. 

 

The CDC provides additional resources describing the progression of a pandemic. The length of each stage will vary depending on the characteristics of the virus and public health response. Some assessments are used to determine when one stage moves to another. Federal, state, and local public health decisions are guided by these results. Although pandemics do not happen frequently, the CDC guidelines, when used properly, are in place to ideally ensure a quick, effective response. With each new virus, guidelines must be reevaluated for efficacy. 

What is the Responsibility of Healthcare Professionals During a Pandemic?

During a pandemic, the government and healthcare workers have a responsibility to follow guidelines and provide care to the people affected. Globally, healthcare systems have had to adapt rapidly in order to respond to novel pandemics. Healthcare professionals have to quickly learn and update protocols for diagnosing, treating, containing, and curing disease when pandemics occur.

Frontline workers also take on greater roles and responsibilities while combating novel viruses. For example, in order to reduce traffic in and out of patient rooms, nurses and medical assistants may take on the duties of other departments, such as technological and disinfecting services. As physicians become overloaded, many other personnel step up to battle these unique and unprecedented challenges. 

During an epidemic, healthcare professionals face higher risk of infection, mental and emotional stress, and a shortage of supplies and manpower. With so many unknowns, healthcare professionals act with courage and determination in these times of crisis. 

Alive or Not, Viruses are Dangerous – Especially Novel Ones.

While some viruses are known and researched, the uncertainty around novel viruses make them particularly dangerous. Healthcare professionals must sometimes risk their lives to combat disease without knowing how a specific virus may behave and what impacts it may have on long term health. The human fight against viruses is far from over, and as the historical statistics show, an outbreak can escalate to quickly and overwhelmingly devastate communities worldwide. 

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