Why some viruses become global threats?

Viruses are among the most mysterious and dangerous biological organisms on Earth. One of the main reasons they are a global threat is their ability to mutate. Viral mutation is not just a scientific concept; it is the reason why some outbreaks remain local while others turn into global crises.

What is viral mutation?

Mutation is a change in the genetic material of a virus. Most viruses use ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) to reproduce, and during this process, errors naturally occur. These errors are known as mutations. While many mutations weaken the virus, some give it new advantages.

Why do viruses mutate so quickly?

Viruses reproduce very quickly, especially RNA viruses. Unlike human cells, viruses lack sophisticated mechanisms for correcting errors, which means that mutations occur frequently. Over time, natural selection allows the strongest viral variants to survive.

When do mutations become dangerous?

Some mutations can increase a virus's ability to spread, evade the immune system, or resist treatments. These changes make outbreaks more difficult to control.

Why do some viruses become global?

Local viruses become a global crisis when high mutation rates are combined with human-to-human transmission, global travel, and delayed containment measures.

Examples of viruses that have posed a global threat:

Coronavirus:

Coronavirus is a new type of coronavirus. The first cases appeared in the Chinese city of Wuhan at the end of December 2019, in the form of severe pneumonia. The source of the virus is still unknown, but it is believed to have been transmitted from bats or another animal to humans in this Chinese city.

Typical symptoms of the coronavirus include fever, cough, and shortness of breath. Other less common symptoms that may affect some patients include loss of taste or smell, aches and pains, headache, sore throat, nasal congestion, red eyes, and diarrhea. Sometimes the infection develops into pneumonia. The disease can cause severe complications in people with weakened immune systems, the elderly, and people with chronic diseases such as cancer, diabetes, and chronic lung disease.

Marburg virus:

The Marburg virus is classified as one of the most deadly viruses, causing severe hemorrhagic fever with a mortality rate of up to 88%. This virus belongs to the same viral family as the well-known Ebola virus.

First appearance (1967):

The virus was first identified after simultaneous outbreaks in three European cities: Marburg and Frankfurt (Germany) and Belgrade (Serbia).

Cause of the first outbreak:

The infections were linked to laboratory activities involving African green monkeys imported from Uganda.

Virus record:

Since its discovery until 2022, 15 outbreaks and individual cases have been recorded, most of which (11 cases) were concentrated in Africa, with Equatorial Guinea and Tanzania recently joining the list of affected countries.

The infection is transmitted to humans through two main routes:

Animal to human: Initial infection usually begins as a result of prolonged exposure to mines or caves inhabited by colonies of Rousettus bats.
Human to human (community spread): Once the virus enters a person's body, it spreads among humans through:
Direct contact: through contact with the blood, secretions, or bodily fluids of an infected person (via broken skin or mucous membranes).
Contaminated surfaces: contact with materials contaminated with the patient's fluids, such as clothing or bedding.

For more information on Marburg virus, please visit our previous article

Can science control viral mutations?

While mutations cannot be stopped, scientists can monitor genetic changes, improve vaccines, and detect outbreaks early through genomic surveillance.