How Have Viruses Increased in Recent Times?
From a massive smallpox outbreak in 2022 to the evolution of avian flu and the Marburg virus in Equatorial Guinea, Covid no longer dominates the headlines the way it used to.
Instead, we regularly hear about outbreaks of new or re-emerging viruses.
So, are virus outbreaks on the rise? Or have we become better at detecting outbreaks thanks to improved technologies developed during the Covid pandemic? The answer may be a bit of both.
An estimated 1.67 million viruses have yet to be identified that currently infect mammals and birds. Of these, up to 827,000 viruses are thought to infect humans.
To understand how viruses appeared, we need to go back to the beginning of life on Earth. There are many theories about how the first viruses appeared, but they all agree that viruses have been around for billions of years and have evolved along with living things. And when there is a disturbance in this stable co-evolution, then we can run into problems.
The main factors in the emergence of viruses in humans are associated with people and their actions. Agriculture became a common practice over 10,000 years ago, and with it people came into closer contact with animals. This made it possible for the viruses that naturally infected these animals to “species-jump” to humans. This is called zoonosis. About 75% of newly emerging infectious diseases are caused by zoonoses.
With the progress of human civilization and technology, the destruction of the habitat of animals has prompted them to move to new areas in search of food sources. Different species that did not normally come into contact now lived in the same environment. Add humans to this equation and you have the perfect recipe for a new virus.
Urbanization leads to high population density, which creates an ideal environment for the spread of viruses. The rapid development of cities and towns often bypasses proper infrastructure such as sanitation and healthcare, increasing the likelihood of virus outbreaks.
Climate change also contributes to the spread of viruses. For example, arboviruses (viruses spread by arthropods such as mosquitoes) are being discovered in new regions as the range of countries in which mosquitoes can live increases.
We have known these factors for a long time. The emergence of SARS-CoV-2 did not surprise any virologist or epidemiologist. The question was when, not in the event of a pandemic. What was unexpected was the scale of the Covid pandemic and the difficulty of effectively containing the spread of the virus.
We also did not anticipate the impact of misinformation on other areas of public health. In particular, over the past few years, anti-vaccination sentiment has become more prevalent on social media, and we are seeing an increase in reluctance to get vaccinated.
There were also disruptions in routine immunization programs for children, raising the risk of outbreaks of vaccine-preventable diseases such as measles.
During the Covid pandemic, science has advanced at an unprecedented pace, leading to the development of new and improved virus detection methods to track the spread and evolution of the virus. Now, many of the scientists involved in tracking SARS-CoV-2 are turning their attention to monitoring other viruses as well.
For example, wastewater monitoring has been widely used to detect SARS-CoV-2 during the pandemic and may similarly help monitor other viruses that pose a threat to human health.
When someone becomes infected with a virus, some of that virus’s genetic material is usually flushed into the bathroom. Wastewater can show whether infections are increasing in an area, usually before the number of cases in hospitals starts to rise.
Adapting this technology to look for other viruses, such as the flu, measles, or even polio, could provide us with valuable data on the timing of viral outbreaks. To some extent, this is already happening – for example, in 2022, the polio virus was detected in London sewage.
This increase in virus surveillance will naturally lead to more reported virus outbreaks. While some people might consider this a panic, this kind of information could be the key to containing any future outbreaks. If an outbreak occurs in an area lacking proper virus surveillance, the infection is likely to spread too far and be easily contained.
However, surveillance is only part of pandemic preparedness. Governments, medical and scientific institutions around the world need to be (regularly updated) on the emergence of viruses and pandemic protocols so that we don’t try to figure things out when it’s too late.
And it is unlikely that Covid will be the last pandemic that many people alive today will face. Let’s hope that next time we will be better prepared.
The report was prepared by Lindsey Broadbent, Lecturer in Virology at the University of Surrey.
Source: Science Alert
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