Since the emergence of human beings on this blue planet, our existence has been battling with various deadly viruses. For some of these infectious agent-borne diseases, medicines and drugs have taken great strides in the past several decades, to give us protection from the illnesses. But some viruses like Coronavirus, Influenza, and Ebola continue to devour humans as a life-threatening monster.
In the recent times, the novel coronavirus /Covid-19 pandemic has triggered consternation across the world, limiting contact between people, implementing emergency lockdown, and massive quarantines. The deadly virus was officially discovered as a SARS-CoV-2 virus only about 4 months ago, and it has already infected millions of people worldwide, and till the date, over 200 countries have been infected by its bloodcurdling effects.
Due to the coronavirus’s scare, the entire world has cocooned itself. But with the collective battle, we will emerge unscathed as we have, in the history of time.
Several deadly viruses have jumped from animals to humans and triggered massive prevalence, rising higher mortality rates. Before the novel coronavirus, the world has faced many virus borne pandemics like Spanish flu or influenza, Hantavirus, HIV-AIDS, Dengue, Zika, Swine Flu, and Ebola, that completely switched the path of human history, killing people at large-scale.
Here’s a list of most dangerous viruses that claimed countless lives:
Spanish Flu or Influenza
One of the most dangerous viruses in history, Spanish flu was caused by a lethal subtype of the H1N1 virus. The flu leads to about 3 to 5 million cases of severe illness (mainly afflicting young adults and people without a weak immune system) and about 500,000 deaths each year, according to the World Health Organization (WHO). It is believed to be the worst virus in modern history.
AIDS is an auto-immune disease, caused by the human immunodeficiency virus (HIV). This virus destroys a particular type of white blood cell (WBC) that performs a major activity in our body’s immune system. About 35 million people worldwide have died from this sexually transmitted virus or acquired immunodeficiency syndrome (AIDS) related illnesses since 1981, according to a survey by WHO. It was first discovered in the Democratic Republic of the Congo in the year of 1976.
Since it was first identified in 1976, Ebola virus has infected over 30,000 people, and killed more than 13,000 people worldwide, according to the WHO. Unlike other viruses, Ebola is animal-borne. The bats initially bore the virus, transmitting it to other animals, and then spreading it to the human population. Ebola is rare, but the 2014–2016 Ebola virus outbreak that occurred in West Africa was the most dangerous, and largest outbreak since its identification. Another similar virus to Ebola, called the Marburg virus, is also an animal transmitted virion. Researchers identified the Marburg virus in the year of 1967 when small outbreaks originated among lab workers in Germany.
Hantavirus pulmonary syndrome (HPS) first occurred in New Mexico and Arizona in the year 1993. During the Korean War, a deadly subtype of hantavirus had infected more than 3,000 troops and killed at least 350 soldiers (according to a paper published in the journal- Clinical Microbiology Reviews). This virus is not airborne and can only be transmitted to people if a mouse with hantavirus bites a human or an individual comes in contact with its feces, urine, and saliva. It has a mortality rate of 38%, according to the CDC.
We all know about the swine flu outbreaks that killed roughly 284,500 people in 2009. But, did you know how they died? Among those lives, over 80,000 deaths occurred due to cardiovascular diseases, and over 200,000 deaths due to respiratory tract failures. Caused by the H1N1 influenza virus, swine flu was first identified in central Mexico in March 2009 before it spread to countries across the globe.
Japanese Encephalitis Virus
The encephalitis virus, which better known as the ‘Japanese encephalitis virus’, is the most common risk factor to the humans in many countries across Asia. According to WHO, the Japanese encephalitis virus has an estimated 68,000 clinical cases annually. Encephalitis is an acute inflammation of the brain caused by the virus.
Variola major and Variola minor are the two major virus variants that are responsible for an infectious disease, Smallpox. This is also a transmitted disease that is spread via contaminated objects. But the fortunate thing is that the World Health Assembly declared that the world was officially free from smallpox in 1980. More common in children, the last case caused by smallpox was diagnosed in October 1977. In the 20th century, smallpox killed over 300 million people.
Dengue fever is an Aedes mosquito-borne disease caused by the dengue virus. It was first identified in the Philippines and Thailand in 1950, and since then it is spreading throughout the tropical and subtropical regions of the world.
Zika is also a mosquito-borne disease caused by the Zika virus, which is spread through insect bites or stings. The virus first appeared in French Polynesia in the year of 2013. Although Zika is not a life-threatening virus, it has evolved twice in the past decade. In its second outbreak, the virus began to circulate in Brazil in 2015, and after that WHO declared the Zika virus fever as an epidemic.
Like SARS-CoV-2 or COVID-19, the MERS-CoV (Middle East Respiratory Syndrome) belongs to the same large family of viruses, known as coronaviruses, and was first identified in Saudi Arabia in 2012. The virus has spread twice in the past decade – first in Saudi Arabia in 2012 and the second in South Korea in 2015. Being a part of the coronavirus family, MERS-CoV has infected 2,499 people and killed 861 people across the world, according to the WHO. Unlike COVID-19, MERS-CoV infected camels before passing onto humans and shows symptoms like fever, cough, and shortness of breath in infected people.
These were some deadly viruses that humans were inflicted to, in the past. But we conquered them and emerged successful in saving ourselves from mass-extinction. With the current challenging time, the threat has again been posed in front of us. However, we are optimistic that our collective strength and the will to fight, will help us overcome present medical, economic, social challenges.