The Deadliest Viruses Present on Planet Earth

Today we all know that viruses are infectious agents also known as parasites that reproduce after entering inside the body of their living host. The host could be plant, animal or human. It does not have any ability to reproduce by itself. They infect their host and in return, the host cell produces several duplicate copies of the virus. These viruses destroy the host cells attacking them and causing severe infection and illness. Thus the viruses are called the deadliest things present on our planet.

Where did the virus come from?

The answer to this question is still unknown. Several theories describe the evolution of viruses. Some say that the virus originated from bacteria while others say that they are already present in the living bodies. They are body plasmids and they are transferable from one living being to another.

Until today nearly 4,800 new species of the virus have been discovered. Their size is not more than an inch, they are usually measured in nanometers and their weight depends on the type of specie they belong to.

deadliest viruses. Different types of virus.

Their spreading way varies from specie to specie. The plants virus spread from plants through insects or other living organisms.

plant virus

Animal or mammal viruses are mostly transferred through bodily fluids, through droplets or direct exposure. Every year virus infection causes severe illness among animals, plants and human beings. Every year scientists are in an urge to create a new vaccine for the newly developed deadly viruses.

How to treat a viral infection?

Till date no treatment or cure is introduced to treat any viral infection. It is said that viral infections are only defended by the strong immune system. The anti-biotic drugs are used to treat other illness or bacterial diseases because they have zero effect to treat the viral infection. However, there are some vaccines produced that can help to restrain the viral infection.

Deadliest viruses in history

Studies have claimed that among the species discovered so far there are more than 320,000 different types of viruses that can infect the mammals alone. They are responsible for killing nearly 15 million people each year. This is indeed terrifying because we are unaware that most of the deaths around us or the globe are caused by viruses alone. We take the viruses too light but in reality, they are the most deadly micro-organisms present on our planet.

Types of viruses

Viruses are found everywhere and they have infected every type of life on earth. Today through this article, The Planet Today will make you aware of the deadliest viruses present on our planet.

Dengue Virus

Dengue virus is known as the mosquito-borne virus. It is one of the deadliest viruses that the world has ever encountered. The source of this virus is the mosquito.

The deadliest virus is spreading rapidly

The virus spread through dengue mosquitoes and has now spread to almost 110 countries of the world. It is responsible for the death of more than 20,000 people each year infecting more than 100 million people. It causes severe illness. Its fatality rate is less than 1% if the patient is given proper medical care and support.

Deadliest Dengue virus

The patient can easily defeat the virus. The fatality rate increases if it is left unnoticeable because it develops dengue hemorrhagic fever. The incubation period of this deadly virus is four to seven days. The body develops symptoms after four to seven days after the dengue mosquito bite. In several cases, it was declared that dengue fever is not STD but last year the first case of dengue virus sexual transmission was reported.


Rotavirus is also known as a children virus. It is one of the most contagious virus. This deadly virus is known as a child killer because it causes the death of more than 215,000 children every year. The child affected with this virus causes severe diarrhea and illness.

Deadliest virus Rotavirus

This virus is active in winter and causes severe diarrhea, vomiting, fever, abdominal pain and dehydration in children and also some adults. There is no cure to treat this disease. However, a vaccine to prevent rotavirus has been discovered and the infants are required to receive two doses of rotavirus vaccine.

Variola Virus

Variola Virus is the smallpox virus. This virus is further divided into two types: Variola major virus and Variola minor virus. Variola major virus is a deadly virus with the highest mortality rate whereas the variola minor is less fatal. The variola virus is known as the deadliest virus in the history of mankind because it has killed more humans than any other virus.

variola virus

Smallpox virus was diagnosed some 3000 years ago and it has a 90% fatality rate and it has caused the death of nearly 300 million people in the 20th century alone.

The deadly virus was declared eradicated

No case of smallpox was diagnosed after 1977 and in 1980 it was eradicated globally. The evolution of this virus is unclear because it dates back to 12,000 years. Smallpox is eradicated from the world but there are still threats that it could be used as bio-weapons or it can again originate from any source.

Rubeola Virus

Rubeola virus causes measles which is known as one of the most devastating and contagious diseases that spread rapidly.

Rubeola Virus

There is no cure for measles but vaccines have been discovered to stop the spread of this viral disease. Every year thousands of measles case are diagnosed that result in several deaths.

Measles outbreak of this century

The last deadliest measles outbreak occurred in 2018 to 2019 which infected more than 10 million people killing 140,000 people worldwide. However, the only way to stop this disease is by proper vaccination. The disease was eradicated from the world in 2000 but it again showed a comeback last year. Over the last century, the measles virus has killed 200 million people worldwide.

Flavivirus or yellow fever virus

Flavivirus or YFV is known as the biggest killer in history. This is a mosquito-borne virus and a person gets infected by the mosquito or when an infected mosquito bites a person. The mosquito gets infected by biting an infected human or monkey.

deadly viruses flavivirus

The yellow fever is a flu-like virus that later develops high fever and jaundice. This disease does not spread from one person to another. Although there is no cure but a vaccine has been developed to stop the spread of this viral disease.

Cure for YFV

The disease is cured by getting a blood transfusion, taking enough liquid and a healthy immune system. In several extreme cases the virus can cause bleeding from mouth, nose, eyes or stomach and it can also affect your kidneys. It is said that around 50% of people who develop this disease die in a week.

Influenza virus

The influenza virus is responsible for causing the most infectious disease “The Flu”. The flu virus is also known as one of the most contagious and are known to cause global pandemics. The influenza virus is of two types: Type A and type B, that are subdivided into several types. The incubation period of the flu virus is two to three days and a single person can infect several persons for nearly a month.

 dealiest Flu viruses

The virus spreads from an infected person to entire area. The spreading of virus is through cough and sneeze droplets present in the air or through direct contact. Although, there is no cure for influenza but a yearly vaccine has been introduced which is effective for some types of influenza.

Influenza spreading to lungs

Besides this, there are several antiviral drugs like oseltamivir which is used to treat the flu. Every year a flu outbreak is noticed globally. The flu outbreak infects more than 6 million people each year causing the death of 650,000 people including unvaccinated children.

Flu outbreaks in History

The major flu outbreak in history includes:

  1. Spanish flu in 1918 (50 to 100 million confirmed deaths).
  2. Asian Influenza in 1957 that killed two million people.
  3. Hong Kong Flu in 1968 that killed 1 million people.
  4. A new influenza type A virus name H1N1 that created a pandemic in June 2009.

Rabies virus

The most deadly and terrible disease in the history of mankind. Rabies disease is now declared to be under control but still it is present in the list of deadliest viruses. This is one of the ancient diseases that killed millions of people. Ever since 60,000 people die of rabies every year. It is caused by the bite or scratch of a rabid animal like dogs or bats.

Rabies virus

Although rabies vaccine has been introduced and is in use since 1920 that makes this disease rarest but still it could not be eradicated from the world. Rabies destroys the brain of the infected person that could kill the person.


Hantavirus or Hantavirus Pulmonary Syndrome was first diagnosed in the US in 1993. A Navajo man and his fiancé were the first two infected persons to die from the Hantavirus. They developed shortness of breath. According to the US center disease control more than 600 people got infected with the Hantavirus outbreak in the US killing 36% of them.


Later the source of the virus was identified after it was isolated from the deer mouse or rodent living in the home of the dead Navajo man. It was also claimed that this virus caused an outbreak in 1950 during the Korean war infecting more than 3000 people and killing 12% among them. However, it was new to western medicine when it occurred in 1993. This Virus was linked with the droppings of infected mice like urine, saliva or other body fluid and it was also said that it is not spread from person to person but it can be spread through infected person saliva, bite or other body fluid.

A new Hantavirus case

This year on 24 March, 2020, Hantavirus again made a come back in China. A man in China southern province of Yunnan died while traveling on a bus to the Eastern Shandong Province.


HIV (Human Immunodeficiency Virus) is one of the deadliest viruses also known as the killer virus. This virus was first diagnosed in 1980. It infects the human immune system thus damaging it to fight against any infection or disease. Thus if it gets unnoticed and untreated it kills the CD4. These are the immune cells leaving the body prone to several diseases, infections and also cancer.

HIV Virus

HIV is spread through body fluids like blood, semen, breast feeding, drugs needles or infected blood transfusion. This virus cannot spread through the air or casual contacts.

Although there is no cure for HIV, some powerful antiviral drugs can maintain the infected to live for some years. If HIV gets worse it develops AIDS. This disease is common in the WHO African region with 1 in every 25 adults HIV Positive. More than two-thirds of the people are living with HIV Worldwide which means nearly 40 million people are living with HIV.

Hepatitis B virus (HBV)

Hepatitis, a liver disease has several causes. It is caused by viruses, bacteria, microorganisms, parasites, or fungal infection. Hepatitis A virus is known as HAV, Hepatitis B virus is known as HBV and Hepatitis C virus is known as HCV.

Hepatitis B virus

Among the three Hepatitis B is the deadliest viral disease caused by HBV. It has the largest share of fatalities each year with 700,000 death. In this disease, the virus attacks the liver. This results in liver cancer or cirrhosis.

Ebola virus

The most fear causing virus in the 21st century. Ebola is the deadliest virus on earth today with a fatality rate of 90%. It causes fever, body ache, diarrhea and in some cases internal and external bleeding. There is no effective treatment or vaccine developed to treat the disease. The virus is named Ebola after the Ebola river where it was first discovered in the Democratic Republic of Congo.

Ebola Virus

Since then the virus is responsible for creating several outbreaks in the central African Region. There is no cure but it is somehow treated through several experimental treatments. The source of this virus is not confirmed but bats and several other wild animals are declared to be the carrier of EBOV.

Marburg Virus

Similar to Ebola, Marburg Virus is also one of the deadliest and fear creating viruses of all time with no cure and vaccine available. Nearly 88% fatality rate, it causes hemorrhagic fever. It is named after the town in Germany, from where its first outbreak began.

Marburg Virus

Bats are known to be the source or the carrier of this virus because people exposure to mines, caves or inhabited by bat colonies were tested positive for Marburg virus. The Incubation period of this virus is 2 to 21 days.


The family of coronavirus is too vast and they have created several major outbreaks in this century. Coronaviruses is named corona because of their crown-like shape. SARS, MERS, and now COVID 19 are three major coronavirus virus outbreaks in history.

Corona virus


Severe Acute Respiratory Syndrome was first discovered in 2002 in Southern China. The first source of the virus was claimed to be the bats but later civet cats were called to infect humans with this virus. SARS triggered an outbreak in China killing and spreading it to 26 countries worldwide. SARS infected 8000 people and caused the death of 770. It has a mortality rate of 9.6% and there is no cure or approved medicine for treatment.


Middle East Respiratory Syndrome was first identified in Saudi Arabia in 2012. This belongs to the same family of coronavirus. It sparked an outbreak in Saudi Arabia in 2012 and later in South Korea in 2015. The virus was originated from bats and infected camels and then passed to humans. It was the deadliest outbreak with a mortality rate of 30 to 40 %. Starting from coughing and shortness of breath the virus progresses to severe pneumonia.

Deadliest Virus Covid-19

SARS – COV-2 or COVID-19

SARS- COV- 2 belong to the same family of coronavirus and was identified in December 2019 in the Chinese city of Wuhan. The disease caused by SARS-COV-2 is named COVID-19. The virus is known to originate in bats and then passed through another intermediate animal before passing into human beings. Some researches discovered pangolins behind the spread of this virus.

It has an estimated mortality rate of 2%. Common symptoms include fever, shortness of breath cough, taste loss that later progress to severe pneumonia or lung damage. The disease is declared fatal for older people or those with underlying health conditions. As of 4th April 2020 the disease has spread to more than 200 countries infecting 1,121,917 people and killing 59,401.

Viruses and mankind

Although these are some most deadly and terrifying viruses that mankind has encountered until today.  There is no treatment to cure any viral disease. Scientists have developed vaccines to only few viruses while some viruses are still the deadliest with no vaccine and cure available. The best way to defend yourself from any virus is to follow the prevention techniques and restrain from the ways that cause the virus to spread from one being to another.

The COVID-19 outbreak has become the biggest pandemic in the history that the world is facing today. 4 months have passed and still, the world is struggling to contain the virus with hope to contain it soon.


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