There are 320,000 different types of viruses that can infect mammals alone. The deadliest of these viruses are responsible for killing 15 million people every year. They are ancient they are deadly and they are found everywhere killing millions of people every year so far there is no known life-form on earth that viruses cannot infect.

Let's go over the top 10 deadliest viruses has ever seen


The Hantavirus describes several types of viruses. It is named after a river where American soldiers were first thought to have been infected with the Hantavirus, during the Korean War in 1950. Symptoms include lung disease, fever, and kidney failure.



Smallpox virus is one of the world’s deadliest viruses that had killed more humans with fatality rates of up to 90%. There are several different types of smallpox disease that result from an infection, ranging from mild to fatal, but it is generally marked by a fever, rash, and blistering, oozing pustules that develop on the skin. This virus is responsible for killing 300 to 500 million in the 20th century. Fortunately, smallpox was declared eradicated in 1979, as the result of a successful worldwide implementation of a vaccine.


In 2019, there were 1,282 cases of measles in 31 states, mostly among unvaccinated people. Recent studies have shown that measles can do more harm beyond the symptoms of acute illness. Measles has done a pretty good job of killing people throughout the ages over the last 150 years the virus has been responsible for the deaths of around 200 million people. It has a yearly mortality rate of 197,000 deaths.


Dengue is one of the deadliest viruses humanity has ever encountered. The virus spreads via mosquitoes. Now endemic in 110 countries dengue infects more than 100 million people a year and causes 20,000 deaths.

Influenza Virus 

No virus can claim credit for more worldwide pandemics and outbreaks than influenza. The Spanish flu in 1918 is generally considered to be one of the worst pandemics in human history, infecting 20 to 40 percent of the world's population and killing 50 million in the span of just two years. Effective influenza vaccines exist, and most people easily survive infections. But the highly infectious respiratory illness is cunning the virus is constantly mutating and creating new strains.

Yellow Fever

One of history’s biggest killers is yellow fever. This mosquito-borne illness got its name from the jaundiced skin, hair, and nails of infected people suffering from liver failure. Without medical treatment, 50% of infected people die. In 2018, there was an epidemic of yellow fever in Sao Paulo, Brazil. Parks like this one were closed to prevent further infection. In severe cases of yellow fever, the virus causes bleeding from the mouth, nose, eyes, or stomach. Around 50% of the patients who enter this toxic phase are dead within 7 to 10 days.



Rabies has been one of mankind’s most feared diseases since times and with good reason. There have been only a handful of cases in the human history of unvaccinated people surviving the rabies virus. Infection with rabies occurs when bitten or scratched by an infected animal most commonly dogs or bats nearly 60,000 people die of rabies every year. Most of these deaths occur in Africa and southern Asia.

Hepatitis B

Hepatitis B causes the largest share of fatalities each year, with a death toll of around 700,000. The virus attacks liver which results in either liver cancer or cirrhosis. Although the overall death rate from hepatitis C is lower than B. it still kills an estimated 350,000 people every year.

Ebola Virus

If ever there were viruses that could cause fear in the 21st century. It is the Ebola and Marburg viruses. Combined with some very unpleasant symptoms, and are potentially the deadliest viruses on earth. Fruit bats and other African wildlife are the natural hosts of Ebola. Once passed to a human population, the virus is contagious through direct contact with another person. There are no proven treatments or vaccines for the virus at this time.


Today there are about 40 million people living with HIV. Sadly, only around half of those infected have access to the required drugs for treatment so the global death rate from AIDS is still shockingly high. HIV is most often spread through sexual activity or sharing drug needles. Antiviral medications can help keep it in check and reduce the risk of transmission. Estimates suggest there are nearly 2 million deaths every year and ever the last 30 years the virus has claimed over 25 million lives.