Top 10 Worst Human Viruses on Record

For over centuries, humans have been fighting viruses that have tried to eradicate mankind worldwide. For some of these deadly viruses, we have discovered vaccines and treatments to bring infected people back to health but still we are far away to win this battle against the deadliest viruses. Here are the top ten most dangerous human viruses.

10. Hantavirus

The Hantavirus dates back to the 12th century in China, while the first clinical recognition of the Hantavirus was in Northeast China in 1931. This deadly virus was responsible for an outbreak infecting 3,000 people during the Korean war from 1951 to 1953 with a 12% death rate. A more deadly outbreak of the Hantavirus occurred in the United States in 1993 with a 60% death rate that killed 13 people. The Hantavirus gets its name from the Hantan River in South Korea were it was identified in 1976, and infects humans through contact with rodent excrements.

9. Marburg Virus

Marburg Virus

The first outbreak of the Marburg virus was in 1967 by lab workers in Germany who were infected by infected monkey tissues. An infected person of Marburg develops hemorrhagic high fever and bleeding throughout the body. Outbreaks have a mortality rate ranging from 25% to 100% with nearly 400 deaths and nearly 500 cases to date. Both Marburg and Ebola viruses are native to Africa.

9. Ebola Virus

Ebola Virus

The Ebola virus was first identified in 1976 in Sudan and the Democratic Republic of Congo near the Ebola river. This virus spreads through direct contact with body fluids of an infected person or animal. Fruit bats are a known carrier of the Ebola virus without being affected by it. Ebola outbreaks have a risk of death ranging from 25% to as high as 90%. Through 2020, there have been over 34,000 cases and over 15,000 deaths with the largest outbreaks in West Africa from 2014-2016.

7. Coronavirus


The first human coronavirus was discovered in the 1960s causing the common cold. Today it is estimated that the coronavirus causes 15% of all common colds, however recent and far more lethal varieties have been discovered.

The SARS-Cov-1 coronavirus that causes SARS first appeared in 2002 in the Guangdong Province of China and spread to 26 countries. This deadly SARS-CoV-1 virus infected over 8,000 people with a mortality rate of 9.6%. Before infecting humans, this virus likely originated in bats before passing to civet cats, both of which are nocturnal mammals.

in 2012 and again in 2015, outbreaks of the MERS-CoV coronavirus causing MERS have infected over 2,500 people with a mortality rate around 35%.

The SARS-CoV-2 virus causing COVID-19 appeared in December 2019 infected tens of thousands of people in China before spreading to tens of millions of people in almost every country. SARS-CoV-2 causes COVID-19 with over 2 million deaths as of January 2021 and an estimated 2% overall mortality rate. Elderly people and people with underlying health conditions are at highest risk.

6. Rabies Virus

Rabies Virus

Rabies has been known since 2000 BC. Today, rabies is most prevalent in India and most parts of Africa with over 50,000 deaths annually. The Rabies virus spreads by the bite of a rabid animal like a dog or bat, and causes inflammation of the brain with symptoms including violence, fear, confusion, and almost always results in death.

5. Dengue Virus

Dengue Virus

In the 1950s, the Dengue virus was first found in the Philippines and Thailand, and has since spread to more than 120 countries mainly in South and Southeast Asia and South Ameria. The Dengue virus is spread through several species of mosquitos. According to WHO, Dengue fever sickens an estimated 300 to 400 million people per year with 40,000 deaths every year.

4. Rotavirus

Rota Virus

The Rotavirus is the most common cause of severe diarrhea in children and infants worldwide. The dangerous Rotavirus kills about 450,000 infants and young children under age 5 each year in developing countries, which is dramatically lower than a few decades ago thanks to improved therapies. Within the United States, before a vaccine was introduced in 2006, the Rotavirus disease caused more than 200,000 emergency room visits each year, and as many as 60 deaths annually in children younger than five.

3. Variola Virus that causes Smallpox

Small Pox Virus

Smallpox is a disease caused by the Variola virus, and has been around for thousands of years, with medical writings from India in 1500 BC. Smallpox is estimated to have killed 300 million people in the 20th century alone. The Variola virus kills almost 1 in 3 patients it infects and leaves anybody that survives with scars and blindness. Thankfully, Smallpox has been eradicated since 1977 due to improved vaccines.

2. Human Immunodeficiency Virus (HIV)


Since the first outbreak in the early 1980s, this deadly HIV virus has infected over 70 million people and killed over 30 million. The HIV virus attacks the immune system, which can lead to acquired immunodeficiency syndrome (AIDS), the most advanced stage of infection. This worldwide killer is continuously devastating middle and under-developed countries. While new HIV infections are declining due to improved testing and prevention, there were close to 1 million deaths in 2017 compared to almost 2 million deaths at the 2004 peak.

1. Influenza Virus

Influenza Virus

Influenza or “the flu” is caused by the influenza virus, which can cause 5 million cases of severe illness and 500,000 deaths every year. The Spanish Flu that started in 1918 was the most deadly outbreak on record infecting 40% of the world population and killing an estimated 50 million people.