Humans have been facing viruses since before our species evolved into its modern form. For some viral diseases, vaccines and medicines have been developed to prevent the spread of infections and help patients recover. However, as the coronavirus pandemic demonstrated in 2020, we are far from winning the fight against these parasites.
Even when everything seems normal, new ones emerge, bringing other challenges. Furthermore, there are other viruses that are even more dangerous than the coronavirus. I'm Donato de Paula, narrator of Mistérios do Mundo, and here are some of the deadliest viruses in the news.
If you like the video, don't forget to like, subscribe to the Mistérios do Mundo channel and turn on notifications. HIV In the modern world, one of the deadliest viruses of all is still HIV. It is estimated that 36 million people have died from illnesses caused by the virus since the disease was discovered in the early 1980s.
HIV breaks down the defenses of the CD4 cell, which is essential for the functioning of the immune system. By doing this, the body's defenses are weakened, which is why a person who contracts HIV does not die from HIV itself, but can die from a simple flu, as they have no defense to fight it. Powerful antiviral drugs have made it possible for people to live for years with HIV, but the disease continues to haunt many low- and middle-income countries, where 95% of new HIV infections occur.
Rabies Although rabies vaccines for pets were introduced in the 1920s and helped make the disease rare in the developed world, rabies remains a serious problem in India and many parts of Africa. This disease is capable of destroying the brain through progressive and acute encephalitis, caused by a virus of the Lyssavirus genus. Nowadays, if someone is bitten by an infected animal, if the person does not receive treatment soon, the chance of survival is very low.
Flu In typical flu seasons, up to five hundred thousand people die worldwide, according to the WHO. However, occasionally a new strain of flu emerges and, with it, a pandemic with the disease spreading more quickly, often with higher mortality rates. The deadliest flu pandemic in history was the Spanish flu, which began in 1918 and sickened up to 40% of the world's population, killing around 50 million people.
Rotavirus Today, there are two vaccines to protect children from rotavirus, which is extremely deadly for children. Infections with this virus are the main causes of serious diarrheal illnesses among babies and young children, with rotavirus having the ability to spread quickly. The WHO estimates that, worldwide, 453,000 children under the age of 5 died from rotavirus infection in 2008 alone.
Countries that have introduced the vaccine have already reported sharp declines in hospitalizations and deaths. Dengue It was in the 1950s, in the Philippines and Thailand, that what we know today as dengue fever appeared. Since then, the disease has spread throughout the tropical and subtropical regions of the planet.
Dengue fever sickens 50 to 100 million people a year, according to the WHO, and Brazil is one of the countries most affected by the epidemic. In 2024 alone there was an increase of 346% compared to last year. Although the death rate from the disease is lower than some other viruses, it can cause an Ebola-like illness called dengue hemorrhagic fever.
This condition has a 20% mortality rate if left untreated. Fortunately, there is already a vaccine available against the disease. Hantavirus Hantavirus pulmonary syndrome is a viral disease transmitted by wild rodents or human saliva, gaining attention in the United States in 1993 when a healthy young man and his fiancée died within days of contracting the virus.
After a few months, health authorities isolated the hantavirus from a mouse that lived in the home of one of the infected people. More than 600 people in the country have already contracted the disease, and 36% did not survive. The disease causes symptoms such as extreme shortness of breath, tachycardia and pulmonary edema.
Ebola This virus is transmitted through contact with blood or other body fluids, or even tissues from infected people or animals. The first known outbreaks of Ebola in humans occurred in Sudan and the Democratic Republic of Congo in 1976. But known strains vary dramatically in their mortality.
For example, one strain of the virus, Ebola Reston, doesn't even make people sick. Now, the Bundibugyo strain has a mortality rate of up to 71%. Smallpox For a long time, smallpox was a great enemy of the world, especially in Europe.
It is estimated that, in the 18th century, around 400,000 people died each year on the continent. The disease was capable of killing around one in three people infected, leaving the survivor with deep, permanent scars and often blind. What was even worse was what happened to populations outside of Europe.
People had little contact with the virus before European explorers brought it to their regions. Historians estimate that 90% of the native population of the Americas died from smallpox. The World Health Assembly declared the world free of smallpox in 1980, despite the fact that in the 20th century alone the disease killed 300 million people.
Nipah Nipah virus is a zoonotic pathogen, first identified in 1998 in Malaysia. Fruit bats of the genus Pteropus are the natural hosts of the virus, but it can also infect other animals, such as pigs, and humans. Transmission to people can occur through direct contact with bodily fluids from infected animals, consumption of food contaminated by these fluids, or through direct contact with infected people.
The Nipah virus is of particular concern due to its high mortality rate, which can reach 75%, and the lack of specific treatment or vaccine available to date. Symptoms of Nipah virus infection in humans range from asymptomatic infections to acute respiratory illnesses and lethal encephalitis. Early signs include fever, headache, drowsiness, and mental confusion, which can quickly progress to coma.
Given the severity and potential spread, Nipah virus outbreaks require rigorous public health interventions, including surveillance of close contacts, quarantines, and strict control measures. Marburg – The most dangerous virus in the world The Marburg virus was identified by scientists in 1967, when small outbreaks occurred among laboratory workers in Germany who were exposed to infected monkeys that came from Uganda. This virus is similar to Ebola in that both can cause hemorrhagic fever.
This means that infected people experience high fever, delirium, organ failure and bleeding throughout the body, resulting in death. In the outbreak of the 1960s, the mortality rate was 25%, but between 1998 and 2000 it was over 90% in Congo, as well as in the 2005 outbreak in Angola. Did you already know about all these deadly viruses?
Tell us in the comments. To the next.
