A virus is a microscopic infectious agent that can only replicate inside the cells of another organism. It is derived from the Latin word "'virulent" which refers to poison and other noxious substances.
Humans have been battling viruses since before our species had even evolved into its modern form. For some viral diseases, vaccines and antiviral drugs have allowed us to keep infections from spreading, and have helped sick people recover. We've been able to eradicate one such viral disease, smallpox, ridding the world of new cases.
The top 9 deadliest viruses are-
Marburg virus was identified back in 1967 when small outbreaks occurred among lab workers in Germany who were exposed to infected monkeys from Uganda.
The death rate in the first outbreak was 25%, but it was more than 80% in the 1998-2000 outbreak in the Democratic Republic of Congo.
It causes hemorrhagic fever. Infected people develop high fever, there is bleeding throughout the body that can lead to shock, organ failure, and even death.
Ebola, called Zaïre Ebola Virus (EBOV), affects both humans and animals. The disease is rare but very severe and potentially lethal. The Ebola virus is transferable through direct contact with (any kind of) body fluids, such as blood, saliva, or feces. The largest Ebola outbreak started in 2013.
Rabies is a disease that causes inflammation of the brain in humans and other mammals. Symptoms include fever and tingling at the site of exposure. The virus is present in the nerves and saliva of a rabid animal. The route of infection is usually by a bite. In many cases, the infected animal is aggressive, may attack without provocation. Since the virus is also present in sperm and vaginal secretions, it might be possible for rabies to spread through sex.
HIV stands for human immunodeficiency virus. HIV is a virus that attacks cells in the immune system and also destroys a type of white blood cell in the immune system. An estimated 32 million people have died from HIV till now. Antiviral drugs have made it possible for people to live with HIV.
Smallpox was a terrible disease. On average, three out of every ten people who got it died. People who survived usually had scars, which were sometimes severe. Mortality rates were far higher in populations outside of Europe, where people had little contact with the virus before visitors brought it to their regions. In 1980, the World Health Assembly declared the world free of smallpox.
In May 1993, an outbreak of an unexplained pulmonary illness occurred in the southwestern United States, in an area shared by Arizona, New Mexico, Colorado, and Utah. HPS can be fatal. It has a mortality rate of 38%.
In the United States, deer mice along with cotton rats and rice rats, and white-footed mice are reservoirs of the hantaviruses
Influenza is a viral infection that attacks one's respiratory system. Though the annual influenza vaccine isn't 100% effective, it's still your best defense against the flu. The most deadly flu pandemic, sometimes called the Spanish flu, began in 1918 and sickened up to 40% of the world's population, killing an estimated 50 million people. Common signs and symptoms of the flu include:
Dengue fever is a painful, debilitating mosquito-borne disease caused by any one of four closely related dengue viruses. Dengue virus first appeared in the 1950s in the Philippines and Thailand. Dengue sickens 50 to 100 million people a year, according to WHO. The death rate for dengue fever is lower than some other viruses. A vaccine for Dengue was approved in 2019 by the U.S. Food and Drug Administration for use in children 9-16 years.
Rotavirus spreads to infants and young children easily. The virus can cause severe watery diarrhea, vomiting, fever, and abdominal pain. Children who have rotavirus disease become dehydrated and need to be hospitalized.
