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 widely, and have helped sick people recover.
The most dangerous virus is the Marburg virus. It is named after a small and idyllic town on the river Lahn - but that has nothing to do with the disease itself. The Marburg virus is a hemorrhagic fever virus. As with Ebola, the Marburg virus causes convulsions and bleeding of mucous membranes, skin and organs. It has a fatality rate of 90 percent.
There are five strains of the Ebola virus, each named after countries and regions in Africa: Zaire, Sudan, Tai Forest, Bundibugyo and Reston. The Zaire Ebola virus is the deadliest, with a mortality rate of 90 percent. It is the strain currently spreading through Guinea, Sierra Leone and Liberia, and beyond. Scientists say flying foxes probably brought the Zaire Ebola virus into cities.
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
Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus. Most people who fall sick with COVID-19 will experience mild to moderate symptoms and recover without special treatment. The virus that causes COVID-19 is mainly transmitted through droplets generated when an infected person coughs, sneezes, or exhales. These droplets are too heavy to hang in the air, and quickly fall on floors or surfaces. You can be infected by breathing in the virus if you are within close proximity of someone who has COVID-19, or by touching a contaminated surface and then your eyes, nose or mouth.
The Machupo virus is associated with Bolivian hemorrhagic fever, also known as black typhus. The infection causes high fever, accompanied by heavy bleedings. It progresses similar to the Junin virus. The virus can be transmitted from human to human, and rodents often the carry it.