Marburg virus can cause you hemorrhagic fever, meaning infected people can develop high fevers and bleeding that can lead to shock, organ failure and even death.
Ebola disease is spread through an infected person or specie that has Ebola and travelled trough contact with blood and etc.
Rabies can destroy the brain and it you don't get treatment fast, there is a 100% possibility of death.
HIV could possibly be the deadliest virus in the world at this point of time.There has been 32 million people who have died from HIV since the early 1980s.
Smallpox killed roughly 1 out of 3 people who had it also it left survivors with nasty scars and sometimes blindness
Hantavirus is not exposed from one person to another, rather people, you contract the disease from the exposure of droppings of infected mice.
Influenza has killed up to 5000,000 people worldwide during a typical flu season according to the WHO.
Dengue has a lower mortality rate than some viruses at 2.5%. But can cause an Ebola -like disease called dengue hemorrhagic fever, with a 20% mortality.
Rotavirus infection has killed over 453,000 children that is younger of the age of 5 in 2008. Countries that have introduced the vaccine have reported sharp declines in rotavirus deaths.
SARS-CoV causes fever, chills and body aches, and often progresses to pneumonia, a severe condition in which the lungs become inflamed and fill with pus.
COVID - 19, has an estimated mortality rate of 2.3%. People with underlying health conditions or who are older seem to be the most at risk. This year, corona virus has about 428,000 deaths.
MERS-Cov often progresses to badly severe pneumonia and has an estimated mortality between 30%-40% so making it the most lethal of the known coronaviruses.