Marburg virus disease (MVD), formerly known as Marburg hemorrhagic fever.Ebola virus is a rare deadly disease.Rabies is transmitted by pets .HIV is the world's most dangerous virus.Smallpox killed about 200 million people in the 20th century .Hantavirus which is spread by rats.Influenza viruses that mutate have killed nearly 50 million people.Rotavirus, which according to the WHO, kills 400,000 children every year.Discover the Health Benefits of Fennel Seeds