The Worlds Fight Against Microbes Many infectious diseases that were nearly eradicated from the industrialized world, and newly emerging diseases are now breaking out all over the world due to the misuse of medicines, such as antibiotics and antivirals, the destruction of our environment, and shortsighted political action and/or inaction. Viral hemorrhagic fevers are a group of diseases caused by viruses from four distinct families of viruses: filoviruses, arenaviruses, flaviviruses, and bunyaviruses. The usual hosts for most of these viruses are rodents or arthropods, and in some viruses, such as the Ebola virus, the natural host is not