While the perfect virus does not exist yet in the real world, thankfully, my version of it would look like this:
The name of the virus would be Mortem lyssavirus (ML), as mortem is Latin for death and the virus is of the genus lyssavirus. It would be an RNA virus, as the high level of mutation would allow for the virus to better adapt to a new host environment. My virus would be some form of a lyssavirus, most closely related to Rabies lyssavirus, the virus that causes rabies, because rabies, undetected, has an almost 99% fatality rate, meaning that my new virus, ML, would have a similar fatality rate (Centers for Disease Control - Symptoms).
Bats would, like the rabies virus, serve as the host animal for ML, as, like Quammen pointed out in his book, they are abundant (having 1,116 distinct species), have interesting immunology, roost in large communities, are ancient, and can fly, thus allowing the virus to travel (Quammen 348-350). All of these factors make bats the perfect candidates for hosting ML. Specifically, the little brown bat and the big brown bat in North America (the two species of bat that most commonly carry rabies) would be the host species (Centers for Disease Control - Transmission). Both species of brown bat are not affected by the virus, so they live with the virus their entire life, eventually dying from natural causes or hunters.
Like most other lyssaviruses, symptoms of ML would start with a headache and mild fever before progressing to "paralysis, delirium, convulsions, and death" (Centers for Disease Control - Symptoms). Further, symptoms of ML, like other lyssaviruses, would have an incubation period of a month for symptoms to show up (Centers for Disease Control - Symptoms).
However, unlike other lyssaviruses that spread only through the bites of infected animals, ML has mutated to an airborne transmission route, spreading through coughs and sneezes (Centers for Disease Control - Symptoms). During the 30 day incubation period, an individual infected with ML can spread the virus to anyone who comes in contact with infected droplets of coughs and sneezes, thus spreading the virus before they even know that they are sick, starting the cycle over again (much like how HIV/AIDS spread in the 80s).
Finally, ML could be contained by enforcing strict quarantines. Because the virus is so deadly and so infectious, it would scare health officials into banning all public gatherings and contact with other people. Masks could be worn to prevent healthy individuals from inhaling infected droplets and temperature checkpoints could be utilized to prevent infected people from continuing to walk around infecting people.
ML is a terrifying virus that has the capability to wipe out a good portion of the human race, as it is so deadly (99% fatality rate) and so hard to detect before symptoms show up.
REFERENCES:
Centers for Disease Control. How is rabies transmitted? (n.d.). Retrieved from https://www.cdc.gov/rabies/transmission/index.html
Centers for Disease Control. What are the signs and symptoms of rabies? (n.d.). Retrieved from https://www.cdc.gov/rabies/symptoms/index.html
Quammen, David. Spillover. The Bodley Head Ltd., 2012.