SMALLPOX IS GONNA GET YOU, SUCKA!
Smallpox is a contagious disease that is one of the world's most feared. 400,000 people in Europe died as a direct result of smallpox in the 18th century. During the 20th century, smallpox killed 300-500 MILLION deaths. While the disease has been theoretically eradicated, there have been several cases that have popped up in areas of extreme poverty, such as Somalia.
This particular disease is airborne, easily capable of infecting someone from 6 feet away or more. It can also stay alive on objects and be transmitted by touch. It could infect an entire movie theater in less than 2 hours. Without immunity, smallpox will infect anyone, be they young, old, or in the prime.
I won't go into too much detail about the symptoms, but let's just say it's really, really bad and then you die... and that's usually in around 2 weeks from infection to death.
An outbreak of smallpox can come from one of three causes:
1) Random development. Smallpox came from somewhere, and it's entirely possible that it could pop up again. In Somalia it seemed to spring out of nowhere decades after the last case (outside of infection by scientists experimenting with it). This is the worst possibly because it's not preventable.
2) Accidental Release from a lab. Currently there are two locations, the CDC in the US and VECTOR in Koltsovo, Russia. One wrong move and this could easily infect someone unknowingly who walks out the door, meets more people and bam.
3) Intentional release. Let's face it, this could eradicate an entire human populations and there are monsters out there that could use this to their own horrible ends.
JESUS CHRIST, WHAT DO I DO?!
If there is any worry, duct tape windows and unused doors shut and do NOT answer the door. Disinfect the whole house from top to bottom and bleach all clothes in hot water. Check all members of your family for a fever, using rubbing alcohol to clean the thermometer for 15-20 minutes between use. If anyone has the symptoms (outlined below), contact the CDC immediately and quarantine them in the house. Check other members of the family for symptoms for 17 days following.
Listen to and watch the local news as much as possible for up-to-date information. Follow the instructions of public health officials.
If anyone comes to the door, DO NOT OPEN IT (unless they've got credentials, and even then be careful). You must especially keep pets and children safe.
Use the internet (like TFP!) to send and receive information. If you think something funny is going on, post it online.
Sources:
http://en.wikipedia.org/wiki/Smallpox
http://www.bt.cdc.gov/agent/smallpox...s/outbreak.asp