Don't touch your nose, mouth, or inside of your ears while out and about. Any germs on your hands, will get into you that way.
Different quality masks and protective suits are available. Don't think the cheap thing you got at Walmart is going to protect you against everything
Shoot any sick people trying to come on your property. Its either them or you.
Get a filter to block viruses from getting into your home.
Circulate the air in your home through a powerful enough air pump and ionization filters to kill all germs. Also great to get rid of dust, allergens, and odors.
If birds are carrying the disease, see if ultrasound noise from a speaker will keep them away from your property. Poisoned bait and elimination of possible nest sites can work also. Some birds can be scared off by fake snakes or fake large predator birds.
Make sure your children know never to go near a dead wild bird.
If you go out for supplies, make certain to clean anything you bring back thoroughly before letting it back into your home or colony.
Birds have their own calls to warn each other of danger. By broadcasting these songs, you can keep them from flying on your property.
China has done a lot of work in genetic engineering. If they made a virus that recognized the DNA signature of a race, they could release a virus that killed off everyone that wasn't Asian. Thus they would survive just fine, but wipe out much of the world's population, and thus be able to conquer what was left with ease.
In China, pigs and ducks or chickens are often raised together. Strands of the flu virus incubate in pigs and birds and cross back and forth between the two, forming new viruses that are infectious to humans. Do to poor sanitation in that nation, the likelihood of additional and more dangerous viruses appearing in the future is rather high.
The overuse of antibiotics, and the fact that some people refuse to listen to the doctor's instructions to keep taking them a certain number of days, instead deciding to stop taking them once they feel better, allows the infections to survive and recover, becoming resistant to the antibiotics used on them.
Human antibiotics are sold without prescription in pet stores for fish. Some people misuse them, and this could lead to viruses developing into a strain immune to them.
Someone could deliberately expose a virus to small amounts of every medication used to treat it, until a strain was created to be immune to each one of them. Thus it'd be unstoppable and civilization would be doomed.
China produces 60 percent of the world’s farmed seafood. They use massive amounts of antibiotics in their pigs, and the poop is washed out to where they farm seafood at. The U.S. Food and Drug Administration blocked a lot of food imports from China in 2006, but they just started shipping it through other nations to hide its origin. They are even using antibiotics the rest of the world agreed would be for humans only as a last resort if nothing else worked, such as colistin. Already a large number of people in China are immune to various medications.