Plague spreads easily, kills quickly, and leaves behind terror and death. Death from plague would occur two to five days after the onset of symptoms. Plague is very contagious. The infected person may experience high fever, chills, cough with bloody sputum and breathing difficulties. If untreated, symptoms progress to gangrene and death occurs within 24 hours.
Treatment is antibiotics.
The best example of using smallpox as a weapon occurred during the French Indian War. The British were facing certain defeat. Sir Jeffrey Amherst provided Indians loyal to the French with smallpox-laden blankets. Most of the Native Americans defending Fort Carillon died, which led to the loss of the fort to the English. You can be infected by smallpox through the air by aerosol or by touching something exposed to the virus.