Psittacosis known serovars. All should be considered to be readily transmissible to humans. "C. psittaci" serovar A is endemic among psittacine birds and has caused sporadic zoonotic disease in humans, other mammals, and tortoises. Serovar B is endemic among pigeons, has been isolated from turkeys, and has also been identified as the cause of abortion in a dairy herd. Serovars C and D are occupational hazards for slaughterhouse workers and for people in contact with birds. Serovar E isolates (known as Cal-10, MP, or MN) have been obtained from a variety of avian hosts worldwide, and although they were associated with
Disease in colonial America and is extremely contagious, for it is spread by physical contact and affects children and adults alike. Smallpox was contagious, disfiguring, and often deadly. The epidemics of the disease were recurrent, devastating, and frequent. A particularly virulent sequence of smallpox outbreaks took place in Boston, Massachusetts. From 1636 to 1698, Boston endured six epidemics. In 1721, the most severe epidemic occurred. The entire population fled the city, bringing the virus to the rest of the Thirteen Colonies. Colonists tried to prevent the spread of smallpox by isolation and inoculation. Inoculation caused a mild form of the disease; it was new