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
Germ theory of disease of contagion stating that specific 'animalculae' in the soil and the air were responsible for causing specific diseases. Von Plenciz noted the distinction between diseases which are both epidemic and contagious (like measles and dysentry), and diseases which are contagious but not epidemic (like rabies and leprosy). The book cites Anton van Leeuwenhoek to show how ubiquitous such animalculae are, and was unique for describing the presence of germs in ulcerating wounds. Ultimately, the theory espoused by von Plenciz was not accepted by the scientific community. The Italian Agostino Bassi was the first person to prove that a disease was