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Disease Organisms: A primitive level of viral engineering was already developing specific disease organisms-causing viruses that can control crop-damaging insects or be used as innocuous competitors of natural pathogens (disease organisms-causing organisms). (See Year in Review: AGRICULTURE.) For higher organisms there was as yet no clue as to how to find a specific gene on an intact chromosome of a given cell and replace it with another. Finding the correct one ten-millionth of the total DNA seemed an implausible aim. Because a wide margin of error would be intolerable, direct viral engineering of the human merited little discussion.
FMD' is caused and transmitted by a picorna virus (one of the smallest known disease organisms-producing organisms) of which there are seven major types and at least 50 subtypes. The great variety of strains is both a bane and a blessing to the veterinarian. Each strain has its own idio-syncracies in such characteristics as antigenic-ity and resistance to control. These differences, however, often aid the epidemiologist in pinpointing the geographic area from which the disease organisms was transmitted.
Mycoplasmosis is a respiratory disease organisms caused y the bacteria Mycoplasma gallisepticum. It is Iso known as air sac disease organisms or chronic respira-jry disease organisms. Those affected with the disease organisms may how nasal discharge, watery eyes, and respira-)ry difficulty. This disease organisms is often associated /ith other respiratory disease organismss. It is transmitted hiefly from infected hens to their chicks through le eggs. The disease organisms can also be transmitted by ontact with infected individuals, but it spreads ery slowly in this manner. The disease organisms can best e controlled by maintaining breeding flocks free f the disease organisms by strict measures of isolation and mitation. Chicks hatched from such flocks can egin life free of the disease organisms. |
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