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Scrapie Disease Of Sheep: If, for example, a gene is destroyed on both DNA strands before a cell divides, what source of information is used to repair it? As an added complication, it had been shown that peas can remain viable even after irradiation has drastically changed the base composition of their extractable DNA. Then, too, the infectious agent responsible for the scrapie disease of sheep was shown to be protein of relatively low molecular weight and not a nucleic acid. Thus, the simplest "living" organism has no DNA at all.
Foot-ond-Mouth Disease. This is a highly infectious disease that is one of the most dreaded of all livestock diseases. It is caused by a virus and it affects hogs and sheep as well as cattle. The main symptom of the disease is blisters in the mouth and on the feet. The animals may also become lame. The disease causes a severe loss in meat and milk production and sometimes even death.
The disease continues to exist in Africa, Asia, Europe, and South America, and only the utmost vigilance by agents of the U.S. Department of Agriculture keeps it from invading the United States. Cattle, swine, sheep and goats, and the fresh, chilled, or frozen meats of these animals cannot be imported unless they are from countries free from the disease.
In addition to preventing the importation of infected animals, the U.S. Department of Agriculture operates a foot-and-mouth disease research laboratory on an island off the eastern coast. This laboratory is working on new and more effective means of controlling the disease if a new. outbreak should occur.
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