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Unformatted text preview: E xperiments using animals have played a crucial role in the de- velopment of modern medical treatments, and they will continue to be necessary as researchers seek to allevi- ate existing ailments and respond to the emergence of new disease. As any med- ical scientist will readily state, research with animals is but one of several com- plementary approaches. Some questions, however, can be answered only by ani- mal research. We intend to show exact- ly where we regard animal research to have been essential in the past and to point to where we think it will be vital in the future. To detail all the progress that relied on animal experimentation would require many times the amount of space allotted to us. Indeed, we can- not think of an area of medical research that does not owe many of its most im- portant advances to animal experiments. In the mid-19th century, most debili- tating diseases resulted from bacterial or viral infections, but at the time, most physicians considered these ailments to be caused by internal derangements of the body. The proof that such diseases did in fact derive from external micro- organisms originated with work done by the French chemist Louis Pasteur and his contemporaries, who studied infec- tious diseases in domestic animals. Be- cause of his knowledge of how contam- inants caused wine and beer to spoil, Pasteur became convinced that microor- ganisms were also responsible for diseas- es such as chicken cholera and anthrax. To test his hypothesis, Pasteur exam- ined the contents of the guts of chickens suffering from cholera; he isolated a pos- sible causative microbe and then grew the organism in culture. Samples of the culture given to healthy chickens and rabbits produced cholera, thus proving that Pasteur had correctly identified the offending organism. By chance, he no- ticed that after a time, cultures of the microorganisms lost their ability to in- fect. But birds given the ineffective cul- tures became resistant to fresh batches that were otherwise lethal to untreated birds. Physicians had previously ob- served that among people who survived a severe attack of certain diseases, recur- rence of the disease was rare; Pasteur had found a means of producing this resistance without risk of disease. This experience suggested to him that with the administration of a weakened cul- ture of the disease-causing bacteria, doc- tors might be able to induce in their pa- tients immunity to infectious diseases. In similar studies on rabbits and gui- nea pigs, Pasteur isolated the microbe that causes anthrax and then developed a vaccine against the deadly disease. With the information from animal ex- perimentsobviously of an extent that could never have been carried out on humanshe proved not only that infec- tious diseases could be produced by mi- croorganisms but also that immuniza- tion could protect against these diseases....
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- Spring '08
- Infectious Disease, animal research