Studies on Drug Resistance in Coccidia
| Autor: | Ashton C. Cuckler, Christine M. Malanga |
|---|---|
| Rok vydání: | 1955 |
| Předmět: |
biology
business.industry medicine.drug_class Antibiotics Outbreak Zoology Drug resistance biology.organism_classification medicine.disease Biotechnology chemistry.chemical_compound Coccidiosis Coccidia New england chemistry Sulfaquinoxaline medicine Parasitology Flock business Ecology Evolution Behavior and Systematics |
| Zdroj: | The Journal of Parasitology. 41:302 |
| ISSN: | 0022-3395 |
| DOI: | 10.2307/3274212 |
| Popis: | The addition of chemicals to poultry feed for preventing and controlling coccidiosis outbreaks has been widely and intensively applied in the United States during the past 6 years. This development has permitted the poultry-industry to expand greatly and has resulted in more efficient and economical production of poultry. Because of the variability of coccidiosis epidemics, and the difficulties encountered in treatment of outbreaks, continuous medication has become established practice to prevent morbidity and mortality losses in raising broilers and flock replacement chickens. Although this method has been of great economic importance, it has not been ideal from the standpoint of therapeutics. This is because the dosage which is effective for "average" conditions may be sub-curative for "severe" coccidiosis and eventually permit the emergence of resistant strains of coccidia. Even before the time of Ehrlich's (1907) fundamental discoveries on drug-resistance in trypanosomes, it was known that bacteria and protozoa could be adapted to grow and survive in normally toxic concentrations of chemicals by repeatedly exposing the organisms to sub-lethal and increasing concentrations of the compounds. Drugresistance did not become an important practical problem, however, until the development and wide-spread use of the sulfonamides and antibiotics. Later, after the extensive use of certain insecticides, it was found that flies, mosquitoes and other insects had become resistant to these chemicals. Obviously, such changes must occur if the organisms are to succeed in their struggle for survival. Furthermore, it is a well-known biological fact that all organisms are capable of adaptation. Whether these adaptive processes are genetic, enzymic, physico-chemical, or other, they may result in a "resistant" strain which is able to survive and reproduce in its environment. Sulfaquinoxaline had been in continuous and satisfactory use since 1947 for controlling coccidiosis in a typical New England poultry farm and there was no evidence that drug-resistance had developed in the coccidia. Nevertheless, early in 1951, we began laboratory studies to determine whether resistance could be induced in coccidia by repeated exposure to sub-optimal dosages of certain anticoccidial agents. A short time later, studies were also begun on field strains of coccidia. |
| Databáze: | OpenAIRE |
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