Bovine babesiosis in Guyana : a comparison of the indirect fluorescent antibody (IFA) and complement-fixation (CF) tests in determining the prevalence of Babesia bigemina and Babesia bovis infections : a thesis /
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| Format: | Thesis Book |
| Language: | English |
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[College Station, Tex.] :
Applewhaite,
1979.
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| Abstract: | ABSTRACT: The prevalence of bovine babesiosis in Guyana was determined by the indirect fluorescent antibody (IFA) test with 605 sera collected from cattle in four ecologically different areas of the country. One hundred and twenty-eight of these sera were from Holstein-Friesian cattle imported as four- to six-month-old calves from the United States. These results were compared for agreement with those of the complement-fixation (CF) test which were obtained from a previous study. The indirect haemagglutination (IHA) test, also intended for comparison, proved to be unsatisfactory in this study. Sera from native cattle were screened by the IFA test at a serum dilution of 1/40. Likewise, sera from imported animals were titrated with fluorescence being read to extinction. The rate of detection of Babesia antibody in native cattle was considerably greater by the IFA than the CF test, and both methods indicated a higher prevalence of Babesia bigemina than Babesia bovis infection. The prevalence of B. bigemina IFA antibody was 80.1 per cent and that of B. bovis, 61.2 per cent. From the data available, CF antibody to B. bigemina was found to be present in 39.8 per cent of native cattle, and antibody to B. bovis in 16.8 per cent. Agreement between the two tests was poor. The overall agreement for B. bigemina was 53.3 per cent and that for B. bovis 51.3 per cent. The prevalence of positive sera in native calves less than six months of age was compared with mature cattle over six months of age. While the prevalence of IFA and CF B. bigemina antibody was found to be statistically the same (P>0.01) in the calves, the prevalence of IFA antibody was significantly greater (P>0.01) in mature cattle. No differences in the prevalence of IFA and CF antibody were observed between breeds of native cattle. The examination of replicate serum samples taken from calves imported from the United States on the day after arrival and again on days 25, 35 and 51 revealed that CF Babesia antibody and B. bovis IFA antibody were demonstrable on day 25; IFA antibody to B. bigemina first appeared on day 35. By day 51, however, between 87.5 and 95.8 per cent of calves showed evidence of IFA and CF Babesia antibody. Similar rates of prevalence of IFA and CF Babesia antibody were observed in imported calves present in Guyana for six to 18 weeks before they were sampled. These rates were markedly greater than those for native calves six months old and younger. Although the IFA and CF tests proved to be equally capable of detecting Babesia antibody in recently exposed susceptible cattle, the results indicated that the IFA test reflected more accurately the status of bovine babesiosis in Guyana. This technique should be considered more suitable for serological surveys of this nature. |
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| Item Description: | Vita. "Major subject: Veterinary Parasitology." "Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of Master of Science August 1979." |
| Physical Description: | ix, 96 leaves : illustrations ; 28 cm |
| Bibliography: | Includes bibliographical references (leaves 91-95). |