Infectivity and cross immunity studies of Colombian bovine Babesia species : a thesis /
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| Format: | Thesis Book |
| Language: | English |
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[College Station, Tex.] :
[Texas A&M University],
1973.
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| Subjects: |
| Abstract: | ABSTRACT: Colonies of bovine hemotropic disease free Boophilus microplus ticks were established. Adult B. microplus females and eggs were incubated at 28 to 30°C. at a relative humidity of from 70 to 80%. Larvae were maintained at 24 to 28°C. and a relative humidity of 60 to 80% for maximal survival. A colony of B. microplus infected with Babesia argentina was established by allowing non-infected ticks to feed on normal cattle for 10 to 11 days, at which time a stabilate of B. argentina was inoculated into the cattle subcutaneously. This resulted in a parasitemia at the time of final tick engorgement. The organism was maintained in ticks by allowing non-infected ticks to feed on a calf which later infected by the release of infected larvae 11 to 13 days after the non-infected larvae commenced feeding. Diagnosis of Babesia spp. in ticks was done by examination of hemolymph. Diagnosis and estimation of the effects of Babesia spp. infections in cattle were made on the basis of thick and thin blood films, packed cell volumes, rectal temperatures, body weights, cerebral biopsies, complement fixation titers and clinical signs. Boophilus microplus eggs, larvae and nymphs infected with B. argentina were disrupted by several methods and the resulting material inoculated subcutaneously into splenectomized calves. None of the calves showed signs of infection and proved to be fully susceptible when challenged with B. argentina. Babesia bigemina was isolated from other bovine hemotropic agensts by rapid serial passage through splenectomized calves. This isolate was compared with a laboratory strain previously isolated form a different geographic region of Colombia. Two groups of 8 calves each were inoculated subcutaneously with 10⁹ B. bigemina organisms of each isolate. A third group of 8 calves remained as untreated controls. Twenty-eight days later, 4 calves remained as untreated controls. Twenty-eight days later, 4 calves in each of the 3 groups were challenged with 2 X 10¹⁰ B. bigemina organisms of each isolate. The challenge groups were homologous, heterologous and control. Both homologous and heterologous groups demonstrated immunity to challenge groups were homologous, heterologous and control. Both homologous and heterologous groups demonstrated immunity to challenge. No diffeneces in the virulence of the two isolates was demonstrated. |
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| Item Description: | Vita. "Major Subject: Veterinary Microbiology". "Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of Master of Science Decemeber 1973". |
| Physical Description: | xi, 75 leaves : illustrations ; 28 cm |
| Bibliography: | Includes bibliographical references. |