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K C Thompson

Publications and source records attributed to K C Thompson.

27 records · Page 2Linked to original sources

Methods to improve the health of cattle in the tropics: conclusions and economic appraisal.

The results of the immune responses of immunised and chemoprophylactically treated calves to tick-borne (Boophilus microplus) challenge indicate that the system of immunisation was effective in protecting cattle against Anaplasma marginale, Babesia argentina (bovis), and B. bigemina. However, chemoprophylaxis was effective only against Babesia spp. but not against A. marginale. Both methods showed a substantial advantage over no control system when using native cattle breeds in a zone endemic for bovine anaplasmosis and babesiosis. Based on the net economic gain per calf starting the experiment, sizeable differences were noted at 308 days between the calves in the immunised group, chemoprophylaxis group, tick and gastrointestinal parasite control group and the experiment control group.

Anaplasmosis↗

Anti-tick grasses as the basis for developing practical tropical tick control packages.

Of six grass species analysed, Melinis minutiflora (molasses grass) showed the highest anti-tick deterrent properties while Andropogon gayanus (Gamba grass) exhibited the ability to maintain a defined, constantly low, initial host tick infection property and lengthy but low to moderate field tick population. It was concluded that Melinis minutiflora is a species which would best be used in a tick control package within a marginal tick zone while Andropogon gayanus has the advantage within an endemic tick zone.

Animals↗

The immune responses to antigenic variants of Babesia bigemina in the bovine.

Four Babesia bigemina stabilates were used to determine the immune response of cattle to acute and chronic blood- and tick-borne infections. Thirty-two intact calves were divided into 16 groups of two and each calf was inoculated with infective B bigemina erythrocytic stabilates. Twenty-eight days later they were challanged with homologous and heterologous stabilates, and monitored for an additional 20 days. The hosts' apparently reduced response to homologous challenge but marked immune response to heterologous challenge indicated antigenic differences between the isolates and confirmed the conclusions reached by examination of the serological data.

Animals↗

Antigenic variation of Babesia bigemina.

The purpose of the study was to determine whether antigenic differences occurred in four stabilates of Babesia bigemina derived from a single purified isolate and propagated as acute and chronic, blood-borne and tick-borne infections in Colombian cattle. Antigens were characterised by means of the complement fixation (CF), gel diffusion (GD), agar gel electrophoresis (AGE) and the indirect haemagglutination tests (IHA). Differences were detected. Acute blood and chronic blood antigens were similar, as were acute tick and chronic tick antigens, when compared by IHA and GD. Similarities were observed between acute blood anc acute tick and between chronic blood and chronic tick when these antigens were compared by AGE and CF.

Animals↗

Immunization against anaplasmosis and babesiosis: Part I. Evaluation of immunization using minimum infective doses under laboratory conditions.

A method of immunization against anaplasmosis and babesiosis using minimum infective doses was developed under laboratory conditions. Stabilates of Anaplasma marginale stored at -60 degrees C were found infective when diluted 10-fold to 10(-3). Stabilates of Babesia argentina and Babesia bigemina stored under the same conditions were infective when diluted 10-fold to 10(-1). Intact calves inoculated with the above dilutions of stabilates developed moderate parasitemias and recovered from infection without treatment. There was an immune response to vaccination with the formation of specific antibodies to A. marginale, B. bigemina and B. argentina as measured by the complement fixation (CF) test. All calves were found resistant to artificial challenge with lethal doses of the respective parasites.

Anaplasmosis↗