Observations on the use of Anaplasma centrale for immunization of cattle against anaplasmosis in Zimbabwe

A total of 93 Bos taurus cattle was used in pen trials to compare vaccine stocks of Anaplasma centrale from South Africa and Australia (which stock came from South Africa in 1934) in protecting against three virulent field isolates from clinical Anaplasma marginale infections. In addition, field observations were made on the use of a vaccine, prepared from the Australian stock, in over 9553 cattle of mixed age and breeds on 16 co-operator farms and at one communal dip. The results of the pen trials indicated that the two vaccine stocks were comparable and that neither provided adequate protection against two of the three isolates of A. marginale. The field observations indicated that the vaccine was highly infective and produced mild reactions in most recipient cattle, and that users were generally satisfied with the vaccine. These somewhat conflicting results are discussed in the context of observations in Australia and future vaccination against anaplasmosis in Zimbabwe.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Australian Centre for International Agricultural Research. Central Veterinary Laboratory, Zimbabwe. Queensland Department of Primary Industries, Australia.mn201

Congress Paper: Role of gender in the delivery of veterinary service

(Zimbabwe Veterinary Journal, 1998, 29(4): 139-150

A retrospective epidemiological study of parasitic otitis in cattle in South-East Lowveld of Zimbabwe

(Zimbabwe Veterinary Journal, 1999, 30(1): 19-24

The role of iodine in livestock production under natural conditions in Zimbabwe

(Zimbabwe Veterinary Journal, 1997, 28 (3&4): 99-108

A spatially predictive logistic regression model for occurrence of theileriosis outbreaks in Zimbabwe

Multivariate logistic regression models are mostly used to identify risk factors associated withthe occurrence of particular disease processes. Logistic regression models have also been used as tools for veterinary diagnosis by providing the probability of a particular disease in an individual animal given a set of characteristics such as diagnostic test results or other risk factors. They can also be applied to the predicition of the probability of the occurrence of future disease events. Decision making in animal disease control is constrained by cost-benefit considerations, which in turn should take into account the probability of the occurrence of particular disease events. The unit of interest in this context usually is an aggregate of spatial information such as an administrative district, province or state. With the advent of spatial databases and geographic information systems (GIS) the level of spatial aggregation can be easily controlled by the end user and is only limited by the spatial units at which the data has been collected. The relationships between various variables stored in a spatial database can be investigated and used to provide predictive tools allowing more cost-effective spatially optimised disease control. In this study a logistic regression model was developed to estimate the probability of theileriosis occurrence in Zimbabwe, and the usefulness of measures of model goodness-of-fit for decision makers was investigated. Specific attention was given to the potential of effects of spatial autocorrelation on regression coefficient estimates

Observations on the use of Anaplasma centrale for immunization of cattle against anaplasmosis in Zimbabwe

The efficacy of vaccine containing A. centrale against 3 Zimbabwean isolates of A. marginale was evaluated between November 1994 and June 1996. 93 cattle were used in 3 pen trials and 9553 cattle from 16 farms in a field trial. A. centrale stocks used for vaccination of cattle in pen trials were imported from South Africa and from Australia. The vaccine used in the field trial was of Australian origin. The results of pen trials indicated that 2 vaccine stocks were comparable and that neither provided adequate protection against challenge with 2 of 3 A. marginale isolates. The field observations indicated that the vaccine had high antigenicity and produced mild reactions in post-vaccination period. The users were generally satisfied with the cost and efficacy of the vaccine. However, 3 unconfirmed cases of death caused by anaplasmosis were reported on 1 farm 12 months after last vaccination. It is suggested that the use of A. centrale vaccine is justifiable until more effective alternative becomes available