University of Khartoum

Maternally Derived Immunity to Rinderpest Virus in Young Calves

Maternally Derived Immunity to Rinderpest Virus in Young Calves

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Title: Maternally Derived Immunity to Rinderpest Virus in Young Calves
Author: Hanan Yousif Mohamed Ahmed, Ahmed
Abstract: Twenty seven pregnant Holstein Friesian cows immune to rinderpest virus on their mid term of pregnancy (5th month) were selected for studying passive immunity to rinderpest virus in their offspring. Serum samples of cows that were collected on monthly basis and a week before delivery were found positive to rinderpest virus. This gave an indication that rinderpest antibodies were constantly present in the rinderpest immune dam sera before delivery. Serum samples of newly born calves before being fed the colostrum were tested. They were found negative to rinderpest virus. This indicated that antibodies to rinderpest virus could not be transferred from dams to their foetei through the blood (placenta). The maternally derived antibodies to rinderpest virus (MDA) in 28 calves that were born from the immune dams were monitored by ELISA on two weeks basis until 45 weeks of age. Only one calf showed undetectable antibodies to rinderpest at 11 weeks of age. Out of 28 calves in the test, the number of calves negative to rinderpest antibodies continued to gradually increase through 6 and12 calves at ages of 15 and 19 weeks, respectively. A critical increase (57.1%) in the number of negative rinderpest antibody calves was achieved in 21 weeks of age. The increase in negatively immune calves was maintained from 78.6%, 82.1% and 85.7% at ages 23, 27 and 29 weeks, respectively. The maximum increase in number (96.4%) of calves negative to rinderpest antibodies status was achieved in 33 weeks initially, and then repeated in 35 week of age. The study revealed great variations in time concerning decline of antibodies to rinderpest virus from one calf to another was found to be from 9 weeks of age to 35 weeks. The average age, at which antibodies to rinderpest virus reach undetectable level was 21 weeks. This complies with the highest frequency (6 calves) among the calves group. ELISA seemed to be the most useful and suitable technique used for diagnosis of rinderpest. Thus, PARC in 1985 adopted the test to be used in detection of antibodies to rinderpest virus. This is due to its high sensitivity in addition to its specificity which is directed against the rinderpest H protein, giving no cross-reaction to Pest des Petits Ruminants virus. The test is now a worldwide used technique in all national, regional and international reference laboratories to diagnose rinderpest. This is due to its easy use large number of samples could be tested and the simplicity of linking ELISA reader to a computer which allows rapid data analysis and storage.
URI: http://khartoumspace.uofk.edu/handle/123456789/14256
Date: 2015-06-23


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