1999, Number 3
Evaluation in field conditions of inactivated vaccines of Anaplasma marginale named Plazvax
Figueroa MJV, Rojas REE, Ramos AJA, Granjeno CG, García OMA, Canto AGJ, Santiago VC, Parrodi F
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Language: English/Spanish
References: 8
Page: 221-225
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ABSTRACT
In order to determine the effectiveness of the Plazvax vaccine against bovine anaplasmosis, 32 susceptible bovines were used. A group of 24 animals was immunized against the rickettsia by inoculating them subcutaneously with 1 ml of the vaccine in two occasions, 21 days apart. Eight bovines remained as the control group and were not vaccinated. One month after the second immunization, all animals were taken to an endemic area of anaplasmosis to be challenged under field conditions. From day eight after introduction in the field (AIF) and until day 105, the bovines were monitored by recording rectal temperature (RT), packed cell volume (PCV) and percentage of parasitemia (PP). Three animals died of babesiosis, and the rest were monitored twice a week starting on day 42. After 52 days, the first A. marginale infected animals were detected. All of these animals belonged to the vaccinated group, and four of them were treated with oxitetraciclins. From day 84 AIF, the control group animals suffered from severe anaplasmosis with RT mean of 40.5°C, a PCV mean of 13.2% and PP mean of 9.4% the day of treatment (days 87-95). Vaccinated animals presented means of 40.2°C, 16.3% and 3.3% for RT, PCV and PP, respectively, which was evident on the day of treatment (days 95-105). Although there was a difference in PP between the control and vaccinated groups, all animals became infected and required treatment. In conclusion, the current presentation of Plazvax vaccine cannot be recommended to be used in Mexico. The addition of antigenic materials from one or more isolates of A. Marginale is therefore, suggested.REFERENCES