Efficacy of an inactivated oil-adjuvanted rotavirus vaccine in the control of calf diarrhoea in beef herds in Argentina

Abstract

We have assessed the potency of an inactivated oil-adjuvanted rotavirus vaccine in beef herds in Argentina. Two different vaccine trials were conducted. In a small-scale experimental trial, involving 21 pregnant cows (13 vaccinated and eight unvaccinated controls), a significant increase in neutralizing antibody titres against different serotypes of bovine rotaviruses was found in both the colostrum and serum of vaccinated cows compared with that of unvaccinated controls. Seven days after birth, half of the calves born to vaccinated dams or to control cows were challenged with live virulent virus whereas the other half of both groups were left in contact with the infected calves in order to mimic a natural field challenge. Although no statistically significant differences in the rate of protection were observed among the different groups of animals, a larger number of vaccinated calves were protected in comparison with their controls, particularly where animals in contact with infected calves were concerned. Secondly, a large-scale field trial was carried out in 17 beef herds involving a total of 4066 vaccinated pregnant cows. In 11 farms morbidity and mortality in calves from vaccinated cows were compared with historical data from the previous 3 years at the same locations. In the other six herds, control groups were used to compare data of the same year: 1540 cows were vaccinated and 2700 were left as controls. Taking into account the previous and current incidence of diarrhoea, morbidity and mortality were significantly reduced in 16 of the 17 beef herds tested. Vaccine effectiveness was also evident in farms where other enteropathogens such as cryptosporidium and coronaviruses were present, together with rotavirus.

Identification of four VP4 serological types (P serotypes) of bovine rotavirus using viral reassortants

“…Rotaviruses are the major cause of diarrhoea in young calves throughout the world (Bellinzoni et al, 1989;Reynolds et al, 1986;Snodgrass et al, 1986) and of severe acute gastroentreitis in infants and young children . The development of effective vaccines requires an understanding of the major rotaviral antigenic components and their interaction with the host's immune system.…”

Detection and Differentiation of Bovine Group A Rotavirus Serotypes using Polymerase Chain Reaction-Generated Probes to the VP7 Gene

“…Serotypes 6 and 10 BRV have both been identified in serotyping studies 1,31 Limited information available on the prevalence of BRV serotypes suggests that serotype 6 is the predominant field strain among isolates from calf diarrhea cases. 31 A third but less common serotype (serotype 8) has been reported among BRV isolates.…”

“…31 Several other studies have reported BRV strains that are serologitally distinct from serotype 6, but these newly described strains have not been classified relative to other rotavimses. 1,3,4,18,23,32 Although BRV isolates have been detected and serotyped using MAbs, 1,31 there are no reports on the development and use of cDNA probes for the differentiation of BRV serotypes. The objective of this study was to develop and characterize cDNA probes prepared from NCDV, United Kingdom (UK), and Cracker (Cr) VP7 genes for the detection of BRV in cell culture and fecal samples.…”

“…6,[8][9][10]12,19,21,25,26 Nucleic acid probes prepared from rotavirus gene segments coding for VP7 have been utilized for serotyping human and porcine rotavirusFrom the Food Animal Health Research Program, Ohio Agricul-es. 8,25,26 Furthermore, "short" probes limited to hytural Research and Development Center, The Ohio State University, perdivergent regions of the VP7 gene segment have ty 1,31,35,38 The Nebraska calf diarrhea virus (NCDV) .…”

“…All bovine isolates antibodies (MAbs). 1,17,31,34 An alternative approach is tested to date belong to subgroup I. 35 the use of nucleic acid probes for the detection and Group A rotaviruses are classified into 11 serotypes serotypic characterization of rotaviruses.…”