THE EXPECTED BASIC KNOWLEDGE IS A BETTER UNDERSTANDING OF THE SYSTEMATIC OF ROTAVIRUSES, WHICH WILL INDUCE THE POSSIBILITY OF EPIDEMIOLOGY STUDIES ON ROTAVIRUSES DIARRHOEA IN YOUNG ANIMALS. THE SECOND OBJECTIVE IS THE OBTENTION OF CHEAP VACCINES AGAINST THE DISEASES.
Rotaviruses are a major cause of acute viral diarrhoea in all the major species of domestic livestock. Following their recognition as important pathogens, all virus isolates were found to share a common or group (group A) antigen. However, over the last 5 y a number of virus isolates have been made which, although classified as rotaviruses by several criteria, do not possess this group antigen.
Research was carried out in order to develop reagents and assay procedures to facilitate an assessment of the importance of the non group A rotaviruses to the overall problem of acute viral gastroenteritis. It has been possible to divide the non group A isolates made to date into 4 groups (B to E) each of which possesses its own group antigen. Recombinant deoxyribonucleic acid (rDNA) technology has been exploited to both investigate the differences between the various groups at the molecular level and for the synthesis of virus specific proteins for use in diagnostic assays.
Despite the fact that the only source of non group A viral nucleic acids was infected faeces, complementary deoxyribonucleic acid (cDNA) cloning of several of the genome segments of group B and C viruses were obtained. The ribonucleic acid (RNA) sequence of the largest clone obtained from each segment was determined. With the exception of that for gene 6 from the group C virus, none of the sequences obtained showed any significant homology either to each other or to the corresponding group A virus RNA segments. The gene 6 sequence of the group C virus shared 55% homology with that of group A at the nucleic acid level and 42% at the protein level.
The cDNA clones from gene 8 group B and gene 6 of group C virus were both expressed in protein in Escherichia coli. These expressed proteins could form the basis for the development of routine diagnostic tests for these 2 groups of virus.
ROTAVIRUSES ARE THE MAIN CAUSATIVE AGENTS OF ACUTE VIRAL GASTRO-ENTERITIS IN YOUNG ANIMALS. UNTIL RECENTLY IT WAS BELIEVED THAT THESE VIRUSES REPRESENTED A SINGLE GENETIC GROUP, WITH A COMMON GROUP ANTIGEN A. IN THE LAST TWO YEARS IT HAS BECOME APPARENT THAT THE SITUATION IS MUCH MORE COMPLEX THAT ORIGINALLY THOUGHT.
THE PROJECT HAS THREE MAIN OBJECTIVES :
- TO PRODUCE DIAGNOSTIC REGENTS FOR CHARACTERIZATION OF THE ROTAVIRUS GROUPS, (SPECIFIC DNA PROBES).
- TO PRODUCE VIRAL VACCINES (EXPRESSION OF CLONED VIRAL SEQUENCES INTO PROTEINS, IN E. COLI).
- TO OBTAIN MOLECULAR CHARACTERIZATION OF NON-GROUP A ROTAVIRUSES. (COMPARATIVE DNA SEQUENCE ANALYSIS OF THE TERMINI OF CDNA CLONES).
Funding SchemeCSC - Cost-sharing contracts