Virus Tracing and Characterization
Newly emerging and neglected viral zoonoses
“New” viruses may always emerge and known animal viruses may change their genotype or phenotype and cross the species barrier. HIV originates from non human primates and SARS CoV was transmitted to humans via Civet cats. Moreover already known animal viruses may become more virulent to humans. Highly Pathogenic Avian Influenza Virus has been a wellknown pathogen in poultry for decades, but from 1996 on, AI viruses especially H5N1 types which are more virulent to poultry have been causing serious outbreaks with fatal infections in humans also. It is difficult to have detection systems in place for formerly unknown viruses suddenly infecting humans. On the other hand zoonotic viruses of decreasing incidence or decreasing virulence may loose attention. Such negligence may hamper the updating of the used diagnostics and this may result in an increased public health threat. To early detect new and emerging infectious diseases, a syndrome surveillance system could be implemented. To early identify the virus involved, a generic detection system, firstly focusing on virus families could be used (see detection of new and emerging viruses).
Microarray chip hybridisation image
Detection of new and emerging (zoonotic) viruses
By trying to minimize the time period between the occurrence of a new viral disease and the identification of the viral pathogen, the lives of many individuals may be saved. For this purpose the use of classical virus detection methods (i.e. electron microscopy EM, tissue culture) often will be too insensitive, or it will be too time consuming to develop such assays. A promising overall approach would be to use powerful molecular methods for virus discovery, discrimination between virus and identification of genotypes respectively.
For primary detection of different viruses, microarray methods can be used. To identify viral families oligonucleotide probes can be selected for representation on such micro-array systems. The sequences used for designing these probes can be retrieved from already existing databases of diagnostic viral oligonucleotide probes or by alignment studies of viral genome sequences posted in the GenBank. Virus sequences in micro-array virus-positive cDNA specimens can be identified by PCR using virus family specific, degenerate and specific primers. The micro array system can be optimized through continuous selection of representative oligonucleotides..