Six missing genes of the reindeer pseudocowpox virus genome found
Previous studies have revealed that in 1992–1994 the disease was caused by parapoxvirus resembling the ORF virus which is maintained in sheep, but the cause of the epidemic in the winter of 1999–2000 turned out to be a virus resembling pseudocowpox virus (PCPV) in cattle. At the time, when comparing the reindeer PCP virus with the ORF virus, it was observed that the ORF virus has six genes in the right terminus of the genome which are not found in the reindeer PCP virus. The present study indicates that these genes had been deleted from the virus during cell culture.
Reindeer pseudocowpox virus has 137 genes
Individual cases of the mouth disease are diagnosed almost every year, but in early spring 2007 several cases of the disease were discovered again. Some of these cases were found to have the ORF and some the PCP virus. When investigating whether it is possible to use the difference of six genes found between PCP and OFR viruses in the diagnostics of the disease, it was indicated that these genes had deleted from the reindeer PCP virus as a result of cell culture.
The deletion was confirmed when analysing mouth disease samples from 2007 and the bovine PCPV cases that occurred in Finland in 2005–2010; all of these had the genes that had previously been found to be lost in reindeer PCPV genome. In the study now published, the missing area of the genome was determined to be 5,431 base pairs long, and the size of the entire genome of the reindeer PCP virus as 140 kilobase pairs and the number of genes 137.
Finnish parapoxviruses are similar in different animal species
When comparing reindeer parapoxviruses from 1992–2007 with viruses in cattle and sheep from 2005–2010, it was observed that these viruses isolated in Finland were very similar, even identical, in terms of the studied genes. This indicates that infection can be passed from sheep or cattle to reindeer. This information is important in eradicating the disease: it is recommended that direct contact between reindeer, sheep and cattle should be avoided.
Characteristics of mouth disease
Mouth disease occurs usually in the winter. Early symptoms include diminished appetite, drooling, fever, sores and, at a later stage, wart-like formations on lips and the mucous membrane of the mouth. In reindeer, the disease causes pain in the affected areas and, as a result, the animal is unable to feed. The disease exposes the animal to bacterial infections and may eventually lead to death. Therefore, reindeer mouth disease is a significant disease and its prevention is economically worthwhile.
The research results are published in the international scientific publication Virus Res 2011 (160): 326-332. Hautaniemi M, Vaccari F, Scagliarini A, Laaksonen S, Huovilainen A, McInnes CJ., Analysis of deletion within the reindeer pseudocowpox virus genome.
See also the earlier news item concerning a study of the genome of reindeer pseudocowpox virus.
For further information, please contact:
Maria Hautaniemi, Researcher, Veterinary Virology Research Unit,
maria.hautaniemi evira.fi, tel. +358 50 573 6891