PARENT SESSION
Oral Session # 22: Pathogens, Toxins, and Disease I: Modeling ; Mammalian.
Presiding: J Foufopoulos
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Meeting Room 201.
The sudden emergence of rabbit hemorrhagic disease.
Hudson, Peter1, White, Peter2, Boots, Mike2, Trout, Roger2, Forrseter, Naomi 2, 3, Gould, Ernest3, 1 Penn State University, State College, PA2 Stirling University, Stirling, Scotland, UK3 CEH, Oxford, England, UK
ABSTRACT- Rabbit Hemorrhagic Disease emerged suddenly as a virulent and highly infectious disease in a group of domesticated rabbits being air transported to China in 1984. Subsequently, the disease caused massive mortality in domestic and wild rabbits throughout Eurasia and Australia. This paper examines a series of questions relating to why and how the disease emerged. First: Will the disease have a major impact on rabbit populations in all countries? We undertook a large scale sera survey in the United Kingdom and found that most populations had already been exposed to the virus. Serial sampling indicated that an epidemic may pass through the population without massive mortality. Moreover, sera samples collected before the emergence of the disease also found evidence of previous exposure leading us to surmise that an avirulent form of the disease had been circulating. However, sequencing of the capsid gene found no evidence of a clear virulent or avirulent strain. Second: What conditions and evolutionary selective pressures may cause the rapid evolution and emergence of a highly virulent disease? Using a generic, individual-based SIR model we show theoretically that large, stable shifts in virulence may occur in pathogen populations due to a bi-stability in evolutionarily stable virulence caused by the contact/social structure of the host population. We postulate recombination coupled with changes in the social structure of rabbit populations may have initiated the rapid evolution of a virulent strain and caused the observed pandemic.
Key words: community impacts, virus strain, emerging disease, virulence