Emergency rabies control in a community of two high-density hosts.
BACKGROUND
Rabies is a fatal viral disease that potentially can affect all mammals. Terrestrial rabies is not present in the United Kingdom and has been eliminated from Western Europe. Nevertheless the possibility remains that rabies could be introduced to England, where it would find two potentially suitable hosts, red foxes and badgers. With the aim to analyse the spread and emergency control of rabies in this two species host community, a simulation model was constructed. Different control strategies involving anti-rabies vaccination and population culling were developed, considering control application rates, spatial extent and timing. These strategies were evaluated for efficacy and feasibility to control rabies in hypothetical rural areas in the South of England immediately after a disease outbreak.


RESULTS
The model confirmed that both fox and badger populations, separately, were competent hosts for the spread of rabies. Realistic vaccination levels were not sufficient to control rabies in high-density badger populations. The combined species community was a very strong rabies host. However, disease spread within species appeared to be more important than cross-species infection. Thus, the drivers of epidemiology depend on the potential of separate host species to sustain the disease. To control a rabies outbreak in the two species, both species had to be targeted. Realistic and robust control strategies involved vaccination of foxes and badgers, but also required badger culling. Although fox and badger populations in the UK are exceptionally dense, an outbreak of rabies can be controlled with a higher than 90% chance, if control response is quick and follows a strict regime. This requires surveillance and forceful and repeated control campaigns. In contrast, an uncontrolled rabies outbreak in the South of England would quickly develop into a strong epizootic involving tens of thousands of rabid foxes and badgers.


CONCLUSIONS
If populations of both host species are sufficiently large, epizootics are driven by within-species transmission, while cross-species-infection appears to be of minor importance. Thus, the disease control strategy has to target both host populations.
Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, UK. alexander.singer@ufz.de
Alexander
A
Singer
Graham C
GC
Smith
D000818:Animals; D003140:Communicable Disease Control / Q000379:methods; D003198:Computer Simulation; D004196:Disease Outbreaks; D004197:Disease Reservoirs; D004630:Emergencies / Q000662:veterinary; D004739:England / Q000453:epidemiology; D005589:Foxes; D008954:Models, Biological; D045969:Mustelidae; D011156:Population Density; D011818:Rabies / Q000517:prevention & control / Q000662:veterinary*; D011819:Rabies Vaccines / Q000276:immunology*; D013045:Species Specificity
D011819:Rabies Vaccines