SKUNK RABIES: ASPECTS OF EPIZOOTIOLOGY AND SIMULATION MODELING (WILDLIFE, ECOLOGY, ILLINOIS)

Ecological field study, analysis of public health surveillance data and computer simulation were used to gain a better understanding of skunk rabies. Skunks (N = 34) were captured on the SIU Farms, Jackson County, Illinois between June 1982 and November 1984; 9 males and 7 females were radio-collared. Adult males had a greater mean maximum distance between locations (2.1 km) and averaged larger home ranges (50.4 ha) than adult females (0.9 km, 36.6 ha, respectively). Communal denning occurred as early as August. Suitable den sites were probably limited and concentrated around buildings and other man-made disturbances that enhanced burrow structure.; Enzootic/epizootic skunk rabies was recognized in 18 states. Time Series Analysis of the combined rabies incidence of the 18 states indicated an 8 year cycle. Multiple Regression enabled prediction of the yearly reported skunk rabies for 12 of 16 states from knowledge of the other state's reported rabies. Stepwise Analysis revealed which states contributed significantly to the predictive model of an individual state, but did not reveal influence due to geographic proximity. Data on percent rabies positive (number rabid/total number submitted) were available on a monthly basis from 6 states. The monthly percent positive differed significantly in 4 states, but fall and spring peaks did not differ and few monthly differences were found between epizootic and enzootic years.; Based on published data and this field study a stochastic spatial simulation model was developed to mimic a skunk population with rabies. Rabies persisted for at least 20 years in 13 of 20 simulations supporting the hypothesis that certain populations can maintain enzootic and occasionally epizootic rabies without reintroduction, latency periods, or multispecies complexes. The average inter-epizootic interval was 8 years. Rabies acts as a monophagous predator and can control populations under certain conditions without extinction of rabies or the host. Ultimately the model can be used to assess the outcomes of various strategies for proposed vaccination schemes.