Experimental infectious pancreatic necrosis infections: propagative or point-source epidemic?
Experimentally initiated epidemics of infectious pancreatic necrosis in rainbow-trout fry were analyzed using a modification of the standard mathematical model for a simple propagative epidemic. Contrary to expectations, the value of the transmission parameter (beta) was inversely related to initial density of susceptible hosts. This anomaly can be explained if we assume that the experimental epidemics were point-source rather than propagative epidemics. The implications of this conclusion for modeling experimental and natural epidemics are discussed.
Smith
G
G
Section of Epidemiology and Public Health, University of Pennsylvania School of Veterinary Medicine, New Bolton Center, 382 West Street Road, Kennett Square, PA 19348, USA.
Bebak
J
J
McAllister
P E
PE
D000818:Animals; D017756:Aquaculture; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D002353:Carrier State / Q000662:veterinary; D004196:Disease Outbreaks / Q000662:veterinary; D018562:Disease Transmission, Infectious / Q000662:veterinary; D005393:Fish Diseases / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D018061:Infectious pancreatic necrosis virus / Q000254:growth & development*; D008954:Models, Biological; D009716:Numerical Analysis, Computer-Assisted; D017686:Oncorhynchus mykiss; D011897:Random Allocation; D013047:Specific Pathogen-Free Organisms