Computer simulation of Gumboro disease outbreak. II. Results obtained with models G-1 and G-2.

The authors conducted a computer simulation with their Models G-1 and G-2 for Gumboro disease ten times in each of the following initial conditions: (1) size of population, 50, 100, and 1,000 chickens; (2) age of housing, 1, 7, 14, and 21 days; (3) nine levels of parentally conferred immunity in one-day-old chicks; (4) four levels of virus contamination; and (5) three steps of coefficient for aggravating morbid status. Every simulation was operated up to the age when all the birds of a flock turned to be insusceptible so as to yield the daily numbers of chickens (1) susceptible, (2) diseased, (3) immunized, and (4) removed, and (5) the accumulation of diseased chickens. The innate resistance, parentally conferred immunity, virus contamination, and morbid status were expressed in such values that they could be compared with one another. As a result, Model G-2 produced a more realistic epizootic pattern than Model G-1, but both models concealed the effect of differences in size of population and in age of housing. Notwithstanding the incompleteness of the models, the computer simulation gave valuable information for a further advancement in this series of studies.