A REED-FROST MODEL OF THE SPREAD OF TUBERCULOSIS WITHIN 7 SWEDISH EXTENSIVE FARMED FALLOW DEER HERDS

The within-herd transmission of tuberculosis, after introduction of in fection, was evaluated in seven Swedish herds of farmed fallow deer. T he evaluation was based on a subset of data obtained from a previous e pidemiological investigation, comprising 13 tuberculosis-infected deer herds, with the purpose of tracing the source of infection. A compute r spreadsheet model based on the Reed-Frost method was developed to es timate the number of new infections. For each herd, a k-value (the num ber of effective contacts made by an individual during a time period) was estimated through fitting the model to the observed incidence in e ach herd. We concluded that, despite the relatively short observation periods and uncertain tuberculosis incidence estimates for the observe d herds, the k's obtained could be used to quantify the estimated spre ad of tuberculosis in extensive deer herds in Sweden. (C) 1998 Elsevie r Science B.V.