Haydon D T, Woolhouse M E, Kitching R P
Department of Zoology, University of Oxford, UK.
IMA J Math Appl Med Biol. 1997 Mar;14(1):1-9.
There was a major epidemic of the foot-and-mouth-disease virus among cattle herds in the UK in 1967-68 which showed a very rapid early spread, a much slower later spread, and eventually infected 12% of herds in the core epidemic area. A simple discrete-time version of a susceptible-latent-infectious-removed epidemiological model is used to generate a set of estimates of the transmission rate. This parameter has high values over the first few days, then the values are lower and they subsequently decline. The early high values are consistent with the view that unusual meteorological conditions produced exceptionally good conditions for wind-borne spread of the virus over the first few days. The corresponding basic reproduction number, Rzero, is estimated as 38.4. Subsequent low values of the transmission rate correspond to a value of Rzero of 2.0; this is within the range of estimates made from the observed ratio of secondary to primary outbreaks for 25 other epidemics. Prophylactic control measures, such as vaccination, would have to be extremely effective to prevent epidemics with the higher Rzero value.
1967 - 1968年，英国牛群中爆发了一场严重的口蹄疫病毒疫情，疫情初期传播速度极快，后期传播速度则慢得多，最终核心疫区12%的牛群受到感染。一个简单的易感染-潜伏-感染-移除离散时间流行病模型被用来生成一组传播率估计值。该参数在最初几天具有较高值，随后数值降低并持续下降。早期的高值与这样一种观点一致，即异常气象条件在最初几天为病毒的风媒传播创造了异常有利的条件。相应的基本再生数R0估计为38.4。随后传播率的低值对应R0值为2.0；这在根据其他25次疫情中观察到的二代与一代疫情比例所做的估计范围内。预防性控制措施，如疫苗接种，必须极其有效才能预防具有较高R0值的疫情。
