During February and March 2001 an epidemic of Foot and Mouth Disease occured in the UK. With there being very little consenus on the outcome, we sent the following assessment to Prime Minister Tony Blair in time to decide the date of the general election. As far as we have been made aware it was the only correct model of the outbreak available in March 2001.
For more back ground
Response to Newsnight Special on Foot and Mouth 27th March 2001.
Analysis of Reaction Time at Onset Of Epidemic
Land Use Scenarios
Time of Election and Susceptibility To Sunlight and Heat
Analysis of Reaction Time at Onset of Epidemic
Not being an epidemiologist the start of the outbreak was assessed at the time in terms of simple ecological models for population dynamics.
If the virus is considered as a living organism then its rate of increase is its biotic potential. This normally occurs as the first part of an exponential growth curve (e.g. x2). The rate of increase is best judged from its doubling time. The time required to double the number of cases.
The morning the government announced the formation of the countryside task force, immediately afterwards the number of outbreaks was announced as double the daily rate the week before. Those who understood biotic potential, ( or its epidemiological equivalent ) would appreciate that those figures would project to the present situation.
With a given incubation period of 14 days anyone with even the slightest estimate of animal movements within that period would know a different situation would develop than in 1967.
Then FMD was in the main confined to Cheshire, Shropshire, Staffordshire and that area. There were less animal movements. The lag time of the incubation period would mean in the present case there would be multiple foci all with the potential of exponential growth curves, derived from animal movements during the incubation period prior to the to first outbreak and subsequent ban on animal movement. A massive influence for the maximum biotic potential.
A argument could be presented that on notification of the very first outbreak the disease was already out of control. All that could be done was to make the maximum effort to bring it under control. As its increase would be an exponential curve, even one days delay at the beginning would be paid for a few weeks down the progression, such as now with 40 cases a day.
The nature of exponential growth is sometimes difficult to comprehend, such as the example of putting a grain of rice on the first square of a chess board, two on the second, four on the third etc., then seeing how many are needed for the 64th.
Due to the masking affect of the lag time of the incubation period, just based on information from the main news even just an estimate would give a figure that there would be automatically inevitably twice as many cases a day in two weeks time. Those cases having already been infected. That is the most basic and simplest model.
Naturally with access to the data on type of strain, its specific characteristics, approximations of animal movements in the incubation period prior to the first outbreak etc. a more accurate model could have been produced.
The conclusion from the most basic model was the outbreak was out of control as soon as the first case was notified. All that could be done then was to bring it under control. Some models predict 70 cases a day at peak, just one days delay, in dealing with it in the maximum possible capacity when there were only 4 or 5 cases a day still directly relates to number of cases a day now or the prediction for the future.
The above is an explanation for brevity rather than absolute accuracy.
Land Use Scenarios
This in the main relates to the situation if the native fell sheep of the Lake District are lost. This area is called a grazing ecosystem. Bio mass is exported off the land as live weight of sheep.
This productivity is sustainably maximised by grazing pressure. If there are not enough sheep in a given area, the sheep can be selective in what they eat. This allows the growth and increase of plants that the sheep find unpalatable compared to what they prefer. Hence in time the potential productivity of an area falls.
One consequence pointed out was without sheep the traditional Lakeland scenery will disappear. Giving rise to scrub or eventually woodland, depending on what the natural climatic climax for the area was without the sheep.
Though as the Lake District existed before sheep were extensively reared there it is open to debate what ‘traditional’ applies to.
In the evolution of an area to its climatic climax, in this case the Lake District. Storage takes place as woody tissue, increasing in time as mass per square metre. A tree stores more CO2 as tissue than grass per square metre.
This mass is composed by the fixation of CO2 from the atmosphere as plant tissue. The Lake District, for example, then becomes a carbon sink, in effect contributing to a reduction of the affects of climatic change by CO2 emissions.
If an agreement on Climatic Change that ‘polluter pays’ happens, how much is the Lake District worth as a carbon sink if parts of it revert to a natural climatic climax?
The same principle also applies to forestry. Over and above the value of land in producing wood from trees, in a managed cultivation approach, is the fact that the wood is also additionally a carbon sink. Again who does the polluter pay?
One consequence of an evolution of an area to its climatic climax, is the increase in numbers of species of animals and plants. This increase in bio-diversity is directly related to the stability of the ecosystem in question. Such as its ability to adapt to change.
This could relate to the Burns Report on hunting and the control of fox numbers. If there is an increase in numbers of species such as mice and voles or whatever is determined as a main food source for foxes. Then it could be found if more areas of the countryside evolved to a climatic climax, foxes would have more food and not have to have numbers controlled due to their predation on chickens for example.
Flooding is not only caused by an increase in rainfall but importantly, the surge of how quickly runoff from land gets into the main river channel. Water from land evolving to towards a climatic climax with more scrub and trees will enter the river system slower than from a smooth grassland ecosystem. Damage from flooding could therefore be reduced in certain areas. What is it worth to reduce the costs of flood damage?
A model then generates lots of hypothetical scenarios for exploration. For example more people shocked by scenes of mass animal slaughter could turn vegetarian. Demand for meat falls. As a consequence farmers get paid for managing ‘carbon sinks’ and reducing the costs of flooding as well as existing animal husbandry.
Jobs lost from a ban on hunting are also replaced by countryside management as a contribution to sustainable development.
The above is not meant to be totally scientifically accurate. More as a general overview of scenarios and possibilities for the future for discussion and research.
One thing FMD has achieved is the beginning of the coalescence of economic, political, social, cultural, ecological, biological and environmental issues into an understanding of applied planetary engineering.
Time of Election and Susceptibility To Sunlight and Heat
All things being equal the course of the present FMD outbreak could be much worse. It has been reported that sunlight and heat reduce the virulence of the virus.
Had the outbreak began in October for example it would have gone through a longer winter period, as it did in 1967.
Occurring as it has at this side of the winter solstice with increasing day length, sunlight and heat, this could be an important part of its epidemiological transition.
Though this is a strain that is not the normal for this country.
Increasing sunlight and heat could be a key element in the environmental resistance to the biotic potential of the disease. Together with culling, disinfectant, restricted access, limiting vectors of transmission etc.
Increasing day length etc. by May could help bring the disease under control anyway, what ever other steps are taken. Only access to an accurate model of its progress containing all available knowledge and research could answer how much sunlight would play in its control by May.
For so long governments have dealt with only economic, political and social factors.
What FMD has done is show what biological, ecological and environmental factors can do to upset the established apple cart.
Suddenly politicians have had to broaden their agenda of understanding beyond existing domains.
The ecology, epidemiology and vectors of transmission of one small virus that appears suddenly from nowhere can wreak more havoc than any group of strikers or protesters have ever done.
While across the Atlantic Mr Bush turns his back on the Kyoto Treaty.
Ignore the environment and it has an ability of making itself noticed in ways that can only be comprehended when they happen. History might show that will be the lesson he learnt.
Roger Thomas 29 March 2001