In 2001, Great Britain was hit by the most extensive outbreak of foot-and-mouth disease in the modern history of the western world. This disease is caused by an airborne virus that infects cloven-hoofed animals. When it hits, huge geographical regions must be isolated, no transport through, to or from these regions is permitted, and export ceases until the country is declared free of the disease.
The outbreak in 2001 had major socio-economic consequences for Great Britain. A calculation carried out for the British government estimated that the total economic cost for the country had been around GBP 2 billion in the year of the outbreak.
Transports - a way for infections to spread
LiU researcher Tom Lindström combines a model for animal transport with one for the spread of infection. Photo credit Charlotte PerhammarSince then, the EU has introduced directives stating that all transport of animals is to be documented, and the documents archived. Such a system, however, is not in place in the US. And it is here that LiU researcher Tom Lindström comes into the picture.
“It started as long ago as 2009. Together with my supervisor at the time, I established collaboration with researchers in the US and Great Britain in this field.”
This subsequently led to further joint research projects, and eventually to the current project for which Tom Lindström leads the Linköping-based work, financed by American government agencies (the US Department of Agriculture, the National Institute of Food and Agriculture, and the Department of Homeland Security).
“The main part of the work at Linköping University is looking at how animals are transported in the US”, says Tom Lindström. “Such transport provides a way for the infection to spread. And the US, which has the largest livestock population in the world, has enormous animal movements. Some animals are transported across long distances from one side of the country to the other. And with respect to the spread of infection, this can be disastrous.”
The US does not have the same system of documentation and archiving that the EU has.
“Some documents must be submitted when animals are transported between states,” says Tom Lindström, “but these are not collected in digital form. This meant that we had to begin by collecting 20,000 documents on paper and feeding the information into a system, so that we could describe the contact patterns. The system we are trying to describe is complex. Animal husbandry is much more industrialised in the US than it is in, for example, Sweden.”
Obvious benefits to society
Tom Lindström is docent in theoretical biology and has studied the disease-related aspects of animal transport for many years. Another thread of his research is “ensemble modelling”, which is based on the collective use of several models. This project is a large international collaboration with researchers from the US, Great Britain, Australia, New Zealand, Argentina, Japan and Switzerland, all countries that have developed their own models for foot-and-mouth disease and/or have had outbreaks in the modern age.
“What we see is that the models together give more reliable predictions than individually”, says Tom Lindström.
“My strength is that I know a little about many different things and can see connections between the bits that I do know. This project contains two parts, a model for animal transport and a model for the spread of infection, where animal transport is an important part of the process.”
The methods to describe animal transport can be used for other diseases and used to plan surveillance to discover infection. The project includes also a study of bovine tuberculosis, a cattle disease that is present in wildlife reservoirs in the US.
The work will be completed by September, when it will be submitted to the US Department of Agriculture, which is planning to use the model in the future. The methods developed can be used to compare different control measures, such as different strategies for vaccination and slaughter. Preparedness in the US for a possible outbreak can in this way be improved.
“I have also received research funding from the National Institute of Food and Agriculture to investigate diseases and transport of pigs”, says Tom Lindström. “This is extremely important at the moment, given the threat of, for example, African swine fever. Currently, four of the six research projects in my group receive funding from the US.”
“I thoroughly enjoy extensive international research collaboration, which gives valuable contacts all over the world. The work provides obvious benefits to society and we are working close to policy makers”, concludes Tom Lindström.
Translated by George Farrants
LiU Magazin 2/2019