TB or not TB?

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OK, so it’s not the most original title but when I saw this I thought I was back nearer the start of my career, not nearer the end! I thought we’d sorted this battle years ago with the original report. It was so long ago I even had to search for the name. Not Krebs which is the one quoted on the DEFRA site (and also unavailable except in their library!) and which is only 1996 but Zuckerman (quoted as 1980 – I lost my copy 5 moves ago!). Then, as now, there’s a central set of arguments that no-one really challenges. At the time, it made a great set of lessons for students wishing to enquire into this in greater depth because it combined a series of elements that I felt best illustrated the ‘A’ level of the time in “Environmental Science”. Here, students were expected to study a series of facets from ecological and earth sciences and then be able to use this information in a series of problem solving tests. Since this is so old that it now appears revolutionary I guess I’ll keep more discussion on that for another post but it is worthwhile looking at this latest demand for culling.

Let’s start with the basic ideas. As far as I can see, there is little disagreement about most of these statements:

  • Bovine TB has considerable costs for the farming industry. Culling is often the only way forward;
  • Bovine TB can spread to humans but it is difficult and rare;
  • Some badgers do suffer from bovine TB but the exact number and percentage is unclear.

So far, so good. TB is dangerous, it used to be a global health issue but is less so now. Our current concern is for cattle and how we can stop this. Although the risk of cross-contamination is rare, handling infected meat and drinking untreated milk heightens the risk. Next, the leap. Since badgers can suffer from TB and badgers are essentially rural animals, you find badgers where cattle are. If you can stop badgers infecting cattle, you can stop bovine TB. That’s where the crunch comes in. Everyone’s happy up to that point because it assumes a causes b whereas most of the evidence is less certain. Many studies suggest the situation is highly complex and still needs to be fully worked out.  Others point to studies in other countries/animals that say culling is a very good option.

This is where it makes a great study for students because it covers science, politics and emotions (let’s face it, badgers look cute!). It’s precisely because of this that we can craft some excellent lessons and ideas. Here’s what works for me:

  • a quick overview of the case to set the scene;
  • a study of bovine TB as a epidemiological issue;
  • ditto for human TB;
  • ecology of badgers – where are they found, how do they interact;
  • current rates of bovine TB by area.

That’s the scene set up, now for the fun! The statistics of this would be to link badger density with TB occurrences with cattle numbers to see where any correlation could be found. From here you could see the results of the new round of culling to see if it worked. You could look at the options and work out the best for badgers, cattle and farming economics (I’m guessing they’d all be different making this a bit of a wicked problem). It makes a great areas for study with numerous cross-curricular links but also a solid chance to get students to make real-world connections with data. I used to get teams working on the problem with each given an aspect to research (e.g. farmers, ecologists, epidemiologists) which gives you the chance of setting up debates against other schools, holding a “court” to decide. I’ve used these sorts of cases with all sorts of students, locations, ages and syllabi. There’s nothing like a real case to engage the students.

Have you tried anything like this? Do let me know – it would be ideal to build up a bank of ideas.

Just to start you off (there is no shortage of material on this!): DEFRA, Oxford Martin (and again), Team Badger (just one of many pressure groups).

 

Update: Just to prove there’s always something you could add – a useful discussion piece (probably not the additional comments)

 

Photo Credit: Tatterdemalion! via Compfight cc

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