Bovine TB in Hounds

BY LINUS WOODS

Have you heard the newest claims by the anti-hunt brigade that hounds are a major risk in spreading bovine tuberculosis? They have been making pretty maps to “Prove” that hounds are a serious threat to TB in this country. The problem they have is a massive gap in understanding TB, how it’s transmitted and what potential other factors may be at play. So, let us take a look at the other side of the coin. The emotionless data side of it all. The cold hard truth.

I am a fan of raw, hard facts. Manipulating data has never been my thing and it never will be. Although we are all entitled to our own opinions, we are not entitled to our own facts. So whether we like it or not, a fact is a fact. They cannot be denied. However, what can happen is that falsified information can be presented as facts in a way that makes them believable. A perfect example of this is correlation vs causation. My wife is a classic example of someone who uses this. As a vegetarian she likes to point out that vegetarians live longer than meat eaters. I looked into this and found that it is true. So her conclusion is that cutting out meat from a diet increases lifespan. Seems feasible, right? Wrong! This is a fact misrepresented. The truth of the matter was found after a little digging. Turns out it is the abundance of vegetables as opposed to the absence of meat that causes the increased lifespan. More vitamins and minerals as well as increased fibre = longer life. Kind of obvious when you think about it. So for a meat eater to live longer, they do not need to cut out meat, they simply need to have more and a wider variety of vegetables in their diet. This is where the correlation (no meat = live longer) is not incorrect, because that truth is causation (more veg = live longer).

This distortion of facts is exactly what’s been going on with Bovine TB for far too long. If bTB in Area X has increased and hounds are in Area X., hounds caused bTB to spread. See the similarity with the example above? Two things happening alongside each other is incorrect. So let’s put a little more data into the pot on the ‘causation vs correlation’ system.

We’ve all seen the DEFRA pictorials showing the spread of TB from 1986, 1996, 2006 and 2010 and it’s an alarming increase. Maps are as below if you are unaware of these maps.

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These maps show how bTB has spread. Now, the anti-hunting brigade are accusing hounds of spreading this TB because hounds are on those plots of land. However, there’s a bit of an issue there…namely the factual inaccuracy of such blind claims. Hounds are on much more of the UK and have been travelling and hunting for many years. The oldest hunt still running is the Bilsdale Hunt, Yorkshire, which was established in 1668. Hunts have been around for hundreds of years and there are large numbers of hunts. There are over 135 foxhound packs in England, more than 30 in Wales and over 10 in Scotland. Which means there are over 175 fox hound packs as recognised by the Masters of Foxhounds Association.

Considering that TB is highly contagious, if bTB was spread by hounds, why has it taken 350 years and over 175 packs to spread it to half the country? Mathematically that seems incorrect. Historically it would be open to question too. Bovine TB was first recognised in 1932 although TB as a disease was found in 1907.

On the basis that the disease is exactly 80 years old in it’s recognised life, we will go conservative and work on the basis that TB is 50 years old as a disease. That means there are 50 years and 175 packs to spread it. That still seems far fetched to suggest hounds are a major factor in the spread of TB in the UK. In 1 year hounds will cover vast swathes of the UK. Meaning the idea that hounds are a major factor in spreading bTB is laughable.

Maybe the spread is taking so long because of how bTB is transmitted? To compare the spread of bTB we would need to check how such diseases spread through cattle herds via direct contact with bodily fluids, e.g. saliva, blisters, mucus, sneezing, faeces, etc. Tragically we are able to compare the movement of bTB through the spread of foot and mouth. Both diseases spread through direct contact. As already stated, TB is highly contagious as is foot and mouth, so we can eliminate the scientifically ignorant question “What if bTB is not that contagious?” As already stated bTB is highly contagious. We all saw how that foot and mouth was transported rapidly through the country within a very short time period. Going from a few cases to over 800 cases in 2001 alone. An 8000% increase in cases in 1 year (bare in mind foot and mouth was confirmed towards the end of Feb 2001 with 30 cases and was halted in October of 2001, so that is technically 10 months). If 1996 had 2,541 cases of bTB and 2006 had 18,342 cases that is a 722% increase. But it’s over a 10 year period.

If memory serves me correctly, hound movements were tightly controlled during the foot and mouth outbreak, yet there was a massive increase in the number of cases. Maybe hounds are not transporting the disease anywhere near what the antis are claiming?

From this you can see the idea of it taking 50 years to spread bTB via 175 hound packs is laughable. Even one infected hound pack spreading the disease to another and that pack to another, etc, would still take well under 50 years to cover the UK with TB to the extent that it is today. Couple this with the fact that the area hound cover overlaps and often go off to new areas through Kennel Touring, it should all too obviously take under the 50 years or even 30 years to spread. At most, if hounds were spreading bTB, you’d be looking at 2 to 3 years to have the country covered.

There are, however, other animals out there that do present a population sprawl along the same timescale as bovine TB’s development, which may cast light on a few reasons farms are not keen on these species.

Roe Deer

Firstly the Roe Deer Spread over a 30 year time period. It is interesting to note that the areas experiencing an increase in the number of roe deer and the directions of which they travelled do seem to run parallel with the development of bTB for the Southwest, towards the midlands and up the Welsh border. This is correlation and not causation. So I am not saying that TB is spread by deer, although many in the hunting and farming communities believe this to be the case. The pattern and the time period of the spreads are side by side. So you could be forgiven for believing as the country-folk do, that roe deer spread TB.

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See how the spread is so similar to that of bTB? Not to worry, there are culling procedures in place for this. However, there is certainly a fair argument to be made for increasing the length of the shooting season for roe deer (just putting it out there). Although I am picking on roe deer here, I should probably point out that this is applicable to all deer. Early in 2017 a few of my farmer friends, north of Carmarthen in Wales, asked the environment agency for a cull of a herd of red deer because they believed they were spreading TB.

Badgers

There is also the badger spread and numbers maps too. A little look on these will suggest a very similar pattern. Areas with the highest badger density have higher bTB risks. The exception being the North West and Welsh border. Although they are also the lesser checked areas for badger movement, which may explain any missing data for the correlation.

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For those of us old enough to remember 1975 with the controversial act of strategic Gassing of Badgers (ceased in 1982 and replaced with trapping and humane dispatch), bTB was pretty much eliminated for 10 years. Coincidence or causation? Well, a little more wood into the fact filled fire, the process of badger control change in 1986 after recommendation from Professor Dunnet. What has happened since 1986? The number of bTB cases increased year on year. However, the question to ask is, were hunts active from 1975 to 1986? You bet they were. Since bTB was pretty much eradicated during this period, it leads to question how much of a risk are hounds to the transportation of bTB? In the 10 year period of 75 to 85, negligible.

Please note I am completely ignoring the effect of hiking/rambling groups . But there are millions of hikers and ramblers who probably do not know if they are walking through infected areas and spreading the infected soil onto other areas. We’ve all walked through cowpat by accident (usually while deep in conversation) as well as walking along ground that has been subject to large amounts of cow urine, e.g. areas near the stile (always heavy hoof-fall by them around our way). So unless these groups are washing and disinfecting their boots after every walk and between fields, they will be a factor toward the spread too.

There are 2 more maps and 1 revisit that is necessary at this point.

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The first is a map of hunts (if I have missed your hunt, please feel free to let me know. I would be happy to pop down for a visit to clarify the hunt…worth a try). Please remember hunts have been in the countryside for hundreds of years and many tour the country, so bTB should map equally to the hunts.

The second map is from a NASA photo of the UK at night. This is significant because it gives an image of rural vs urban areas. Hunts don’t go around cities and towns, so the areas by them should be pretty much bTB free.

The third map is our old friend DEFRA’s bTB in 2010 map but with a few highlighted colour sections to help point out the obvious.

The black areas are areas of little to no bTB but with a lot of hunt activity. One area not circled is just above the black ringed area Northwest of London where there is a huge density of hunts. If hunts carried bTB and posed a large risk, we should be seeing a high bTB base. However a very low level of bTB cases for hunt density is found.

The blue circled areas are areas with bTB but little to no hunt activity. Looking through, it’s clear Surrey, West Sussex, East Sussex and Kent all have very active hunts, but little to no bTB, except in the Brighton area which has bTB but not that many hunts along the coast (they are more inland but TB is along the coast too). Speaking of coasts, Carmarthen up through Aberystwyth – lots of bTB but little to no hunt activity…lots of badgers there though (check out that badger range map) and you’ll hopefully remember about my friends in that area complaining about red deer.

Do hounds spread bTB? They are potentially a risk, but a VERY minor one, to the point where it is negligible in the grand scheme of things and can be easily managed…and is being manged very sensibly. The simplest solution for any hunt wanting to reduce the small possibility of spreading bTB and to quiet the antis, if they have infected hounds treat them as infected cattle are, which is exactly what Kimblewick Hunt did a little while ago. But the antis got angry about that. Also there is the option to have a hound-friendly disinfectant trough/foot-bath for the hounds to run through before/after every hunt (which I have seen some hunts do). Maybe set up a foot bath at the end of the hounds’ ramp so they have to run through it on the way into and out of their trailers. Spray down the trailer’s with cleaning/disinfectant solution too (I know many of the hunts already do this). The same with hunt horses.

You’ll notice no mention of people with pet dogs, because some are very responsible and others not so responsible. So quantifying that would be near impossible. However dog walkers outnumber hounds at a ratio of 1000 to 1, if I remember rightly (8 million pet dogs vs 8000 hounds). So it would take 999 well behaved and highly responsible dog walkers conscious of TB areas and for 100% of hunts being irresponsible to equal out. We all know the truth there. Just walking down a country lane and seeing the black bag “special fruits” hanging from the trees to know that there is not even a 99 out of 100 ratio of ideal dog walkers.

Do badgers and roe deer spread bTB? If Mark Avery is to be believed “Badgers are bound to be in the news over the next few months – they already are, because of their unarguable role in spreading bovine tuberculosis” (Mark Avery: RSPCA blog 27 Jun 2010 6:34 AM) then badgers are a bTB threat and their common areas of activity are high disease areas. Do roe deer spread bTB? Well, since the dirt is what is carrying the disease, of course they do. Do sabs and protestors spread TB? Unless they are cleaning their boots and clothing thoroughly…well, if the dirty shoe fits…

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