Here in Britain some cattle (Bos primigenius) get bovine tuberculosis (bTB). Symptoms are mild until after the bacterium (Mycobacterium bovis) spreads through the animal’s body. But even in its early stages bTB is a serious problem for the farmer.
Bovine tuberculosis is bad news for the farmer because it’s notifiable. That means that if you suspect your cattle of having bTB, the law says you have to inform a police constable or go straight to the Animal Health and Veterinary Laboratories Agency (AHVLA). AHVLA tells us about notifiable animal diseases. That agency belongs to the Department for Environment Food and Rural Affairs (DEFRA), which also shows us the current list of notifiable animal diseases. Here’s what the law says farmers must do about these diseases.
Right now, bTB is the notifiable animal disease that people are talking about. I’ve been writing about it here under my ‘tuberculosis’, ‘cattle’ and ‘badger’ tags. It’s notifiable because people can get it by drinking milk. People are talking about it because there’s a badger (Meles meles) cull going on, because some people think the wild badger is a reservoir of bTB.
This isn’t the kind of tuberculosis people give each other when poor and overcrowded. That’s Mycobacterium tuberculosis, the classical human TB that remains a problem in poor countries and that’s increasing in some rich countries. We know these are two different diseases because, as Animal Research Info explains, the great Robert Koch discovered that TB in humans and cattle are caused by different bacteria.
That article quotes Professors Paul and Roger Torgerson saying, ‘In the UK, cattle-to-human transmission is negligible. Aerosol transmission, the only probable route of human acquisition, occurs at inconsequential levels when milk is pasteurised, even when bTB is highly endemic in cattle… Before milk pasteurisation, M. bovis was isolated from 8% of churn samples and almost all 3000-gallon tankers suggesting widespread exposure to bTB. Even then most did not get the diease. Since milk pasteurisation was generally introduced in the UK in the early 1960s, bTB has declined drastically.’
In fact, say those professors, bTB control in Britain is now irrelevant. Here’s their science.
I’ve more to say about TB but this is enough for today. Here in my well-ventilated home, I’ll sip some more tea with pasteurised milk.
[Edit] My fellow blogger Tegan Tallulah at Earth Baby is not impressed by the badger cull. She says, ‘Because cattle are kept in such large herds, the disease spreads rapidly and the centralised food system means it’s spread around the country – and beyond – quickly as well.’ Tegan also says, ‘Why the government have decided to completely ignore the study that was commissioned, I have no idea. I can only imagine it’s because they can’t think of anything better to do, and culling badgers makes it look like they’re dealing with the problem.’ I say it’s a lot to do with the power of the National Farmers Union. I’m gestating a post about the vaccine against TB; hopefully I’ll be able to shed some light with that.