Wednesday, April 29, 2009

A scientist says it - so it's official.

We have spoken many times including posts here and here on this site, from our own experiences of animal behaviour how routes of transmission can be overlooked by ignoring the obvious. If you scroll down, that posting has a photo of a young, pregnant dairy heifer sniffing a collie. Sniff: as in 'investigate', 'identify' and label friend or foe. That's what animals do. They use scent to identify each other and more importantly in the case of badgers, cattle and tuberculosis, they sniff other species too. And lick. And the most common scent vehicle is urine which is used to attract, repel, warn and mark territories.

It was thought that contact with the infected detritus of TB infected badgers was the main route of transmission opportunity for bTB, but research just published has shown that badgers had more and closer contact with cattle at grass, than with other badgers.
Western Morning News has a more readable version. This story also labels Defra's 'bio garbage' as 'futile'.

But having spent all this cash, and produced the seismic observation that badgers had closer and more frequent contact with cattle, and particularly high ranking 'boss' cattle, than each other, what do you suppose is the conclusion of the boffins at York University and Edinburgh SAC?

Yup, you got it - more cattle testing. So what do you do, test and shoot the dominant boss cow? And then what? Another takes its place. Yup, you shoot that too. Sheesh. Could that be applied to the hierarchy of 'scientists' we wonder? That was a rhetorical question by the way. The paper's conclusion is:
When considered alongside the heterogeneous pattern of cattle contact between farms, our results emphasise the potential benefits of more targeted cattle-bTB control regimes at both between- and within-farm levels. The current testing regimes recommended by Defra have failed to control bTB in cattle [26]. A higher frequency of bTB testing of highly connected markets and farms [17], combined with more frequent, targeted testing of dominant individuals within herds and a similarly targeted and therefore cost-effective application of any prospective cattle bTB vaccination programmes [52], [53], are likely to contribute to more effective and efficient strategies for controlling disease.

We are not sure just how more frequent than 60 day interval testing, the scientists envisage, but surely, that is missing the point?

Now we've had time to peruse this paper a little more closely, there are few gems worthy of 'quote' status - apart from the conclusion above. During the exercise, collars were attached to 13 cattle and 12 badgers (from two social groups) and data was logged if they had contact of more than 1 second;
" at an average contact initiation distance of 1.69±0.11 m and a contact termination distance of 2.74±0.12 m "
which is considerably less than the 3 - 4 m presumed by previous observations.

The results showed that a single badger (V59) had recordable contacts with 5 of the 13 cattle. Intergroup contact between the two badger social groups was recorded, mainly in September.
Six proximity data loggers (two badger loggers and four cattle loggers) recorded 103 and 32 inter-species interactions respectively (Tables 3 & 4). Overall, two Valley badgers and five cattle were implicated in inter-specific contacts, with the two badgers contacting all of the five cattle. All five cattle were in the top eight for CI rankings in cattle, with four out of the five amongst the top five.

So just two badgers recorded 103 inter species interactions? (Inter species = contact with cattle) and the authors reckon Defra should test the cattle more regularly? Mmmmm. Even though as they point out in the quote below, the badger /cattle contact was higher than between badgers or between cattle.

In multi-host disease systems, where a pathogen can infect more than one of the species present, host species may combine to form a joint host community in which a pathogen can persist, depending on the extent of inter-specific interaction [50]. In terms of direct contacts, the two hosts in our wildlife-livestock system were mainly decoupled from each other, although episodic inter-species contact rates recorded by badger loggers exceeded interaction rates between neighbouring social groups in badgers (Table 3). In populations with strong spacing patterns, such as those caused by territoriality, disease establishment and persistence may be highly dependent on comparatively more frequent inter-species transmission instead of intra-species transmission [2]. This appears to be the case for the Valley badger group in our badger-cattle system."

and finally,
Here, the daily contact frequency and duration were higher in badger-cattle interactions than Valley badger group interactions; the true difference may be even greater due to the lower power settings and hence lower sensitivity employed by the cattle loggers.


Anonymous said...

1. So – let me see if I’ve got it right

2. Diseased badgers mix with cattle and pass on TB to the cattle.

3. Diseased cattle are slaughtered – but the infective badgers are not.

4. I just wonder if it has occurred to anyone that if we culled the sick badgers we would break the disease cycle?

I do hope that DEFRA scientists read this blog and seriously consider my proposal albeit a simple one – or have I missed something?

Peter Brady

Matthew said...

No Peter, you haven't missed anything except that bTB gravy train perhaps! In which caase, join the club.

The Badger Trust have issued a press release spluttering that the paper's claims are both 'ludicrous' and 'absurd'.
Which makes us think it may have merit after all.

They (BT) conclude that of course bTB transmission is all cow to cow. Of course it is. And the earth is flat.

Anonymous said...

Hi Matthew

So if the earth's flat couldn't we push all the badger's off the edge?


Matthew said...

I think the poor old badger is as much a victim as our cattle. And increasingly, the pets and other species now contracting badger TB.

IMO the 'species' that needs the push, are the self serving, self interested lightweights who are widening the polemic and thus fuelling this disease. They are not a solution; not even close to it. They are the problem.