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Part 1 . A Historical Overview Of Cattle TB Schemes Section 2

3. Additional Measures. At the low point three extra measures are essential :
  1. It is vital to tackle the problem of residual TB circulating freely "below the radar" within a "hidden reservoir". Explained more fully later .. but very simply, a minority of "Problem"/chronic herds not actually "cleared" by routine skin testing ARE hence not under restriction and are exporting a random scatter of early and unconfirmed Cases causing some 75-85 % of new often unconfirmed breakdowns .. a gentle wave in an outwards ripple from the hotspot "pond":- See Fig. 1, maps 2 to 3 .. or Krebs colour maps p. 156. It was assumed this residual reservoir Must be badgers in the 1970s Wilesmith 1983, Zuckerman 1980 .. but this 75 % hidden reservoir has been re-discovered recently ( Green 2008, Bieck 2012).

    The Area Eradication scheme in the early days recognised that if half or even a quarter of a herd affected, rather than years of re-tests, the quickest /simplest option was to depopulate , disinfect, rest grazings a month or two then restock with "clean" cattle (Macrae, Ritchie). Not too traumatic when big herds only 50 strong .. unwelcome now with chronic herds of 300-1000 or so .. but there are now antibody tests to find non-reactor "anergic" culprit cows. A recent case being the Welsh Gelli Aur university herd under restriction for a decade, where 1 cow that repeatedly tested clear was found at slaughter to be riddled with TB. In fact the infamous "intractable" West Penwith area was also a textbook example. Some 18 breakdowns linked to just 3 anergic cows, amounting to 10 % of the 178 breakdowns in the 2 1/4 year study, so depopulating a dozen or so problem herds allowed area to go clear 1985, alas TB re-introduced 1988-9 with imported cattle (Richards 1972).

    Tragically, presumably since "everyone knows badgers are the main problem" .. DEFRA have so far failed to consider the late TB tests which could find the anergic culprits within weeks ..Ireland routinely use the Enfer Chemiluminescent Multiplex ELISA blood test; the O.I.E. have recently approved the IDEXX M. bovis.Ab. test. .. and since a cow with advanced lung TB may be shedding 38 million bacilli in 30 pounds of faeces / day .. PCR on faecal swabs could find the culprit fast too.
  2. With widespread intensive testing progressively producing fewer reactors, it has always been tempting in country TB schemes to reduce testing, which usually meant going prematurely to 2 year or even longer testing intervals. IF the area still has residual unrecognised TB there will be a flare up of new breakdowns, many of them bad ones with many reactors... so an immediate return to annual testing essential to nip this upsurge in its tracks. This problem has been very obvious all along .. the first seen perhaps in the 1970s Hartland flare-up (Maps re gassing cull Section 4 , Figure 6). There was a similar local flare-up Thornbury and with gassing badgers. Ironically, the 96 %" alleged drop" in the Four Areas Donegal cull, was in fact a flare up in the reference or "no cull" area, which incidentally had the fewest TB badgers culled (Section 4 culls; Olea Popelka 2006). Bad breakdowns heralded the return to clear areas, over last two decades : Carmarthen; start Hereford/Worcs ; also Staffs. (TBF 61); and recently in Shrops/Leics ; Arran .. and 2 cases in Scotland 2012 slipped through the net (MAFF Reports, farming press). Many countries find in the late stages of eradication, that huge numbers must be tested to find the last few herds .. not cost-effective, so switch to abattoir surveillance with trace-back and draconian herd depopulation / tracing of any exported cattle needed. USA still has problems with Mexican imports, and some textbook re-introductions Schoenbaum etc in Menzies 2000.
  3. A combination of the last 2 problems, means that it is vital to prevent TB simply moving back into cleared areas. A total ban on movement is draconian but works ; Jersey, a 200 year old ban on any imports ...just hope their allowing import of new "Jerseys" blood with "pre-export" & post-import testing/quarantining will be very rigorous ! Isle of Man and european countries such as Germany and Switzerland, the main problem is such re-introductions. The Dutch were understandably cross at receiving TB calves from GB a couple of years ago ..their hard won TB free status needing unremitting surveillance (Fischer 2005). There have been some near misses in accidentally allowing brucellosis from Ireland back into GB , Scotland particularly ; luckily, computerisation a few times meant alerts, to double check recent imports from newly discovered affected herds.

    Next best thing just about acceptable to farmers is pre-movement tests, (from 2006 GB), with post-import /quarantining in Scotland now officially TB-free. Sad that the Preparing for a new strategy consultation (DEFRA 2004), which high-lighted various options, plus a committee enquiry ..ended up with pre-movement tests from 1 & 2 year test areas to 3 & 4 yearly ones ..this does absolutely nothing to stop the outwards ripple wave from 1 to 2 year areas. Indeed , the traditional ring fence /firewall of a parish wide 2 year test ring around annual foci completely failed to prevent cattle moves outwards (Annex E in DEFRA 2004; also see Figure 2, dramatic expansion over just 15 years )... the TBEG Report 2-parish wide one equally ineffectual, and ideas of a 2 km-wide badger vaccination ring fence /firebreak totally absurd ! Good to hear that in the 19th October 2012 new measures there will be 10 additional frontier county-wide barriers on annual tests (Map 4 in Fig. 1), which will hopefully "get ahead" of the expansion instead of hitherto playing catchup !

    Very sad, that just after foot & mouth ended in 2001, despite numerous warnings, MAFF allowed more or less free movement even from TB hotspots . Just a tiny number of the worst herds restricted ( Anderson and Follet 2002 FMD inquiries , and EFRA Committee 2003). Inevitable re-introduction of TB via re-stocking in worst FMD areas such as Cumbria, just as happened in 1960s FMD , reintroduction to Cheshire. And in Southern Ireland , pre-movement testing abandoned in 1996, an inevitable upsurge in new countrywide TB pockets eg. in Four Areas study. Sadly, it was subsequently recognised that brucellosis spreads from other cattle, so pre-movement tests re-introduced ; BUT since TB supposedly comes to a large extent from badgers, overlooking the hidden cattle reservoir; a model suggesting only marginal benefits, so not brought back for cattle .. one reason why up to 46 % of breakdowns found by abattoir surveillance rather than annual testing (More 2006, Clegg 2008).
  4. GB had a textbook scheme which brought TB down from countrywide to tiny southwest hotspots Figure 1, Maps 1 to 2 .( Atkins , Barrow, Evans, Macrae, Proud, Richards, Ritchie, Steward, TBEG 2009.. and equivalent in Eire Watchorn 1965 ). The pragmatic three phases were :-

    1. Removal of Stage 3 Clinically sick cattle with advanced TB.. emaciation, tuberculous cough, microscopic stained smears of sputum/milk reveal AFBs acid fast ie tubercle bacilli. (Steward 1941). 24,000 cases in 1938 down to none by early 1960s. Cases with udder TB do still appear rarely and may be very damaging .. bulk milk can infect a whole batch of calves.. pasteurisation was brought in to protect calves/piglets from this, later used for human milk . It is striking that cows with udder TB are very rare nowadays, but DO occur. One case in Dorset in the mid-1990s meant exported cattle to within Dorset, to Aberdeen, Bedford, Devon, Cornwall . A bad breakdown in Cornwall linked to BVD (Monies 2006). One case in Wales led to depopulation of the herd of some 850 cattle. Another case in Ireland spread to human contacts ( CVERA report 2007).
    2. Voluntary joining testing scheme with bonus payments for " Attested milk/beef ".
    3. Having thinned out the problem, from 1950 areas were brought into Compulsory annual testing ; Area Eradication worked from low to high TB areas, essentially from north to south with whole of GB in scheme by 1960 . Sadly, during the low period to 1985 ( see Figure 1, graph ), 6 of the 7 southwest "problem" counties got down to single figures for yearly breakdowns .. with numbers doubling or halving according to efficacy of testing ; from say 4 up to 8, or 11 down to 5 breakdowns .. but now have several hundred breakdowns / a each. Southern Ireland had an identical scheme which likewise shrank TB from national to the 6 southwest high density dairying counties (Watchorn 1965). Small countries such as Ulster and Switzerland could tackle the whole national herd from outset .. bigger countries, pragmatically tackle eradication in stages since vet resources, replacement cattle better focussed in lowest TB level areas first.
Why Did TB In GB / EIRE Return To Crisis Proportions

Tragically, both GB and EIRE then assumed TB was more or less "solved", complacency set in, and they failed to implement the Three Additional Measures above , SO, cattle TB has simply spread outwards from the several residual pockets Map 2 in Fig.1; imperceptibly spreading across Cornwall with a new eastern Lanreath cluster (Figure 6), and to the whole of Devon, back throughout Somerset .. advancing by c. 10 km a year, now encompassing half of GB, Map 4, and increasing by c. 18 % a year ie. doubling every 2-3 years. It is astonishing that no-one realised this crisis was happening over the last 3 decades , and so did not re-impose tighter testing to stop the rot ....presumably , everyone too focussed on The Badger Problem and failure to realise that up to 85 % of this was via the "hidden circulation-expansion" of Unconfirmed cases.

A Wide range of factors are behind the relaxation of cattle controls and emergent crisis and include :- Testing factors .. there were 9 million tests / a at the start of Area Eradication ie. whole national herd (except calves under 2 mnths old which wouldnt be reactors yet); but prematurely relaxed to c. 2 million 1988-1994. Switch to up to 4 year tests 1993, when MAFF overstretched due to Mad Cows .

Cattle Population restructuring :- success of TB eradication allowed doubling southwest numbers 1964-74 (Pout 1981). Intensification arose from introduction of milking parlours --hand milking OK with herds up to 50 cows into 1960s, but now 150 normal, many of 300 or 1000 cows , and with an 80 % accurate skin test more will be missed each time the bigger the herd..gradual switch from traditional breeds such as Jerseys to Friesian, or high yield Holsteins, with greater use of indoor overwintering facilitating TB spread ; obviously rationalisation of manpower inputs/ herd management or "Economy of Scale" favours bigger more intensive farms too; loss of Milk Marketing board and EC regulations over milk quotas also prompted drop from 240,000 herds 1960 to 90,000 now.. dispersal sales a factor risking spread from "apparently" test negative herds, dairy herds nearly halved over last decade; also inevitably the fewer herds with more cows led to farm fragmentation or rented grazings .. 4 or 5 farms / village reduced to 1-2 bigger farms.. And risk of contiguous spread (breakdowns often occur in clusters of herds ).. Ulster is unusual in having many small farms, but 60 % are fragmented, with up to 9 holdings / "farm" , so that there may be c. 13 contiguous neighbours (4-36 ) , and the 1984 Dept. Agric. study suggested 30 % of breakdowns were due to bought in cattle but up to 70 % were contiguous (McIlroy 1986). During the low period, GB had greatly reduced within herd spread, so drop in contiguous cases too, but MAFF figures greatly underestimate this as they are assumed to be "due to badgers" with TB caught from next doors earlier breakdown eg. the Woodchester 1986-7 cluster in Section 4 (Wilesmith 1986).

It is remarkable how the TB hotspots areas have changed dramatically : Figure l, Map 1 showed in the 1940s a bad northwest cluster of counties linked to Irish imports and intensive dairying. The southwest of England/Wales were NOT hotspots back then, although presumably having high badger populations. They became the new hotspot areas with a big increase of stocking, particularly of intensive dairying with bigger herds possibly due to new milking parlours. Traditonal Irish imports particularly to the north of England and Scotland , particularly beef stores to rear on/ "finish" have long been a "problem" , 40 % of non-southwest breakdowns due to Irish imports (Dunnet 1986; Rees 1987) . MAFF Report for 1972-89 attribution of confirmed breakdowns for 1589 herds in southwest / 646 herds in non-southwest were :- Irish 2/ 222; bought in 140/95; contiguous 24/ 22; badgers 932/41; UNKNOWN 491/ 256; miscellaneous 0/10.. BUT NB if "Alleged" badger lumped with actually "unknown" then this figure would be 89 % / 46 %... lumping Irish and bought would be 9 % / 59 %.

Given the steady flow of imported Irish cattle into the north of England, the vet strikes 1975-6 & 1981 prompted MAFF to insist on pre-export tests, with follow up post-import ones too, to minimise this (Goodchild 2001) ; and which is why the north did NOT acquire a major problem via imported, particularly store cattle. Cumbria is particularly interesting , only 2 TB badgers 1972-96; the FMD re-stocking after-effect was reintroduced TB as noted above. The Furness peninsula deer farm outbreak 2002 was initially attributed to a Shropshire spoligotype, but later DNA/ VNTR sub-sampling suggested it was actually from Ireland in the cattle brought in in 1990, perhaps post-BSE, hence to deer, then back to cattle 2003 .. sampling wildlife found no TB cases (ISGs TBF papers).

Surprisingly also a unique Irish DNA Spoligotype introduced to cattle & badgers in Sussex (Wilesmith 1983, Krebs maps p. 67, 173).

The outwards expansion from annual testing hotspot areas is very clearly via cattle movements (Maps 2 to 3 in Figure 1 & Figure 2). Shown by three examples :-

  1. Thus by 1999 over 50% of breakdowns were happening in areas TB free for 10 years (cattle or badgers !):- Avon 15 out of 25 breakdowns; Cornwall 103 of 139; Devon 54 of 90; and frontier counties even more Shropshire 4 of 5; Derbyshire 6 of 6; Staffs. 29 out of 30 new breakdowns (J.Paice unpub.).
  2. A very simple outwards spread of the locally prevalent DNA Spoligotype as a "clonal Cluster" ( Gallagher 2009, Gopal 2006, Jahans 2006, Krebs 1997 maps pp. 67, 173-4, Smith 2006/2003 ).
  3. And a very elegant analysis of cattle movement records from the new computerised database (Mitchell 2006) :- 43 % of moves under 20 km , 21 % were 20 - 39 km; and in 2002 there were 453,000 cattle movements in the West Area , 87 % recycling within the west, 13 % going to East/North/Wales..and critically going from annual to 2 and 4 year testing areas some 40, 000 cattle each , SO IF there was say 5 % with TB thats 2000 new breakdowns that year.. no wonder the outwardly expanding inexorable TB tsunami ! Cattle movements "consistently outperform other variables" in modelling studies (Gilbert 2005, Green 2007, Kao 1997).
There are five jumps in this inexorable rise as shown in the Figure 1 Graph :
  1. BSE or mad cows. Starting in the mid 1980s, this lead to a southwest doubling of confirmed herds from 121 to 232 1992-3. But more importantly, with a 1993 peak of 36,000 BSE cases to be replaced , this resulted in a scatter on up to 85 % unconfirmed new breakdowns spreading into areas TB free for 20 years or so... notably, Thornbury, Exmoor, Hereford/Worcs, Shrops/Cheshire, Staffs/Derbyshire, a new French restocking DNA Spoligotype .. and a decade later some 6000 reactors from this new hotspot (DEFRA 2004) . Expansion very clearly shown in Maps in Krebs report 1997, spanning BSE peak, unconfirmed breakdowns pp. 156-7, confirmeds 57, and repeat breakdowns 58, 91 (these hotspot pockets the basis selection RBCT trial cull areas).
  2. Foot & Mouth ; FMD, 2001; lack of testing for a year.. so doubling in breakdowns, but since many herds went 2 years untested a three or fourfold increase in reactors in England /Wales, with the jump from 8000 to 23,000 reactors Figure 1 graph, also critically the number of bad breakdowns with over 6 reactors went from 23 % 2000, to 42 % 2002, back to 17 % 2005. The ISG failed to recognise that their increase in Reactive and in the 2 km Outside ring AND Beyond the Proactive cull areas was simply part of the national upswing (SEE Section 4 reappraisal culls "work"). The detailed study of reactive badger culls in Triplet E Wilts , noted an increase in both cull and no cull areas (Macdonald 2006) . Ironically, there was even a 1967-8 FMD related upswing in cattle TB in the Lands End study (Richards 1972).
  3. 2005 : The autumn package of measures 2004 with zero tolerance in testing overdue herds (26, 000 in 2002) plus bringing many bordering parishes back to annual testing simply caught up on accumulated cases so 30, 000 reactors.
  4. 2008 : 40, 000 reactors . Nearly as bad as 1950s before eradication scheme fully underway ..again simply recruiting c. 1000 hotspot fringe parishes , particularly Devon/Dyfed caught up on accumulated cases; many were bad breakdowns of 6 + reactors as above; also more use IFN test, and impact of pre-movement tests began to appear ; Also, Wales entire national herd checked so a 50 % jump 2006 with 6000 reactors to 12,000 in 2008.. and creep east from Dyfed linking up with westwards creep from Hereford/Worcs/ Gwent met in Powys . It has Always been the case that testing expanded to "allegedly clear" areas on 2, 3, 4 year tests WILL find more cases ; In Eire, with routinely 20,000-30,000 reactors a year, the 4 year intensive ERAD scheme 1988-1991 saw a peak of 40, 000 reactors and it was estimated that the true number "out there" was probably 60,000, so normal "testing " only skimming half the actual recruitment (More 2006).
  5. 2012. As in 3 & 4 above, with expansion of annual test areas following the TBEG Report 2009, the final figure for 2012 was not unexpectedly over 38, 000; so not far short of the 2008 "worst peak".
Figure 1

Figure 2
Quo Vadis ?

The 19th October 2012 new measures with an additional 10 fringing counties (Map 4 in Figure 1) in one big annual testing area has effectively brought GB back to the 1960s start point, the ring fence should " get ahead" of and contain any further spread .. into the rest of England on 4 year testing, still with pre-movement tests and rigorous tackling any herds that slip through this net. Hopefully, too the BCMS, cattle movement database which had a 12 % error initially (Mitchell 2006) will be more effective. Pity MAFF/DEFRA (J. Rooker to 2008 EFRA committee) are so reluctant to put TB test history on "catttle passports" which would greatly help in tracing.

The TBEG Oct. 2009 report AT LAST recognised that Unconfirmed cases should stop being treated as False positives, THEY DO HAVE TB . So, under EC Directive 64/432, 2 clear tests needed to de-restrict; and incidentally remove IR Inconclusive reactors at first re-test.

Better tests to identify anergic non-reactor culprits in chronic herds need to be used : antibody blood test or PCR on faecal swabs (see above 3. Additional measures ) Sad that the DIVA test distinguishing cattle vaccinated versus TB carriers has been around a decade, but DEFRA only just starting to try and get EU permission to use vaccination (2013 request rejected because trials in Ethiopia !) may take another decade to unscramble the legal bureaucracy . (EFRA Committee 2013 on vaccines ; will probably endorse badger vaccination; as in Kilkenny trial Ireland, Byrne 2012...even though utterly pointless since badgers are NOT the problem.. and even if trial in tiny area of a few hundred does eventually show a spurious "result" .. the TB hotspot is now 1/2 of GB , Map 4 .. my submissions Appendix 1 & 2 ignored by Committee as usual ! ).