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Pipe 3.

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth ."

Sherlock Holmes in The Sign of Four; Also, The Adventure of the Beryl Coronet. Badger TB source ruled out :- so it must be cows after all !

The Cornerstone Initial Assumption of the whole debate; Ruling out a Cattle source is based on two simply wrong pivotal ideas : only Open lesion cattle infectious / and NVL no visible lesion reactors are false positive (like up to 14 % with M. avium, hence EC derogation to GB & Ireland to use Comparative Skin Test). RE-appraising these twin errors :

1. Transmission
  • A. Only "Open" VL Cases ?. One of the saddest aspects in the history of science is how often new facts fail to become accepted wisdom, so need to be re-discovered anew many decades later. Koch's new TB antigen/skin test sparked early Eradication Schemes a century ago, but pioneers were very aware cattle cases were infectious before becoming reactors, or developing Visible Lesions VL in the lungs; and warned of the wholly artificial false distinction between No Visible Lesion NVL vs "Open" VL cases ( M'Fadyean 1988; Bang 1892). Some 20 % of NVL reactors sputum positive infectious rediscovered by McIlroy 1986, Neill1988, 1992; Wright 1986.

    Both the Ostertag Method focussing on Open Cases ; and similarly British and Irish "Badger TB Eradication Schemes " hence guaranteed to fail . "The hidden (latent cattle) cases which remained and were continually coming to the surface "(Bang in Myers 1940; Francis 1958; Collins 1983). Primary lung foci remaining latent many years Bang 1899, M'Fadyean 1899. Francis 1947 , "ALL tuberculin positive cattle even with very slight lesions ARE infectious so if left in a herd spread will be more or less rapid". Lung lesions remain "open" throughout, unlike in man, this is a fundamental difference ... ditto, Blood 1989, spreading overtakes culling rate; Infectious at any stage of the disease Richards 1972, O'Connor 1986. Bang 1892 "It is found that the tuberculin test is no more perfect than are other things in this world ; animals with a very real degreeof tuberculosis will sometimes fail to react, and the same appertains to animals with a very slight degree of the disease.

  • B. Cattle an airborne respiratory (broncho-)Pneumonia or "Consumption". Francis 1947 & 1958 reaffirmed Bang's view that cattle do not normally catch TB until they enter the cowshed, joining the breeding herd . So, do NOT Usually get TB even from shared heavily contaminated pasture ..a dose of several million bacilli needed to bypass gut lymphatics , so badger urine with a mere 300,000 bacilli/ ml an irrelevance (Maddocks 1934, 1936; Schellner 1959). Long forgotten, but Svensson's classic 1904 study showed 13 calves caught aerogenous TB separated by a 6 m gap from the main herd, 5 reacted by 6 m, rest by 12 months (M'Fadyean 1910). . Incidentally that is why cattle which test "clear" at spring turnout from barns, meet those terrible badgers and are immediately riddled with TB (Delayed test reactivity).

2. Hidden Cattle TB Reservoir

False positives ? The True self-maintaining reservoir has been cattle all along , Blood 1989, "it is the poorly sensitised early or late TB cases which are the USUAL Cause of recrudescence of TB in herds" . SEE Cattle Section, 2 parts, historical & indentifying the hidden reservoir . TWO Elements :-

  • A. Problem Herds. A classic study ; the intractable infamous West Penwith ie. Lands End Study , Richards 1972 :- over 2 1/4 years, 3 anergic or non-reactor cows caused 18 herd breakdowns, ie 10 % of the total .. so selective depopulation of a dozen or so chronic herds allowed area to go TB Free 1985, alas cattle reintroduction 1989-90. Francis 1958 " problem herds in which infection continues to show up on retests indicates the need for indentifying non-reactor spreader cows ". NB ... with some 2000 Chronic herds Currently under TB restriction up to 16 years plus, As I've been pointing out for several years, herd depopulation to remove key "anergic" cows unnecessary now; Ireland routinely use a fast ENFER Chemiluminescent Multiplex ELISA antibody blood test ; the OIE recently approved an IDEXX M.bovis Ab test ; and since a "bad" tubercular cow may shed 38 million bacilli in 30 lbs of faeces / day ; PCR of faecal swabs could also yield results within days .

  • B. Unconfirmed Reactors . This is The single biggest mistake in the whole badgers and TB saga ; in wrongly assuming that some 2 in 3 reactors and herd breakdowns with No Visible Lesion reactors are false positive, they ARE NOT; Merely early cases, NVL, without detectable M. bovis :- EC 64 / 432 , ALL reactors ARE infected ; a fact re-discovered in the 2009 TBEG Report Specificity of skin test 99.99 % ie. only 1 in a thousand truly do not have TB, Truly False positive. More detailed studies than c. 50 % accurate abattoir gross inspection .... serial lung sections Do show micro-lesions in 73-89 % McIlroy 1986, Nassel 1956 in Myers 1969; Stamp 1948 .... and up to 80 % detectable M. bovis after all using guinea pigs or more sensitive eg. BACTEC/ DNA spoligotyping etc ( Wilesmith 1987; Dunnet 1986 para. 32). Confusion over actual status/ role of unconfirmeds eg. ISG 2007, p. 59, 140-1, 179, 237 .. and nil effect of culls on unconfirmed breakdowns due to unconfirmed reactors !! p. 96, 101 ; ISG 3RD report (more at spring tests.. see B above);

NB. Since foot and mouth 2001, some 340, 000 cattle removed , of which c. 200, 000 unconfirmeds = a huge reservoir of TB "hidden " in plain view circulating within the cattle population in a hotspot area now of half of GB ..map 4. (This rather puts into perspective a mere 1515 TB badgers in 11,000 culled in RBCT Trial from 1900 sq.km).

Also .. the spread of TB via bse/ mad cow replacements back into areas clear for 20 years plus, was up to 85 % due to a random scatter "clonal expansion "of unconfirmed cattle reactors / breakdowns; and with the same dna spoligotypes spillover to badgers (see elegant maps in Krebs 1997; online, pp. 57-8, 91, 156-7, and, 67, 165-8, 173-4).

Alas poor Brock; "to be or not TB " quoth hamlet; victim, not villain !

Figure 3