Parliamentary Questions

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs how long Mycobacterium bovis bacilli can survive on open pasture; and under what conditions. [141395]

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Mr. Bradshaw: Mycobacterium bovis may be present within a variety of media on open pasture, each influencing the survival of the bacilli. In cow manure M. bovis may survive for up to four months in autumn, five months in winter and two months in spring, dependent on concentration. Greater concentrations promote survival.

When exposed to sunlight at 24–34 degrees celsius M. bovis has survived for 5–11 months in manure at pasture. Survival in samples buried in 1cm deep pits has been up to one year and at 5cm deep up to two years.

M. bovis can be highly concentrated in badger urine and can survive for over a week on open pasture during the winter but very few bacilli survive after four weeks. During the summer survival can reduce to less than three days in badger urine.

M. bovis in badger bronchial pus and sputum can survive for up to 10 weeks on open pasture in winter but less than one week in summer. Survival in badger faeces can be for up to one month during the winter but less than two weeks in summer.

Survival may also be influenced by the presence of other microorganisms in the environment. Fungi, algae, protozoans and many other bacteria compete with M. bovis for nutrients, may have greater growth rates, and may produce natural antibiotics.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs how many TB reactor cattle were reported to her Department and its predecessors, (a) in each year from 1990 to 2002 and (b) from 1 January to 31 October; how many were subject to culture testing; and how many proved TB positive on culture. [142468]

Mr. Bradshaw: Table 1 shows the number of TB reactors, how many were subject to culture for Mycobacterium bovis, and the number successfully cultured for the years 1990–2002 in Great Britain.

Table 2 gives provisional data for the number of TB reactors, the number subject to culture, and the number successfully cultured for Mycobacterium bovis in Great Britain for 2003 (till end of October).

Table 1 GB Figures Number of TB Reactors Number Subject To Culture Testing TB Positive on Culture
1990 719 4 (1)—
1991 1,050 4 (1)—
1992 1,086 (1)— (1)—
1993 1,814 2 (1)—
1994 2,248 515 238
1995 2,861 2,492 1,051
1996 3,296 2,852 1,163
1997 3,358 3,005 1,196
1998 5,063 4,121 1,645
1999 6,047 4,894 2,033
2000 7,143 5,456 2,550
2001 5,472 3,818 1,447
2002 20,053 14,102 2,557
(1)— Data not available

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Table 2 2003 GB Figures (provisional) January to October 2003
Number of TB Reactors 17,589
Number Subject To Culture 12,228
TB Positive on Culture 2,681

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what assessment has been made of whether badgers infected by TB may excrete urine from which viable M. bovis bacilli may be isolated; what the typical quantities per millilitre are; and whether such levels are capable of causing infection in cattle through (a) contamination of feed and (b) other mechanisms. [144445]

Mr. Bradshaw: Some badgers develop TB infection in the kidneys 37 per cent. of infected badgers sampled post mortem between 1971 and 1978 m. bovis was isolated from the kidneys and may excrete M. bovis bacilli in urine. Urine is typically left in trails up to a metre or more in length and may be focussed at a latrine or distributed more randomly as the badger forages. Concentrations of up to 300,000 bacilli per ml of badger urine have been reported and experimental nasal inoculation of cattle suggests that, at this concentration of viable microbes, less than 0.03 ml would need to be inhaled by cattle in order to promote slow infection.

Investigations into infection of cattle from feed and other sources contaminated with infected badger urine are lacking. However, risk of infection to cattle by infected badger urine on cattle feed would be a function of the survival of the microbe in the feed (which is dependent on, for example, duration since excretion, moisture content of the environment, exposure to UV rays) the number of microbes consumed by the cattle and the method of consumption (i.e. ingestion or inhalation). I am unaware of measurements of M. bovis survival in cattle feed but the environment inside farm buildings is generally considered to be conducive to longer periods of survival than at pasture, where M. bovis in badger urine has survived for three days in summer and 28 days in winter.

Cattle appear less able to detect badger urine than faeces at pasture away from latrines. In addition, patches contaminated with urine detected by cattle appear to be sniffed more than those contaminated with faeces. Furthermore, some cattle do not select against latrines and freely graze over them. Therefore, potential sources of risk of cattle contact with infected badger urine include the ingestion of contaminated feed from feed stores or in troughs; investigation/grazing at and around latrines; and the investigation/grazing of contaminated pasture.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what controls there are on the movement of wild badgers, for relocation elsewhere, with particular reference to Krebs trapping areas. [144446]

Mr. Bradshaw: Badgers are a protected species and it is an offence to take (or attempt to take) a badger from the wild, including for the purpose of relocation elsewhere (Protection of Badgers Act 1992, s.1(1)). A person guilty of this offence is liable on summary conviction to imprisonment for up to six months and/or a fine of up to £5,000.

There are certain exceptions to this offence, two of which are specifically relevant to the issue of relocating badgers. These are the treatment of injured or sick badgers, and relocations licensed by the appropriate statutory conservation agency or agricultural department (English Nature and Defra, respectively, in England).

Under section 6, a person is not guilty of an offence by reason only of:

"(a) taking or attempting to take a badger which has been disabled otherwise than by this act and is taken or to be taken solely for the purpose of tending it".

As a native species, there are no specific restrictions under current law regulating where badgers are released once they have recovered. Normally, once fit enough to be released into the wild, the badger will be returned to the location where it was originally found. This approach is recommended on welfare grounds due to their territorial nature, and also to avoid any risk of transmitting disease. However, there are situations in which this course of action may not be feasible (particularly in the case of orphaned cubs).

There is a voluntary code of practice covering the rehabilitation and release of badgers, and this has a precautionary approach aimed at minimising the risk of transmitting bovine tuberculosis (TB). All badgers to be relocated are tested for TB three times. Only animals testing negative to all three tests are released and any animal testing positive is euthanased. The code also requires that all released badgers are permanently marked (by a tattoo or microchip) and registered. The code is available via the internet at: http://www. badger.org.uk/action/badger-rehabilitation-protocol-contents.html

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Under section 10 of the Act, licences may be issued to permit badgers to be taken from the wild (and relocated if necessary) for a limited range of specified purposes, including scientific investigation, preventing the spread of disease, and preventing serious damage to property.

Relocating badgers is only permitted where there is considered to be a very low risk of transmitting TB, and before any badgers are released at a new location all animals are tested three times for the disease. All badgers testing positive to any of the three tests, or in contact with a badger testing positive, are euthanased.

Badgers are not relocated as part of the Randomised Badger Culling Trial (the so-called Kreb's trial), and the Independent Scientific Group on Cattle TB have advised that are no special arrangements relating to the relocation of badgers in trial areas.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what plans she has for post movement testing of cattle for exposure to M. bovis; and what assessment she has made of the implications of such testing (a) within four months of movement and (b) by the date of the next due test of the herd from which the animal came. [144436]

Mr. Bradshaw: All farmers have been sent a leaflet "Golden rules for a healthy herd", which advises purchasers to check the disease status of cattle prior to purchase and to consider arranging a private TB test for their herd.

In February 2003, the Secretary of State for Environment, Food and Rural Affairs announced a review of our bovine tuberculosis strategy. Early in the new year we will be publishing a consultation document which will represent the outcome of the first stage of that review. The consultation document will include proposals for short term measures for reducing the risk of geographic spread of bovine TB from high to low incidence areas, including consideration of proposals for the pre and/or post movement testing of cattle.

When considering post-movement testing of cattle sold from farm to farm, we have envisaged that, as a general rule, such tests would be administered between 60 and 120 days after movement (i.e. 2–4 months post movement). This is to ensure that a minimum of 60 days have elapsed since the last test and since any potential exposure to M. bovis on the premises of origin, to avoid problems of de-sensitisation caused by recent testing and to allow for the normal delay in the development of a response to the skin test. Knowledge of whether a pre-movement test had taken place and when, would allow the post movement test to be better targeted.

Assuming post-movement testing is carried out as outlined, the date of the next due test of the herd of origin need not be considered.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what the recognised minimum time required is from exposure of cattle to M. bovis to an immune response which will show in the skin test used by her Department. [144437]

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Mr. Bradshaw: The immune response elicited by Mycobacterium bovis in cattle takes several weeks to develop to a stage where it is detectable. For the single intradermal comparative test used in the UK and Ireland, this period of "unresponsiveness" or latency varies between 30 and 50 days.

To allow for random and natural variation in the latency period of individual animals, the legislation requires repeat testing to be carried out at intervals of at least 60 days from the date of the removal (or isolation) of all the reactors identified at the previous skin test.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what significant variations in incubation period have been observed in herd breakdowns involving several cattle reactors resulting from infection with M.bovis. [144439]

Mr. Bradshaw: Many factors influence the progression of Mycobacterium bovis, infection into detectable disease, including the strain of the bacterium, size of bacterial challenge and route of infection. Other factors include affected animal (species, breed, genotype, age) or the effects of its environment (nutritional status, stress, other infections and environmental bacteria).

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs how many strains of M.bovis have been found in (a) cattle and (b) badgers in the UK; and what assessment has been made of the virulence of each strain. [144440]

Mr. Bradshaw: M. bovis isolates are routinely typed using a DNA fingerprinting technique called spoligotyping. In Great Britain 30 different spoligotypes have been identified in cattle and in 16 badgers. Of those in cattle, 12 of those account for 99 per cent. of the isolates.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what assessment she has made of whether development of lesions in cattle following exposure to M.bovis is the result of (a) a more virulent strain, (b) the level of infective dose and (c) the frequency of the infective dose. [144441]

Mr. Bradshaw: The pathogenesis of bovine TB is not yet fully understood. As a result, Defra is funding several research projects into the pathogenesis and immunology of the disease.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what the average length of herd breakdown was in (a) 2002–03 and (b) 1998; how many 60 day tests were needed to clear (i) suspect and (ii) infected herds in each year; and what the cost of the tests were. [144442]

Mr. Bradshaw: The information is as follows:

(a) The average duration of TB incidents ending in 2002 was skewed by those herds already restricted when TB testing was suspended during the foot and mouth disease outbreak of 2001. The figures for TB incidents ending in 2002 (the last year for which statistics are available) were as follows: unconfirmed incidents—149 days; confirmed incident—291 days.

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(b) The mean length of unconfirmed new TB incidents (herd breakdowns) ending in 1998 was 114 days, i.e. slightly less than two short interval (60-day) tests. In the same year, the mean length of confirmed new incidents was 208 days.

Information on the cost of tests needed to clear unconfirmed and confirmed herd incidents in each year is not readily available and can be obtained only at a disproportionate cost.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what proportion of badgers which appeared TB free in post-mortem examination were culture positive to M.bovis, in the last year for which figures are available. [144443]

Mr. Bradshaw: The last year for which data are available is 1999. These are from Badger Removal Operations and the Road Traffic Accident (RTA) survey that predate the Randomised Badger Culling Trial and associated RTA survey.

In 1999, 874 badger carcasses were considered suitable for post-mortem examination. 753 displayed no visible lesions suggestive of TB. Mycobacterium bovis was isolated in 54 of these. Therefore, the proportion appearing TB free at post-mortem, but culture positive for m. bovis is 7.2 per cent.

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Mr. Paterson: To ask the Secretary of State for Environment, Food and Rural Affairs what proportion of cattle showed no visible lesions in post mortem examination but were culture positive for M.bovis, in the last year for which figures are available. [144444]

Mr. Bradshaw: Last year, 6,600 samples were sent for laboratory culture after no visible lesions were found at post mortem. Mycobacterium bovis was successfully cultured in 5.6 per cent. of these.