§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs pursuant to her Answer of 8 December 2003,Official Report, column 218W on bovine TB, how many countries use the current skin sensitivity test as the primary diagnostic tool for bovine TB; and how many have reported problems with this test. [150492]
§ Mr. BradshawThere are a number of different types of skin test in use around the world. We do not hold comprehensive information on the number of countries using each of these tests nor the way in which these tests are interpreted.
All countries that have either eradicated, or have a programme to control, bovine tuberculosis use one or more forms of the skin test. The Government have close links with a number of countries in various stages of eradication and exchanges information and experiences on the use of the tests in the context of these programmes.
The Government are not aware of any country that has replaced the skin test as the primary test for bovine tuberculosis.
§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs whether it is possible to determine the relative culpability of an owner of a herd in which a TB breakdown is recorded as to why animals become infected. [150502]
§ Mr. BradshawIn some cases, a TB breakdown may be attributable to a specific event, for example the purchase of an infected animal. In many cases, despite a veterinary investigation, it is not possible to determine the source of the infection with certainty. Defra does not attempt to determine relative culpability but has encouraged all farmers to take sensible precautions to reduce the risk to their cattle through the issue of the yellow "Better biosecurity" card and various booklets which contain guidance on disease prevention and control measures.
§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs (1) how many deer have been subject to post mortem examinations by her Department for the presence of TB during the least five years; and how many were found to be infected; [150514]
(2) what historical data are held by her Department on the prevalence of bovine TB in the British deer population; and what those data indicate as to the incidence of bovine TB in that population; [150516]
542W(3) what her estimate is of the population of wild deer in England and Wales; what the estimated prevalence is of bovine TB in that population; and what concentrations there are of the disease in the wild population. [150515]
§ Mr. BradshawNo statutory body routinely collects information on overall wild deer numbers in England and Wales. Stephen Harriset al. (1995) estimated the pre-breeding population sizes for deer in Great Britain (Table 1).
Table 1: Population of wild deer in England and Wales (estimated) Species England Wales Red deer 12,500 <50 Fallow deer 95,000 <1,000 Roe deer 150,000 50 Sika deer 2,500 0 Muntjac deer 40,000 <250 Chinese water deer 650 0 Total 300,650 <1,350 Source:
Harris, S., Morris P., Wray S. and Yalden D. 1995. "A Review of British Mammals: Population Estimates and Conservation Status of British Mammals Other than Cetaceans". JNCC, Peterborough.
Table 2 shows the number of wild and farmed deer carcases, investigated for TB between 1992 and 2002 and the number of samples where Mycobacteriutn bovis (M. bovis) was found following bacteriological culture.
Table 2: Deer samples tested for bovine TB Total number of deer tissue submissions investigated by Veterinary Laboratories Agency (VLA) Number of confirmed TB cases in wild deer Number of confirmed TB cases farmed/park deer Total number of deer confirmed with TB 1992 50 0 1 1 1993 33 1 0 1 1994 21 1 0 1 1995 1— 3 0 3 1996 217 11 0 11 1997 11 3 0 3 1998 37 6 1 7 1999 49 7 3 10 2000 39 3 6 9 2001 28 0 1 1 2002 54 3 10 13 1 Data not available. 2 Most accurate data currently available. Defra has funded a survey of wildlife in the south-west of England by the Central Science Laboratory. The first phase established whether Mycobacterium bovis (M. bovis—the causative organism for bovine tuberculosis) was present in a number of wild mammal species, including deer. M. bovis has been confirmed in five of the six established wild and feral species of deer in GB. The second phase of the survey (due to end March 2004) is to estimate prevalence of M. bovis in those species where it is found, by carrying out a more targeted and extensive sampling.
§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs (1) pursuant to her Answer of 8 December 2003,Official Report, column 218W, on bovine TB, whether the occasions of severe interference in the operational Krebs triplets areas represented a significant interference; whether that level of interference affected the conduct and outcome of 543W the trials; and what the effects were of that interference in terms of (a) the outcomes and (b) the costs involved; [150565]
(2) how many farms were affected during the Krebs trials by a partial clearance of the badger population which was subsequently stopped; how many partial clearances were undertaken after a delayed start; and how the incomplete clearances affected (a) the conduct of the trials and (b) their outcome. [150575]
§ Mr. BradshawThere has been a level of illegal activity and interference with the operation of the Randomised Badger Culling Trial which is certainly undesirable and could be considered significant. The cost of replacing stolen, lost and damaged traps is estimated to be approximately £400,000. Other costs relate chiefly to the loss of staff time, which cannot be provided at proportionate cost.
At the time of cessation of the reactive strategy one premises was in the process of being trapped and the operation was concluded with only half the number of trapping nights completed. A number of other operations have been stopped early for a variety of reasons, for example bad weather or activity by animal activists. If an operation is not able to start as scheduled, it is extended to ensure that the standard period of two weeks' trapping is maintained.
Standard Operating Procedures take account of the possibility of interruption to trapping operations. Although interference varied across trial areas, the Independent Scientific Group on Cattle TB found that the increase in the incidence of TB in reactive culling areas when compared with control (no culling) areas was consistent across all triplets.
§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs what the percentage increase was in the number of TB reactor herds reported in 2003 compared with 2002; and what factors are believed to be responsible for this increase. [150576]
§ Mr. BradshawIn 2003, up to the end of November, there had been 2,880 new cattle herd TB incidents in Great Britain. In the same period in 2002, there were 3,035 new TB herd incidents reported.
It is difficult to draw comparison between 2002 and 2003, because the testing effort in 2002 was very much increased to clear the backlog of testing after the foot and mouth disease outbreak in 2001.
§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs how many herds required 60-day tuberculosis tests in 1988. [150586]
§ Mr. BradshawIn 1988, 351 herds required short-interval ('60-day') tests.
§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs what the estimated infective dose is of TB bacilli (var bovis) in respect of cattle, by reference to infection portals; what the peak load is of bacilli that can be excreted in the urine of infected badgers; and what the predicted die-off rate is of the TB bacilli on grassland. [150591]
544W
§ Mr. BradshawDetermination of the minimum infectious dose ofMycobacterium bovis in cattle is part of the TB pathogenesis research programme. Early indications are that the minimum infectious dose for cattle via the respiratory tract is relatively small; the lowest infectious dose recorded so far is 70 colony forming units CFU, when introduced by the intracheal route or 9,600 CPU by the intranasal route.
Relatively high levels of M. bovis in the urine of badgers with renal TB have been identified by culture methods, so far bacterial loads of up to 300,000 colony forming units per millilitre of urine have been measured.
It is known that the survival of M. bovis on pasture is widely variable depending on climate and pasture type. In hot dry weather survival may be a day or less whereas in cool damp weather M. bovis may survive for several months and in some circumstances in excess of six months.
§ Mr. PatersonTo ask the Secretary of State for Environment, Food and Rural Affairs pursuant to her answer of 8 December 2003,Official Report, column 216W, on bovine TB, what other rapid assay techniques are (a) available and (b) in the course of development which have the potential to speed up the detection of M. bovis in suspected TB lesions submitted for laboratory analysis. [150597]
§ Mr. BradshawSeveral liquid culture methods are commercially available for the isolation of bacteria of theMycobacterium tuberculosis complex from clinical samples. These methods are mainly used in medical laboratories for the diagnosis of TB in humans. Although the liquid culture media can significantly shorten culture times, they have not been optimised for isolation of M. bovis. The growth requirements of M. bovis and M. tuberculosis are slightly different and culture media that work for one mycobacterium may not work so well for the other.
The Veterinary Laboratories Agency (VLA) is evaluating the M. bovis recovery rates and ease of use of two of these liquid culture media compared with the traditional method used for cattle and badger tissues. Preliminary findings suggest that one of these systems might be adequate for rapid isolation of M. bovis from badger tissues. Additional experiments are under way to validate these findings and see if they can be extrapolated to cattle samples.
The VLA is also collaborating with the Imperial College in the design and optimisation of a polymerase chain reaction (PCR) assay for the detection of M. bovis DMA in suspect TB lesions.
Although this is a priority area of research for Defra, it is unlikely that any of the new laboratory tests being evaluated can totally replace the traditional culture technique.