Yorkshire and Humberside (low risk area) year end report 2022
Updated 20 November 2023
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Introduction
The Low Risk Area (LRA) of England was established in 2013. In 2014 this area was incorporated into the UK government’s strategy to achieve Officially Tuberculosis-Free (OTF) status for England by 2038. A key action was to recognise the different levels of bovine tuberculosis (TB) in different parts of the country and to vary the approach to control accordingly. Overall, the LRA has a very low and stable incidence of infected herds. The current strategy seeks to rapidly control infection when it arises through:
- high sensitivity testing of affected herds
- temporarily enhanced local surveillance (radial and hotspot testing)
- mandatory pre- and post-movement testing of cattle entering the LRA from higher risk areas of the UK
The aim is to preserve the favourable disease status of this area so that its counties can be declared OTF as soon as possible.
This report describes the frequency and geographical distribution of TB in 2022 in cattle herds in Yorkshire and Humberside, which includes North Yorkshire, South Yorkshire, West Yorkshire, and Humberside, which are all part of the LRA. In 2022, 21% of all new TB incidents in the LRA were detected in Yorkshire and Humberside.
TB in cattle and other mammals is primarily caused by the bacterium Mycobacterium bovis (M. bovis) and the disease is subsequently referred to as TB in this report. Although other sources may refer to TB ‘breakdowns’, this report will use the term ‘incidents’ throughout.
This report is intended for individuals involved in the control of TB, both locally and nationally. This includes, but is not limited to farmers, veterinarians, policy makers and the scientific community.
Details of the data handling methodology used in this report, a glossary of terms, and the TB control measures adopted in the LRA, can be found in the explanatory supplement for the annual reports 2022.
Types of TB incident
Unless otherwise specified, this report includes all new TB incidents detected during the reporting period, 1 January to 31 December 2022. This includes both ‘Officially Tuberculosis-Free Status Withdrawn’ (OTF-W) and ‘Officially Tuberculosis-Free Status Suspended’ (OTF-S) incidents.
OTF-W incidents are those involving at least one skin test reactor (an animal positive to the Single Intradermal Comparative Cervical Tuberculin, or SICCT test) with either typical lesions of TB identified at post-mortem (PM) meat inspection, or at least one animal with M. bovis-positive culture results from tissue samples collected from carcases during the PM inspection, or both.
OTF-S incidents are triggered by reactors to the skin test, but without subsequent detection of TB lesions or positive culture results in any of those animals.
Cattle industry
In 2022 over 70% of the cattle in the region were located in North Yorkshire. The number of cattle and herds in Yorkshire and Humberside remained the same as in 2021. Small holdings with fewer than 50 animals were the most common herd structure across all counties in the region as seen in Appendix 1. In all areas, beef animals predominated, ranging from 63% to 82%, whereas dairy animals accounted for 15% to 33%.
There were 5 TB approved livestock markets operating across the region in 2022, all in North Yorkshire. There were 27 Licensed Finishing Units (LFUs) across Yorkshire and Humberside: 21 in North Yorkshire, 5 in South Yorkshire, and one in Humberside. There was one slaughterhouse (SLH) in North Yorkshire contracted by APHA to process TB reactor cattle in 2022.
New TB incidents
A total of 31 new TB incidents were disclosed across the Yorkshire and Humberside region during 2022 (6 OTF-W and 25 OTF-S) (Figures 1a and 1b). This was a slight increase from the 29 incidents disclosed during 2021 (7 OTF-W and 22 OTF-S).
In Humberside in 2022, there were no OTF-W incidents and 2 OTF-S incidents, compared to one OTF-W and one OTF-S incident in 2021.
In North Yorkshire, there were 4 OTF-W and 13 OTF-S incidents during 2022, compared to 4 OTF-W and 16 OTF-S incidents in 2021.
Compared to 2021, the number of OTF-W incidents in South and West Yorkshire remained unchanged at 0 and 2 incidents, respectively. However, there was an increase in the number of OTF-S incidents in both counties. There were 2 OTF-S incidents in South Yorkshire (no incidents in 2021) and 8 in West Yorkshire (5 in 2021).
There were no incidents of TB reported in non-bovine species in Yorkshire and Humberside during 2022.
Figure 1: Annual number of new TB incidents (OTF-W and OTF-S) in Yorkshire and Humberside, from 2013 to 2022
| County and year | OTF-W incidents | OTF-S incidents | Total |
|---|---|---|---|
| Humberside 2013 | 1 | 3 | 4 |
| Humberside 2014 | 2 | 2 | 4 |
| Humberside 2015 | 0 | 1 | 1 |
| Humberside 2016 | 2 | 1 | 3 |
| Humberside 2017 | 3 | 2 | 5 |
| Humberside 2018 | 0 | 2 | 2 |
| Humberside 2019 | 1 | 0 | 1 |
| Humberside 2020 | 1 | 3 | 4 |
| Humberside 2021 | 1 | 1 | 2 |
| Humberside 2022 | 0 | 2 | 2 |
| North Yorkshire 2013 | 6 | 13 | 19 |
| North Yorkshire 2014 | 6 | 17 | 23 |
| North Yorkshire 2015 | 11 | 12 | 23 |
| North Yorkshire 2016 | 3 | 8 | 11 |
| North Yorkshire 2017 | 2 | 9 | 11 |
| North Yorkshire 2018 | 6 | 10 | 16 |
| North Yorkshire 2019 | 4 | 12 | 16 |
| North Yorkshire 2020 | 9 | 9 | 18 |
| North Yorkshire 2021 | 4 | 16 | 20 |
| North Yorkshire 2022 | 4 | 13 | 17 |
| South Yorkshire 2013 | 4 | 3 | 7 |
| South Yorkshire 2014 | 0 | 1 | 1 |
| South Yorkshire 2015 | 2 | 3 | 5 |
| South Yorkshire 2016 | 1 | 7 | 8 |
| South Yorkshire 2017 | 1 | 3 | 4 |
| South Yorkshire 2018 | 2 | 1 | 3 |
| South Yorkshire 2019 | 2 | 8 | 10 |
| South Yorkshire 2020 | 1 | 2 | 3 |
| South Yorkshire 2021 | 0 | 0 | 0 |
| South Yorkshire 2022 | 0 | 2 | 2 |
| West Yorkshire 2013 | 2 | 3 | 5 |
| West Yorkshire 2014 | 0 | 1 | 1 |
| West Yorkshire 2015 | 2 | 6 | 8 |
| West Yorkshire 2016 | 0 | 1 | 1 |
| West Yorkshire 2017 | 0 | 1 | 1 |
| West Yorkshire 2018 | 0 | 2 | 2 |
| West Yorkshire 2019 | 0 | 3 | 3 |
| West Yorkshire 2020 | 3 | 8 | 11 |
| West Yorkshire 2021 | 2 | 5 | 7 |
| West Yorkshire 2022 | 2 | 8 | 10 |
The headline cattle TB statistics for Yorkshire and Humberside are summarised in Appendix 2.
Disclosing test type
As shown in Figure 2, of the 31 new TB incidents in the region in 2022, routine herd testing detected 12 new TB incidents, followed by radial surveillance testing 11, and pre-movement testing 3. Twelve-month check testing and surveillance of routinely slaughtered cattle triggered 2 new incidents each. Trace testing detected one.
Regarding the individual counties, the spread of disclosing test types is largely consistent with 2021, with the exception of an increase in disclosing radial tests in West Yorkshire (increased from 3 out of a total of 7 incidents to 7 out of a total of 10 incidents).
Figure 2: Number of new TB incidents (OTF-W and OTF-S) in Yorkshire and Humberside, in 2022 according to the surveillance method that detected them
| County | Other | 12 month test | Post-movement test | Radial test | Routine herd test | Slaughterhouse | Tracing test | Total |
|---|---|---|---|---|---|---|---|---|
| Humberside | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 2 |
| North Yorkshire | 0 | 2 | 2 | 4 | 8 | 1 | 0 | 17 |
| South Yorkshire | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 2 |
| West Yorkshire | 1 | 0 | 0 | 7 | 1 | 0 | 1 | 10 |
Duration of TB incidents
A total of 32 TB incidents were resolved during 2022. Of these, 23 were new TB incidents that started in 2022 and closed before the end of the year. A further 9 incidents were resolved that had started in 2021.
Throughout the Yorkshire and Humberside region in 2022, there were no persistent incidents (under movement restrictions for more than 550 days). All OTF-S incidents that ended in Humberside and South Yorkshire in 2022 were resolved quickly, in less than 150 days. In West Yorkshire, all incidents that ended in 2022 resolved within 240 days. In North Yorkshire, 15 out of the total 19 incidents resolved within 240 days and the remaining 4 incidents resolved within 550 days.
Geographical distribution of TB incidents
New TB incidents in Yorkshire typically occurred in areas of higher cattle density, which is consistent with previous years. The 2 incidents in Humberside occurred in areas of lower cattle density (Figure 3).
Figure 3: Location of cattle holdings in Yorkshire and Humberside with new TB incidents (OTF-W and OTF-S) in 2022, and cattle holdings with pre-2022 OTF-W incidents still ongoing at the beginning of 2022, overlaid on a cattle density map. Note that ‘OTF-W Introduced 2022’ refers to OTF-W incidents in which cattle movements were the most likely source of infection.
Whole genome sequencing (WGS) replaced genotyping at APHA in 2021. During 2022, there were 2 different WGS clades of M. bovis detected across Yorkshire and Humberside.
The 3 OTF-W incidents in West Yorkshire (labelled 5 to 7 in figure 3), were all detected to the west of the county, towards the borders with Lancashire, Greater Manchester and Derbyshire. These were all associated with clade B3-11, which has a homerange across much of the North Midlands, extending up into Greater Manchester. There were some new OTF-S incidents in this area in 2022, and OTF-S incidents were previously detected in this area.
In North Yorkshire, 2 OTF-W incidents caused by clade B3-11 (labelled 2 and 3 in Figure 3), were detected in the centre of the county. There had also been a B3-11 incident in this area in 2021 and various other OTF-W incidents.
Two new OTF-W incidents in North Yorkshire were caused by clade B6-11, which is widespread across the West Midlands and parts of Wales. One of the incidents occurred in the north of the county (labelled 1 in Figure 3) and the other in potential hotspot area 27, in the west of the county (labelled 4 in Figure 3).
As can be seen from Figure 4 and Appendix 3 Table 5, OTF-W incidents in Yorkshire and Humberside in 2022 were attributed to various sources of infection. The possible involvement of wildlife in 2 incidents in West Yorkshire is of concern. In North Yorkshire, cattle movements and contiguous cattle risk pathways were potential sources of infection.
Figure 4: Map of the source of infection pathway recorded with the highest level of certainty, for OTF-W incidents, and the location of OTF-S incidents in Yorkshire and Humberside which started in 2022. Local cattle refer to residual infection and contiguous cattle risk pathways. Purchased refers to cattle movement risk pathways. Wildlife refers to both badger and other wildlife risk pathways.
Figure 5 shows the hotspot areas and radial surveillance zones around OTF-W incidents since 2012.
In the centre of North Yorkshire, there is a cluster of incidents which have triggered radial zones over the past few years, with 2 new OTF-W incidents in 2022 (both with the same clade, B3-11). The 2021 active radial zone in this area was triggered by an incident which also had clade B3-11 isolated. All 3 of these recent B3-11 incidents have been attributed to cattle movements. The 2020 incidents in this area had genotype 25:a isolates, which can be equivalent to clade B3-11, but again, all these incidents were attributable to infected cattle movements.
To the west of the region in PHA27, there was one new OTF-W incident triggering a radial zone in 2022 and one active radial zone ongoing from 2021.
No new OTF-W incidents occurred in South Yorkshire or Humberside in 2022.
Figure 5: Hotspot areas and radial surveillance zones around OTF-W incidents that were active, completed or not instigated in Yorkshire and Humberside during 2022, by year of initiation.
Potential or confirmed TB hotspots
Potential Hotspot Area 27
Potential Hotspot Area (PHA27) was instated in January 2020 in the south-western corner of North Yorkshire, straddling the county boundary with Lancashire (Figures 3 to 5). It was set up following an incident from which genotype 17:z (clade B6-23) of M. bovis was isolated.
During the reporting period, there was one new OTF-W incident in a herd located in the North Yorkshire part of the potential hotspot. Clade B6-11 was isolated. This is different from the clade isolated from the index OTF-W incident that triggered the potential hotspot. Introduction of infected cattle and residual infection in the affected herd were found to be likely risk pathways. Since its implementation, only one wild deer carcase has been submitted to APHA for examination, with negative culture results for M. bovis.
Potential Hotspot Area 28
Potential Hotspot Area (PHA28) was first set up 2020 in East Lincolnshire and could pose a risk to the region (WGS clade B3-11, genotype 25:a). A very small area of this potential hotspot spans the county boundary into Humberside. During 2021 and 2022, there have been no OTF-W incidents in the vicinity of the Humberside border. There was one OTF-S incident in the northeast of the potential hotspot in 2021.
Skin test reactors and interferon gamma test positive animals removed
During 2022, a total of 93 animals were removed as TB test reactors from herds affected by TB incidents in this region of the LRA. Of these, 66 were skin test reactors and 27 were positive by the supplementary interferon gamma (IFN-γ) blood test, as shown in Figure 6a and 6b. Compared with 2021, this was an increase on the number of skin reactors from 35, and a decrease in the number of IFN-γ test positive animals from 42. The IFN-γ test has a higher sensitivity but lower specificity than the comparative skin test and so is likely to disclose more TB positive animals. It can also detect infection at an earlier stage of infection than the skin test.
In West Yorkshire, the number of both skin test reactors and IFN-γ test positive animals increased to 30 and 11, from 9 and 0 in 2021, respectively. North Yorkshire also sustained increased number of skin test reactors compared to 2021, although the number of IFN-γ test positive cattle removed was nearly half of those in the previous year.
Figure 6: Number of cattle that tested positive to the skin test or interferon gamma test and were removed by APHA for TB control reasons in Yorkshire and Humberside, from 2017 to 2022
| County and year | Skin test | Interferon gamma test | Total |
|---|---|---|---|
| Humberside 2017 | 3 | 1 | 4 |
| Humberside 2018 | 3 | 7 | 10 |
| Humberside 2019 | 0 | 0 | 0 |
| Humberside 2020 | 4 | 10 | 14 |
| Humberside 2021 | 2 | 4 | 6 |
| Humberside 2022 | 2 | 0 | 2 |
| North Yorkshire 2017 | 21 | 41 | 62 |
| North Yorkshire 2018 | 29 | 30 | 59 |
| North Yorkshire 2019 | 28 | 25 | 53 |
| North Yorkshire 2020 | 26 | 15 | 41 |
| North Yorkshire 2021 | 24 | 27 | 51 |
| North Yorkshire 2022 | 32 | 16 | 48 |
| South Yorkshire 2017 | 9 | 0 | 9 |
| South Yorkshire 2018 | 12 | 11 | 23 |
| South Yorkshire 2019 | 16 | 7 | 23 |
| South Yorkshire 2020 | 4 | 0 | 4 |
| South Yorkshire 2021 | 0 | 11 | 11 |
| South Yorkshire 2022 | 2 | 0 | 2 |
| West Yorkshire 2017 | 2 | 0 | 2 |
| West Yorkshire 2018 | 3 | 0 | 3 |
| West Yorkshire 2019 | 38 | 8 | 46 |
| West Yorkshire 2020 | 17 | 4 | 21 |
| West Yorkshire 2021 | 9 | 0 | 9 |
| West Yorkshire 2022 | 30 | 11 | 41 |
Main risk pathways and key drivers for TB infection
Evidence collected during APHA veterinary investigations into the source of infection within herds was used to inform this understanding. In 2022, 11 out of 31 (35%) new TB incidents in Yorkshire and Humberside received a preliminary or final APHA veterinary investigation to identify the source of infection.
It can be challenging to retrospectively establish the route of infection for a TB incident herd. Ideally this investigation includes a thorough on-farm investigation and scrutiny of routinely collected data, such as cattle movement records, and the results of WGS where available. Up to 3 hazards and risk pathways were selected for each incident investigated. Each of these potential sources were given a score that reflects the likelihood of that pathway being the true one, based on the available evidence.
Details of the protocol used for these investigations, and the subsequent methodology used to calculate the weighted contribution of the different suspected sources of M. bovis infection can be found in the explanatory supplement to the annual reports 2022.
The key drivers of the TB epidemic in Yorkshire and Humberside during 2022 were identified as follows:
- introductions of undetected infected cattle
- local spread into the region from adjoining LRA and Edge Area counties
The main TB risk factor for cattle herds in this region remains the movement of undetected infected animals from higher risk areas of the country. This was the main pathway of infection for cattle herds in Yorkshire and Humberside in 2022, resulting in a weighted contribution of 30%. This is very similar to findings in 2021 when this risk pathway had a weighted contribution of 28%.
Similarly, exposure to infected badgers remained similar (10% compared to 10.5% in 2021). However, it should be noted that comparison of risk pathways in 2022 with risk pathways in 2021 is unlikely to be informative due to only 32% of the required DRFs for herds with new TB incidents in 2022 being carried out.
There is some risk of local spread into the region from adjoining LRA and Edge Area counties. Particular sources of risk include PHA27 and PHA28 (north-east Lincolnshire), and north Derbyshire. Apart from one new OTF-S TB incident in PHA27 (described above) there were no new TB incidents in these areas in 2022. These areas will continue to be monitored.
As in previous years, there was a high degree of uncertainty around the source of TB infections in 2022, with 27% of the herd incidents attributed to ‘other or unknown source’. This category is added to those incidents in which there was high uncertainty around the selected pathways (see explanatory supplement to the annual reports 2022 for methodology).
Forward look
Continued publicity and education to the farming industry to ensure that everyone is equally aware of, and aims to minimise, the risk from purchasing cattle is central to reducing the incidence of TB into the area. This is likely to be particularly pertinent in the central North Yorkshire area, where there has been a succession of OTF-W incidents over the last few years, mostly attributed to cattle movements. There is a risk that cattle may pass the infection to badgers in the area.
The area to the west of West Yorkshire, where potential involvement of wildlife mediated risk pathways has been identified will require careful monitoring.
The promotion and use of interactive mapping tools such as the ibTB interactive map may help to mitigate some of the risk from cattle movements. This, coupled with further education on good herd biosecurity practice, will help to maintain and reduce the low incidence of TB we currently enjoy across the region.
The ongoing routine and targeted TB surveillance methods for cattle are critical in enabling Yorkshire and Humberside to maintain its low incidence of TB. Radial testing, post-movement and traced bovine tests remain key to promptly disclose incidents and limit the potential for further spread. If the combination of these different testing regimes alongside routine surveillance continues, there is a good prospect that the region of Yorkshire and Humberside will maintain its low TB risk status.
Appendix 1: cattle industry demographics
Table 1: Number of cattle herds by size band in Yorkshire and Humberside at 31 December 2022 (RADAR data)
| Size of herds | Number of herds in Humberside | Number of herds in North Yorkshire | Number of herds in South Yorkshire | Number of herds in West Yorkshire |
|---|---|---|---|---|
| Undetermined | 4 | 21 | 5 | 5 |
| 1 to 50 | 297 | 1,241 | 198 | 564 |
| 51 to 100 | 116 | 546 | 71 | 144 |
| 101 to 200 | 110 | 545 | 52 | 106 |
| 201 to 350 | 46 | 309 | 26 | 47 |
| 351 to 500 | 13 | 109 | 17 | 15 |
| Greater than 500 | 9 | 121 | 4 | 10 |
| Total number of herds | 595 | 2,892 | 373 | 891 |
| Mean herd size | 90 | 127 | 87 | 71 |
| Median herd size | 49 | 64 | 41 | 29 |
Table 2: Number (and percentage of total) of animals by breed purpose in Yorkshire and Humberside at 31 December 2022
| Breed purpose | Number (and percentage of total) cattle in Humberside | Number (and percentage of total) cattle in North Yorkshire | Number (and percentage of total) cattle in South Yorkshire | Number (and percentage of total) cattle in West Yorkshire |
|---|---|---|---|---|
| Beef | 44,587 (83%) | 236,826 (64%) | 23,918 (73%) | 43,466 (69%) |
| Dairy | 7,496 (14%) | 119,748 (32%) | 7,302 (22%) | 16,929 (26%) |
| Dual purpose | 1,347 (2%) | 10,190 (2%) | 1,164 (3%) | 2,473 (3%) |
| Unknown | 1 (0.002%) | 23 (0.006%) | 1 | (0%) |
| Total | 53,431 | 366,787 | 32,385 | 62,868 |
Appendix 2: summary of headline cattle TB statistics
Table 3: Herd-level summary statistics for TB in cattle in Yorkshire and Humberside in 2022
| Herd-level statistics | Humberside | North Yorkshire | South Yorkshire | West Yorkshire |
|---|---|---|---|---|
| (a) Total number of cattle herds live on Sam at the end of the reporting period | 791 | 3,559 | 459 | 1,158 |
| (b) Total number of cattle herds subject to annual TB testing (or more frequent) at the end of the reporting period (any reason) | 23 | 257 | 26 | 164 |
| (c) Total number of whole herd skin tests carried out at any time in the period | 136 | 918 | 109 | 488 |
| (d) Total number of OTF cattle herds having TB whole herd tests during the period for any reason | 131 | 850 | 97 | 384 |
| (e) Total number of OTF cattle herds at the end of the report period (herds not under any type of Notice Prohibiting the Movement of Bovine Animals (TB02) restrictions) | 784 | 3,488 | 439 | 1,128 |
| (f) Total number of cattle herds that were not under restrictions due to an ongoing TB incident at the end of the report period | 790 | 3,549 | 459 | 1,155 |
| (g.1) Total number of new OTF-S TB incidents detected in cattle herds during the report period | 2 | 13 | 2 | 8 |
| (g.2) Total number of new OTF-W TB incidents detected in cattle herds during the report period | 0 | 4 | 0 | 2 |
| (h.1) Of the new OTF-W herd incidents, how many occurred in a holding affected by another OTF-W incident in the previous 3 years? | 0 | 1 | 0 | 0 |
| (h.2) Of the new OTF-W herd incidents, how many could be considered secondary to a primary incident based on current evidence? | 0 | 0 | 0 | 0 |
| (h.3) Of the new OTF-W herd incidents, how many were triggered by skin test reactors or 2 time inconclusive reactors (2xIRs) at routine herd tests? | 0 | 1 | 0 | 1 |
| (h.4) Of the new OTF-W herd incidents, how many were triggered by skin test reactors or 2xIRs at other TB test types (such as forward and back-tracings, contiguous, check tests)? | 0 | 3 | 0 | 1 |
| (h.5) Of the new OTF-W herd incidents, how many were first detected through routine slaughterhouse TB surveillance? | 0 | 0 | 0 | 1 |
| (i.1) Number of new OTF-S incidents revealed by enhanced TB surveillance (radial testing) conducted around those OTF-W herds | 0 | 2 | 0 | 6 |
| (i.2) Number of new OTF-W incidents revealed by enhanced TB surveillance (radial testing) conducted around those OTF-W herds | 0 | 2 | 0 | 1 |
| (j) Number of OTF-W herds still open at the end of the period (including any ongoing OTF-W incidents that began in a previous reporting period) | 1 | 7 | 0 | 1 |
| (k) Number of OTF-W herds still open at the end of the period that are within a finishing unit | 1 | 5 | 0 | 0 |
| (l) New confirmed (positive M. bovis culture) incidents in non-bovine species detected during the report period (indicate host species involved) | 0 | 0 | 0 | 0 |
Table 4: Animal-level summary statistics for TB in cattle in Yorkshire and Humberside during 2022
Note (c) Reactors detected during year per incidents disclosed during year, reactors may be from incidents disclosed in earlier years, as any found through testing during the report year count here.
Note (g) SLH cases confirmed by culture of M. bovis, not all cases reported are submitted for culture analysis. All cases reported are from any period prior to or during restrictions.
| Animal-level statistics (cattle) | Humberside | North Yorkshire | South Yorkshire | West Yorkshire |
|---|---|---|---|---|
| (a) Total number of cattle tested with tuberculin skin tests or additional IFN-γ blood tests in the period (animal tests) | 12,932 | 104,680 | 9,619 | 32,862 |
| (b.1) Reactors detected by tuberculin skin tests during the year | 2 | 32 | 2 | 30 |
| (b.2) Reactors detected by additional IFN-γ blood tests (skin-test negative or IR animals) during the year | 0 | 16 | 0 | 11 |
| (c) Reactors detected during year per incidents disclosed during year | 1.00 | 2.82 | 1.00 | 4.10 |
| (d) Reactors per 1,000 animal tests | 0.15 | 0.46 | 0.21 | 1.25 |
| (e.1) Additional animals slaughtered during the year for TB control reasons (dangerous contacts, including any first time IRs) | 0 | 0 | 0 | 0 |
| (e.2) Additional animals slaughtered during the year for TB control reasons (private slaughters) | 0 | 3 | 0 | 0 |
| (f) SLH cases (tuberculous carcases) reported by the Food Standards Agency (FSA) during routine meat inspection | 4 | 7 | 1 | 0 |
| (g) SLH cases confirmed by culture of M. bovis | 0 | 0 | 0 | 1 |
Appendix 3: suspected sources of M. bovis infection for all of the new OTF-W and OTF-S incidents identified in the report period
In 2022, 11 out of 31 (35%) new TB incidents in Yorkshire and Humberside received a preliminary or final APHA veterinary investigation to identify the source of infection.
Each TB incident could have up to 3 potential risk pathways identified. Each risk pathway is given a score that reflects the likelihood of that pathway bringing TB into the herd. The score is recorded as either:
- definite (score 8)
- most likely (score 6)
- likely (score 4)
- possible (score 1)
The sources for each incident are weighted by the certainty ascribed. Any combination of definite, most likely, likely, or possible can contribute towards the overall picture for possible routes of introduction into a herd.
If the overall score for a herd is less than 6, then the score is made up to 6 using the ‘Other or unknown source’ option. Buffering up to 6 in this way helps to reflect the uncertainty in assessments where only ‘likely’ or ‘possible’ sources are identified.
Table 5 combines the data from multiple herds and provides the proportion of pathways in which each source was identified, weighted by the certainty that each source caused the introduction of TB.
The output does not show the proportion of herds where each pathway was identified (this is skewed by the certainty calculation).
WGS of M. bovis isolates can be a powerful tool in identifying a likely source of infection, however WGS clades have not been determined for OTF-S herds. As a result of varying levels of uncertainty, only broad generalisations should be made from these data. A more detailed description of this methodology is provided in the explanatory supplement for the annual reports 2022.
Table 5: Suspected sources of M. bovis infection for all new OTF-W and OTF-S incidents identified in Yorkshire and Humberside in 2022
Please note each TB incident could have up to 3 potential pathways so totals may not equate to the number of actual incidents that have occurred.
| Source of infection | Possible (1) | Likely (4) | Most likely (6) | Definite (8) | Weighted contribution |
|---|---|---|---|---|---|
| Badgers | 2 | 0 | 2 | 0 | 10% |
| Cattle movements | 2 | 2 | 3 | 0 | 31% |
| Contiguous | 1 | 0 | 1 | 0 | 6% |
| Residual cattle infection | 0 | 1 | 0 | 0 | 4% |
| Domestic animals | 0 | 0 | 0 | 0 | 0% |
| Non-specific reactor | 0 | 1 | 1 | 0 | 15% |
| Fomites | 1 | 0 | 0 | 0 | 5% |
| Other wildlife | 1 | 0 | 0 | 0 | 5% |
| Other or unknown source | 1 | 2 | 0 | 0 | 25% |