Department of Agriculture, Food and the MarineTeagascDeposited by bulk impor

Costello, Eamon

Flynn, Orla

Griffin, John M.

Hammond, Robert F.

McGrath, Guy

O'Grady, D.

Quigley, Frances

O\u27Grady, D.

Irish Universities

Spatial distribution of RFLP types identified in Mycobacterium bovis isolates from badgers and cattle in a study area in the Republic of Ireland

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Title Spatial distribution of RFLP types identified in Mycobacterium bovis isolates from badgers and cattle in a study area in the Republic of IrelandAuthors(s) Costello, Eamon, Flynn, Orla, Griffin, John M., Quigley, Frances, O'Grady, D., McGrath, Guy, Hammond, Robert F.Publication date 2000-10Publication information Costello, Eamon, Orla Flynn, John M. Griffin, Frances Quigley, D. O’Grady, Guy McGrath, and Robert F. Hammond. Spatial Distribution of RFLP Types Identified in Mycobacterium Bovis Isolates from Badgers and Cattle in a Study Area in the Republic of Ireland. Edited by John D. Collins and Robert F. Hammond. University College Dublin. Centre for Veterinary Epidemiology and Risk Analysis, October, 2000.Series Selected Papers, 1999Publisher University College Dublin. Centre for Veterinary Epidemiology and Risk AnalysisItem record/more informationhttp://hdl.handle.net/10197/8846Downloaded 2023-11-01T04:02:15ZThe UCD community has made this article openly available. Please share how this accessbenefits you. Your story matters! (@ucd_oa)© Some rights reserved. For more informationSpatial Distribution of RFLP Types Identified in Mycobacterium bovis Isolates from Badgers and Cattle in a Study Area in the Republic of Ireland E. Costello, 1 0. Flynn, 1 J. Griffin, F. Quigley, 1 D. O'Grady, 1 G. McGrath and R.Hammond Introduction A programme to eradicate bovine tuberculosis commenced in the Republic of Ireland in 1954. The prevalence of disease decreased rapidly in the first ten years of the programme. However, since then a low level of infection has persisted within the cattle population, despite annual tuberculin testing of herds and removal of reactor cattle. Mycobacterium bovis infection has been identified in some populations of feral deer and is endemic in badger populations. Badgers are widely distributed throughout the country: the prevalence of infection has been estimated to be 17% and infected badgers have been identified in every county (Dolan and Lynch, 1992). Badgers forage for food on pastures grazed by cattle: therefore, there is a possible risk of transmission of infection between the two species. Differentiation of M. bovis strains by DNA fingerprinting is a potentially useful m ethod of investigating possible transmission of infection between cattle and badgers. A survey of strain types occurring in cattle and badger isolates in the Republic of Ireland has recently been completed (Costello et al., 1999). Restriction fragment length polymorphism (RFLP) analysis was performed on a small number of cattle and badger isolates from each county, using IS6110, PGRS and DR probes. A total of 85 RFLP types were identified in 452 isolates examined; however, approximately 70% of the isolates were represented by nine RFLP types. All of these prevalent types were identified in both cattle and badger isolates and there was a similar geographic distribution of the RFLP types identified in both species. A further study is presently in progress which will complement this overview of the distribution of RFLP types with a more detailed examination of the spatial distribution of RFLP types in badgers and cattle herds in four geographic areas. Interim results from one of these study areas are presented in this paper. Materials and methods The study area selected was situated in county Cork, and had an area of approximately 300 km2. This was one of four areas where badgers are being culled in order to study the effect of badger removal on the incidence of tuberculosis in cattle. The area was surveyed in detail and the location of all badger setts was recorded on a Geographic Information System (GIS) database. The current intensive badger removal programme has been in progress over the past three years. Tissues from all badgers removed were cultured. RFLP analysis was performed on M. bovis isolates using IS6110, PGRS and DR probes. RFLP types were named by assignment of an alphanumeric designation to each probe in the order, 1 Central Veterinary Research Laboratory, Abbotstown, Dublin 15, Ireland. ERADITEAGASC 26 Veterinary Epidemiology & Tuberculosis lnvest1gotJon Unit, UCD IS6110, PGRS, DR. There are approximately 700 cattle herds with approximately 60,000 cattle in the study area. The location and boundaries of all farms were entered on the GIS. Macroscopic lesions detected in cattle were cultured and RFLP analysis was performed on isolates. Results and Discussion A total of 202 main setts and 905 other setts were identified in the study area. Over the study period 623 badgers were removed. M. bovis was isolated from 177 (28%) of the badgers. One or more infected badgers was found at 75 (37%) of the main setts and at 45 (5%) of the other setts.To date RFLP analysis has been performed on isolates from 121 (68%) of the 177 infected badgers and on 86 isolates from 59 cattle herds. Using a combination of the three probes 13 RFLP types were identified in the badger isolates and 12 RFLP types were identified in the cattle isolates. The most common RFLP type was C1 H 1 J, which was identified in isolates from badgers in 43 setts and from cattle in 27 herds. The second most common RFLP type was Al A3 A which was identified in isolates from badgers in 33 setts and from cattle in 14 herds. These two prevalent types were identified in isolates from 76 (79%) of the 96 badger setts, and in isolates from 41 (69%) of the 59 cattle herds for which results of RFLP analysis are available. A further five RFLP types were identified in isolates from both badgers and cattle. Six RFLP types were identified only in isolates from badgers. One of these was identified in badgers from four setts, one was identified in badgers from two setts and the other four were only identified in badgers from a single sett. Five RFLP types were identified only in isolates from cattle herds, each of which was confined to a single herd. The most prevalent RFLP type (Cl H l J) was widely distributed throughout the study area, both in badgers (Figure 1) and cattle. RFLP type A1 A3 A was concentrated in the western half of the study area, again both in badgers (Figure 1) and cattle. T he third most prevalent type A2 Al B was found predominantly in the eastern part of the study area, w here it was identified in badgers from seven setts and in cattle from three herds. Three other RFLP types were identified in isolates from cattle herds and badger setts w hich were in close proximity (i.e. less than 2 km apart). One R FLP type was identified in cattle from two herds and badgers from two setts that were not in close proximity. Frequently, more than one RFLP type was present in a locality; usually, between two and four RFLP types were identified in cattle and badger isolates in a 10 km2 area. In almost all instances w here the same RFLP type was present in badgers and cattle in a locality, the sett from which the infected badger was culled was not on the infected farm but was located some distance away (Figures 2 and 3). This distance typically varied from 200 metres to 2 kilometres. The results of this study show that there was some correlation between the spatial distribution of RFLP types in badgers and cattle, and suggests that transmission of infection occurs between these species. Further analysis of these data will include mapping the extent of badger social group territories and determining the proximity of the territories of infected social groups and infected farms, which have the same RFLP type. This may provide further evidence regarding the modes of spread of M. bovis. Additional RFLP analysis w ill be carried out on all isolates using the probe pUCD (O'Brien et al., 2000). As the study progresses, changes in the distribution of RFLP types over time will be assessed. ERADITEAGASC 27 Veterinary Epidemiology & Tuberculosis Investigation Uni~ UCD Aclmowledgments The authors thank Mr. Michael Sheridan, Mr. Ian O'Boyle and Ms. Margaret Good, Department of Agriculture Food and Rural Development for their contribution to the organisation of this study. We also thank Dr Paddy Sleeman, University College Cork, who supervised the survey of badger setts and Mr. Kieran Towey, Veterinary Epidemiology and Tuberculosis Investigation Unit for data analysis. We also thank Mr.Arthur O'Grady and staff at Cork District Veterinary Office and staff at Cork Regional Veterinary Laboratory. We also thank staff at the CVRL, Abbotstown for culture of samples. References Costello, E., O'Grady, D., Flynn, 0., O'Brien, R., Rogers, M., Quigley, F., Egan,]. and Griffin,]. (1999). Study of restriction fragment length polymorphism analysis and spoligotyping for epidemiological investigation of Mycobacterium bovis infection. Journal ef Clinical Microbiology 3 7: 3,217- 3,222. Dolan, L.A. & Lynch, K. (1992). Badgers and Bovine Tuberculosis. Tuberculosis Investigation Unit, University College Dublin, Selected Papers 1990-1991. 31-34. O'Brien, R., Danilowicz, B.S., Bailey, L., Flynn, 0., Costello, E., O'Grady, D. and Rogers, M. (2000). Characterisation of the Mycobacterium bovis restriction fragment length polymorphism DNA probe pUCD and performance comparison with standard methods.Journal ef Clinical Microbiology 38: 3,362-3,369. ERADITEAGASC 28 Veterinary Epidemiology & Tuberculosis lnvest1gat1on Unit UCO Figure 1. Spatial distribution of prevalent RFLP types in M. bovis isolates from badgers in the Cork Study Area. Each coloured square shows the location of setts at which badgers, infected with an M. bovis strain of the RFLP type represented by the colour shown, were captured . RFLP types D Cl HI 1 • AI AJA Ill A2Al B D A2A2B IJ AIAIA • A2Ll D • B2A3Y 0 Al E3 A • Cl H7 J •. ' . . . . : Ill r-T"l~ ~ P.. ~· ~ • . 7 b t....1-1.. • • .. ·'~ 4• : .. tJ 0 . J:l. .· . , ' . 0- Ll ,.. . ...... ..,.. ··O-· • .. \ . 1 o• •• I W • ~ • • r-.. 0 • • • • • • n Si"'l. • • • a .. · ...... I • • 1-J au' 0 .. • Jj" • • .,. ' I ·~- . . . ·. • .. -· .. - :. . .,, ~ • . . •Ll .. • • • • # .. •: ..!'.!'. ' .. •• .. I' , ,,1 .: 13. • · ..• -.,, : , •. '-• ·· .: ... l]l ·m: • · ·.~ ; • _; ·. ' · II· . --r ~ .. ll. . '· -Q ' . • ... . - . • 1f • \ •\ '" • "• • • .. ~ • ··~-~· • • I"• •., • a ,~ I • ~ -· •.,• • a ~· 911' • a • • • Ill• • .-- • • • ... • •• • ._,. •. ,,..,• r__. . • ,• , • "' • • • ;'_.,,., •-' • • I • I.!) (. •• '1' . . . - -, .. tJ . .. . . . ,, . . .. .. • • ..... • • .,.~ . : -. ·' • _.I . . u • .,, . ~· • . .• . v • • ,..1 • • I • • • • '1 .. , ' ·. . • II : . I .. J ' ... MO . • • . . .... ~ .. . .. ·• ,_ .  • II ·' .. ..... . .. .....  . .... . 5 kilometres Figure 2. Spatial distribution of RFLP types in M. bovis isolates from cattle and badgers in southwest part of the Cork Study Area. The irregu lar coloured areas show the location of farms from which M. bovis isolates from cattle were the RFLP type represented by the colour shown. Similarly, the coloured squares show the location of setts at which badgers, infected with an M. bovis strain of the RFLP type represented by the colour shown, were captured. RFLP types 0 CJHIJ • AI A3A O AIAIA • CIH7 l • B2 A3Y · 1 kilometre ERADITEAGASC 29 Veterinary Epidemiology & Tuberculosis Investigation Unit, UCO Figure 3. Spatial distribution of RFLP types in M. bovis isolates from cattle and badgers in the northeast part of the Cork Study Area. The irregular coloured areas show the location of farms from which M. bovis isolates from cattle were the RFLP type represented by the colour shown. Similarly, the coloured squares show the location of setts at which badgers, infected with an M. bovis strain of the RFLP type represented by the colour shown, were captu red. RFLP types D C l HI I • AIA3A D A2A! B D A2A2B a AIAIA • BI CIC 1 ki lometre ERADITEAGASC 30 Veterinary Epidemiology & Tuberculosis lnvesvgovon Unit UCO 

Spatial distribution of RFLP types identified in Mycobacterium bovis isolates from badgers and cattle in a study area in the Republic of Ireland

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