Summary1. The European badger (Meles meles) is implicated as a reservoir of Mycobacterium bovis (bovine TB) infection for cattle in Britain and Ireland. In the present study the spatio-temporal distribution of M. bovis infection was investigated. Analyses were carried out on data from a long-term epidemiological and ecological study of the dynamics of bovine TB in a wild population of badgers at Woodchester Park in south-west England. 2. During the 15 years of the capture±mark±recapture study (1982±96), 3316 trapping and post-mortem records were obtained from 1270 individual badgers. Annual prevalence of infection based on positive serological and bacterial tests varies between 10Á3% and 17Á7% of the population. 3. Infection was aggregated in social groups in the west of the study area, con®rm-ing the ®ndings of previous studies. However, temporal trends in disease were not synchronized amongst neighbouring groups, suggesting low rates of disease transfer between them. 4. There was signi®cant serial correlation in the disease status within groups over time, suggesting that infection persists for many years in some social groups. The presence of infectious adult female badgers in groups was associated with new infections, and provides further evidence for their importance in the maintenance of infection within groups. However, no statistically signi®cant correlations were detected between the demographic characteristics of social groups and group infection status. 5. The distribution of disease re¯ects stable persistent foci of infection in the badger population, with limited evidence of transfer between social groups. The accurate identi®cation of stable foci of infection would allow a range of management strategies for the control of bovine TB to be eciently targeted in such populations. However, the extent to which this pattern of infection is representative of low-density and disturbed badger populations is unknown.

The movement of 1763 badgers trapped between 36 social groups in Woodchester Park, Gloucestershire, over 18 years was analysed to determine the frequency and duration of moves, the factors associated with a predisposition to move and the spatial pattern of movements. Of those badgers whose capture history could be categorized, nearly half had moved. Of these, 73.1% were classi¢ed as`occasional movers', 22.1% as`permanent movers' and 4.8% as`frequent movers'. Most adult badgers that moved made occasional moves (78.8%, n 67). Cubs made all types of move including permanent moves (29%, n 10). Seventy per cent of females were non-movers compared with 37% of males. Badgers were signi¢cantly more likely to move to smaller groups, whereas male badgers were signi¢cantly more likely to move to groups with a greater proportion of females. The spatial pattern of movement di¡ered from the distribution of groups with bovine tuberculosis in the study area. However, temporal changes in movement were signi¢cantly related to the incidence of Mycobacterium bovis infection in the following year, indicating that as the movement of badgers between groups varies so does the incidence of bovine tuberculosis in the population. This ¢nding is of central importance in the formulation of badger control policy.

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The Eurasian badger (Meles meles) is implicated in the transmission of bovine tuberculosis (TB) to cattle in the UK and Republic of Ireland. Badger culling has been employed for the control of TB in cattle in both countries, with varying results. Social perturbation of badger populations following culling has been proposed as an explanation for the failure of culling to consistently demonstrate significant reductions in cattle TB. Field studies indicate that culling badgers may result in increased immigration into culled areas, disruption of territoriality, increased ranging and mixing between social groups. Our analysis shows that some measures of sociality may remain significantly disrupted for up to 8 years after culling. This may have epidemiological consequences because previous research has shown that even in a relatively undisturbed badger population, movements between groups are associated with increases in the incidence of Mycobacterium bovis infection. This is consistent with the results from a large-scale field trial, which demonstrated decreased benefits of culling at the edges of culled areas, and an increase in herd breakdown rates in neighbouring cattle.

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Control of bovine tuberculosis (TB) in cattle has proven particularly challenging where reservoirs of infection exist in wildlife populations. In Britain and Ireland, control is hampered by a reservoir of infection in Eurasian badgers (Meles meles). Badger culling has positive and negative effects on bovine TB in cattle and is difficult, costly and controversial. Here we show that Bacillus Calmette-Guérin (BCG) vaccination of captive badgers reduced the progression, severity and excretion of Mycobacterium bovis infection after experimental challenge. In a clinical field study, BCG vaccination of free-living badgers reduced the incidence of positive serological test results by 73.8 per cent. In common with other species, BCG did not appear to prevent infection of badgers subjected to experimental challenge, but did significantly reduce the overall disease burden. BCG vaccination of badgers could comprise an important component of a comprehensive programme of measures to control bovine TB in cattle.

We describe epidemiological trends in Mycobacterium bovis infection in an undisturbed wild badger (Meles meles) population. Data were derived from the capture, clinical sampling and serological testing of 1803 badgers over 9945 capture events spanning 24 years. Incidence and prevalence increased over time, exhibiting no simple relationship with host density. Potential explanations are presented for a marked increase in the frequency of positive serological test results. Transmission rates (R0) estimated from empirical data were consistent with modelled estimates and robust to changes in test sensitivity and the spatial extent of the population at risk. The risk of a positive culture or serological test result increased with badger age, and varied seasonally. Evidence consistent with progressive disease was found in cubs. This study demonstrates the value of long-term data and the repeated application of imperfect diagnostic tests as indices of infection to reveal epidemiological trends in M. bovis infection in badgers.