In a high incidence area of tuberculosis (TB), clinicians and nurses identified a sharp increase in the number of TB cases originating from a single country in March 2012 (average 3 per year in 2006–2008, 9 per year in 2009–2010, 20 cases in 2011 and 13 cases to March 2012). We undertook a social network approach to identify whether recent transmission had occurred.
56/66 (85%) cases from 2009 onwards were interviewed in their homes and perceptions of TB were explored. Median number of years in the UK was 4 years (IQR 2–5). Socialisation occured mainly in private homes and places of worship, with 44/56 (78%) attending 9 places of worship. Twenty-three cases could be epidemiologically linked to an index case who was a prominent community member who had been symptomatic for 10 months. 24 loci mycobacterial interspersed repetitive unit-variable number tandem repeats (MIRU-VNTRs) strain typing was available in 19/24 (79%). Twelve had identical strain type to the index case. Six cases unexpectedly clustered in 4 other strain types.
As a result of the cluster investigation the TB service were invited to talk at a religious service and two community members became crucial in raising awareness. An additional 77 contacts identified themselves for screening with 59 (77%) completing investigations. Sixteen latent TB cases were treated, 7 were given BCG vaccination and 13 are still undergoing assessment.
Cluster investigation builds relationships and trust to provide accessible TB services in diverse communities. This new migrant community now has a high awareness of TB and future delays in TB diagnosis can be avoided.