Investigating Transmission of Mycobacterium bovis in the United Kingdom in 2005 to 2008

Abstract

Due to an increase in bovine tuberculosis in cattle in the United Kingdom, we investigated the characteristics of Mycobacterium bovis infection in humans and assessed whether extensive transmission of M. bovis between humans has occurred. A cross-sectional study linking demographic, clinical, and DNA fingerprinting (using 15-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat [MIRU-VNTR] typing) data on cases reported between 2005 and 2008 was undertaken. A total of 129 cases of M. bovis infection in humans were reported over the period, with a decrease in annual incidence from 0.065 to 0.047 cases per 100,000 persons. Most patients were born pre-1960, before widespread pasteurization was introduced (73%), were of white ethnicity (83%), and were born in the United Kingdom (76%). A total of 102 patients (79%) had MIRU-VNTR typing data. A total of 31 of 69 complete MIRU-VNTR profiles formed eight distinct clusters. The overall clustering proportion determined using the n ؊ 1 method was 33%. The largest cluster, comprising 12 cases, was indistinguishable from a previously reported West Midlands outbreak strain cluster and included those cases. This cluster was heterogeneous, having characteristics supporting recent zoonotic and humanto-human transmission as well as reactivation of latent disease. Seven other, smaller clusters identified had demographics supporting recrudescence rather than recent infection. A total of 33 patients had incomplete MIRU-VNTR profiles, of which 11 may have yielded 2 to 6 further small clusters if typed to completion. The incidence of M. bovis in humans in the United Kingdom remains low, and the epidemiology is predominantly that of reactivated disease.

Epidemiology of Mycobacterium bovis Disease in Humans in England, Wales, and Northern Ireland, 2002–2014

“…We identified, unlike previous studies ( 4 , 5 ), that although the number of M. bovis patients not born in the United Kingdom remained low and fluctuated over time, the annual number of cases in this group increased slightly over time. Our finding may be confounded by better recording of place of birth but is not unexpected given the increase during this period in the overall number of TB patients not born in the United Kingdom ( 13 ).…”

“…Our finding may be confounded by better recording of place of birth but is not unexpected given the increase during this period in the overall number of TB patients not born in the United Kingdom ( 13 ). Similar to previous findings ( 5 ), our findings indicate that most M. bovis patients not born in the United Kingdom lived in urban areas, specifically London. These patients originated mostly from low-income countries where TB incidence is high and therefore are at higher risk for human-to-human transmission and animal-to-human transmission because of limited detection of M. bovis in animals and less frequent milk pasteurization ( 24 ).…”

Disseminated tuberculosis caused by Mycobacterium bovis presenting as a tongue base mass

“…Zoonotic tuberculosis, which is caused by the bacteria Mycobacterium bovis is typically passed on by consumption of unpasteurised dairy products, but also by blood contact or droplet transmission. It predominately causes tuberculosis in cattle and is the causative organism in <0.5% of culture-confirmed tuberculosis in the UK 3. It manifests almost identically to M. tuberculosis infection, and although pulmonary tuberculosis remains the most common presentation, extrapulmonary disease is more frequent, particularly involvement of the gastrointestinal system 4.…”

Lessons learnt in Europe on tuberculosis surveillance, outbreaks and BCG vaccination in 2011

“…Two studies reported on M. bovis [19,20]. In the UK and the Netherlands the number of M. bovis cases is low compared to the number of M. tuberculosis cases.…”

“…The studies reporting surveillance data are summarised in table 2 [11][12][13][14][15][16][17][18][19][20][21][22].…”