Migrants are not responsible for the increasing incidence of tuberculosis (TB) in the UK, according to research presented to the April meeting of the Society of General Microbiology. This finding stands in stark contrast to sensationalist media reporting which has blamed a recent increase in the incidence of TB in the UK on asylum seekers, particularly those infected with HIV.
Investigators from the University of Surrey fingerprinted the DNA of the different strains of TB in the UK. They found that the DNA of TB-infected individuals born in the UK was “markedly different from that in patients born overseas”. Samples were obtained in London between 1995 and 1997, the period during which TB diagnoses in both UK-born residents and migrants to the UK began to increase markedly.
Infection patterns in UK-born TB patients suggest that many cases are due to reactivation of a previous TB infection which had been controlled by the immune system.
The DNA fingerprints of the TB seen in patients born abroad were characteristic of the strains of TB seen in their country of origin. This confirmed to the investigators that there was little spread of TB from migrant communities to the resident UK population.
The Surrey investigators are also trying to establish how TB travels long distances. A group of very closely related tuberculosis bacteria, called the Beijing family, was found to be dominant amongst the identifiable strains the investigators looked at. This strain of TB was first found in China, and is now the major strain of the disease in parts of Asia and has been responsible for many of the outbreaks of multidrug-resistant TB seen recently.
Further information on this website
Tuberculosis - overview
Tuberculosis - factsheet
HIV infection changes the genes that affect development of tuberculosis - news story
TB doesn't cause faster disease progression in European AIDS patients - news story