Prevalence of human tuberculosis in a Medieval population of Lithuania studied by ancient DNA analysis
ENIn ancient Europe, tuberculosis was one of the most widely prevalent infectious diseases. Incidence of bone pathology in skeletal remains from medieval Lithuania suggests that 18-25% of the population suffered from the disease. We have detected the presence of Mycobacterium tuberculosis in skeletal remains from Lithuania, dated to the 15th-17th centuries, by amplifying a part of a repetitive insertion element-like sequence (IS 6110). DNA of the bacillus has been identified both in pathological and normal tissues (bones and even teeth) of the same individuals, proving hematogenous spread of bacilli. Moreover, the precence of M. tuberculosis DNA has also been demonstrated in skeletal remains of individuals without specific lesions. The results indicate that a much higher percentage of individuals were infected than previously thought. We have found that soil contamination was not responsible for the surprisingly high incidence of positive results, as soil separated from the skeletal remains and soft tissues was negative. Our findings open the possibility of examining the actual prevalence of tuberculosis in ancient populations from collections in which individuals are represented by single bones or teeth. Keywords: ancient DNA, bone tuberculosis, Lithuania, PCR.
