Molecular Epidemiology of Tuberculosis in Finland, 2008-2011

Abstract

In industrialized countries the majority of tuberculosis (TB) cases are linked to immigration. In Finland, most cases are still Finnish born but the number of foreign born cases is steadily increasing. In this 4-year population based study, the TB situation in Finland was characterized by a genotypic analysis of Mycobacterium tuberculosis isolates. A total of 1048 M. tuberculosis isolates (representing 99.4% of all culture positive cases) were analyzed by spoligotyping and MIRU. Spoligotype lineages belonging to the Euro-American family were predominant among the Finnish isolates, particularly T (n=346, 33.0%) and Haarlem (n=237, 22.6%) strains. The lineage signature was unknown for 130 (12.4%) isolates. Out of the 17 multi-drug resistant TB strains, 10 (58.8%) belonged to the Beijing lineage. In total, 23 new SIT designations were given and 51 orphan strains were found, of which 58 patterns were unique to Finland. Phylogeographical TB mapping as compared to neighboring countries showed that the population structure in Finland most closely resembled that observed in Sweden. By combining spoligotyping and MIRU results, 98 clusters comprising 355 isolates (33.9%) were found. Only 10 clusters contained both Finnish and foreign born cases. In conclusion, a large proportion of the M. tuberculosis isolates were from Finnish born elderly patients. Moreover, many previously unidentified spoligotype profiles and isolates belonging to unknown lineages were encountered.

Trends and differences in tuberculosis incidences and clustering among natives in Denmark, Sweden and Finland: comparison of native incidences and molecular epidemiology among three low-incidence countries

“…In addition, we assume that clustering represents recent transmission. This assumption should be analysed with caution, as predominant strains in the populations may possibly represent well-preserved TB strains contracted in the past [16]. Cases today may represent reactivation of previous dominant TB strains rather than recent transmission, and could possibly explain some of the clustering in Finland.…”

Molecular Epidemiology of Tuberculosis in the Kaliningrad Region of Russia: 10 Years After

“…В целом штаммы генотипа Beijing преобладают в структуре российской популяции M. tuberculosis (в среднем около 50%) и в странах постсоветского пространства: Бе-ларусь -36,2%, Украина -31,6%, Эстония -39,2% [7,15,20,25,28]. Напротив, в других странах Европы распространенность штаммов Beijing относительно невелика: Финляндия -5,2%, Швеция -5,8%, Польша -6,5%, причем их источники иные и более разнообразные, включая, в частности, штаммы, занесенные из Восточной Азии [6,11,24]. Известно, что на Северо-Западе России в по-пуляции M. tuberculosis генотипа Beijing широко представлены штаммы кластера В0/W148, ра-нее определенного как успешный российский вариант микобактерий туберкулеза [14].…”

“…Распределе-ние штаммов LAM в Северо-Западном регионе России неоднородно. Так, если в Карелии и Ле-нинградской области их доля составляла 10,3% (что сопоставимо с Финляндией -7,3%), то в Псковской области превышала 20%, что близ-ко к показателю в Эстонии (17,8%) [1,3,18,24,25]. В Беларуси и Украине штаммы семейства LAM занимают второе место по распростра-ненности (около 23%) после Beijing и в структу-ре МЛУ штаммов (39,5 и 22,9% соответственно) [7,22,28].…”

“…Штаммы Ural (5,5%) были малочислен-ны, что сопоставимо с суммарными данными по СЗФО РФ и Финляндии [2,18,24]. В то же время в последние годы отмечен рост циркуля-ции ассоциированного с МЛУ субтипа семей-ства Ural в ряде стран Восточной Европы (Мол-дова, Литва) и на Северо-Западе России [2,15].…”

Genotypic characterization and historical perspective of Mycobacterium tuberculosis among older and younger Finns, 2008–2011

“…Monitoring changes in the demographic characteristics of tuberculosis (TB) cases is important to ensure that target interventions and control measures are appropriately focused. While some low-incidence countries are close to elimination of TB among the native population, patients born in Finland still account for >70% of all TB cases [1]. This is particularly contrary to countries like Sweden, Norway and the Netherlands where >70% of all TB cases are found among foreign-born individuals [2][3][4].…”