Dominant Mycobacterium tuberculosis Lineages in Elderly Patients Born in Norway

Background: During the previous century Norway had a high incidence of tuberculosis, but no molecular epidemiological studies could be performed and these previously epidemic strains have been disappearing during the last decades. Currently, tuberculosis among native Norwegians is in the elimination phase, and it is still not known what type of M. tuberculosis was so efficiently controlled during the second half of the 20th century. However, many elderly Norwegian-born people still develop TB that cannot be clustered to imported or recently transmitted strains of M. tuberculosis. Thus, the majority of these cases are results of reactivation of disease that was transmitted many decades ago. Methodology/Principal Findings: A total of 213 strains of M. tuberculosis isolated during 1998–2005, from patients born in Norway before 1950 were genotyped in the current study. The findings demonstrated a highly homogenous M. tuberculosis population among the patients. A total of 40 % belonged to the T-family, were 35 % were assigned to T1 sub- family (T2 = 0, 93%, T3 = 1, 4 % and T4 = 2, 3%). As many as 35 % of the isolates belonged to the Haarlem family, were 15 % were assigned to Haarlem1 and 19 % to Haarlem3. The remaining 25 % belonged to 15 different other families. The RFLP-patterns indicated that the isolates were not a result of recent transmission, but rather represented well established strains that apparently dominated in Norway many decades ago. Conclusions/Significance: The T 1, Haarlem 1, and Haarlem 3 families of M. tuberculosis were abundant among patient

Genetic diversity of Mycobacterium tuberculosis Complex in Jos, Nigeria

<p>Abstract</p> <p>Background</p> <p>Nigeria has a high tuberculosis incidence, and genotyping studies of <it>Mycobacterium tuberculosis </it>Complex (MTC) in the country are necessary in order to improve our understanding of the epidemic.</p> <p>Methods</p> <p>Isolates of MTC were isolated from cases of pulmonary tuberculosis in Jos, North Central region of Nigeria during 2006-2008. Drug susceptibility test (DST) was performed on 77 of 111 isolates by proportion method on Lowenstein Jensen (LJ) slope while genotyping of mycobacterial DNA was performed by spoligotyping. The SpolDB4 database and the model-based program 'spotclust' were used to assign isolates to families, subfamilies and variants.</p> <p>Results</p> <p>A total of 111 pulmonary isolates from consecutive tuberculosis patients in the city of Jos, Plateau State, Nigeria were spoligotyped. A total of 84 (76%) of the isolates belonged to the Latin American Mediterranean (LAM) family. Of these, 78 isolates were assigned to the LAM10 lineage. Among these, 66 exhibited identical spoligopatterns. Drug susceptibility profiles obtained were not consistently associated with any spoligopattern.</p> <p>Conclusions</p> <p>The dominance of few <it>M. tuberculosis </it>lineages suggests either a high rate of transmission, frequent import of closely related strains, or a highly conserved genotype. It remains to be confirmed whether the predominance of identical LAM10 represent an outbreak.</p> <p>Spoligotyping was useful to gain an overall understanding of the local TB epidemic. This study demonstrated that the incidence of TB in Jos, Nigeria may be caused by a few successful <it>M. tuberculosis </it>families, dominated by the LAM10 family.</p

Evolution of Bordetella pertussis in the acellular vaccine era in Norway, 1996 to 2019

publishedVersio

Tracing the evolutionary history of the Atlas flycatcher (Ficedula speculigera) : a molecular genetic approach

Abstract The Atlas flycatcher (Ficedula speculigera) is a poorly studied species in an otherwise thoroughly studied species complex. In this study I attempt to reconstruct the evolutionary history of this species, I look for possible traces of introgression, I test whether there is contrasting patterns of polymorphism and divergence at autosomal and Z-linked genes as has been found in other flycatcher species, and finally whether the Atlas flycatcher show reduced genetic variation which would be expected due to recent habitat fragmentation. To address these problems I used multilocus sequence analysis, with loci from both autosomes and Z-chromosomes, and compared these with previously published sequences from two other species, the pied flycatcher (F. hypoleuca) and the collared flycatcher (F. albicollis). Finally, phenotypic measures of the Atlas flycatcher were compared with measures of these other two species. The results appear consistent with a scenario in which an ancestral flycatcher species became isolated in different refugia, presumably around the Mediterranean Sea, at the onset of the Pleistocene glaciations and diverged into the present species. I found no traces of introgression between the Atlas flycatcher and any of the two other species. Further, the Atlas flycatcher showed reduced variation at Z-linked loci compared to autosomal loci, which may indicate a complex demographic history or possibly selection. The Atlas flycatcher also showed high variation compared to the other two species, and therefore seems to have a rather large effective population size

Incidence of tuberculosis and distribution of birth-year of patients from where the current <i>M. tuberculosis</i> strains originated.

<p>The incidence of pulmonary tuberculosis in Norway 1910–1990 (dotted line) is presented in a logarithmic scale (left axis). The distribution of year of birth of the patients from whom the current <i>M. tuberculosis</i> population had been isolated during 1998–2008 (solid line) is given in percent (right axis).</p

<i>M. tuberculosis</i> families identified in cases of reactivated disease among patients born in Norway before 1950.

<p><i>M. tuberculosis</i> families identified in cases of reactivated disease among patients born in Norway before 1950.</p

Diversity and RFLP patterns observed among <i>M. tuberculosis</i> strains, sex, and year of birth of patients from whom these were isolated.

<p>Genetic diversity and IS<i>6110</i>- RFLP patterns of the isolates assigned to the Haarlem- family from patients born in Norway 1910–1950.</p

Diversity and RFLP patterns observed among <i>M. tuberculosis</i> strains, sex, and year of birth of patients from whom these were isolated.

<p>Genetic diversity and IS<i>6110</i>- RFLP patterns of the isolates assigned to the T- family from patients born in Norway 1910-1950.</p