Monday, March 27, 2017

ECDC: Rapid Risk Assessment On Multi-Country Cluster Of MDR-TB In Migrants


Whether it is a tourist returning from Carnival in Rio, a businessman traveling from the Arabian Peninsula to Asia, or a migrant making their way from North Africa into Europe - they all have one thing in common.

They all have the ability to be exposed to - and then inadvertently carry - exotic infectious diseases (like Zika, MERS, Dengue, Yellow Fever, Avian Flu, TB, etc.) from one part of the world to another.

Last December the ECDC reported on a cluster of MDR-TB among a group of 16 migrants who had recently entered the EU during the first six months of 2016 (see Multidrug-resistant tuberculosis in migrants, multi-country cluster, first update 19 Dec 2016).

An international whole genome sequencing cluster involving 16 cases of multidrug-resistant tuberculosis (MDR TB) in asylum seekers has been detected. The first seven cases were identified in Switzerland between February and August 2016. Their countries of origin are Somalia (5 cases), Eritrea (1) and Ethiopia (1). Whole genome sequencing (WGS) showed no difference among isolates in four cases and differences of one allele in the three others. Based on the WGS results, the strains belong to a single molecular cluster. The same genetic clone with the same and so far unknown drug resistance profile was detected in nine additional cases from Somalia, six of them diagnosed in Germany, two in Austria, and one in Sweden.
Fast forward a little more than 3 months and the ECDC has published an updated RRA, which has now identified 25 cases.  Follow the link to read the full 4-page report.

Conclusions and options for response 

A multi-country cluster of multidrug-resistant tuberculosis (MDR TB) involving 25 migrants has been delineated by whole genome sequencing (WGS). All cases have a recent history of migration from Somalia (22 cases), Eritrea (2 cases) and Ethiopia (1 case). Cases have been reported by Germany (13 cases), Switzerland (8 cases), Austria (2 cases), Finland and Sweden (1 case each). 

A WGS analysis of the 25 cluster isolates supports the hypothesis that the cases are part of a chain of recent transmission likely to have taken place either in the country of origin or in a place along the migration route to the country of destination. Based on the currently available information, it is not possible as of yet to rule out that transmission occurred in an EU/EFTA country. 

It therefore remains important to rapidly investigate exposure risk factors, including the travel history and itineraries of patients and their contacts, and share this information to determine whether transmission may have taken place in the EU/EFTA, during migration, or in the country of origin. Depending on the results of the investigation, appropriate prevention and control measures should be taken. 

Although the number of cases detected so far suggests that there is only a limited risk of this cluster becoming a widespread event in Europe, more cases may yet be identified in association with this cluster. Early case finding of active TB and drug susceptibility testing, especially in newly arriving migrants from the Horn of Africa, is important in order to identify and treat active cases and to provide preventive treatment or monitoring for those diagnosed with latent tuberculosis infection.

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