Role of Sequencing the Measles Virus Hemagglutinin Gene and Hypervariable Region in the Measles Outbreak Investigations in Sweden During 2013-2014.
BACKGROUND
It is increasingly difficult to differentiate measles viruses (MeVs) relating to certain outbreaks on the basis of the nucleoprotein (N) gene sequence only, as the diversity of circulating MeV strains has decreased. We studied genomic regions that could provide better molecular discrimination between epidemiologically linked and unlinked MeV variants identified in Sweden during 2013-2014.


METHODS
The hemagglutinin (H) gene and hypervariable region between the fusion and matrix genes (MF-HVR) from 53 MeV-positive samples were amplified and sequenced. Data on phylogenetic clustering of MeVs on the basis of N, H, and MF-HVR sequences were compared to epidemiological data.


RESULTS
MeVs were genotyped: 27 were B3, and 26 were D8. One genotype B3 cluster based on the N gene sequence contained epidemiologically unrelated viruses from 4 outbreaks, whereas analysis of H and MF-HVR sequences separated them into phylogenetic clusters consistent with the epidemiological data. Similarly, the single cluster of viruses with a genotype D8 N gene could be divided into the 5 outbreak groups on the basis of the phylogeny of MF-HVR sequences.


CONCLUSIONS
A detailed picture of MeV circulation with more-defined links between outbreaks was obtained by sequencing the H gene and MF-HVR. Further identification and better genetic characterization of MeVs internationally is essential in identifying sources and routes of MeV spread within and beyond Europe in the elimination end game.
Public Health Agency of Sweden, Solna European Programme for Public Health Microbiology Training, European Centre for Disease Prevention and Control, Stockholm, Sweden.
Heli
H
Harvala
Public Health Agency of Sweden, Solna.
Åsa
Å
Wiman
Public Health Agency of Sweden, Solna.
Anders
A
Wallensten
Public Health Agency of Sweden, Solna.
Katherina
K
Zakikhany
Public Health Agency of Sweden, Solna.
Hélène
H
Englund
Public Health Agency of Sweden, Solna.
Maria
M
Brytting
D002648:Child; D016000:Cluster Analysis; D004196:Disease Outbreaks; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006389:Hemagglutinins, Viral / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D008457:Measles / Q000453:epidemiology* / Q000821:virology*; D008459:Measles virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008875:Middle Aged; D017720:Molecular Epidemiology; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000235:genetics; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013548:Sweden / Q000453:epidemiology; D014760:Viral Fusion Proteins / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics
D006389:Hemagglutinins, Viral; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D014760:Viral Fusion Proteins; D014764:Viral Proteins; C032397:hemagglutinin protein G, measles virus; C058314:nucleoprotein, Measles virus
elimination; hemagglutinin; hypervariable region; measles; phylogeny