Arch Hellen Med, 26(1), January-February 2009, 90-97
Laboratory investigation of a measles outbreak in Greece, 2005–2006
M. LOGOTHETI,1 S. KOKOTAS,1 E. HOREFTI,1 M. GIANNAKI,2 A. PAGALI,2 V. POGA,1 K. PAPADAKOS,1
OBJECTIVES (a) Laboratory confirmation of cases suspicious for measles during the 2005–2006 measles outbreak in Greece, (b) comparative evaluation of conventional and molecular methods for measles diagnosis, and (c) molecular characterization of measles virus (MV) strains.
METHOD A total of 421 clinical specimens, specifically peripheral blood mononuclear cells (PBMCs), respiratory exudate, urine and serum derived from 222 suspected measles cases were received between December 2005 and July 2006. The majority of the specimens were collected from Roma children and young adults and children of the general population in southern Greece. Measles cases were confirmed by MV-specific IgM antibodies determination by ELISA and immunofluorescense (IF) assays. Serology was considered as the “gold standard” for the evaluation of an in house real time RT-PCR for the MV RNA detection. Measles virus genotyping was carried out by partial sequencing and phylogenetic analysis of the MV nucleoprotein gene.
RESULTS MV specific IgM antibodies were detected in 84.5% of patients. IF and ELISA were equally sensitive in the detection of specific IgM antibodies. MV RNA was detected in 87.9% of the 272 samples tested by real time PCR, with a higher detection rate observed in urine (93.3%), and respiratory samples (92.4%). Phylogenetic analysis revealed the circulation of MV D6 genotype in the wider region of Greece during the outbreak, while the D4 genotype was detected only after March 2006, exclusively in specimens from southern Greece.
CONCLUSIONS An outbreak of measles took place in Greece during the period of 2005–2006, with a considerable number of laboratory confirmed cases. Molecular methods are a useful alternative to serology for measles confirmation in the early stages of measles, when serological tests are negative. Molecular genotyping revealed the co-circulation of two distinct MV genotypes at the end of the outbreak.
Key words: Genotype, Greece, Measles, Outbreak, Real time PCR.