The importance of serological and molecular analyses for the diagnosis of measles cases and for meeting elimination targets in Turkey from 2007 to 2015.

Measles is an important childhood infection targeted to be eliminated by the World Health Organization (WHO). Virus circulation has not been interrupted in the European Region because high vaccination rates could not be achieved among some countries of the WHO European Region including Turkey. The purpose of this study was to evaluate the laboratory findings of measles cases confirmed in the last nine years, to assess the epidemiological data of the cases, to determine the molecular genotyping studies and to emphasise the importance of laboratory-based surveillance in measles. From 2007 to 2010, only 18 imported cases were detected in Turkey. However, this number increased with a local outbreak of 111 cases in 2011, followed by another outbreak in 2012 in Istanbul that spread countrywide in the following two years; a total of 8661 laboratory-confirmed measles cases were reported from 2012 to 2015. After ELISA detection of a measles IgM-positive result in serum samples of potential measles cases, RT-PCR was performed with urine or nasopharyngeal swab samples of patients, and amplicons were subjected to sequencing. In the samples of 2010 and 2011, D4 and D9 genotypes were mainly detected; as of 2012, the D8 genotype has gained importance. Although D8 was also identified in 2014, in the same year genotype H1 viruses were detected in Turkey for the first time. Therefore, it is important to perform a genotypic analysis of the virus causing the outbreak, analyse epidemiological connections of the contact, determine the source of the outbreak and plan measures based on this information.