SORVEGLIANZA DEL MORBILLO ED APPROCCI INNOVATIVI DI FILOGENETICA NELL'AMBITO DEL GLOBAL MEASLES STRATEGIC PLAN 2012-2020

1. Introduction
Measles and rubella are infectious diseases and humans are the only reservoir of these infections. effective vaccines are available with the potential for measles (MV) and rubella (RuV) virus eradication. according to the World health Organisation guidelines, a national plan was approved in Italy in 2013 to achieve the MV/RuV elimination by 2015, and active MV/RuV integrated surveillance initiated. Towards this purpose, a regional laboratory centre was set up on July 2013 in Lombardy, Northern Italy.
2. The aim
The aim of this paper is to describe the epidemiological and virological trends of measles virus in Lombardy in the biennium 2013-2014. And to describe the genotype circulation in Lombardy.
3. Materials and methods
Urine and saliva samples were collected between July 2013 and November 2014, in order to find the origins and routes of wild type measles virus circulation. Real-time RT-PCR was performed for the identification of nucleic acids of measles virus and the virus rubella of patients from Lombardy region. To assess the genetic variability and molecular evolution of morbillivirus circulating in Lombardia all positive samples were subjected to nested PCR for the amplification of a fragment of the gene N. The sequences were genotyped by comparing the fragment coding for the carboxyl terminus of the nucleoprotein (450 nucleotides) with that one of the WHO reference strains.
4. Results
From July 2013 to November 2014 in Lombardy were reported 528 measles cases (possible, probable and confirmed) in Lombardy. The majority of cases (359 cases, 68%) occurred in the age group 15-39 year old.
As a regional referral center for surveillance integrated measles-rubella, by July 2013 to September 2014, we were collected 115 suspected cases of MV/RuV for virological analysis. Laboratory analysis of samples collected from these 115 suspected cases revealed that 54.8% (63/115) were MV-positive by RT-PCR. Most 60.3% (38/63) MV-positive cases were unvaccinated. Highest number of confirmed cases (76.2%; 48/63) was observed in the age group between 15 and 39, followed by the age group 40-64 years, 12.7% (8/63).
The analysis of the viral genotype was completed successfully for 53 of the 63 confirmed cases. From the year 2012 to the year 2013 phylogenetic analysis of measles sequences showed a predominant circulation of the D8 genotype. During the same period B3 and D9 genotypes were also detected.
5. Conclusions
Genetic characterization of wild-type MV provides a means to study the transmission pathways of the virus, and is an essential component of laboratory-based surveillance. Knowledge of currently circulating measles virus genotype in Lombardy will help in monitoring the success of the measles elimination programme and will contribute to evaluate the effectiveness of future vaccination campaigns.