Aseptic meningitis outbreak caused by echovirus 30 in two regions in Bulgaria, May-August 2012.

An aseptic meningitis outbreak emerged in two regions in Bulgaria in 2012 and echovirus 30 (E30) was established as the aetiological agent by cell culture isolation, serological test, and molecular-based techniques. A total of 157 patients with aseptic meningitis were investigated, of which 117 were confirmed as having E30-associated disease. Molecular analysis of 12 E30 isolates revealed 99-100% nucleotide and amino-acid identity between them and a close correlation with a Greek strain involved in an E30 outbreak in 2012. Children aged 5-14 years were mainly affected, which could reflect the absence of E30 epidemics in Bulgaria for a period of 11 years. The first case with E30 isolation (a 2-year-old patient from Plovdiv) was notified at the end of April 2012. This was most likely the index case, from which the spread of the virus started, causing sporadic cases first, which later led to an aseptic meningitis outbreak facilitated by person-to-person viral transmission.

Rotavirus genotypes co-circulating in Europe between 2006 and 2009 as determined by EuroRotaNet, a pan-European collaborative strain surveillance network.

EuroRotaNet, a laboratory network, was established in order to determine the diversity of co-circulating rotavirus strains in Europe over three or more rotavirus seasons from 2006/2007 and currently includes 16 countries. This report highlights the tremendous diversity of rotavirus strains co-circulating in the European population during three years of surveillance since 2006/2007 and points to the possible origins of these strains including genetic reassortment and interspecies transmission. Furthermore, the ability of the network to identify strains circulating with an incidence of ≥1% allowed the identification of possible emerging strains such as G8 and G12 since the beginning of the study; analysis of recent data indicates their increased incidence. The introduction of universal rotavirus vaccination in at least two of the participating countries, and partial vaccine coverage in some others may provide data on diversity driven by vaccine introduction and possible strain replacement in Europe.

Molecular epidemiology of rotaviruses in Bulgaria: annual shift of the predominant genotype.

Rotavirus molecular epidemiology investigations provide important information about the incidence of rotavirus diseases and rotavirus strains in circulation in the prevaccine era. The purpose of this investigation was to study the burden of rotavirus disease, rotavirus strain diversity, and epidemiology specificities of rotavirus infections in Bulgaria. A total of 3,130 stools collected between 2005 and 2008 were tested by immune enzyme tests. G-P genotype identification of rotavirus strains were performed by reverse transcriptase polymerase chain reaction (RT-PCR). Rotavirus etiology was confirmed in 32.4% of the samples tested. Rotaviruses affected predominantly children under 5 years of age (95.5%), with a peak prevalence between the ages of 7 and 36 months. Four of the five globally distributed rotavirus strains (G1P[8], G2P[4], G4P[8], and G9P[8]) constituted 97.7% of all rotavirus strains in circulation. However, annual shifts of predominant rotavirus G-P genotypes were observed from season to season-G4P[8] was predominant in rotavirus season 2004/2005 (56.8%), but was replaced by G9P[8] in 2005/2006 (77.7%), and G2P[4] (41.6%) and G1P[8] (39.5%) in the following two consecutive rotavirus seasons. Year-round circulation of rotaviruses in the country with increased incidence in the winter-spring season and unexpected peaks preceding the rotavirus seasons were observed. Molecular epidemiology data are needed in Bulgaria for health policy makers in order to introduce routine rotavirus vaccination. The monitoring of rotavirus genetic diversity in Bulgaria in the postvaccination period will contribute to a successful rotavirus vaccination program.

Rotavirus surveillance in europe, 2005-2008: web-enabled reporting and real-time analysis of genotyping and epidemiological data.

BACKGROUND: The first European rotavirus surveillance network, EuroRotaNet, comprising 16 laboratories in 15 European countries, has been established. METHODS: Fecal samples from gastroenteritis cases positive for group A rotavirus antigen were collected from multiple European countries from 2005 to mid-2008 and were subjected to G and P genotyping. Epidemiological data collected included age, sex, geographical location, setting, dates of onset and sample collection, and clinical symptoms. RESULTS: A total of 8879 rotavirus-positive samples were characterized: 2129 cases were from the 2005-2006 season, 4030 from the 2006-2007 season, and 2720 from the ongoing 2007-2008 season. A total of 30 different G and P type combinations of strains circulated in the region from 2005 through 2008. Of these strains, 90% had genotypes commonly associated with human infections-G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8]-and 1.37% represented potential zoonotic introductions. G1P[8] remained the most prevalent genotype in Europe as a whole, but the incidence of infection with G1P[8] rotavirus strains was <50% overall, and all 3 seasons were characterized by a significant diversity of cocirculating strains. The peak incidence of rotavirus infection occurred from January through May, and 81% of case patients were aged <2.5 years. Conclusions. Data gathered through EuroRotaNet will provide valuable background information on the rotavirus strain diversity in Europe before the introduction of rotavirus vaccines, and the network will provide a robust method for surveillance during vaccine implementation.