Prevalence of tick-borne encephalitis virus in Ixodes ricinus from a novel endemic area of North Eastern Italy.

In Alpine area of extreme North Eastern Italy the first autochthonous case of TBE was reported in 1998 and was followed by 45 cases during the period 2001-2007, thus defining this area as definitely endemic. An ecological survey evaluated the tick density and the Tick-borne encephalitis virus (TBEV) infection prevalence in tick collected in selected sites. In addition, TBE strains were characterized by sequencing and phylogenetic analysis. Overall, 2,361 ticks (2,198 nymphs and 163 adults) of the Ixodes ricinus L. species collected during 2005 and 2006 were examined. Five samples were positive for TBEV, corresponding to an overall prevalence rate of 0.21%. When analyzed by place, TBEV was discovered in three sites where the highest tick density was found. The difference of prevalence between high and low density areas tested to be statistically significant (P = 0.028). Phylogenetic analysis showed that four sequences clustered with the Neudoerfl prototype, while the other clustered with the Isosaari 17 strain and with a number of Slovenian isolates. In addition, a sequence detected in archival samples from one human case segregated with another variant, namely the Swedish Torö strain.

The molecular epidemiology of influenza viruses: a lesson from a highly epidemic season.

AIMS: To analyse the epidemiological and molecular features of a long-lasting epidemic (12 weeks) of influenza in north-eastern Italy during the 2004-05 season. METHODS: Morbidity rates were analysed by time and age. Influenza virus isolates (93 strains) were submitted to antigenic evaluation by haemagglutination inhibition test and to molecular assessment by sequencing. RESULTS: The incidence peak (16.4 per thousand) was the highest recorded over the last six years in north-eastern Italy. The epidemic was sustained by two subsequent waves of circulating viruses: an H3N2 variant and two type B variants, respectively. In addition, scattered isolation of an H1N1 variant occurred. Antigenic and molecular characterisation showed the emergence of an H3N2 virus drifted with respect to vaccine strain, which also had a substantial impact on morbidity in vaccinated subjects. Moreover, a single K145N substitution in the HA1 site of H3N2 was the starting point of two evolutionary branches. No change was observed in H1N1 isolates. B-type virus was mainly represented by Victoria-lineage strains, though Yamagata-lineage viruses were also identified. The fluctuating circulation of these two clades has characterised B virus epidemics in recent years. CONCLUSIONS: The assessment of the H3N2 molecular change in this area was in line with results used for establishing the vaccine composition for the incoming season. The particular epidemiological features of two B virus clades, namely Yamagata-like and Victoria-like, may be considered for introduction into the influenza vaccine.

[HHV-6, new perspectives]. / HHV-6: nuovi ruoli per un patogeno antico.

HHV-6 is the etiological agent of Exanthema subitum, and its role in human infection is well known. Recently, molecular diagnostics tools showed for HHV-6 new pathogenetic features and new clinical implication. The present paper highlights recent knowledge on HHV-6 infection and presents a number of results concerning HHV-6 infection in children who had undergone BMT and concerning the roles of endothelial cells as viral reservoir.

Three-year (1999-2002) of epidemiological and virological surveillance of influenza in north-east Italy.

The results of the epidemiological and virological surveillance of influenza performed during the 1999/2000, 2000/2001 and 2001/2002 seasons in the northeastern Italy were presented and the relationship between age-specific morbidity rates and circulating strains were discussed.The epidemiological findings pointed out a change in age distribution. During the 1999/2000 season, characterized by a circulation of viruses antigenically close to the vaccine strain, a similar incidence rate in the 0-14 and 15-64-year-old groups was observed, while during the 2001/ 2002 winter the virus infected mostly children. During 2001/2002 season, B type viruses predominated with at least three distinguishable molecular variants. In particular, B/Victoria/2/87-like viruses re-emerged after more than a decade, and the antibodies elicited by the vaccine strain and by the strains circulating in previous seasons were poor or not protecting. The accumulation of susceptible subjects in young age group during the 1990s, due to the lack of circulation of B/Victoria/2/87-like viruses, was responsible for the unusual morbidity in the 0-14 year group. No circulation of B/Victoria/2/87-like viruses was observed in > 64-year-old group during 2001/2002 epidemic, probably due to a long-lasting immunity against viruses belonging to this lineage.

Surveillance of cytomegalovirus infections in bone marrow transplant in Trieste: seven years' experience.

Forty-five consecutive patients submitted to a bone marrow transplant (BMT) were followed up weekly in order to evaluate the incidence of cytomegalovirus (CMV) infections on the basis of CMV antigenemia and polymerase chain reaction. All but one transplanted patients engrafted; fourteen patients out of these were CMV antigenemia positive after 16-184 days (median 32.5, mean 43.4) with an 31.8% incidence. CMV infections were associated with graft-versus-host disease and immunogenetic relationship between the donor and the recipient. No CMV infection was detectable in autologous transplants while antigenemia was demonstrated in 3/11 and 6/7 patients with BMT from respectively mismatched related and matched unrelated donors.