Recombination of Globally Circulating Varicella-Zoster Virus.

UNLABELLED: Varicella-zoster virus (VZV) is a human herpesvirus, which during primary infection typically causes varicella (chicken pox) and establishes lifelong latency in sensory and autonomic ganglia. Later in life, the virus may reactivate to cause herpes zoster (HZ; also known as shingles). To prevent these diseases, a live-attenuated heterogeneous vaccine preparation, vOka, is used routinely in many countries worldwide. Recent studies of another alphaherpes virus, infectious laryngotracheitis virus, demonstrate that live-attenuated vaccine strains can recombine in vivo, creating virulent progeny. These findings raised concerns about using attenuated herpesvirus vaccines under conditions that favor recombination. To investigate whether VZV may undergo recombination, which is a prerequisite for VZV vaccination to create such conditions, we here analyzed 115 complete VZV genomes. Our results demonstrate that recombination occurs frequently for VZV. It thus seems that VZV is fully capable of recombination if given the opportunity, which may have important implications for continued VZV vaccination. Although no interclade vaccine wild-type recombinant strains were found, intraclade recombinants were frequently detected in clade 2, which harbors the vaccine strains, suggesting that the vaccine strains have already been involved in recombination events, either in vivo or in vitro during passages in cell culture. Finally, previous partial and complete genomic studies have described strains that do not cluster phylogenetically to any of the five established clades. The additional VZV strains sequenced here, in combination with those previously published, have enabled us to formally define a novel sixth VZV clade. IMPORTANCE: Although genetic recombination has been demonstrated to frequently occur for other human alphaherpesviruses, herpes simplex viruses 1 and 2, only a few ancient and isolated recent recombination events have hitherto been demonstrated for VZV. In the present study, we demonstrate that VZV also frequently undergoes genetic recombination, including strains belonging to the clade containing the vOKA strain.

Trends in the incidence of HIV in Scotland, 1988-2009.

OBJECTIVES: To estimate temporal trends in HIV incidence and prevalence in Scotland, according to three main risk groups for infection: men who have sex with men (MSM), injecting drug users (IDUs) and heterosexuals. METHODS: The authors extracted data for all single- and multiple-tested individuals from the national HIV test database covering the period 1980-2009 and calculated the incidence of HIV infection in each risk group and estimated RRs by fitting Poisson regression models. RESULTS: 620 of 59,807 individuals tested positive following an initial negative HIV test, generating an overall incidence rate of 3.7/1000 person-years (95% CI 3.4 to 4.0); 60%, 20% and 37% of the 620 were associated with the risk behaviour categories MSM, IDU and heterosexual, respectively. The incidence rate among MSM in Scotland remained relatively stable between the periods <1995 and 2005-2009 (overall: 15.3/1000 person-years, 95% CI 13.8 to 17.0), whereas the incidence among IDUs decreased between the periods <1995 and 2005-2009, from 5.1/1000 to 1.7/1000 person-years, and also decreased among heterosexuals, from 2.9/1000 to 1.4/1000 person-years. CONCLUSIONS: The reduction in the incidence rate among IDUs suggests that harm reduction measures initiated from the late 1980s were effective in reducing HIV transmission in this risk group; however, the absence of a reduction in HIV incidence rates among MSM is disappointing and highlights the need for renewed efforts in the prevention of HIV in this major risk group.

Comparison of mumps-IgM ELISAs in acute infection.

BACKGROUND: In Scotland there has been an outbreak of mumps with over 4000 confirmed cases in the last 2 years. As laboratory diagnosis is usually requested on patients with symptoms, a prompt diagnosis early in the illness is required. OBJECTIVES: To assess the performance of the five different commercial IgM-ELISAs used in Scottish Virus laboratories. STUDY DESIGN: The Specialist Virology Laboratory (SVC) Edinburgh distributed a serum panel to all Scottish laboratories that diagnose mumps by IgM-ELISA. The panel consisted of 45 sera from patients with confirmed mumps (date of onset known for 44/45) and 11 sera from patients with alternative diagnoses. Each laboratory performed their own commercial IgM-ELISAs blindly and reported results to the SVC Edinburgh. RESULTS: Sensitivity ranged from 24% to 51%. Assays performed better on samples taken later than 10 days after onset of symptoms. Specificity was about 82% for most assays. CONCLUSION: The sensitivity of commercial mumps IgM-ELISAs varied greatly. The Microimmune mumps-IgM ELISA had the best overall sensitivity in acute serum specimens. Diagnostic laboratories should be developing the means to perform direct detection of mumps virus for acute presentation and requesting convalescent bloods, if acute blood samples have no detectable IgM.

Rise in testing and diagnosis associated with Scotland's Action Plan on Hepatitis C and introduction of dried blood spot testing.

BACKGROUND: A key aim of the Hepatitis C Action Plan for Scotland was to reduce the undiagnosed population through awareness-raising activities, for general practitioners and those at risk, and the introduction of dried blood spot (DBS) sampling in community drug services to overcome barriers to testing. This study evaluates the impact of these activities on testing and diagnosis. METHODS: Data on hepatitis C virus (HCV) testing undertaken between January 1999 and December 2011 in Scotland's four largest health boards were analysed. Segmented regression analysis was used to examine changes in testing following the (1) launch of the Action Plan and (2) introduction of DBS testing. RESULTS: Between the pre-Action Plan and Action Plan periods, increases were observed in the average number of HCV tests (19 058-29 045), positive tests (1993-2405) and new diagnoses (1221-1367). Since July 2009, 26% of new diagnoses were made in drug services. The trend in the number of positive tests was raised during the Action Plan, compared to pre-Action Plan, particularly in drug services (rate ratio (RR)=1.4, p<0.001) and prisons (RR=1.2, p<0.001); no change was observed in general practice. Following introduction of DBS testing, there was a 3-fold increase in testing (RR=3.5, p<0.001) and 12-fold increase in positives (RR=12.1, p<0.001) in drug services. CONCLUSIONS: The introduction of DBS sampling in community drug services has made an appreciable contribution to efforts to diagnose the HCV-infected population in Scotland. These findings are important to other countries, with injecting-related HCV epidemics, needing to scale-up testing/case-finding initiatives.