Vaccine-related mumps infections in Thailand and the identification of a novel mutation in the mumps fusion protein.

An outbreak of nine cases of mumps was reported from a total of 97 vaccinated nursing students at two medical colleges in Thailand in 2010, 16-26 days after administration of MMR vaccine containing the L-Zagreb mumps strain. Symptoms ranged in severity from fever and parotid swelling to orchitis. Clinical samples were obtained from seven patients and three were suitable for further study. Sequencing confirmed that the SH gene of the mumps virus in the unpassaged clinical specimens was identical to the L-Zagreb SH gene in the vaccine. Further analysis of the viral genome identified nucleotide position 5170 as a novel mutation which corresponds to an amino acid change in the fusion protein. This study provides another virologically confirmed example of mumps resulting from the L-Zagreb vaccine strain.

Genetic characterization of measles viruses that circulated in Thailand from 1998 to 2008.

During the period between 1998 and 2008, 48 representative measles viruses (MeVs) circulating in Thailand were subjected to genetic characterization. Three genotypes, G2, D5, and D9 were detected. The results suggested that measles genotype D5, which has been circulating since at least 1998, is the endemic genotype in Thailand. Genotype G2 was detected between 1998 and 2001. In addition, almost all of the MeVs detected throughout the country in 2008 were genotype D9. This is the first report of genotype D9 in Thailand. This report provides important baseline data about measles genotypes in Thailand and this information will be needed to help verify measles elimination in Thailand.

Global distribution of measles genotypes and measles molecular epidemiology.

A critical component of laboratory surveillance for measles is the genetic characterization of circulating wild-type viruses. The World Health Organization (WHO) Measles and Rubella Laboratory Network (LabNet), provides for standardized testing in 183 countries and supports genetic characterization of currently circulating strains of measles viruses. The goal of this report is to describe the lessons learned from nearly 20 years of virologic surveillance for measles, to describe the global databases for measles sequences, and to provide regional updates about measles genotypes detected by recent surveillance activities. Virologic surveillance for measles is now well established in all of the WHO regions, and most countries have conducted at least some baseline surveillance. The WHO Global Genotype Database contains >7000 genotype reports, and the Measles Nucleotide Surveillance (MeaNS) contains >4000 entries. This sequence information has proven to be extremely useful for tracking global transmission patterns and for documenting the interruption of transmission in some countries. The future challenges will be to develop quality control programs for molecular methods and to continue to expand virologic surveillance activities in all regions.

Status of global virologic surveillance for rubella viruses.

The suspected measles case definition captures rubella cases. Therefore, measles surveillance will be improved in the course of the control and eventual elimination of rubella transmission. One aspect of rubella control, virologic surveillance, is reviewed here. A systematic nomenclature for rubella viruses (RVs) based on 13 genotypes has been established and is updated when warranted by increases in information about RVs. From 2005 through 2010, the genotypes of RVs most frequently reported were 1E, 1G, and 2B, and genotypes 1a, 1B, 1C, 1h, 1j, and 2C were less frequently reported. Virologic surveillance can support rubella control and elimination. Synopses of rubella virologic surveillance in various countries, regions, and globally are given, including characterization of viruses from imported cases in a country that has eliminated rubella and studies of endemic viruses circulating in countries without rubella control objectives. Current challenges are discussed.

Establishment of real-time polymerase chain reaction-based assay for quantitation of Epstein-Barr virus DNA in healthy donors and in patients with EBV associated lymphoma.

Epstein-Barr virus (EBV) is associated with several malignancies including nasopharyngeal carcinoma and lymphoma in immunocompromised patients. Quantitative monitoring of EBV DNA in these patients has recently become essential for management of the disease. In the present study the authors developed a rapid and reliable real-time PCR to quantify the EBV DNA in peripheral blood mononuclear cell (PBMC) using hybridization probe technique. The real-time primers and probes in this real-time PCR system were designed based on EBNA-1 sequence. The newly-established real-time PCR demonstrated its high sensitivity (as few as 10 copies of EBV could be detected) and specificity. The intra- and inter-assay variations of the assay were shown to be within a 0.5-log10-difference range. A total of 2 EBV-seronegative, 14 EBV-seropositive healthy donors and 4 patients with PCNSL were enrolled into the study. Our results revealed the median of EBV-DNA in lymphoma patients (7886 copies/10(6) PBMC or 15,150 copies /microg DNA) was higher than that of healthy donors (<10 copies/l0(6) PBMC or <10 copies/microg DNA) with statistic significance (P < 0.01). Assessment of this assay in larger number of donors and patients will provide clinical cut-off values which are essential for monitoring and diagnosis of EBV-associated diseases.

Establishment of cytotoxic T lymphocytes specific for autologous Epstein-Barr virus in HIV-infected patients: the feasibility study of EBV-specific immunotherapy for patients with EBV-associated lymphoma.

Cytotoxic T lymphocytes specific for Epstein-Barr virus (EBV) have previously been successfully used in immunotherapy of Posttransplant lymphoproliferative disease (PTLD) and Hodgkin's disease. A similar strategy has never been employed in HIV/AIDS patients who also have high risk of developing EBV-associated lymphoma. A total of 5 HIV-infected patients were enrolled to evaluate their EBV-specific T cell responses by Interferon-gamma (IFNgamma) ELISpot assays. Most patients had detectable T cell responses, mainly directed at Epstein-Barr nuclear antigen (EBNA-3). The authors wanted to see whether it was possible to augment magnitude and spectrum of the EBV responses by stimulating patient PBMC with cells presenting autologous EBV antigens. The authors successfully established spontaneously EBV-transformed lymphoblastoid cell lines (EBVh-BCL) and used them for generation of EBV-specific CTL (EBV-CTL). The EBVh-CTL lines established in the present study were not only highly cytotoxic against the autologous virus but also able to secrete IFNgamma detected by ELISpot. The authors are now in the process of generating these lines in a large number and in a clinical grade for adoptive immunotherapy.