Control of an Outbreak of Human Parainfluenza Virus 3 in Hematopoietic Stem Cell Transplant Recipients

Human parainfluenza virus 3 (HPIV3) infection can cause significant morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). There are no standard guidelines for the prevention and control of HPIV3 in the outpatient setting. After 2 HSCT inpatients diagnosed with HPIV3 were noted to have had multiple recent HSCT outpatient clinic (OPC) visits, an investigation of policy and procedures in the HSCT OPC was undertaken, and active surveillance for respiratory viral illness was instituted in the at-risk HSCT population. Between July 19 and August 30, 2005, 13 patients were diagnosed with HPIV3 infection. Morbidity in affected patients was significant, and mortality was high (38.5%) and not affected by antiviral therapy. Molecular typing identified several genetically distinct groups of the hemagglutinin-neuraminidase gene of the 11 available isolates. Based on sequence relatedness among the isolates and the demographic and exposure history of the patients, in many of these cases HPIV3 infection likely was acquired in the HSCT OPC. The major infection control interventions were introduced between August 20 and August 24. An epidemic curve revealed that HPIV3 infection frequency peaked between August 17 and August 26, with no cases identified after August 30. Prompt attention and focus on infection control interventions were associated with a rapid decrease in the number of incident cases. Policies and procedures regarding patients with respiratory viral illnesses in HSCT OPC populations should be formulated and universally reinforced with HSCT clinic staff to prevent the spread of these infections

Positive Selection Results in Frequent Reversible Amino Acid Replacements in the G Protein Gene of Human Respiratory Syncytial Virus

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a “flip-flop” phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites

Results from the WHO external quality assessment for the respiratory syncytial virus pilot, 2016-17

Background: External quality assessments (EQAs) for the molecular detection of respiratory syncytial virus (RSV) are necessary to ensure the provision of reliable and accurate results. One of the objectives of the pilot of the World Health Organization (WHO) Global RSV Surveillance, 2016-2017, was to evaluate and standardize RSV molecular tests used by participating countries. This paper describes the first WHO RSV EQA for the molecular detection of RSV. Methods: The WHO implemented the pilot of Global RSV Surveillance based on the WHO Global Influenza Surveillance and Response System (GISRS) from 2016 to 2018 in 14 countries. To ensure standardization of tests, 13 participating laboratories were required to complete a 12 panel RSV EQA prepared and distributed by the Centers for Disease Control and Prevention (CDC), USA. The 14th laboratory joined the pilot late and participated in a separate EQA. Laboratories evaluated a RSV rRT-PCR assay developed by CDC and compared where applicable, other Laboratory Developed Tests (LDTs) or commercial assays already in use at their laboratories. Results: Laboratories performed well using the CDC RSV rRT-PCR in comparison with LDTs and commercial assays. Using the CDC assay, 11 of 13 laboratories reported correct results. Two laboratories each reported one false-positive finding. Of the laboratories using LDTs or commercial assays, results as assessed by Ct values were 100% correct for 1/5 (20%). With corrective actions, all laboratories achieved satisfactory outputs. Conclusions: These findings indicate that reliable results can be expected from this pilot. Continued participation in EQAs for the molecular detection of RSV is recommended. </div

Results from the WHO external quality assessment for the respiratory syncytial virus pilot, 2016-17

BACKGROUND : External quality assessments (EQAs) for the molecular detection of respiratory syncytial virus (RSV) are necessary to ensure the provision of reliable and accurate results. One of the objectives of the pilot of the World Health Organization (WHO) Global RSV Surveillance, 2016-2017, was to evaluate and standardize RSV molecular tests used by participating countries. This paper describes the first WHO RSV EQA for the molecular detection of RSV. METHODS : The WHO implemented the pilot of Global RSV Surveillance based on the WHO Global Influenza Surveillance and Response System (GISRS) from 2016 to 2018 in 14 countries. To ensure standardization of tests, 13 participating laboratories were required to complete a 12 panel RSV EQA prepared and distributed by the Centers for Disease Control and Prevention (CDC), USA. The 14th laboratory joined the pilot late and participated in a separate EQA. Laboratories evaluated a RSV rRT-PCR assay developed by CDC and compared where applicable, other Laboratory Developed Tests (LDTs) or commercial assays already in use at their laboratories. RESULTS : Laboratories performed well using the CDC RSV rRT-PCR in comparison with LDTs and commercial assays. Using the CDC assay, 11 of 13 laboratories reported correct results. Two laboratories each reported one false-positive finding. Of the laboratories using LDTs or commercial assays, results as assessed by Ct values were 100% correct for 1/5 (20%). With corrective actions, all laboratories achieved satisfactory outputs. CONCLUSIONS : These findings indicate that reliable results can be expected from this pilot. Continued participation in EQAs for the molecular detection of RSV is recommended.The Bill and Melinda Gates Foundation, the Respiratory Viruses Branch, Division of Viral Diseases, CDC, Atlanta, and the CDC International Reagent Resource (IRR), USA.http://www.wileyonlinelibrary.com/journal/irvam2020Medical Virolog

Detection of Human Metapneumovirus in Clinical Samples by Immunofluorescence Staining of Shell Vial Centrifugation Cultures Prepared from Three Different Cell Lines

Monoclonal antibody MAb-8 was evaluated for detection of human metapneumovirus (HMPV) in shell vial centrifugation cultures (SVCC). Detection of HMPV was similar in A549, HEp-2, and LLC-MK2 SVCC, and MAb-8 staining was optimal on day 2 postinoculation. Availability of SVCC for HMPV will be of significant benefit to clinical laboratories

The burden of hospitalized lower respiratory tract infection due to respiratory syncytial virus in rural Thailand.

BACKGROUND: We describe the epidemiology of hospitalized RSV infections for all age groups from population-based surveillance in two rural provinces in Thailand. METHODS: From September 1, 2003 through December 31, 2007, we enrolled hospitalized patients with acute lower respiratory tract illness, who had a chest radiograph ordered by the physician, from all hospitals in SaKaeo and Nakhom Phanom Provinces. We tested nasopharyngeal specimens for RSV with reverse transcriptase polymerase chain reaction (RT-PCR) assays and paired-sera from a subset of patients with IgG enzyme immunoassay. Rates were adjusted for enrollment. RESULTS: Among 11,097 enrolled patients, 987 (8.9%) had RSV infection. Rates of hospitalized RSV infection overall (and radiographically-confirmed pneumonia) were highest among children aged<1 year: 1,067/100,000 (534/100,000 radiographically-confirmed pneumonia) and 1-4 year: 403/100,000 (222/100,000), but low among enrolled adults aged≥65 years: 42/100,000. Age<1 year (adjusted odds ratio [aOR]=13.2, 95% confidence interval [CI] 7.7, 22.5) and 1-4 year (aOR=8.3, 95% CI 5.0, 13.9) were independent predictors of hospitalized RSV infection. CONCLUSIONS: The incidence of hospitalized RSV lower respiratory tract illness among children<5 years was high in rural Thailand. Efforts to prevent RSV infection could substantially reduce the pneumonia burden in children aged<5 years

SYNOPSIS Cell Culture and Electron Microscopy for Identifying Viruses in Diseases of Unknown Cause

During outbreaks of infectious diseases or in cases of severely ill patients, it is imperative to identify the causative agent. This report describes several events in which virus isolation and identification by electron microscopy were critical to initial recognition of the etiologic agent, which was further analyzed by additional laboratory diagnostic assays. Examples include severe acute respiratory syndrome coronavirus, and Nipah, lymphocytic choriomeningitis, West Nile, Cache Valley, and Heartland viruses. These cases illustrate the importance of the techniques of cell culture and electron microscopy in pathogen identification and recognition of emerging diseases. Thin section and negative stain electron microscopy (EM) examination of viruses grown in cultured cells have been instrumental in determining an etiologic agent in numerous disease outbreaks caused by previously unknown viruses. Many examples have been reported. In 1976, EM of cell culture isolates identified the causative virus of an outbreak of hemorrhagic fever in Zaire as a member of the family Filoviridae, now known as Zaire ebolavirus (1–3). Reston ebolavirus was another previously unrecognized virus that was detected by cell culture and EM in 1989; it was isolated from cynomolgus monkeys imported into th