Molecular investigations of an outbreak of parainfluenza virus type 3 and respiratory syncytial virus infections in a hematology unit.

A large simultaneous outbreak of respiratory syncytial virus (RSV) and parainfluenza type 3 (PIV-3) infections occurred on an adult hematology unit. Implementation of enhanced infection control was complicated by cocirculation of the two different viruses, with prolonged viral shedding from infected patients, and placed great pressure on health care staff; of 27 infected hematopoietic stem cell transplant patients, 9 died, and the unit was closed for 2 months. Retrospective molecular investigation of the virus strains involved in the outbreak was performed by analyzing part of the fusion gene of PIV-3 and part of the glycoprotein gene of RSV. Reverse transcription-PCR on nasopharyngeal aspirates from patients infected before and during the simultaneous outbreak generated amplicons for sequence analysis. A single strain of RSV and a single strain of PIV-3 had spread from person to person within the unit; 7 patients were infected with RSV, 22 were infected with PIV-3, and 4 were infected with both viruses. The PIV-3 outbreak had started at the beginning of August 3 months before the RSV outbreak; it had arisen when PIV-3 was introduced from the community by a patient and passed to another patient, who became chronically infected with the identical strain and, in spite of being nursed in isolation, was most likely the source from which widespread infection occurred in November. Had these early cases been linked to a common PIV-3 strain at the time of diagnosis, enhanced infection control precautions might have prevented the eventual extensive spread of PIV-3, making it much easier to deal with the later RSV outbreak.

The impact of high risk human papillomavirus testing in an inner London colposcopy clinic.

This is an audit of a new technique to improve the colposcopy service. Samples were tested for high risk HPV DNA using Digene Hybrid Capture II. Sixty-four percent of the sampled women under 30 had detectable high risk HPV DNA, decreasing to 44% in 30--39 year olds and to 27% in women over 40. High risk HPV prevalence increased with severity of cytology, although 22% with normal colposcopy had detectable high risk HPV. Of those women treated for cervical dysplasia, 83% had detectable high risk HPV prior to treatment, compared to only 32% afterwards. The audit has shown that high risk HPV testing has considerable discriminatory value. It has been integrated successfully into the service, particularly to manage low grade cervical abnormalities and to add valuable information following treatment for cervical dysplasia. Results need to be interpreted alongside colposcopy, cytology, and histology, and care must be taken in the interpretation of a single high risk HPV result.

First reported outbreak of diarrhea due to adenovirus infection in a hematology unit for adults.

Numerous outbreaks of adenovirus infection from different types of health care settings, except a hematology unit, have been reported. This is the first report describing an outbreak of adenovirus infection causing diarrhea among adult hematopoietic stem cell transplant recipients. Six of 21 patients from the outbreak cohort were affected with diarrhea. Electron microscopy, cell culture, and direct DNA sequencing of amplicons generated from stool and blood samples were used to investigate this outbreak. Electron microscopy and cell culture detected adenovirus in stools from symptomatic patients. DNA sequencing of amplicons generated from stool samples confirmed nosocomial transmission of infection from a single index case. The outbreak strain was also detected in plasma of four of these patients, suggesting systemic infection. The outbreak strain was identified as type 12. Standard infection control measures were effective to control this outbreak.

Detection of persistent high risk human papillomavirus infections with hybrid capture II and SPF10/LiPA.

BACKGROUND: HPV infection in young women is common. However only a certain number of HPV genotypes are oncogenic. It is necessary for high risk HPV infection to persist at the cervix for a considerable time before oncogenesis occurs. OBJECTIVES: To look for persistence of high risk HPV in women attending a colposcopy clinic. Two DNA detection methods were used and the results compared to determine the rates of persistent, resolved and acquired infections over a 6-month period. HPV genotyping was used to determine type specific persistence. STUDY DESIGN: One hundred and thirty-eight women were tested for HPV infection when attending the colposcopy clinic at UCLH and then tested again at a subsequent visit approximately 6 months later. HPV DNA was detected by the Digene HC II assay using the high risk probes only and by PCR with the SPF10 primer set. All SPF10 PCR-positive samples were then specifically genotyped by a Line Probe Assay (LiPA) [Kleter et al. 1999. J. Clin. Microbiol. 1999;37:2508]. RESULTS: At entry of the study high risk HPV was detected in 43% of the samples by Digene HC II and in 60% of the samples by SPF10/LiPA. Thirty-eight (28%) of the women had a true persistent infection with the same high risk HPV genotype over a median period of 6.3 months. Nine (7%) women resolved one HR HPV infection after their first colposcopy visit, but obtained a different high risk HPV infection by the time they were tested at their second visit as identified by LiPA. Thirty-seven (27%) of the 138 women had mixed HPV infections, representing 45% of all those infected. CONCLUSIONS: The SPF10/LiPA assay detected more high risk infections than the Digene HC II assay. The Digene HC II assay was unable to distinguish between persistent infections with the same high risk genotype and those where the genotype had changed between visits.

Prenatal diagnosis of congenital rubella infection in the second trimester of pregnancy.

OBJECTIVES: This case report describes the clinical presentation, diagnosis and management of a case of acute rubella infection in the second trimester. The complex issues of prenatal diagnosis of a congenital rubella infection are discussed. METHODS: A 30-year-old woman presented with a fine macular rash at 15 weeks' gestation. Laboratory testing included maternal rubella-specific IgG and IgM detection (booking blood and acute-phase sample) together with measurement of IgG avidity. Prenatal diagnosis at 19 weeks (amniocentesis) and 23 weeks (amniocentesis and fetal blood) was done using a reverse-transcriptase polymerase chain reaction to detect rubella-specific RNA. The fetal blood sample was also tested for rubella-specific IgM. RESULTS: Maternal serological results confirmed an acute rubella infection at 15 weeks' gestation. Rubella-specific RNA and IgM were detected in the fetal blood taken at 23 weeks' gestation. However, no rubella RNA was detected in either of the amniotic fluid samples collected at 19 and 23 weeks. CONCLUSION: In second-trimester rubella where risk of fetal damage is low, prenatal diagnosis can identify the rubella-infected fetus, allowing the parents to make a more informed decision about their options. The optimal sample for prenatal diagnosis is fetal blood as no rubella-specific RNA was detected in the amniotic fluid.

Development and clinical application of a fully controlled quantitative PCR assay for cell-free cytomegalovirus in human plasma.

BACKGROUND: Cytomegalovirus (HCMV) disease continues to be a major problem in certain patient groups, including bone marrow transplant (BMT) recipients. The quantification of HCMV genome is clinically useful for the diagnosis of HCMV disease, for the virological surveillance of high-risk patients and for monitoring antiviral therapy. OBJECTIVES: To develop a novel, robust, and fully controlled PCR (qPCR) for the quantification of HCMV DNA in plasma samples and to demonstrate its clinical usefulness in the BMT setting. STUDY DESIGN: The newly developed HCMV qPCR employs cell culture-derived murine CMV as an internal control for both extraction and amplification. Following amplification using common primers, detection of both internal control and patient HCMV amplicons is by specific probes and a chemiluminescence microtitre plate system. Its performance was evaluated using the routine non-quantitative nested HCMV PCR on whole blood (NQPCR) and correlated with clinical events such as disease and antiviral therapy. RESULTS: A high level of concordance (85.1%) was found between the novel assay and the NQPCR, with the qPCR being slightly more sensitive. The samples giving discordant results generally had levels of HCMV DNA close to the limit of detectability or had been stored for prolonged periods. CONCLUSIONS: The use of plasma as an analyte by the newly developed assay avoids the detection of cell-associated virus. On the other hand, testing a comparatively large volume of plasma ensures that sensitivity is not compromised by not detecting cell-associated HCMV. In a small preliminary evaluation in BMT recipients, changes in HCMV 'viral load' correlated with initiation and discontinuation of antiviral therapy and were biologically plausible.

Case report: rapid ante-mortem diagnosis of a human case of rabies imported into the UK from the Philippines.

The United Kingdom is free from rabies, with the last human death from indigenous rabies recorded in 1902. However, between 1946 and 2000, 20 deaths were reported in the United Kingdom in people who were bitten and infected while abroad in rabies endemic areas. The rapid diagnosis of suspected human rabies cases influences the use of anti-rabies post-exposure prophylaxis for potential contacts with the victim. In addition, the occurrence of a human rabies case requires urgent investigation to support patient management policies. In May 2001, a case of human rabies imported into the United Kingdom from the Philippines was identified. A 55-year-old man was admitted to University College Hospital, London, with clinical symptoms and a history consistent with exposure to rabies. Saliva, cerebrospinal fluid), and skin biopsies (from the wound site and nape of the neck) were submitted for conventional ante-mortem diagnostic techniques. Established diagnostic techniques, including the fluorescent antibody test (FAT), mouse inoculation test, (MIT) and the rabies tissue culture inoculation test (RTCIT), failed to detect the virus. In contrast, hemi-nested reverse transcription-polymerase chain reaction (RT-PCR), followed by automated sequencing confirmed the presence of classical rabies virus (genotype 1) in both the saliva and skin specimens within 36 hr of sample submission. Subsequent phylogenetic analysis demonstrated that this isolate was closely related to that of canine variants currently circulating in the Philippines.

Glomerulonephritis after human parvovirus infection in homozygous sickle-cell disease

Glomerulonephritis with proteinuria of sufficient degree to manifest the nephrotic syndrome followed aplastic crises induced by human parvovirus (B19) in seven patients with homozygous sickle-cell disease, within 7 days in five patients and 6-7 weeks in two. Segmental proliferative glomerulonephritis was found in all four patients who underwent acute renal biopsies and focal segmental glomerulosclerosis was found in the fifth patient who had a biopsy 4 months later. One patient recovered completely, one died in chronic renal failure after 3 months, and the others had impaired creatinine clearance, four with continuing proteinuria (AU)

Nephrotic syndrome and human parvovirus infection in homozygous sickle-cell disease: a temporal association - abstract

Proteinuria of sufficient severity to manifest the nephrotic syndrome and renal impairment has been associated with human parvovirus (B19) infection in 7 patients with homozygous sickle-cell (SS) disease. In most patients, the proteinuria resolved but renal impairment remained. The glomerular histology showed evidence of segmental proliferative glomerulonephritis in 4 out of 5 biopsies. Most events occurred within 2 weeks of B19 associated aplastic crisis, and the mechanism is at present unknown. This association may add to the pathogenic significance of B19 infection in SS disease (AU)