Khidir Hawrami

Analysis of United Kingdom wild-type strains of varicella-zoster virus: differentiation from the Oka vaccine strain.

In Japan and the United States, where vaccination against varicella‐zoster virus (VZV) infection with the live attenuated Oka strain of varicella is routine, cases of chickenpox or shingles occurring in vaccinees can be caused by either wild‐type or vaccine virus. Differentiating such cases is important epidemiologically and can be achieved only using molecular typing methods. In the United Kingdom, the Oka vaccine is being considered for use in groups at risk of severe primary varicella, such as seronegative immunocompromised patients and women who may be considering pregnancy. In addition, seronegative health workers who may be occupationally exposed to VZV infection might also be offered vaccination. We analysed 249 U.K. wild‐type VZV strains, 105 from cases of chickenpox and 144 from shingles cases, to determine whether they could be distinguished from Oka by the genotyping systems used in Japan and the United States. Four polymorphic loci were examined, a Pst 1 restriction site in gene 38, a Bgl 1 restriction site in gene 54, the R5 repeat region, and the R2 repeat region. The results suggest that U.K. strains of VZV are more similar to U.S. strains than to Japanese strains. All the U.K. wild‐type viruses were positive for the Pst 1‐1 restriction site, unlike Oka, which is negative. However, one of thirty strains was indistinguishable from Oka at all other loci. J. Med. Virol. 53:60–62, 1997.

Influenza A community-acquired pneumonia in East London infants and young children

Background. Community-acquired pneumonia (CAP) is common in young children, but there are few data in Europe on influenza A virus as a cause of childhood CAP. The aim of this study was to determine the relative contributions of different etiologic agents to CAP in children. Methods. This was a 6-month prospective study of pediatric accident and emergency and general practice consultations with a diagnosis of CAP. Nasopharyngeal aspirates for viral immunofluorescence and PCR studies and blood cultures for bacterial studies were taken from 51 children with symptoms, signs and chest radiographic features that satisfied a diagnosis of pneumonia. Results. An etiologic agent was isolated from 25 patients (49%). A viral cause was identified in 22 patients (43%), and influenza A virus and respiratory syncytial virus (RSV) were detected in 16 and 18% of all cases, respectively. Only four patients (8%) had a positive bacterial blood culture; three had Streptococcus pneumoniae and one had Neisseria meningitidis W135. Mycoplasma pneumoniae was detected in 2 children, and mixed infections were detected in 5 (10%). The use of viral PCR increased the detection rate of influenza A virus by 100%. Conclusion. Influenza A virus caused more than one-third of all viral CAP cases, a rate comparable with that of RSV CAP. Viral PCR doubled the diagnostic yield of influenza A virus. The clinical burden of influenza A CAP was comparable with that of RSV CAP, as measured by the duration of fever, hospital stay and total duration of illness.

Typing of varicella zoster virus by amplification of DNA polymorphisms

The polymerase chain reaction was used to amplify five variable regions of varicella zoster virus DNA from 20 samples of vesicle fluid. Two of the regions, R1 and R5, were found to be polymorphic, with the former having three alleles (A, B and C) and the latter, two (A and B). The R1 and R5 polymorphisms were stable up to passage five in tissue culture. The sensitivity of the PCR (down to six copies) enabled detection of virus from vesicle fluid dried on glass slides and overall the method was five times more sensitive than conventional tissue culture. The method described is simple, sensitive and informative and provides a means by which questions about the epidemiology and clinical biology of VZV infection may begin to be addressed.

Investigation of varicella-zoster virus variation by heteroduplex mobility assay

Heteroduplex mobility assays of 37 regions were performed on ten UK isolates of varicella zoster virus, four from cases of zoster, and six from cases of chickenpox. The variation between isolates was found to be 0.061%, which is at least five times lower than any other member of the human herpesvirus family. Fifteen of the 37 regions tested had 29 single nucleotide polymorphisms, and over half the polymorphisms were located in four gene fragments. Of the 29 SNPs, eleven were non-synonymous and these were clustered in six genes. Isolates from a child and her mother to whom she had transmitted the virus, were identical at every locus tested. All other viruses could be distinguished by a combination of SNPs and length polymorphisms of the repeat regions R1, R2 and R5.

Influenza A and respiratory syncytial virus hospital burden in young children in East London

Epidemiological studies have demonstrated high hospitalization rates attributable to influenza and RSV in children aged 6 months and those aged <12 months, respectively (43 and 92.5/10 000 person-months, respectively). In conclusion, these high paediatric RSV and influenza incidence rates can be used to inform UK policy on childhood influenza immunization and subsequent RSV immunization in the future.

Performance of a nurse-led paediatric point of care service for respiratory syncytial virus testing in secondary care

OBJECTIVES To evaluate respiratory syncytial virus (RSV)-point-of-care-testing (POCT) performance among paediatric patients with respiratory symptoms, using the BinaxNOW(®) RSV assay performed by trained nurses on the paediatric ward, and compare results with those obtained by real-time polymerase chain reaction (PCR). METHODS Four paediatric nurses were trained and certified in using RSV-POCT. Between October 2008 and March 2009, all hospitalised children below 5 years of age presenting with a suspected RSV infection had nasopharyngeal swabs (NPS) tested by RSV-POCT by the nurses and a real-time PCR targeting common respiratory viruses by laboratory staff. RESULTS Among 159 NPS, 21 (13.2%) were RSV-POCT positive and 138 (86.8%) negative. All 21 RSV-POCT positive samples were positive by PCR, yielding a specificity of 100% (95% CI 95.7%, 100.0%). Of 138 RSV-POCT negative samples, 30 (21.7%) were RSV positive by PCR (sensitivity 41.2%; 95% CI: 27.9%, 55.8%). The positive and negative predictive values for RSV-POCT were 100% (95% CI 80.8%, 100.0%) and 78.3% (95% CI 70.3%, 84.6%) respectively. Other respiratory viruses were detected in 52/138 (39.9%) NPS. CONCLUSIONS A POCT for RSV run by trained nurses can be used reliably as a first screening step in symptomatic children. Negative samples should be analysed for RSV and other respiratory pathogens by real-time PCR.

Simultaneous treatment of cytomegalovirus and varicella zoster infections in a renal transplant recipient with ganciclovir: use of viral load to monitor response to treatment.

Disseminated zoster occurring simultaneously with cytomegalovirus (CMV) disease in a renal transplant recipient is potentially life threatening. We describe the use of intravenous ganciclovir to treat both infections. The efficacy of treatment was assessed clinically and by the measurement of CMV viral load using the hybrid capture (Murex version 2) and varicella zoster (VZV) viral load using an in‐house assay. Results from this case suggest that clinical resolution in severe viral infections such as described below may be related to early control of viraemia. 1999 J. Med. Virol. 59:412–414, 1999.