Ian J. Hart

Viral encephalitis: a clinician’s guide

The management of patients with suspected viral encephalitis has been revolutionised in recent years with improved imaging and viral diagnostics, better antiviral and immunomodulatory therapies, and enhanced neurointensive care. Despite this, disasters in patient management are sadly not uncommon. While some patients are attacked with all known antimicrobials with little thought to investigation of the cause of their illness, for others there are prolonged and inappropriate delays before treatment is started. Although viral encephalitis is relatively rare, patients with suspected central nervous system (CNS) infections, who might have viral encephalitis, are not. In addition, the increasing number of immunocompromised patients who may have viral CNS infections, plus the spread of encephalitis caused by arthropod-borne viruses, present new challenges to clinicians. This article discusses the Liverpool approach to the investigation and treatment of adults with suspected viral encephalitis, and introduces the Liverpool algorithm for investigation and treatment of immunocompetent adults with suspected viral encephalitis (available at www.liv.ac.uk/braininfections).

Prevalence of infection with hepatitis B and C virus and coinfection with HIV in medical inpatients in Malawi

BACKGROUND Coinfection with hepatitis B (HBV) or hepatitis C (HCV) adversely affects the prognosis of HIV infection and vice versa, and results in complex interactions with antiretroviral therapy. These infections are common in sub-Saharan Africa but there are few data on prevalence of coinfection. All three components of the most common ART regimen used in Africa, stavudine, lamivudine and nevirapine, can cause hepatic problems and lamivudine resistant HBV is known to emerge after HBV monotherapy in coinfected patients. Point of care (POC) tests for HBV and HCV are widely used but have not been validated in field tests in sub-Saharan Africa. METHODS Prospective observational study of sequential adult inpatients in medical wards of a large urban teaching hospital in Malawi in 2004. Comparison of demographic risk factors with HIV antibody status determined using local double POC test protocols, and with HBsAg and HCV antibody prevalence as estimated in a reference laboratory in Liverpool, UK. Results of locally performed POC tests for HBV using Determine HBsAg (Abbott) and for HCV antibody using HCV-SPOT (Genelabs) were compared with results of reference methods in the UK. RESULTS Of 226 adults (39% male), median (range) age 35 (14-80) years, 81% had a history of traditional scarification, 12% a history of blood transfusion and 11% a history of jaundice. HIV antibodies were present in 76.1%, HBsAg in 17.5% and HCV in 4.5%, with HIV/HBV coinfection in 20.4% and HIV/HCV coinfection in 5% of those with HIV. There was no correlation between prevalence of any of the three viruses and demographic risk factors or presence of either of the other two viruses. Point of care tests gave misleading results with prevalence estimates of 38% for HBV and 4.5% for HCV. For both of these POC tests the performance indices were unacceptable for individual patient management or epidemiological survey purposes. CONCLUSIONS The high prevalence of hepatitis/HIV coinfections may impact on treatment with antiretroviral therapy, especially if there are unintended interruptions of therapy, and studies are needed to document the possible clinical impact on ART programmes. The poor performance of POC tests for HBV and HCV may be due to local operational problems or to unexpected technical issues not revealed by early validation tests. These tests are widely used in resource poor settings and should be revalidated in prospective field studies in areas of the tropics with high HIV prevalence rates.

Neurological Manifestations of Influenza Infection in Children and Adults: Results of a National British Surveillance Study

BACKGROUND The emergence of influenza A(H1N1) 2009 was met with increased reports of associated neurological manifestations. We aimed to describe neurological manifestations of influenza in adults and children in the United Kingdom that presented at this time. METHODS A 2-year surveillance study was undertaken through the British adult and pediatric neurological surveillance units from February 2011. Patients were included if they met clinical case definitions within 1 month of proven influenza infection. RESULTS Twenty-five cases were identified: 21 (84%) in children and 4 (16%) in adults. Six (29%) children had preexisting neurological disorders. Polymerase chain reaction of respiratory secretions identified influenza A in 21 (81%; 20 of which [95%] were H1N1) and influenza B in 4 (15%). Twelve children had encephalopathy (1 with movement disorder), 8 had encephalitis, and 1 had meningoencephalitis. Two adults had encephalopathy with movement disorder, 1 had encephalitis, and 1 had Guillain-Barré syndrome. Seven individuals (6 children) had specific acute encephalopathy syndromes (4 acute necrotizing encephalopathy, 1 acute infantile encephalopathy predominantly affecting the frontal lobes, 1 hemorrhagic shock and encephalopathy, 1 acute hemorrhagic leukoencephalopathy). Twenty (80%) required intensive care, 17 (68%) had poor outcome, and 4 (16%) died. CONCLUSIONS This surveillance study described a cohort of adults and children with neurological manifestations of influenza. The majority were due to H1N1. More children than adults were identified; many children had specific encephalopathy syndromes with poor outcomes. None had been vaccinated, although 8 (32%) had indications for this. A modified classification system is proposed based on our data and the increasing spectrum of recognized acute encephalopathy syndromes.

Favourable one-year ART outcomes in adult Malawians with hepatitis B and C co-infection

BACKGROUND Few studies have investigated the impact of chronic hepatitis B and C infection on antiretroviral therapy (ART) outcomes in sub-Saharan Africa. Hepatotoxicity may be a particular concern in co-infected patients taking nevirapine-stavudine-lamivudine. METHODS We conducted a prospective cohort study of 300 Malawian adults starting ART and describe one-year ART outcomes according to viral hepatitis status. RESULTS At baseline, patients had advanced HIV disease (29.3% were in WHO stage 4; mean CD4 = 157 cells/microL; mean log(10)HIV-1 RNA = 5.24 copies/ml). Co-infection with hepatitis B, C and B + C were present in 6.7%, 5.7% and 1.7% respectively. At 50 weeks, all-cause mortality was 43 (14.3%). Sixteen (5.3%) had transferred to another unit. Eight (2.7%) were lost to follow up. Sixteen (5.3%) had stopped ART. 217 (72.3%) were alive on ART, of whom 82.5% had an HIV-1 RNA <400 copies/ml at week 50. During the first 50 weeks of ART, severe hepatotoxicity (liver enzyme values >5 times upper level of normal) occurred in 9%, but did not result in any ART discontinuations. Clinical hepatitis or jaundice was not observed. There were no significant differences in occurrence of hepatotoxicity, other side effects, mortality, severe morbidity, immune reconstitution or virological failure between hepatitis B and/or C co-infected patients and those who were not. Viral hepatitis co-infection was not associated with severe hepatotoxicity, mortality, severe morbidity or virological failure in multivariate analyses. CONCLUSION Our data suggest that screening for viral hepatitis B and C and liver enzyme monitoring may not require high priority in ART programmes in sub-Saharan Africa.

Common and new acyclovir resistant herpes simplex virus-1 mutants causing bilateral recurrent herpetic keratitis in an immunocompetent patient.

We investigated thymidine kinase (tk) mutants isolated during multiple episodes of recurrent bilateral acyclovir resistant herpes simplex keratitis in an immunocompetent patient. From one eye, we found a single guanine insertion, previously shown to greatly reduce TK expression, and from the other, a previously unidentified substitution, which genetic experiments confirmed confers drug resistance. The substitution, although distant from substrate binding sites, reduced thymidine phosphorylation 10-20-fold, and acyclovir phosphorylation >100-fold. This phenotype should permit reactivation from latency to cause recurrent disease. The results may have implications for the prevalence and prevention of acyclovir resistance in patients with herpes simplex keratitis.

Reliability of rapid testing for hepatitis B in a region of high HIV endemicity

Hepatitis B (HBV) and HIV co-infection is common in resource-poor settings. A recent study from Malawi revealed poor correlation between hepatitis B surface antigen (HBsAg) point-of-care tests and reference tests in patients co-infected with HIV. We studied a cohort of 300 Malawian adults entering a treatment programme for HIV. Sera were tested for HBsAg first using the Determine rapid test and re-tested using a commercial enzyme immunoassay (EIA). All tests were done under optimal conditions in Liverpool, UK. Sera from all 25 patients positive for HBsAg using the rapid test and from 50 who were negative, were re-tested using the EIA, with complete concordance of results. The kappa correlation was 1, specificity 100% (93-100%) and sensitivity 100% (86-100%) compared to the reference test. Patients had advanced immune suppression (mean CD4=175 cells x 10(6)/l). In a non-field setting, the results of point-of-care Determine rapid hepatitis B tests appear reliable in patients with HIV-1 co-infection.

Detection and characterisation of human metapneumovirus from children with acute respiratory symptoms in north-west England, UK

BACKGROUND Human metapneumovirus (hMPV) causes a spectrum of respiratory disease ranging from trivial coryzal symptoms to fatal pneumonia, with a predilection for the very young, the immune suppressed and the frail elderly. Five distinct lineages of the virus genome have been described. OBJECTIVES To develop and evaluate a sensitive, real-time PCR (RT-PCR) assay capable of detecting all lineages of hMPV, suitable for use in a diagnostic laboratory. STUDY DESIGN An RT-PCR assay was developed using novel primers and dual-labelled minor-groove-binding (MGB) probes complementary to consensus sequences. The assay and two alternative assays were tested against external quality assurance (EQA) panels. 221 respiratory samples collected during 2003-2004 were screened using the new assay. hMPV positive samples were sequenced and phylogenetically analysed. RESULTS Three genetic lineages of hMPV were detected during 2003-2004. Incidence was low (2.3%) compared to previous years. All five lineages had been present in the same community within the past 3 years. CONCLUSIONS The new assay correctly identified more EQA samples, including those at greatest dilution, than the alternative assays and detected all five lineages. Seasonal circulation of hMPV in paediatric patients with acute respiratory symptoms is dynamic with respect to incidence and viral genotype.

Detection of norovirus infection in the hospital setting using vomit samples.

Nosocomial norovirus outbreaks are associated with significant ealth care costs and the only intervention associated with reducions in the size of outbreaks is early ward closure.1 Achieving arlier ward closures may be more easily achieved with earlier aboratory diagnosis of norovirus infection. One strategy to faciltate earlier laboratory diagnosis of norovirus infection is the use f vomit samples for testing because vomiting often precedes diarhoea. On this basis the virology laboratory at the Royal Liverpool niversity Hospital, Liverpool, UK, has tested vomit samples for orovirus by RT-PCR since 2007.2 We therefore report the results f norovirus testing completed on vomit samples over a three year eriod, between December 2007 and November 2010. In total 2924 faecal and 442 vomit samples were received for orovirus RT-PCR testing. Vomit samples were classified as being atched or unmatched. Matched vomit samples had a faecal samle collected from the same patient within a seven-day period. nmatched samples had no faecal sample collected at any time rom the same patient. Matched faecal samples were used as the eference standard for corresponding vomit samples. Within the matched samples 34 samples were positive for orovirus in both vomit and faeces; and 75 samples were negative n both vomit and faeces. There were 12 matched samples positive or norovirus in faeces and negative in the vomit; and 3 positive in omit and negative in the faecal sample (Table 1). The sensitivity of omit samples for norovirus testing by RT-PCR, compared to faecal amples, was 74% and the specificity 96%. Within this study setting his gave the results a positive predictive value of 92% and a negtive predictive value of 86%. Of 260 unmatched samples 62 were ositive for norovirus. The sensitivity of norovirus testing of vomit was moderately igh at 74%. Possible explanations for the diagnostic gap between

Validation of a Laboratory Developed Real-Time PCR Protocol for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Urine

Objective To evaluate a sensitive and specific, real-time PCR assay with internal control for Chlamydia trachomatis and Neisseria gonorrhoeae DNA detection in urine specimens. Methods The diagnostic performance of a laboratory-developed quadruplex assay (LDQA) targeting the cryptic plasmid and MOMP genes of C trachomatis, the porA pseudogene of N gonorrhoeae and a synthetic internal control was assessed using 1028 urine specimens. The LDQA was compared with the Roche COBAS Taqman CT test and the COBAS Amplicor NG assay with supplemental confirmation tests. The subsequent performance of the LDQA in detecting N gonorrhoeae was monitored in comparison with bacterial culture from swabs. Results 88 (8.6%) urines were determined as C trachomatis positive in the diagnostic evaluation. LDQA sensitivity and specificity were calculated to be 100% and 99.9%, respectively, for C trachomatis. The LDQA showed high specificity with isolates of other Neisseria species and gave complete concordance with resolved data for N gonorrhoeae detection. However, the incidence of N gonorrhoeae infection was low, with 17 (1.7%) positive patients. A post-implementation audit of 14 316 patients gave the LDQA N gonorrhoeae urine PCR protocol (porA, OPA, 16s rDNA) a sensitivity of 96.9% and specificity of 99.8% in comparison with bacterial culture from swabs. Conclusions The LDQA was found to be an effective method for the detection of C trachomatis and N gonorrhoeae DNA in urine samples, and the PCR protocol has replaced bacterial culture for the screening of N gonorrhoeae in asymptomatic men and women in the laboratory.

Using the full spectral capacity (six channels) of a real‐time PCR instrument can simplify diagnostic laboratory screening and typing protocols for pandemic H1N1 influenza

Please cite this paper as: Hopkins et al. (2011) Using the full spectral capacity (six channels) of a real‐time PCR instrument can simplify diagnostic laboratory screening and typing protocols for pandemic H1N1 influenza. Influenza and Other Respiratory Viruses 5(2), 110–114.