Laura Mannonen

Infections of the central nervous system of suspected viral origin: a collaborative study from Finland.

We studied 3231 patients with acute central nervous system (CNS) symptoms of suspected viral origin to elucidate the current etiologic spectrum. In 46% of the cases, a viral finding was observed. Varicella-zoster virus (VZV) was the main agent associated with encephalitis, as well as meningitis and myelitis. VZV comprised 29% of all confirmed or probable etiologic agents. Herpes simplex virus (HSV) and enteroviruses accounted 11% each, and influenza A virus 7%. VZV seems to have achieved a major role in viral infections of CNS. In encephalitis in our population, VZV is clearly more commonly associated with these neurological diseases than HSV. The increase in VZV findings may in part be a pseudophenomenon due to improved diagnostic methods, however, a true increase may have occurred and the pathogenetic mechanisms behind this should be elucidated.

Herpes encephalitis is a disease of middle aged and elderly people: polymerase chain reaction for detection of herpes simplex virus in the CSF of 516 patients with encephalitis. The Study Group.

OBJECTIVE--To assess the diagnostic potential of the polymerase chain reaction (PCR) in herpes simplex virus (HSV) encephalitis. METHODS--Samples of CSF from 516 patients with encephalitis were studied for HSV-DNA by PCR. RESULTS--Samples taken one to 29 days from the onset of symptoms from 38 patients (7.4%) were positive, 32 (6.2%) for HSV-1 and six (1.2%) for HSV-2. At follow up, eight of 28 patients studied were still HSV-PCR positive. A diagnostic serum:CSF antibody ratio to HSV but not to other viruses was detected in 25 of the 38 HSV-PCR positive patients thus supporting the initial PCR findings. Patients positive by HSV-PCR were concentrated in the age group > or = 40 years, and especially in patients aged 60-64 years, of whom nine of 24 (37.5%) were positive. The HSV-PCR was negative in all other patients with encephalitis of known or unknown aetiology. This group included 34 patients with a diagnostic serum:CSF antibody ratio to other viruses. A dual infection, HSV and another microbe, was considered possible in seven patients. CONCLUSIONS--The HSV-PCR is a rapid and useful diagnostic method during the early phase of encephalitis. It may be useful in monitoring the efficacy of treatment and allowing the recognition of new features in the appearance of herpes encephalitis. The HSV-PCR test and antibody determinations from serum and CSF are complementary methods, which should both be applied in pursuit of clinical laboratory diagnosis of these conditions.

Genetic Diversity of the 2009 Pandemic Influenza A(H1N1) Viruses in Finland

Background In Finland, the first infections caused by the 2009 pandemic influenza A(H1N1) virus were identified on May 10. During the next three months almost all infections were found from patients who had recently traveled abroad. In September 2009 the pandemic virus started to spread in the general population, leading to localized outbreaks and peak epidemic activity was reached during weeks 43–48. Methods/Results The nucleotide sequences of the hemagglutinin (HA) and neuraminidase (NA) genes from viruses collected from 138 patients were determined. The analyzed viruses represented mild and severe infections and different geographic regions and time periods. Based on HA and NA gene sequences, the Finnish pandemic viruses clustered in four groups. Finnish epidemic viruses and A/California/07/2009 vaccine virus strain varied from 2–8 and 0–5 amino acids in HA and NA molecules, respectively, giving a respective maximal evolution speed of 1.4% and 1.1%. Most amino acid changes in HA and NA molecules accumulated on the surface of the molecule and were partly located in antigenic sites. Three severe infections were detected with a mutation at HA residue 222, in two viruses with a change D222G, and in one virus D222Y. Also viruses with change D222E were identified. All Finnish pandemic viruses were sensitive to oseltamivir having the amino acid histidine at residue 275 of the neuraminidase molecule. Conclusions The Finnish pandemic viruses were quite closely related to A/California/07/2009 vaccine virus. Neither in the HA nor in the NA were changes identified that may lead to the selection of a virus with increased epidemic potential or exceptionally high virulence. Continued laboratory-based surveillance of the 2009 pandemic influenza A(H1N1) is important in order to rapidly identify drug resistant viruses and/or virus variants with potential ability to cause severe forms of infection and an ability to circumvent vaccine-induced immunity.

Prolonged norovirus outbreak in a Finnish tertiary care hospital caused by GII.4-2006b subvariants

Norovirus outbreaks are difficult to control in hospitals. Cohorting and contact isolation, disinfective surface cleaning and hand hygiene are key elements in outbreak control. A new norovirus variant, GII.4.-2006b, spreading across many continents, caused an exceptionally long epidemic period in Finland, from November 2006 to June 2007. Here, we describe the clinical and molecular characteristics of a norovirus outbreak in a large tertiary care hospital in Finland. Altogether 240 (18%) patients and 205 (19%) healthcare workers fell ill in the 504 bedded main building of Helsinki University Central Hospital during December 2006 to May 2007. The epidemic curve had three peaks in January, February and April, and different wards were affected each time. During the outbreak, 502 patient stool specimens were tested for norovirus RNA, 181 (36%) of which were positive. Molecular analysis of 48 positive specimens revealed three main subvariants of GII.4.-2006b circulating temporally within distinct wards. Of all microbiologically confirmed cases, 121 (67%) were nosocomial and nine (5%) died within 30 days of diagnosis. Molecular analysis suggested that the three main GII.4-2006b subvariants entered the hospital with gastroenteritis patients, and the nosocomial spread within wards coincided with the epidemic peaks. Active control measures, including temporary closure of the wards, ultimately confined the single-ward outbreaks. A prolonged outbreak in the community was probably the source for the prolonged outbreak period in the hospital.

Luminometric microplate hybridization for detection of varicella-zoster virus PCR product from cerebrospinal fluid

We modified and optimized a new microplate hybridization assay to detect the varciella-zoster virus (VZV) PCR product, and studied cerebrospinal fluid (CSF) samples of 287 patients with meningitis, encephalitis or other neurological diseases or symptoms. Specific antibodies to VZV and reference antigens were determined by enzyme immunoassay from serum and CSF, they were then compared with clinical findings and with the results obtained by VZV-PCR using different detection methods for VZV-specific amplified DNA. VZV DNA was found in the CSF of 25 patients using the microplate hybridization assay and chemiluminescence detection for amplified DNA. All 25 CSF samples were also positive in Southern blotting. Among the patients, 10 had chickenpox, 4 had shingles, and 11 had no rash at all. The detection rate of VZV-specific DNA by microplate hybridization was 30% higher than that obtained by conventional agarose gel electrophoresis. In most patients the diagnosis was confirmed by demonstrating specific intrathecal antibody production to VZV but not to other viruses. These results indicate the presence of VZV in the central nervous system (CNS) in many patients with chickenpox or shingles, and even in patients without a rash. The microplate hybridization assay based on chemiluminescence detection improves considerably the detection rate of the VZV-PCR product compared to agarose gel electrophoresis and will add to the list of recognized VZV infections in the CNS. It is especially useful in cases where there is no cutaneous manifestation.

A Case of Primary JC Polyomavirus Infection–Associated Nephropathy

A 15‐year‐old boy with a posterior urethral valve received a deceased donor kidney transplant (KT) in March 2011. Basiliximab induction followed by tacrolimus‐based triple medication was used as immunosuppression. Eleven months after KT, the graft function deteriorated and the biopsy demonstrated interstitial nephritis suggestive of acute rejection. BK polyomavirus (BKPyV) surveillance in urine and plasma was negative. The patient received methylprednisolone pulses and anti‐thymocyte globulin. Immunohistochemistry was positive for simian virus 40 (SV40) large T‐antigen (LTag) in the biopsies, and quantitative polymerase chain reaction for JC polyomavirus (JCPyV) indicated high viral loads in urine and borderline levels in plasma. Immunosuppression was reduced and follow‐up biopsies showed tubular atrophy and interstitial fibrosis. Two years after KT, antibody‐mediated rejection resulted in graft loss and return to hemodialysis. Retrospective serologic work‐up indicated a primary JCPyV infection with seroconversion first for IgM, followed by IgG, but no indication of BKPyV infection. In the SV40 LTag positive biopsies, JCPyV deoxyribonucleic acid (DNA) with archetype noncoding control region was detected, while BKPyV DNA was undetectable. To the best of our knowledge, this is the first reported case of primary JCPyV infection as the cause of PyV‐associated nephropathy in KT.

Comparison of two quantitative real-time CMV-PCR tests calibrated against the 1st WHO international standard for viral load monitoring of renal transplant patients

Cytomegalovirus (CMV) replication in organ transplant recipients is commonly diagnosed by quantitative PCR methods. However, there has been a poor inter‐laboratory correlation of viral load values due to the lack of an international reference standard. In a recent study, the COBAS® AmpliPrep/COBAS® TaqMan® (CAP/CTM) CMV test calibrated to the 1st WHO CMV standard, showed good reproducibility in CMV load values across multiple laboratories. Fifty‐seven follow‐up plasma specimens from 10 kidney transplant recipients with CMV replication were examined using the new quantitative CAP/CTM CMV test and the “in‐house” quantitative CMV real‐time PCR method, also calibrated against the 1st WHO CMV standard for their clinical applicability for monitoring CMV load in renal transplant patients. By CAP/CTM CMV test 49/57 specimens were CMV‐DNA positive compared to 44/57 by the “in‐house” PCR test. The “in‐house” PCR and CAP/CTM CMV test correlated well in monitoring individual kidney transplant patients. Conversion of the CMV‐DNA copies to IUs made the results of the “in‐house” PCR and CAP/CTM CMV test less uniform in analysis of the patient samples. In specimens of one patient, significant underquantification of CMV load with “in‐house” PCR emerged during follow‐up due to a point mutation in the “in‐house” PCR primer sequence. The CAP/CTM CMV test was found suitable for diagnosing and monitoring CMV replication in renal transplant patients. Multicenter studies are needed to provide more information of the commutability of the 1st WHO CMV standard and to define the clinical thresholds. J. Med. Virol. 86:576–584, 2014.

A major role of viruses in convulsive status epilepticus in children: a prospective study of 22 children.

Abstract A group of 22 previously healthy children with their first convulsive status epilepticus (SE), treated at Kuopio University Hospital, Finland, were prospectively studied. Eleven children had febrile and 11 afebrile SE. Polymerase chain reaction was used to detect specific DNA from CSF, enzyme immunoassays and immunofluorescence assays to detect specific antibodies in serum and CSF, viral cultures were obtained from CSF, throat and stool and antigen detection from throat specimens. Viral infection was identified in 10 of 11 children with febrile SE (91%) and in 7 of 11 with afebrile SE (64%). Human herpes virus 6 infection was identified in 12 children (55%), and in at least six of them the infection was primary. Single cases of human herpes virus 7, parainfluenza 3, adenovirus 1, echovirus 22, rota, influenza A and Mycoplasma pneumoniae infection were diagnosed. Conclusion Viruses, human herpes virus 6 in particular, seem to be major associated factors in convulsive status epilepticus, both febrile and afebrile. Human herpes virus 7 and Mycoplasma pneumoniae are novel agents associated with status epilepticus.

Search for Herpesviruses in cerebrospinal fluid of facial palsy patients by PCR.

Conclusions: Herpes simplex virus 1 (HSV-1) and varicella-zoster virus (VZV) DNA were not detected in the cerebrospinal fluid (CSF) of patients with acute idiopathic peripheral facial palsy (Bells palsy). Our results indicate either the absence of these viruses or the presence of technical shortcomings. The role of human herpesvirus 6 (HHV-6) in this disorder and the significance of a positive HHV-6 DNA finding in the central nervous system need further investigation. Objective: Our goal was to determine whether DNA of HSV-1, VZV, or HHV-6 can be found by polymerase chain reaction (PCR) in the CSF of peripheral facial palsy patients. Materials and methods: We used PCR to detect the presence of HSV-1, VZV, and HHV-6 DNA in CSF. This was a retrospective case control study with 33 peripheral facial palsy patients (34 CSF samples) in the study group (26 with Bells palsy, 5 with simultaneously diagnosed herpesvirus infection, 1 with puerperal facial palsy, 1 with Melkersson-Rosenthal syndrome). The control group included 36 patients, most with diagnosed or suspected Borreliosis and facial palsy or sudden deafness. Results: One patient with Bells palsy had HHV-6 DNA in CSF. Neither HSV-1 nor VZV DNA was detected in patients or controls.

Human herpesvirus-6 associated encephalitis with subsequent infantile spasms and cerebellar astrocytoma

A 14‐month‐old girl presented after 3 days of fever, floppiness, and diffuse urticarial exanthem. She developed encephalitis and carditis and 1 week later, intractable seizures. Initial CT and MRI showed no changes in the brain parenchyma. On days 14 and 34 after the onset of symptoms, a human herpesvirus‐6 (HHV‐6) genome in cerebrospinal fluid was identified by polymerase chain reaction (PCR). Convulsions became more frequent and 11 weeks from the onset, they changed to typical infantile spasms with hypsarrhythmic electroencephalogram. She gradually lost her social contact and ability to walk and sit. Eleven months after the primary infection, a repeated MRI of the brain revealed a cystic tumour of 2 cm in diameter near the vermis. The tumour was surgically removed, and shown to be a pilocytic astrocytoma on histopathological examination. HHV‐6 DNA was detected by PCR in new tumour tissue. This is the first reported case of HHV‐6 encephalitis associated with carditis, infantile spasms, and a subsequent brain tumour containing the HHV‐6 genome.