Pekka Kolehmainen

Human parechoviruses are frequently detected in stool of healthy Finnish children

BACKGROUND Human parechoviruses (HPeVs) are common viruses mainly infecting young children. Most infections are mild, but HPeV3 causes severe CNS infections in new-born infants. OBJECTIVES The aim was to study the epidemiology of HPeVs in Finnish general population in the period 1996-2007, with special emphasis on the different types circulating in Finland. STUDY DESIGN A total of 2236 stool specimens were collected from 200 healthy Finnish children in a prospective birth cohort study, most before the age of 2 years. Samples were tested for the presence of HPeV RNA using a specific RT-PCR. The genotype of HPeV was determined by sequencing the VP1 genomic region. RESULTS HPeV RNA was detected in 144 (6.4%) specimens from 78 (39%) children. The dominant type was HPeV1 (93% of the type-identified 105 samples), although types 3 and 6 were also identified. HPeV was found sequentially in more than one sample in 43 infections lasting up to 93 days. The positive findings were distributed equally in young ages and declined towards the age of 2 years. Infections clustered around the autumn months with no obvious change between years. No significant differences were seen between boys and girls. CONCLUSIONS HPeV is a common virus infecting Finnish children under 2 years of age. HPeVs circulate throughout the year with clear accumulation on autumn, also seen in individual years over the 11-year study period. The virus deserves increased attention and should be included in the test panel of clinical virus laboratories.

Human parechovirus seroprevalence in Finland and the Netherlands

BACKGROUND Human parechoviruses (HPeVs) are RNA viruses associated with mild gastrointestinal and respiratory infections in children, but may also cause neonatal sepsis and CNS infections in infants. While the prevalence of HPeVs is known mostly among hospitalized populations, the knowledge of HPeV seroprevalence in the general population is poor. OBJECTIVES The aim of this study was to identify and compare the HPeV1-6 seroprevalence in Finnish and Dutch populations. STUDY DESIGN A type specific microneutralization assay was set up for detecting neutralizing antibodies (nABs) against HPeV types 1-6. Altogether 616 serum samples from Finnish and Dutch population were analyzed for antibodies against HPeVs. The samples were collected from Finnish children aged 1, 5 or 10 years, Finnish adults, 0- to 5-year-old Dutch children, Dutch women of childbearing age and Dutch HIV-positive men. RESULTS In both adult populations, seropositivity was high against HPeV1 (99% in Finnish and 92% in Dutch samples) and HPeV2 (86% and 95%). Against HPeV4, the seropositivity was similar (62% and 60%). In Dutch adults, nABs against HPeV5 and 6 (75% and 74%) were detected more often than in Finnish adults (35% and 57%, respectively). In contrast, seropositivity against HPeV3 was as low as 13% in the Finnish and 10% in the Dutch adults. The seroprevalence of all HPeV types increased with age. CONCLUSIONS The seroprevalence of HPeVs is high in Finnish and Dutch populations and HPeV type 2 and types 4-6 are significantly more prevalent compared to earlier reports. The seroprevalence of antibodies observed against HPeV3 was low.

Human parechovirus type 3 and 4 associated with severe infections in young children.

Background: The symptoms observed in children with human parechovirus (HPeV) infection vary widely from asymptomatic or mild gastrointestinal infections to more severe central nervous system infections and sepsis-like disease. Many of the disease associations are, however, only suggestive. In this study, we examined the connection between HPeV and acute otitis media, lower respiratory infections and suspected central nervous system infections. Methods: An HPeV specific real-time reverese transcriptase polymerase chain reaction was used to detect HPeV RNA. We analyzed altogether 200 middle-ear fluid samples, 192 nasopharyngeal aspirates, 79 cerebrospinal fluid specimens and 50 serum and 5 fecal or fecal culture samples. Positive samples were typed by sequencing the VP1 region. Results: Seven (8%) of 85 children with suspected central nervous system infections were positive for HPeV. Of these, 4 (all in autumn 2012 and from children <3 months of age) were typed to be HPeV4, whereas 1 child had HPeV3. HPeV4 was detected from stool, serum and cerebrospinal fluid. The children with acute otitis media tested HPeV positive in 2.5% episodes. In the lower respiratory cases, HPeV was absent. Conclusions: The findings reported in this study suggest that HPeV4 can cause sepsis-like disease in young infants and be present in cerebrospinal fluid. Furthermore, this report shows that HPeV findings in children with more severe symptoms occur also in Finland.

Evidence of ljungan virus specific antibodies in humans and rodents, Finland

Ljungan virus (LV, genus Parechovirus, family Picornaviridae) is considered currently to be a rodent‐borne virus. Despite suggested human disease associations, its zoonotic potential remains unclear. To date, LV antibody prevalence in both humans and rodents has not been studied. In this study, two different LV immunofluorescence assays (LV IFAs) were developed with LV genotypes 1 (LV strain 87‐012G) and 2 (LV strain 145SLG), and cross‐neutralization and ‐reaction studies were carried out with LV strain 145SLG. Finally, a panel of 37 Finnish sera was screened for anti‐LV antibodies using two different LV IFAs (LV 145SLG and LV 87‐012G) and a neutralization (NT) assay (LV 145SLG), and 50 samples from Myodes glareolus by LV IFA (LV 145SLG). The LV seroprevalence study showed 38% and 18% positivity in humans and M. glareolus, respectively. LV IFAs and NT assays were compared, and the results were in good agreement. The data are the first evidence of humans and rodents coming into contact with LV in Finland. Additional studies are required in order to acquire a better understanding of the prevalence, epidemiological patterns and possible disease association of LV infections. J Med. Virol. 85:2001–2008, 2013.

Human parechovirus and the risk of type 1 diabetes

Human parechoviruses (HPeVs) are RNA viruses associated mainly with mild gastrointestinal and respiratory infections in children and also cause neonatal sepsis and CNS infections. Human enteroviruses, close relatives of HPeVs, associate with the development of type 1 diabetes. In this study, the potential role of HPeV infections in promoting beta cell autoimmunity was investigated by analyzing stool samples of 54 prediabetic case and 134 healthy control children for the presence of HPeV RNA and comparing the derived infection frequencies. All 188 children were participants of the Finnish prospective Diabetes Prediction and Prevention study. Viral RNA was screened for using an HPeV‐specific RT‐PCR method coupled to liquid hybridization of the PCR product. The overall HPeV infection frequency did not differ between prediabetic case and control children. However, case boys had more HPeV positive samples in the 6‐month period before becoming autoantibody positive, when compared to the matching time‐period in controls (P < 0.01). HPeV infection at a young age does not appear to play a major role in the development of beta‐cell autoimmunity. In boys, however, HPeVs showed time‐dependent association with the first detection of diabetes‐associated autoantibodies. Thus, in boys, HPeV infections cannot be excluded as a gender‐specific risk factor which promotes the development of type 1 diabetes. J. Med. Virol. 85:1619‐1623, 2013.

First two cases of neonatal human parechovirus 4 infection with manifestation of suspected sepsis, Finland

Human parechoviruses are a family of viruses closely related to enteroviruses, and associated with neonatal sepsis-like syndrome, respiratory symptoms and gastrointestinal infection. Here we present clinical details of two neonatal sepsis cases suspected to be caused by HPeV4 infection. The patients were hospitalized in October, 2012. No other causative agents were detected.

ADEM and virus infection

Fig. 1. T1 weighted pre- (a) and post-contrast (b) images. Multiple lesions of white matter show contrast enhancement.∗ Corresponding author at: Haartman institute, Department of Virology, Haartmaninkatu 3, POB 21 FIN-00014 University of Helsinki, Finland. Tel.: +358 9 19126579;fax: +358 9 19126491.E-mail address: jenna.pietilainen@helsinki.fi (J. Pietilainen-Nicklen).

Intertypic recombination of human parechovirus 4 isolated from infants with sepsis-like disease

BACKGROUND Human parechoviruses (HPeVs) (family Picornaviridae), are common pathogens in young children. Despite their high prevalence, research on their genetic identity, diversity and evolution have remained scarce. OBJECTIVES Complete coding regions of three previously reported HPeV-4 isolates from Finnish children with sepsis-like disease were sequenced in order to elucidate the phylogenetic relationships and potential recombination events during the evolution of these isolates. STUDY DESIGN The isolated viruses were sequenced and aligned with all HPeV complete genome sequences available in GenBank. Phylogenetic trees were constructed and similarity plot and bootscanning methods were used for recombination analysis. RESULTS The three HPeV-4 isolates had 99.8% nucleotide sequence similarity. The phylogenetic analysis indicated that capsid-encoding sequences of these HPeV-4 isolates were closely related to other HPeV-4 strains (80.7-94.7% nucleotide similarity), whereas their non-structural region genes 2A to 3C clustered together with several HPeV-1 and HPeV-3 strains, in addition to the HPeV-4 strain K251176-02 (isolated 2002 in the Netherlands), but not with other HPeV-4 strains. However, in 3D-encoding sequence the Finnish HPeV-4 isolates did not cluster with the strain HPeV-4/K251176-02, but instead, formed a distinct group together with several HPeV-1 and HPeV-3 strains. Similarity plot and Bootscan analyses further confirmed intertypic recombination events in the evolution of the Finnish HPeV-4 isolates. CONCLUSION Intertypic recombination event(s) have occurred during the evolution of HPeV-4 isolates from children with sepsis-like disease. However, due to the low number of parechovirus complete genomes available, the precise recombination partners could not be detected. The results suggest frequent intratypic recombination among parechoviruses.