Seropositivity and epidemiology of human parechovirus types 1, 3, and 6 in Japan

Abstract

Human parechoviruses (HPeVs) mainly infect young children, causing mild gastrointestinal and respiratory diseases; however, HPeV type 3 (HPeV3) causes severe systemic diseases in young infants. To clarify the characteristics of HPeV infections from the aspects of seropositivity and epidemiology, we measured neutralizing antibody titres against HPeVs in individuals of in different age groups and isolated HPeVs from various clinical specimens in Niigata, Japan. The seropositivity to HPeV1, 3, and 6 was higher in older age group. HPeV1 and HPeV6 seropositivities were maintained in adults, whereas HPeV3 seropositivity was significantly lower in subjects aged >40 years (P < 0·001, P = 0·003). This result suggests that adults have increased susceptibility to HPeV3 as they lack neutralizing antibodies against HPeV3. Of the HPeV isolates, HPeV1 and HPeV6 frequently caused gastrointestinal symptoms. Moreover, gastroenteritis patients with HPeV1 and HPeV6 were mainly aged 6 months-1 year and ⩾2 years, respectively. In contrast, only HPeV3 was isolated from neonates and young infants with sepsis or sepsis-like syndrome, often with respiratory symptoms. These results suggest that clinical symptoms are clinically related to HPeV genotype and patients' age.

Parechovirus A Infections in Healthy Australian Children During the First 2 Years of Life: A Community-based Longitudinal Birth Cohort Study

“…PeV-A1 detections occurred earlier than PeV-A3, agreeing with seroprevalence findings [10,11], but conflicting with RT-PCR-based studies [11,31]. However, the RT-PCR studies relied upon clinical samples, which may bias the PeV detection ages as PeV-A3 is associated primarily with disease before age 3 months [2,3,5,7,11]. Unlike stools, PeV was detected rarely in nasal swabs (0.2%) and was always associated with a PeV-positive stool of the same genotype, supporting fecal-oral as one transmission route.…”

“…PeV infection risk increased during summer, in agreement with some [2,3,7,11,15], but not all studies as late autumn peaks are also reported [6,11,13,15]. Presence of older household siblings was not associated with PeV or PeV-A3 infections within ORChID, a finding contrasting with hospital-based studies focusing mainly on PeV-A3 cases [33,34].…”

“…PeV-A1 detections occurred earlier than PeV-A3, agreeing with seroprevalence findings [10,11], but conflicting with RT-PCR-based studies [11,31]. However, the RT-PCR studies relied upon clinical samples, which may bias the PeV detection ages as PeV-A3 is associated primarily with disease before age 3 months [2,3,5,7,11].…”

“…However, neither study recruited before 3 months of age, and both sampled less frequently (monthly) and could sequence fewer (30%-73%) positive samples, meaning short or sequential episodes may have been missed [13,15]. By age 24 months, 94.9% of ORChID children had at least 1 PeV infection, agreeing with the Norwegian (86%), but not Finnish (48%) studies [10,13,15], and aligning with seroprevalence surveys [10,11,30]. In ORChID, primary…”

Parechovirus: an important emerging infection in young infants

“…Like enteroviruses, the epidemiology and clinical syndromes associated with HPeV vary by genotype 5 . HPeV1 and HPeV6 are primarily associated with milder gastrointestinal symptoms and presentation in children aged > 6 months 18 , 19 . HPeV may be isolated from respiratory specimens in children presenting with influenza‐like illness 20 and in faecal specimens from children presenting with viral diarrhoea 21 …”