Year: 2014
Type: dissertation
Study design: Observational Study
Abstract: Human parechovirus (HPeV) and Ljungan virus (LV) are non-enveloped, single-stranded RNA viruses that form the genus Parechovirus in the family Picornaviridae. The interest in these viruses has notably increased over the past 15 years because of their strengthened associations to human and animal diseases. HPeV types 1 and 3 have been associated with more severe infections in young children, such as infections of the central nervous system (CNS) and sepsis-like disease. Rodent-infecting LV has been suggested to possess zoonotic potential and induce various human diseases. However, the proof for this remains lacking. This study aimed to describe the epidemiological features of HPeVs in Finland and in the Netherlands, to examine the connection between HPeV-induced infection and human diseases and to study the circulation of LV in Finland. The epidemiological analysis of stool samples, collected from 1996 to 2007, revealed that HPeVs are highly common in healthy Finnish children. HPeV was primarily detectable in children under 2 years of age. Altogether, 39% of the study participants tested positive for HPeV at least once during the study period. HPeVs circulated throughout the year, with a distinct seasonal peak in October-November. The results indicated that not only the previously described HPeV1 but also HPeV genotypes 3 and 6 circulate in Finland. Microneutralisation assays, which were set up to detect HPeV1 to 6, the most common genotypes in Europe, provided a deeper understanding of HPeV seroprevalence in the Finnish and Dutch populations. Seropositivity for HPeV1, 2 and HPeV4 to 6 was high and moderate in adults, in contrast to seropositivity for HPeV3, which was extremely low. The serological data demonstrate that HPeV types 1 to 6 might be even more prevalent than previously assumed. All six HPeV types circulate in Finland. In addition to HPeV detection in background populations, we presented the first cases of severe infection in neonates with HPeV4 and, subsequently, the first isolation of this genotype in Finland. Five hospitalised neonates with a sepsis-like disease in the fall of 2012 were positive for HPeV. Four of these children had HPeV4, indicating a potential small epidemic of this genotype, whereas one HPeV remained untyped. In addition, we detected HPeV3 in a neonate with suspected viral sepsis in October 2011 and another untyped HPeV in a child with symptoms corresponding to acute disseminated encephalomyelitis in May 2012. Following these findings, we promoted the addition of HPeV detection to routine diagnostics of young children. To extend the knowledge regarding other parechoviruses in Finland, we studied LV antibody prevalence in both humans and rodents. The seroprevalence detected for LV was 38% in humans and 18% in bank voles (Myodes glareolus). The observation of LV antibodies in humans is relatively high because LV has never been isolated from humans. These results suggest that an LV or LV-like virus, in addition to HPeVs, circulates frequently among human populations in Finland.
Source: Työväentutkimus Vuosikirja
Author: Pekka Kolehmainen
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1572361833