Svetlana Kaijalainen

Co-circulation of coxsackieviruses A6 and A10 in hand, foot and mouth disease outbreak in Finland

BACKGROUND A nationwide outbreak of hand, foot and mouth disease (HFMD) occurred in Finland in autumn 2008. The outbreak was untypical since a considerable number of clinically diagnosed patients were adults. Furthermore, many of the patients suffered from onychomadesis several weeks after the acute phase of HFMD. OBJECTIVES Detection, identification and phylogenetic analysis of human enteroviruses (HEV) that caused the outbreak. STUDY DESIGN A total of 420 clinical specimens were obtained from 317 HFMD cases all over the country. The presence of HEV in the specimens was analysed by virus isolation and/or direct real-time RT-PCR; selected HEV strains were further typed by molecular methods. The genetic similarities of HEV strains were assessed by phylogenetic analyses on partial VP1 sequences. RESULTS HEV were detected in 212 HFMD cases, including both children and adults, throughout Finland. Two HEV types, coxsackieviruses A6 (CV-A6) and A10 (CV-A10), were identified as the causative agents of the outbreak. One genetic variant of CV-A6 predominated, but, additionally, three other genetically distinct CV-A6 strains were found. All CV-A10 strains segregated into one genetic cluster distinct from previously reported CV-A10 sequences. CONCLUSIONS The Finnish 2008 HFMD outbreak was caused by two infrequently detected, co-circulating, coxsackie A viruses. Our data suggest endemic circulation of both CV-A types in Northern Europe and that the outbreak was due to the emergence of new genetic variants of these viruses.

Cellular tropism of human enterovirus D species serotypes EV-94, EV-70, and EV-68 in vitro: implications for pathogenesis.

Enterovirus 94 (EV‐94) is an enterovirus serotype described recently which, together with EV‐68 and EV‐70, forms human enterovirus D species. This study investigates the seroprevalences of these three serotypes and their abilities to infect, replicate, and damage cell types considered to be essential for enterovirus‐induced diseases. The cell types studied included human leukocyte cell lines, primary endothelial cells, and pancreatic islets. High prevalence of neutralizing antibodies against EV‐68 and EV‐94 was found in the Finnish population. The virus strains studied had wide leukocyte tropism. EV‐94 and EV‐68 were able to produce infectious progeny in leukocyte cell lines with monocytic, granulocytic, T‐cell, or B‐cell characteristics. EV‐94 and EV‐70 were capable of infecting primary human umbilical vein endothelial cells, whereas EV‐68 had only marginal progeny production and did not induce cytopathic effects in these cells. Intriguingly, EV‐94 was able to damage pancreatic islet β‐cells, to infect, replicate, and cause necrosis in human pancreatic islets, and to induce proinflammatory and chemoattractive cytokine expression in endothelial cells. These results suggest that HEV‐D viruses may be more prevalent than has been thought previously, and they provide in vitro evidence that EV‐94 may be a potent pathogen and should be considered a potentially diabetogenic enterovirus type. J. Med. Virol. 82:1940–1949, 2010.

Enterovirus-induced gene expression profile is critical for human pancreatic islet destruction.

Aims/hypothesisVirally induced inflammatory responses, beta cell destruction and release of beta cell autoantigens may lead to autoimmune reactions culminating in type 1 diabetes. Therefore, viral capability to induce beta cell death and the nature of virus-induced immune responses are among key determinants of diabetogenic viruses. We hypothesised that enterovirus infection induces a specific gene expression pattern that results in islet destruction and that such a host response pattern is not shared among all enterovirus infections but varies between virus strains.MethodsThe changes in global gene expression and secreted cytokine profiles induced by lytic or benign enterovirus infections were studied in primary human pancreatic islet using DNA microarrays and viral strains either isolated at the clinical onset of type 1 diabetes or capable of causing a diabetes-like condition in mice.ResultsThe expression of pro-inflammatory cytokine genes (IL-1-α, IL-1-β and TNF-α) that also mediate cytokine-induced beta cell dysfunction correlated with the lytic potential of a virus. Temporally increasing gene expression levels of double-stranded RNA recognition receptors, antiviral molecules, cytokines and chemokines were detected for all studied virus strains. Lytic coxsackievirus B5 (CBV-5)-DS infection also downregulated genes involved in glycolysis and insulin secretion.Conclusions/interpretationThe results suggest a distinct, virus-strain-specific, gene expression pattern leading to pancreatic islet destruction and pro-inflammatory effects after enterovirus infection. However, neither viral replication nor cytotoxic cytokine production alone are sufficient to induce necrotic cell death. More likely the combined effect of these and possibly cellular energy depletion lie behind the enterovirus-induced necrosis of islets.

All Known Human Rhinovirus Species Are Present in Sputum Specimens of Military Recruits During Respiratory Infection

Human rhinoviruses (HRV) are known to cause common cold as well as more complicated respiratory infections. HRV species -A, -B and -C have all been associated with lower respiratory infections and exacerbations of asthma. However, the type distribution of strains connected to different kinds of lower respiratory conditions is not clearly known. We have analysed the presence of HRV in sputum specimens derived from military recruits with and without pre-diagnosed asthma at times of acute respiratory infection (CIAS Study, 2004–2005). The analysis was performed with HRV and HEV real-time RT-PCR assays. Subsequently we studied type distribution of HRV strains by genetic typing in the VP4/VP2 genomic region. In total 146 (38.8%) specimens were HRV-positive and 36 (9.3%) HEV-positive. No difference was found in HRV detection between the asthmatic vs. non-asthmatic patients. Most of the genetically typed strains, 18 (62.1%), belonged to HRV-A, while HRV-B strains constituted five (17.2%) of the HRV-positive strains. HRV-C strain was typed four times from the HRV-positive cases and a HEV-D strain twice. We further typed six HEV positive strains in the partial VP1 region. Three of these belonged to HRV-A and three to HEV-D. HRV-A strains were discovered throughout the study period, while HRV-C strains originated from winter and spring specimens. Interestingly, four out of five typed HRV-B strains originated from the summer season specimens.

Diabetogenic Effects of the Most Prevalent Enteroviruses in Finnish Sewage

Common enterovirus infections appear to initiate or facilitate the pathogenetic processes leading to type 1 diabetes (T1D) and also sometimes precipitate the clinical disease. We have recently demonstrated that (1) enterovirus‐positive islet cells were seen on postmortem pancreatic specimens of several T1D patients but not in the corresponding samples of nondiabetic controls, and (2) several different enteroviruses can be associated with T1D. Enterovirus infections are transmitted from person to person by fecal–oral or respiratory routes, which means that infections usually start from the respiratory or gastrointestinal mucosa. Regardless of the clinical symptoms of the disease, viral replication continues in the submucosal lymphatic tissue for several weeks, up to a couple of months, and during that time the virus is excreted into the feces and translocated to the environment. Monitoring of sewage samples for enteroviruses can be used as a tool in epidemiologic studies of enterovirus. Finland has successfully used environmental control data in poliovirus surveillance for decades. About 24 samples have been collected annually from the Helsinki region, which covers about 20% of the population. In the present study, we have reanalyzed the sewage samples of the years 1993–2004 for nonpolio enteroviruses by inoculating them into five different continuous cell lines known to cover a wide range of serotypes. Isolated strains were identified by RT‐PCR and VP1 sequencing. The most commonly detected serotypes were coxsackie B viruses (CBV1–5) and echoviruses (E6, 7, 11, 25, 30). Diabetogenic effects of the most prevalent enterovirus serotypes were studied in primary human β cells.

Virus infections among young children—the first year of the INDIS study

The frequencies of early childhood infections were studied in healthy children with increased genetic risk for type 1 diabetes participating in the ongoing prospective high intensive infection follow‐up Study, INDIS, started in 2009 in Turku, Finland. Here the results obtained from 160 stool to 160 nasal swab specimens collected in parallel at times of infectious symptoms in 2009–2010 from 45 children at the age of 24 months or younger are reported. The specimens were analyzed for enteric (human enterovirus, norovirus, rotavirus, sapovirus, astrovirus) and respiratory RNA viruses (human enterovirus and rhinovirus) common in early childhood, respectively, using highly validated virus‐specific real‐time PCR methods. According to the results 96% of the children had at least one virus infection during the study period and one or several viral agents were detected in 76% of sample sets. The most prevalent viral agents were human rhinovirus, enterovirus, parechovirus, and norovirus (genotype GII) with positive specimens 57.5%, 28.8%, 19.4%, and 6.9%, respectively. Other intestinal viruses were found in less than 2% of stool specimens. Single infections covered 40.0% of the specimens while multiple infections with two or more infectious agents were detected in 36.3% of specimens and altogether 11 combinations of viruses were included in the mixed infections. Although human enterovirus is known to be a frequent finding in stool specimens, especially during early childhood, it was found in this study more frequently in nasal swab specimens. Whether this is true, more general, in countries with the high hygiene level remains to be shown. J. Med. Virol. 85:1678–1684, 2013.

Detection of Imported Wild Polioviruses and of Vaccine-Derived Polioviruses by Environmental Surveillance in Egypt

ABSTRACT Systematic environmental surveillance for poliovirus circulation has been conducted in Egypt since 2000. The surveillance has revealed three independent importations of wild-type poliovirus. In addition, several vaccine-derived polioviruses have been detected in various locations in Egypt. In addition to acute flaccid paralysis (AFP) surveillance, environmental surveillance can be used to monitor the wild poliovirus and vaccine-derived poliovirus circulation in populations in support of polio eradication initiatives.

Picornaviruses in cerebrospinal fluid of children with meningitis in Luanda, Angola†

Human enteroviruses are the most common cause of viral meningitis. Viral–bacterial interaction may affect the clinical course and outcome of bacterial meningitis. In Africa, viruses might be responsible for 14–25% of all meningitis cases. However, only few studies from Africa have reported detection of viruses in the cerebrospinal fluid (CSF) or mixed viral–bacterial infections of the central nervous system (CNS). The aim of the present study was to investigate the presence of picornaviruses in the CSF of children suffering from meningitis in Luanda, Angola. The study included 142 consecutive children enrolled in a prospective study of bacterial meningitis in Luanda between 2005 and 2006, from whom a CSF sample was available. CSF samples were obtained at hospital admission, stored in a deep‐freeze, and transported to Finland for testing by real‐time PCR for picornaviruses. Enteroviruses were detected in 4 (3%) of 142 children with presumed bacterial meningitis. A 5‐month‐old girl with rhinovirus and Haemophilus influenzae meningitis recovered uneventfully. An 8‐year‐old girl with human enterovirus and pneumococcal meningitis developed no sequelae. A 2‐month‐old girl with human enterovirus and malaria recovered quickly. A 7‐month‐old girl with human enterovirus was treated for presumed tuberculous meningitis and survived with severe sequelae. Mixed infections of the CNS with picornaviruses and bacteria are rare. Detection of an enterovirus does not affect the clinical picture and outcome of bacterial meningitis. J. Med. Virol. 84: 1080–1083, 2012.

Human rhino- and enteroviruses in children with respiratory symptoms in Luanda, Angola

Abstract Objectives: The role of human rhinoviruses (HRV) and human enteroviruses (HEV) in common colds, as well as their seasonality, remains largely unknown in tropical environments. The study aimed to define the frequency and clinical features of HRV and HEV in children with respiratory symptoms in tropical Africa during autumn and winter. Methods: Clinical data and PCR assays of nasopharyngeal swabs (NPS) were collected from 67 (66%) children with and 35 (34%) children without chronic illnesses who were attending different outpatient clinics at a paediatric tertiary-care hospital in Luanda, Angola. Results: Thirty-six (35%) children had HIV infection, and 27 (26%) were malnourished. Thirty-seven (36%) out of 102 NPS specimens were virus-positive: 34 (33%) for HRV and 10 (10%) for HEV. Seven (7%) had co-infection. The highest HRV-positivity rate (47%) occurred in July (P = 0·02), a mid-winter month with high relative humidity but no precipitation. Virus positivity was associated with younger age (median 36 vs 52 months, P = 0·02) but not with specific symptoms or findings. Conclusions: HRVs play a major role in young children’s respiratory infections in urban tropical Angola during autumn and winter. A better understanding is required of the seasonality and clinical outcomes of these viruses in children living in resource-poor tropical countries.