High Frequency of Enterovirus D68 in Children Hospitalised With Respiratory Illness in Norway, Autumn 2014

Karoline Bragstad; Kirsti Jakobsen; Astrid E. Rojahn; Marius K. Skram; Kirsti Vainio; Mona Holberg- Petersen; Olav Hungnes; Susanne G. Dudman; Anne-Marte B. Kran

Disclosures

Influenza Resp Viruses. 2015;9(2):59-63. 

In This Article

Abstract and Introduction

Abstract

Objectives An unexpectedly high proportion of children were admitted for severe respiratory infections at the Oslo University Hospital, Ullevål, Norway, during September and October, 2014. In light of the ongoing outbreak of enterovirus-D68 (EV-D68) in North America a real-time RT-PCR for screening of enterovirus and enterovirus D68 was established.

Design We developed a duplex real-time RT-PCR for rapid screening of enterovirus D68. The method target the 5' non-translated region (NTR) of the HEV genome at a location generally used for enterovirus detection.

Sample Nasopharyngeal samples (n = 354), from children <15 years of age, received for respiratory virus analysis in OUH during September 1st and October 31nd, 2014, were tested for enterovirus and screened for enterovirus D68.

Main outcome measures and results The duplex real-time RT-PCR method was an efficient tool for rapid screening for EV-D68 in respiratory specimens. Enterovirus was detected in 66 (22%) of 303 pediatric nasopharyngeal samples collected from children hospitalised with acute respiratory infection within the two-month period. Out of these, 33 (50%) were EV-D68. EV-D68 was associated with acute flaccid paralysis in one child.

Conclusions An unexpectedly high proportion of children admitted for severe respiratory infections at the Oslo University Hospital, Ullevål, Norway, were diagnosed with EV- D68 during September 1st and October 31nd, 2014. These results emphasise that greater vigilance is required throughout Europe as enteroviruses are cause of severe respiratory disease.

Introduction

EV-D68 was first described in 1962[1] and has been sporadically detected up to 2008. EV-D68 is one of the four serotypes (-D70, -D94, -D111 and -D68) assigned to human enterovirus (HEV)-D. Several outbreaks have occurred in recent years, and the largest outbreak is currently ongoing in North America.[2] Over the last several months (August to November 2014), EV-D68 has been associated with severe respiratory illness and comprises 40% of enterovirus-positive respiratory samples in North America (CDC, 2014). Also in the Netherlands, EV-D68 continues to circulate in a seasonal pattern after an outbreak in 2010.[3] Enteroviruses cause a broad variety of illnesses, mild to severe, mainly in children (e.g. hand-foot-and-mouth disease, meningitis and encephalitis, febrile exanthematous illness and conjunctivitis). Non-polio enteroviruses have also been associated with acute flaccid paralysis (AFP).[4,5]

EV-D68 has rarely been detected in Norway since the surveillance of enteroviruses started in 1965. Respiratory samples are only occasionally investigated for enteroviruses in hospitals, and samples received for surveillance of respiratory illness are mainly tested by a generic enterovirus PCR not distinguishing the different serotypes. However, enteroviruses from stool samples are typed by neutralisation test using antisera (monovalent and pools) supplied by WHO as part of the AFP surveillance.

In September 2014, the Oslo University Hospital (OUH) noticed an increased number of children with severe respiratory symptoms admitted to the hospital. Due to the recent outbreak of EV-D68 in America, nasopharyngeal samples from these patients were tested specifically for this virus, rendering a high proportion of EV-D68. Subsequently, nasopharyngeal samples from all children <15 years in OUH, hospitalised with respiratory illness from 1 September 2014 to 31 October 2014, were screened for enterovirus. By applying a highly sensitive duplex real-time RT-PCR distinguishing between enteroviruses and D68 (including EV-D viruses and polio), an ongoing large outbreak with EV-D68 in the Oslo area was effectively identified.

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