Human coronavirus NL63, France

Abstract

The human coronavirus NL63 (HCoV-NL63) was first identified in The Netherlands, and its circulation in France has not been investigated. We studied HCoV-NL63 infection in hospitalized children diagnosed with respiratory tract infections. From November 2002 to April 2003, we evaluated 300 respiratory specimens for HCoV-NL63. Of the 300 samples, 28 (9.3%) were positive for HCoV-NL63. The highest prevalence was found in February (18%). The main symptoms were fever (61%), rhinitis (39%), bronchiolitis (39%), digestive problems (33%), otitis (28%), pharyngitis (22%), and conjunctivitis (17%). A fragment of the spike protein gene was sequenced to determine the variety of circulating HCoV-NL63. Phylogenetic analysis indicated that strains with different genetic markers cocirculate in France.

Figure 1

Ethidium bromide stain of 2% agarose gel showing reverse transcription–polymerase chain reaction (RT-PCR) products of human coronaviruses (HCoVs). A) Simple 1-step RT-PCR (HCoV-NL63, gene N): lane 1, size markers (100 bp); lane 2, negative control RT-PCR mix; lane 3, positive control HCoV-NL63. B) Multiplex 1-step RT-PCR (HCoVs NL63, OC43, 229E): lane 4, size markers (100 bp); lane 5, negative control RT-PCR mix; lane 6, positive control HCoV-NL63; lane 7, positive control HCoV-OC43; lane 8, positive control HCoV-229E; lane 9, mix of 3 positive control HCoVs (NL63, OC43, and 229E).

Figure 2

Number of human coronavirus NL63–positive samples per month. Fifty samples from patients hospitalized for acute respiratory symptoms were tested each month.

Figure 3

A) Phylogenetic analysis of a 523-bp region of the partial spike gene of 12 human coronavirus (HCoV)-NL63 isolates from France. To construct the trees, the 2 prototype strains NL63-Amsterdam1 and NL-AY518894 were included. HCoV-229E is used as an outgroup. A) Nucleotide sequence alignments created with ClustalX 1.83; bootstrap values ≥70 are indicated. B) Predicted amino acid sequences; bootstrap values ≥50 are indicated.