Detection of the new human coronavirus HKU1: a report of 6 cases

Abstract

Background: Human coronavirus HKU1 (HCoV-HKU1), a new group 2 coronavirus, was first characterized in 2005 from 2 adults with pneumonia in Hong Kong, China. To the best of our knowledge, there is no other report to date about the detection of this new virus. We report a molecular method allowing for the detection of HCoV-HKU1 and also report the clinical presentation of 6 infected patients.

Methods: We screened 141 specimens (135 nasal samples and 6 stool samples) received in February and March 2005 in our laboratory and obtained from 135 hospitalized patients (61.5% of whom were <5 years old and 34.1% of whom were >20 years old) for HCoV-HKU1.

Results: HCoV-HKU1 was detected in 6 (4.4%) of the 135 nasal specimens and in 2 (33.3%) of the 6 stool samples; the positive samples were obtained from 6 patients (5 children and 1 adult). The clinical presentation of these 6 patients was as follows: 3 were admitted to the hospital for acute enteric disease resulting in severe dehydration associated with upper respiratory symptoms; 1 had fever, otitis, and febrile seizure; 1 had a sample obtained to investigate failure to thrive; and 1 had a sample obtained for exploration of X-linked agammaglobulinemia and hyperleucocytosis.

Conclusion: HCoV-HKU1 can be detected in respiratory and stool samples from children and adults in a part of the world other than Hong Kong. Our results suggest that HCoV-HKU1 could be associated with respiratory and enteric diseases, and its detection can be related to a persistent asymptomatic infection in patients with poor underlying conditions.

Figure 1

Ethidium bromide stain of 2% agarose gel showing RT-PCR products (443 bp) of partial coronavirus N gene with human coronavirus HKU1—specific primers. Lane 1, size marker (100 bp); lanes 2, 4–7, and 9, positive respiratory samples; lanes 3 and 8, negative control RT-PCR mix.

Figure 2

Phylogenetic analysis of a 603-bp region of partial spike gene of 4 human coronavirus (HCoV)-HKU1 isolates from France. The phylogenetic tree was constructed by the neighbor-joining method, and bootstrap values were determined by 1000 replicates in Clustal X, version 1.83. To construct the tree, the reference strain HCoV-HKU1 (NC006577) was included. HCoV-OC43 is used as the outgroup.

Table 1

Clinical presentation of patients infected with human coronavirus HKU1.