Korean Investigators Characterize Respiratory Viruses Causative of Croup

   Participants at the 50th annual meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy in Boston heard details of a study out of the Department of Pediatrics at Seoul National University in Korea describing the respiratory viruses involved in croup, a common respiratory tract infection in infants and children.

   Ji Yeon Sung, MD, and colleagues collected nasopharyngeal aspirates from children who visited the emergency department or were admitted at Seoul National University’s Bundang Hospital with the diagnosis of croup between January 2005 and June 2009. The condition is often thought to occur as a result of a recent viral infection, causing inflammation, edema, and narrowing of the larynx and trachea; the main manifestations are barking cough, hoarseness, and stridor.

   Viral agents account for most acute infectious croup; parainfluenza viruses (PIVs) are known as the most common etiological agent. However, human coronavirus NL63 (HCoV-NL63), originally described in 2004, was recently implicated as a common cause of croup in children below three years of age. In the study reported on at ICAAC, croup patients were analyzed to compare prevalence, epidemiology, and clinical manifestations of common etiologic viruses.

   Viruses were identified in 147 (80.8%) of the 182 croup patients. Coinfection with two viruses were found in 20 (11%) patients. The three most common detected were PIV1, HCoV-NL63, and influenza A. Patients with HCoV-NL63 were younger at the onset of illness and had shorter duration of fever.

   Forty-four patients (24.2%) were found to have PIV1. The second and the third most common viruses were HCoV-NL63 in 30 (16.5%) patients and influenza A virus in 25 (13.7%) patients. Other detected viruses include rhinovirus in 22 (12.1%) patients, PIV type 3 and respiratory syncytial virus (RSV) in 15 (8.2%) patients, human bocavirus (HBoV) in eight (4.4%) patients, human metapneumovirus in five (2.7%) patients, adenovirus in two (1.1%) patients, and influenza virus B and HCoV OC43/229E were identified in on (0.5%) patient.

   According to the Korean investigator’s experience, the outcome of coup was excellent, and management was not significantly different between the virus groups.

   Their presentation was titled “Role of Human Coronavirus NL63 in Hospitalized Children with Croup.”