Enterovirus infection among patients admitted to hospital in Hong Kong in 2010: epidemiology, clinical characteristics, and importance of molecular diagnosis.

The activity of hand, foot, and mouth disease (HFMD) in Hong Kong was high in 2010. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) had been performed routinely for diagnosis of enterovirus (EV) infection among hospitals in a geographical cluster. The aim of the study was to describe the epidemiology and the clinical pattern of EV-related hospital admission in 2010, and evaluate the impact of RT-PCR compared to conventional method. This was a retrospective study and patients with laboratory confirmed EV infection were included. Demographic information, clinical features, complications, and laboratory findings were analyzed. Among the 113 patients identified, HFMD was the most common presentation (84/113, 74%), followed by meningitis (10/113, 9%). Respiratory (52/113, 46%) and gastrointestinal symptoms like vomiting (36/113, 32%) and diarrhea (15/113, 13%) were quite common. For cases with central nervous system (CNS) or myocardial complications, there were significantly fewer oral ulcer and rash over hands and feet compared to their counter group. Serious infection mainly affected children younger than 1-year old and adults. Dual infection was noted among seven patients (6%). Compared to RT-PCR, conventional virus isolation detected only 14-16% of the infections. The relative low culture positive rate could be explained by the circulation of Coxsackie A6 in 2010 which was difficult to be isolated by cell culture. Diagnosis of EV infection among hospitalized patients may not be straightforward. EV RT-PCR significantly improved laboratory diagnosis and delineation of epidemiology of EV infection compared to conventional methods.