An outbreak of human metapneumovirus infection in hospitalized psychiatric adult patients in Taiwan.

Human metapneumovirus (hMPV) is a paramyxovirus that is associated with respiratory tract infection (RTI) mostly in children, but these outbreaks have rarely been reported in adults. We encountered an outbreak of this disease involving 10 adults in a psychiatric ward in eastern Taiwan. The nasopharyngeal swab specimens from 13 patients with symptoms of RTI were obtained and analyzed. The RT-PCR tests were negative to influenza virus A/B, adenovirus, RSV, parainfluenza virus, coronavirus, Nipah virus and Legionella. The antigen tests were negative to Legionella, Chlamydia, and Mycoplasma. Blood culture was negative in all except patient no. 1, who was found positive for coagulase-negative staphylococci. The hMPV was identified in 10 of 13 adults (77%), but negative for the other virus. Cough was present in all (100%), fever in 90%, and X-ray evidence of pneumonia in 7 patients. One patient died of respiratory failure. We report this outbreak in a mental hospital to alert the medical profession that this unusual infection of hMPV can occur as an outbreak in an adult setting and is an occupational hazard for healthcare personnel.