Characteristics of human metapneumovirus infection prevailing in hospital wards housing patients with severe disabilities.

Epidemics of infectious diseases often occur at long-term inpatient facilities for patients with severe motor and intellectual disabilities. However, the pathogens causing these infections remain unknown in approximately half of such epidemics. Two epidemics of respiratory tract infection occurred in 2 wards in the National Hospital Organization Ehime Hospital (prevalence 1, 34 infected out of 59 inpatients in the A ward in September 2011; prevalence 2, 8 infected out of 58 inpatients in the B ward in June 2012). Human metapneumovirus (HMPV) was detected from the nasal (and some pharyngeal) swabs from 17 patients. Based on phylogenetic analysis of viral genomes, the virus was grouped in subgroup A2 (prevalence 1) and B2 (prevalence 2). We considered that the viruses had spread through the 2 wards. The average duration of high fever in the 42 patients was 6.8 days, with the majority of fevers exceeding 38℃ (79%) and being accompanied by a productive cough. Ten out of 17 patients (59%) in whom HMPV was detected had decreased lymphocyte and increased monocyte counts in the blood. Eleven cases (65%) had elevated-C reactive protein levels and fever protraction as well as images of bronchitis or pneumonia on chest radiographs approximately 1 week after onset. Anti-HMPV antibody in the blood was positive in 95% of patients (151 of 159 inpatients), indicating no relation between HMPV infection and antibody titer but revealing recurrent infections. In view of the fever protraction and frequent co-occurrence of bronchitis and pneumonia at long-term inpatient facilities for immunocompromised patients such as the ones in this study, the prevalence of HMPV must be carefully monitored, and preventive measures and early-stage treatments are required.

[Prevalence of human metapneumovirus infection in hospital wards handling patients with severe motor and intellectual disabilities].

Epidemics of infectious diseases often occur in hospital wards handling patients with severe motor and intellectual disabilities. However, the causative pathogens are not identified in half of these epidemics. Recently, an epidemic occurred in 2 wards consecutively in the National Hospital Organization Ehime Hospital in March-April, 2010. In this epidemic, 18 of 40 patients in one ward and 14 of 60 patients in another ward showed symptoms, and human metapneumovirus (HMPV) was detected from pharyngeal and/or nasal swabs of 4 patients. Phylogenetic analysis of the viral genomes showed that the virus belonged to subgroup B2, and the same virus had spread consecutively in 2 wards. High fever lasted for 5.3 days on average in the 32 inpatients, was mostly over 38 degrees C and was accompanied by productive coughs. In the 4 patients in whom human HMPV was detected, the number of peripheral blood lymphocytes decreased but that of monocytes increased. Pneumonia developed in two patients as shown by chest radiography, and an increased number of peripheral blood neutrocytes and increased CRP levels were noted. Of the 151 inpatients, anti-human HMPV antibody was found in the sera of 143 (95%), and the relationship between high fever and antibody titer was not significant, indicating that HMPV infection could recur in spite of the presence of specific antibodies. Because human HMPV is highly prevalent, and causes high fever and pneumonia, hospital staff should be vigilant for any signs of this virus in hospital wards and take steps to prevent infection in long-term inpatients.

Detection of sapoviruses and noroviruses in an outbreak of gastroenteritis linked genetically to shellfish.

Norovirus (NoV) and sapovirus (SaV) are important pathogens of human gastroenteritis. Compared to NoV, the transmission route of SaV is unclear. An outbreak of gastroenteritis occurred at a restaurant in June 2008, and SaV and NoV were detected in fecal specimens from 17 people who ate at the restaurant and one asymptomatic food handler and also in stripped shellfish and liquids remaining in the shellfish packages by reverse transcription-polymerase chain reaction (RT-PCR) and/or real-time RT-PCR. Nucleotide sequencing analysis of the RT-PCR products corresponding to the partial capsid region revealed 99.3-100% identities for SaV and 98.6-99.3% identities for NoV among the digestive diverticulum of the frozen stripped shellfish (Ruditapes philippinarum), "Asari," the package liquid, and feces from symptomatic or asymptomatic guests. These results suggested a link between the consumption of contaminated shellfish and clinical features in the patients. While the transmission of NoV by shellfish has been reported, this report shows that SaV can also be transmitted by shellfish.