Excretion patterns of human metapneumovirus and respiratory syncytial virus among young children

As respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) cause serious respiratory tract infections, the routes of transmission of these viruses are important to elucidate. We examined the modes of virus shedding and shedding duration of RSV and hMPV in young children.

From each child in a group of 44 children (37 RSV-positive, 6 hMPV-positive, and 1 co-infected child), aged between 0.5-38 months, hospitalised at Hvidovre Hospital, Copenhagen, Denmark, one nasopharyngeal aspirate (NPA), saliva, urine, and faeces sample were collected at inclusion and weekly in a three-week period. Sweat and blood samples were obtained at inclusion. The presence of RSV and hMPV RNA was detected using real-time RT-PCR.

We detected RSV RNA in 28 saliva specimens, 5 stool samples, and 3 sweat samples. hMPV RNA was detected in one saliva specimen and two sweat samples. Four of the five children shedding RNA in faeces had diarrhoea and children shedding RNA in sweat were either less than five weeks of age or had a chronic lung disease. RSV and hMPV RNA was shed in nasal secretions for a median of 11.5 and 5.0 days respectively (p = 0.001). More than 75% of the family members of the infected children showed to have an upper respiratory tract infection when following up.

Viral RNA was present in nasal secretions, saliva, sweat, and faeces, but whether or not the virions were infectious and constitute a potential mode of transmission remains to be shown in future studies.