Human rhinovirus and human respiratory enterovirus (EV68 and EV104) infections in hospitalized patients in Italy, 2008-2009.

The epidemiology of picornavirus infections along with associated risk factors for lower respiratory tract infections (LRTI) and duration of virus shedding were investigated in 985 hospitalized patients in the period October 2008 September 2009. One-third of patients were human rhinovirus (HRV) positive. Of 336 HRV-associated episodes, 153 (45.5%) were sustained by HRV-A, 31 (9.2%) by HRV-B, and 93 (27.7%) by HRV-C, while 7 episodes showed multiple HRV types and 52 were sustained by undefined HRV species. Independent risk factors for LRTI included high viral load and age less than 5 years. Twenty (2.1%) patients were enterovirus (EV)-positive (12 had EV-68, 7 EV-104, and 1 E-13 infection). Half of the EV-positive patients had a LRTI and were younger with respect to patients with upper RTI (median 18 months versus 37 years; P < 0.001). HRVs are often the cause of LRTI in children less than 5 years, frequently in association with a high viral load.