http://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-11-16 http://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-... Recent bus or tram use w

http://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-11-16 http://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-... Recent bus or tram use within five days of symptom onset was associated with an almost six-fold increased risk of consulting for ARI.