Fig. 1From: Use of laboratory and administrative data to understand the potential impact of human parainfluenza virus 4 on cases of bronchiolitis, croup, and pneumonia in Alberta, CanadaTemporal distribution of positive (a) hPIV1 specimens, (b) hPIV2 specimens, (c) hPIV3 specimens and (d) hPIV4 specimens. Only hPIV1 and hPIV3 specimens had peak rates of positivity greater than 5Â % when compared to total numbers of specimens tested by RVP. Rates of hPIV2 and hPIV4 specimen positivity were consistently below 1.5 and 2.5Â % respectively and were not analyzed for seasonal or yearly trendsBack to article page