Avian pneumovirus (APV) causes acute respiratory tract infection both in turkeys (turkey rhinotracheitis) and chickens (swollen head syndrome (SHS)) with sudden onset and rapid spread through the flocks. In this study, an immunochemiluminescent Southern blot RT-PCR assay was employed to detect a F gene transcript of the APV in two European turkey isolates and two Brazilian chicken isolates. Limiting dilution PCR was carried out to compare the sensitivity of immunochemiluminescent Southern blot assay and nested PCR assay (nPCR). The sensitivity and specificity of immunochemiluminescent Southern blot RT-PCR assay were comparable to that of nPCR, and at least 100 fold more sensitive than a single PCR amplification. Sequence analysis of the 175 bp product of the F gene revealed 100% identity with APV sequences described earlier. (C) 1999 Elsevier Science B.V. All rights reserved.792237241