Circulation and in vivo distribution of duck hepatitis A virus types 1 and 3 in infected ducklings

The circulation of duck hepatitis A virus types 1 (DHAV-1) and 3 (DHAV-3) in Southeast Asia has resulted in a continuously changing epidemiological scenario. In this study, a duplex real-time PCR assay for simultaneous quantitative detection of DHAV-1 and DHAV-3 was established, and 200 liver samples from dead ducklings collected from 31 different flocks in Shandong province, China, were tested. Fifty-eight (29.0 %) samples from 13 flocks were positive for DHAV-1 single infection, 113 (56.5 %) samples from 13 other flocks were positive for DHAV-3 single infection, and 24 samples (12.0 %) from four flocks were positive for both viruses. DHAV-1 and DHAV-3 were detected with high viral loads in all of the organs tested (liver, spleen, pancreas, kidney, heart, thymus, bursa of Fabricius and brain). No significant difference in DHAV-1 and DHAV-3 viral loads was found between singly infected and coinfected samples, and there was no correlation between the viral loads of the two viruses and the age of dead ducklings. To the best of our knowledge, this is the first report about the in vivo distribution of DHAV-1 and DHAV-3 in clinically infected ducklings.