AHRI report No.18

EPIDEMIOLOGICAL STUDIES ON DUCK VIRAL HEPATITIS

aiwan Provincial Research Institute for Animal Health, Tan-Sui, Taipei, Taiwan, R.O.C. 

Yong-Siu Lu 

This study succeeded in f"mding serologic evidence of duck hepatitis virus (DHV) in many kinds of domestic fowl. The antJ"body investigation revealed that 55% of duck flocks in Taiwan had been exposed to DHV. The antibody response of five survivors were evaluated for 120 days. 
Twenty-three strains of DHV were isolated from intestines of Common carp and Tilapia taken from ponds where affected ducklings were raised. The titer was 104^2.7-4.2 PFU/ml. Virus could be iaolated from f"JSh of the same pond even six years after the last DVH outbreak. V"U11Bes isolated from f"JSh were pathogenic to S days old duckling and produced typical lesion of DVH. 
DHV (10^2.0-3.6 PFU/ml) was recovered from Tilapia 3-5 days after oral inoculation with 0.1 ml of Hunei-6 strain (10^5.2 PFU/ml). DHV (10^1.9-5.9 PFU/ml) was also . recovered from Tilapia 2-7 days after feeding with intestines of ducklings died by intravenous injection with I-Lan strain (10^7.0 EID50/ml). 
The data strongly suggested that Common carp, Tilapia and domestic fowls acted as a reservoir or carrier for DHV. They provided constant SQurces of infection and made it difficult to prevent DVH outbreak. 

DUCK VIRAL HEPATITIS ;DHV