Identification and virulence characterization of fowl adenoviruses in Korea.
Since 2007, 55 adenovirus strains have been isolated from commercial chicken flocks in Korea and have been identified and the pathogenicity of these isolates was confirmed in specific-pathogen-free chickens of different age. Based on sequencing analysis of the hexon gene, 55 FAdV isolates were genetically related to the IBH-2A strain of FAdV3 (4 isolates, 99.2% to 100%), the KR5 strain of FAdV4 (22 isolates, 97.9% to 99.2%), the 764 strain of FAdV9 (11 isolates, 99.1% to 99.3%), and the 1047 strain of FAdV11 (18 isolates, > 99%). Experimental infections with four serotypes of FAdV resulted in high mortality of 18-day-old chicken embryos and 1-day-old chicks with marked liver necrosis similar to those observed in the natural outbreaks. Notably, specific hydropericardium was observed in chicks challenged with the K531 strain (serotype 4). However, 3-wk-old chickens challenged with FAdVs, regardless of serotype, did not show any clinical signs or mortality except histologic lesions of focal hepatocytic necrosis with mild lymphocytic infiltration. The results indicate that four FAdV serotypes (3, 4, 9, and 11) are the dominant serotypes of FAdVs in the Korea and are pathogenic enough to cause clinical disease in young chicks. The present investigation provides important information on the epidemiology and pathogenesis of FAdVs and highlights the importance of control strategies against FAdV infection in Korea.
Avian Disease Laboratory, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.
Tae-Hyun
TH
Lim
Hyun-Jeong
HJ
Lee
Dong-Hun
DH
Lee
Yu-Na
YN
Lee
Jae-Keun
JK
Park
Ha-Na
HN
Youn
Myung-Seob
MS
Kim
Ho-Sik
HS
Youn
Joong-Bok
JB
Lee
Seung-Yong
SY
Park
In-Soo
IS
Choi
Chang-Seon
CS
Song
D000257:Adenoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D000818:Animals; D000259:Aviadenovirus / Q000302:isolation & purification / Q000472:pathogenicity*; D002645:Chickens; D010063:Ovum / Q000821:virology; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D056910:Republic of Korea / Q000453:epidemiology; D013047:Specific Pathogen-Free Organisms; D014774:Virulence