Joubert Hilda W, Aitchison Henry, Maartens Louis H, Venter Estelle H
Deltamune (Pty) Ltd., Lyttelton.
J S Afr Vet Assoc. 2014 Nov 5;85(1):1058. doi: 10.4102/jsava.v85i1.1058.
Fowl adenovirus (FAdV) is a member of the genus Aviadenovirus and causes a number of economically important poultry diseases. One of these diseases, inclusion body hepatitis (IBH), has a worldwide distribution and is characterised by acute mortality (5% - 20%) in production chickens. The disease was first described in the United States of America in 1963 and has also been reported in Canada, the United Kingdom, Australia, France and Ireland, but until now, not in South Africa. Adenoviruses isolated from the first outbreak of IBH in South Africa were able to reproduce the disease in chicken embryo livers. The aim of the present study was to characterise the viruses and determine the pathogenicity of the FAdV strains responsible for the first reported case of IBH in South Africa. Polymerase chain reaction (PCR) amplification of the L1 loop region of the fowl adenovirus hexon gene using degenerate primer pair hexon A/B was used to identify the viruses that were isolated. Restriction fragment length polymorphism (RFLP) of the amplification products was used for the differentiation of 14 isolates of fowl adenovirus. Sequencing of the PCR products followed by amino acid comparison and phylogenetic analysis using the L1 loop region of the hexon protein was done to determine the identity of the isolates. Amino acid sequences of the hexon genes of all the South African isolates were compared with those of reference strains representing FAdV species. Amino acid comparison of 12 South Africa field isolates to FAdV reference strains revealed a high sequence identity (> 93.33%) with reference strains T8-A and 764. Two of the isolates had high sequence identity (93.40%) with reference strains P7-A, C2B and SR48. Phylogenetic analysis of the L1 loop region of the hexon protein of all 14 South African isolates was consistent with their RFLP clusters. The mortality rates of embryos challenged with 106 egg infective doses (EID50) FAdV 2 were 80% - 87% and mortality rates for embryos challenged with 105.95 (EID50) FAdV 8b were 65% - 80%.
禽腺病毒（FAdV）是禽腺病毒属的成员，可引发多种具有重要经济意义的家禽疾病。其中一种疾病，即包涵体肝炎（IBH），在全球范围内均有分布，其特征是产蛋鸡急性死亡率为5% - 20%。该疾病于1963年在美国首次被描述，在加拿大、英国、澳大利亚、法国和爱尔兰也有相关报道，但截至目前，南非尚未有此病例报告。从南非首次爆发的IBH疫情中分离出的腺病毒能够在鸡胚肝脏中引发该疾病。本研究的目的是对病毒进行特征分析，并确定导致南非首例报告的IBH病例的FAdV毒株的致病性。使用简并引物对hexon A/B对禽腺病毒六邻体基因的L1环区域进行聚合酶链反应（PCR）扩增，以鉴定分离出的病毒。扩增产物的限制性片段长度多态性（RFLP）用于区分14株禽腺病毒分离株。对PCR产物进行测序，随后使用六邻体蛋白的L1环区域进行氨基酸比较和系统发育分析，以确定分离株的身份。将所有南非分离株的六邻体基因氨基酸序列与代表FAdV种的参考菌株的序列进行比较。12株南非野外分离株与FAdV参考菌株的氨基酸比较显示，与参考菌株T8 - A和764具有高度序列同一性（> 93.33%）。其中两株分离株与参考菌株P7 - A、C2B和SR48具有高度序列同一性（93.40%）。对所有14株南非分离株的六邻体蛋白L1环区域进行的系统发育分析与它们的RFLP聚类结果一致。用106个鸡胚感染剂量（EID50）的FAdV 2攻击的胚胎死亡率为80% - 87%，用105.95（EID50）的FAdV 8b攻击的胚胎死亡率为65% - 80%。
