本試驗由無臨床症狀的一日齡小雞分離到八株家禽腺病毒(FAVs),萃取FAV分離株之DNA並依照Zsak和Kisary(Intervirology 22:110-114, 1984)的分類方法進行限制酶切割反應,可將此八株分離株區分為A及C基因群。另外,依照Raue和Hess(J Virol Methods 73:211-217, 1998)之分類方法亦可將此八株分離株歸類到與上述相同的A、C基因群,並可對照限制酶切割圖譜推測分離株屬於第1及第4血清型(FAV-1&FAV-4)。以病毒中和試驗區分FAV分離株血清型的結果印證了上述推測。爾後進行病原性試驗,取FAV分離株口服接種103 TCID50於一日齡無特定病原(SPF)小雞,並接種cyclophosphamide測試分離株於免疫抑制下之病原性。結果A基因群之兩株分離株於免疫抑制下可顯著抑制雞隻之生長,但C基因群之分離株無須免疫抑制即可抑制雞隻生長。調查本試驗之八株FAV分離株來源雞場的10個血清型中和抗體力價,除了B場偵測不到FAV-3的抗體外,其餘血清型之抗體陽性率介於4.2%到91.7%之間。調查台灣肉雞、有色雞及種雞之FAV-1、FAV-4與FAV-8之中和抗體,小於2週之白肉雞其FAV-1、FAV-4與FAV-8抗體陽性率分別為58.1%、12.9%及70.4%,大於25週之種雞其FAV-1、FAV-4與FAV-8抗體陽性率分別為46.4%、12.1%與69.0%,其餘週齡雞群之FAV-1與FAV-4中和力價都偏低,但大於8週有色雞之FAV-8中和抗體陽性率卻高於76.0%,以上結果顯示FAV-8於所有雞場之感染皆是三者中最嚴重的。另2000-2001年間於台灣全省所收集之鴿子血清,檢測1080個樣本之FAV-1中和抗體與888個樣本之FAV-8中和抗體,結果均偵測不到任何抗體。
Eight fowl adenoviruses (FAVs) were isolated from day-old chicks without clinical signs. The DNA of these FAVs was extracted and analyzed by the restriction enzyme digestion method as described by Zsak and Kisary (Intervirology 22:110-114, 1984). The result indicated that FAV strains isolated in Taiwan can be grouped into two major DNA groups, A and C. Further comparison based on the method by Raue and Hess (J Virol Methods 73:211-217, 1998), showed that the eight Taiwanese FAVs were assigned into the same two DNA groups and corresponded to the serotype 1 and 4 (FAV-1&FAV-4). The virus neutralization test of the eight FAVs also showed the same result. The virulence of Taiwanese isolates was studied in day-old specific-pathogen-free (SPF) chicks. Each chick was orally inoculated with one strain of the virus at the dose of 103 TCID50. The results revealed that two DNA-group A strains significantly retarded the growth of the chicks with immunosuppression but the DNA-group C trains did without immuno- suppression. Serums from the flocks that the eight Taiwanese strains were isolated from were tested for virus-neutralizing antibody against 10 serotypes of FAV. In addition to FAV-3 in flock B, the antibody positive rates of the other serotypes were between 4.2% and 91.7%. The virus-neutralizing test was also used to examine serum obtained from white broilers, hybrid broilers, and breeder chickens in Taiwan. The seroprevalence of FAV-1, FAV-4, and FAV-8 were 58.1%, 12.9%, and 70.4% respectively in white broilers younger than 2 weeks, and 46.4%, 12.1%, and 69.0% respectively in breeders older than 25 weeks. The other age flocks showed very low antibody positive rates of FAV-1 and FAV-4, but the antibody positive rate of FAV-8 in hybrid broilers older than 8 weeks was higher than 76.0%. The result revealed that FAV-8 infection was the most common of them in all flocks. Antibodies against FAV-1 and FAV-8 were not detected in serum samples from the 1080 and 888 pigeons collected between Oct. 2000 and Sep. 2001 in Taiwan.