台灣伴侶動物A型流行性感冒病毒之鑑定

Abstract

A型流行性感冒病毒在染伴侶動物犬和貓的感染報告非常少，然而近來許多A型流感病毒陸續從患有呼吸道疾病之犬貓被分離出來，部份亞型已經被證實可持續性在犬之間傳播。但在台灣的伴侶動物研究中，目前並無相關的A型流感病毒報告。本研究目的是以血清抗體檢測法及基因檢測法來調查臺灣地區伴侶動物A型流感病毒感染情形。以Blocking ELISA血清抗體檢測結果，台大動物醫院就診之家犬血清檢體，陽性率為1.1% (3/281)；北中南等鄉村縣市，採集放養犬隻的血清檢體，陽性率則為3.1% (6/193)。針對H6亞型A型流感病毒的血清凝集抑制試驗 (HI) 結果發現9隻blocking ELISA的陽性檢體中，有3隻測得為HI H6亞型陽性。One-step RT-PCR檢測部份，犬126隻檢體中有4隻為陽性，陽性率為2.1% (4/185)。PCR陽性檢體中，成功從一隻有呼吸道症狀的病犬分離出A型流感病毒，命名為A/canine/Taiwan/E01/2014 (H6N1)，此為世界首例犬H6N1自然感染之發現。此外，研究也分離出一起台灣雪貂自然感染H1N1新型流感之病例。研究結果顯示台灣伴侶動物確實存在A型流行性感冒病毒之感染，依據血清抗體和病毒基因檢測之陽性率，推測台灣犬流感病毒感染情形仍屬與散發性 (sporadic) 流行病，但未來仍有必要進一步對伴侶動A型流行性感冒持續的監控。

Influenza was not considered an infectious disease in companion animals before. However, many subtypes of influenza A viruses have been isolated from dogs and cats around the world recently, such as H3N8, H3N2, H5N1, H5N2 and H1N1. Canine influenza virus (CIV) H3N8 and H3N2 subtypes were confirmed to be transmissible among dogs. The aim of this study was to investigate the prevalence of influenza A virus infection in companion animals in Taiwan using serological survey and one-step RT-PCR detection. Using blocking ELISA assay (bELISA), our results showed that the seroprevalence of pet dogs and rural free-ranging dogs was 1.1% (3/281) and 3.1% (6/193), respectively. The hemagglutination inhibition assay against avian H6 subtype also showed the presence of H6 antibody in three of nine bELISA positive serum samples. Furthermore, 2.1% (4/185) of positive RT-PCR detection in nasal swab samples were found in dogs. Among these four positive cases, an avian-origin influenza A virus was successfully isolated and designated as A/canine/Taiwan/E01/2014 (H6N1). It was the world's first report on dog naturally infected with an avian influenza H6N1 virus. Besides, we also identified a natural infection of influenza A(H1N1)pdm09 virus in a pet ferret in Taiwan. The results of this study indicated that the influenza A virus indeed exists in companion animals in Taiwan. According to the positive rate of influenza A antibody survey and nucleic acid detection, CIV infection in Taiwan belongs to sporadic cases, However, continual surveillance for influenza A virus infection in companion animals is still suggested.