|摘要: ||胸膜肺炎放線桿菌 (Actinobacillus pleuropneumoniae, APP)是種會造成豬隻呼吸道疾病的病原。在急性病程中，APP造成豬隻纖維素性出血性壞死性胸膜肺炎並造成死亡；然而在慢性病程或輕微病變中，則形成慢性胸膜炎 (Chronic Pleuritis)與肋壁連黏，降低豬隻生長性能與飼料換肉率，造成經濟上無形的損失。本研究利用屠宰場胸膜炎評估系統 (slaughterhouse pleuritis evaluation systems, SPES)評分法則調查台灣屠宰豬隻，結果37.6%的屠宰豬豬具有胸膜炎病變 (955/2542)，其中56.5% (540/955)為出現於膈葉的胸膜炎，顯示胸膜炎在台灣具高度盛行率，但無明顯季節性變化。以ELISA檢測血清APP抗體及PCR檢測病變組織中APP核酸方式其陽性率皆與病變嚴重度呈顯著之正相關並存在有趨勢效應。族群中胸膜炎嚴重程度並無顯著的臨床表徵，故經常被忽略，因此本研究於APP的感染場，以APP疫苗及免疫策略對APP疫情的改善，並同時利用ELISA及SPES方式評估，發現牧場經由APP免疫前，其族群APP抗體及APPI皆為高值，於免疫處理後其抗體陽性率與APP index有明顯的下降，經分析後可知族群APP抗體強度與族群APPI呈現顯著正相關。於試驗場中若肥育時期追加第三劑疫苗免疫可增強改善的幅度，胸膜炎相對危險性下降為0.69，另外族群若於哺乳時期免疫豬環狀病毒第二型 (PCV2)疫苗後，胸膜炎相對危險性下降為0.64，亦可顯著改善APP疫情。若牧場免疫PCV2疫苗及三劑APP疫苗後，胸膜炎相對危險性則下降至0.13。本試驗中使用之SPES方法為一快速、經濟且有效的監控方式，可於臨床準確評估族群APP感染程度，藉由觀察屠宰豬隻胸膜炎，可提供我們另一種資訊來更加正確地了解牧場呼吸道疾病的嚴重程度，了解牧場潛在的經濟損失或評估疫苗保護之效力，可做為牧場制定免疫計畫的參考，減少養豬產業之損失。|
Actinobacillus pleuropneumoniae (APP) is a contagious respiratory pathogen in swine industry. During acute phase, fibrinous hemorrhagic necrotizing pleuropneumonia then sudden death can be observed in pigs. However, once pigs recover from acute infection or chronic infection, chronic pleuritis becomes obvious. The chronic pleuritis may hamper growth performance and feed conversion rate for pigs, leading to significant economic losses. In this study, we used pleurisy scoring system to monitor slaughtered pigs (slaughterhouse pleuritis evaluation systems SPES) during 2010-2013. We found that the prevalence of pleuritis of slaughtered pigs in Taiwan is 37.6% (955/2542), and 56.5% (540/955) of them had pleurisy located at diaphragmatic lobe of lung. There is no significant seasonal variation in the prevalence of pleuritis. Detection of antibodies and nucleic acid by ELISA and PCR, respectively, suggest the positive rate of APP infection and the severity of lesions are significantly related and have trend effect. In our study, we tried to control the disease by vaccination strategies in endemic farms. Although pigs with pleuritis usually showed no clinical signs we evaluated the improvement by ELISA and SPES. It was found that the levels of APP antibodies and APPI of batch are highly connected. After vaccination with APP vaccines, the seroprevalence and APP index declined as assessed by ELISA and SPES. Moreover, an additional third dose of vaccine in fattening period could enhance the protection effect and the relative risk of pleuritis was 0.69. The relative risk of pleuritis of the batch with porcine circovirus (PCV2) vaccine prior to the APP vaccination (2 doses) was 0.64. Both vaccination strategies described above are able to decrease the APP infection at similar level. PCV2 vaccination in suckling prior to APP vaccination (3 doses) showed relative risk of pleuritis at 0.13. Together, the SPES can (1) provide valuable information of severity of the disease, (2) evaluate the potential economic loss, and (3) assess the efficacy of vaccination. SPES, therefore, is a convenient, economic and efficient method to evaluate the severity of APP infection in a pig population. Moreover, we can also estimate the economic loss of APP, protection efficacy of vaccine and vaccination strategy by the SPES.