Experimental reproduction of severe disease in CD/CD pigs concurrently infected with type 2 porcine circovirus and porcine reproductive and respiratory syndrome virus
Experimental reproduction of severe disease in CD/CD pigs concurrently infected with type 2 porcine circovirus and porcine reproductive and respiratory syndrome virus
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DOI：
10.1354/vp.38-5-528
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发表时间：
2001-09-01
影响因子：
2.4
通讯作者：
Paul, PS
中科院分区：
文献类型：
--
作者：
Harms, PA;Sorden, SD;Paul, PS
三周龄剖宫产剥夺初乳 (CD/CD) 猪接种猪圆环病毒 2 型 (PCV2, n = 19)、猪繁殖与呼吸综合征病毒 (PRRSV, n = 13)、并发 PCV2 和 PRRSV (PCV2/PRRSV n = 17) 或假接种物 (n = 12)，以比较独立接种物和联合接种物这些药剂的作用。在接种后 7、10、14、21、35 和 49 天 (dpi) 或当猪濒临死亡时进行尸检。到 10 dpi 时，接种 PCV2/PRRSV 的猪出现严重呼吸困难、嗜睡，偶尔出现黄疸； 10 dpi 后，该组的死亡率为 10/11 (91%)，所有接种 PCV2/PRRSV 的猪均在 20 dpi 时死亡。接种PCV2的猪出现嗜睡和散发性黄疸，8/19（42%）出现渗出性表皮炎；死亡率为 5/19 (26%)。接种 PRRSV 的猪出现呼吸困难和轻度嗜睡，这些症状在 28 dpi 后消失。接种 PCV2 和 PCV2/PRRSV 的猪均出现与断奶后多系统消耗综合征 (PMWS) 一致的显微病变，包括淋巴耗竭、坏死性肝炎、轻度坏死性细支气管炎以及巨噬细胞浸润，淋巴和其他组织中偶尔含有嗜碱性胞浆内包涵体。接种 PCV2/PRRSV 的猪也患有严重的增殖性间质性肺炎和更一致的肝脏病变。最严重的病变包含最多数量的含 PCV2 抗原的细胞。接种 PRRSV 的猪患有中度增殖性间质性肺炎，但没有出现细支气管或肝脏病变或淋巴耗竭。所有组均保持猪细小病毒血清阴性。结果表明：1) PCV2 共感染会增加 CD/CD 猪中 PRRSV 诱导的间质性肺炎的严重程度，2) PCV2 而不是 PRRSV 会诱导 PMWS 特征性的淋巴耗竭、肉芽肿性炎症和坏死性肝炎。
Three-week-old cesarean-derived colostrum-deprived (CD/CD) pigs were inoculated with porcine circovirus type 2 (PCV2, n = 19), porcine reproductive and respiratory syndrome virus (PRRSV, n = 13), concurrent PCV2 and PRRSV (PCV2/PRRSV n = 17), or a sham inoculum (n = 12) to compare the independent and combined effects of these agents. Necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. By 10 dpi, PCV2/PRRSV-inoculated pigs had severe dyspnea, lethargy, and occasional icterus; after 10 dpi, mortality in this group was 10/11 (91%), and all PCV2/ PRRSV-inoculated pigs were dead by 20 dpi. PCV2-inoculated pigs developed lethargy and sporadic icterus, and 8/19 (42%) developed exudative epidermitis; mortality was 5/19 (26%). PRRSV-inoculated pigs developed dyspnea and mild lethargy that resolved by 28 dpi. Microscopic lesions consistent with postweaning multisystemic wasting syndrome (PMWS) were present in both PCV2- and PCV2/PRRSV-inoculated pigs and included lymphoid depletion, necrotizing hepatitis, mild necrotizing bronchiolitis, and infiltrates of macrophages that occasionally contained basophilic intracytoplasmic inclusion bodies in lymphoid and other tissues. PCV2/ PRRSV-inoculated pigs also had severe proliferative interstitial pneumonia and more consistent hepatic lesions. The most severe lesions contained the greatest number of PCV2 antigen-containing cells. PRRSV-inoculated pigs had moderate proliferative interstitial pneumonia but did not develop bronchiolar or hepatic lesions or lymphoid depletion. All groups remained seronegative to porcine parvovirus. The results indicate that 1) PCV2 coinfection increases the severity of PRRSV-induced interstitial pneumonia in CD/CD pigs and 2) PCV2 but not PRRSV induces the lymphoid depletion, granulomatous inflammation, and necrotizing hepatitis characteristic of PMWS.