Clinic for Ruminants and Swine, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 11, 04103 Leipzig, Germany.
Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
Viruses. 2020 Feb 20;12(2):234. doi: 10.3390/v12020234.
In Europe, cowpox virus (CPXV) infection in South American camelids occurs as a so-called spill-over infection. Although infected animals generally have a mild form of the disease and survive, cases of fatal generalised CPXV infection have also been described. Prevention by prophylactic vaccination is the only way to protect animals from disease. In the present study, modified vaccinia virus Ankara (MVA) vaccine, which has been successfully used in many animal species, was used in a prime-boost vaccination regimen in two alpaca herds with a history of CPXV infection. The focus of the study was the prevention of further clinical cases, and to determine the safety and immunogenicity of the MVA vaccine in alpacas. The MVA vaccine was well tolerated and safe in the 94 animals vaccinated. An indirect immunofluorescence assay (IFA) using MVA as an antigen showed that the seroprevalence of antibody after booster vaccination was 81.3% in herd I and 91.7% in herd II. Detectable antibody titres declined to 15.6% in herd I and 45.8% in herd II over a 12-month period after booster vaccination. Animals could be divided into four groups based on individual antibody titres determined over one year: Group 1 consisted of 19.3% of animals that were seropositive until the end of the trial period; Group 2 consisted of 58.0% of animals that were seropositive after booster vaccination, but seronegative one year later; Group 3 consisted of 14.7% of animals that were not seropositive at any time point; and Group 4 consisted of 7.9% of animals that were seropositive after initial immunisation, seronegative six months later, but seropositive or intermediate in IFA one year after immunisation, likely because of natural exposure. In new-born crias born to MVA-vaccinated mares, specific maternal antibodies were detected in 50.0% of animals up to 14 weeks of age. Our results confirm that MVA vaccination is a feasible tool for the prevention of CPXV disease in alpacas. Long-term studies are needed to verify future vaccination regimen in CPXV affected herds.
在欧洲，牛痘病毒（CPXV）感染在南美的骆驼科动物中发生所谓的溢出感染。虽然受感染的动物通常具有疾病的轻度形式并且存活下来，但也描述了致命的全身性 CPXV 感染的病例。通过预防性疫苗接种来预防是保护动物免受疾病侵害的唯一方法。在本研究中，已成功用于许多动物物种的改良痘苗病毒安卡拉（MVA）疫苗在两个有 CPXV 感染史的羊驼群中使用了一种初免-加强免疫方案。研究的重点是预防进一步的临床病例，并确定 MVA 疫苗在羊驼中的安全性和免疫原性。在接种疫苗的 94 只动物中，MVA 疫苗耐受性良好且安全。使用 MVA 作为抗原的间接免疫荧光测定（IFA）表明，在 herd I 中，加强免疫后的血清阳性率为 81.3%，在 herd II 中为 91.7%。在加强免疫后 12 个月内，在 herd I 中，可检测到的抗体滴度下降到 15.6%，在 herd II 中下降到 45.8%。可以根据一年期间确定的个体抗体滴度将动物分为四组：第 1 组由 19.3%的动物组成，这些动物在试验结束时仍呈血清阳性；第 2 组由 58.0%的动物组成，这些动物在加强免疫后呈血清阳性，但一年后呈血清阴性；第 3 组由 14.7%的动物组成，这些动物在任何时间点均未呈血清阳性；第 4 组由 7.9%的动物组成，这些动物在初次免疫后呈血清阳性，六个月后呈血清阴性，但在免疫后一年的 IFA 中呈血清阳性或中间，可能是由于自然暴露。在接种 MVA 的母马所生的新生 Criados 中，在 14 周龄以下的动物中，有 50.0%的动物检测到特异性的母源抗体。我们的结果证实，MVA 疫苗接种是预防羊驼 CPXV 疾病的一种可行工具。需要进行长期研究以验证受 CPXV 影响的畜群未来的疫苗接种方案。
