Departamento de Medicina Veterinária Preventiva, Laboratório de Pesquisa em Virologia Animal, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, CEP: 31270-901, Belo Horizonte, MG, Brazil.
Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Laboratório de Microbiologia de Alimentos, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, CEP: 31270-901, Belo Horizonte, MG, Brazil.
J Dairy Sci. 2017 Sep;100(9):7051-7054. doi: 10.3168/jds.2017-12560. Epub 2017 Jul 19.
Bovine vaccinia is a neglected zoonosis caused by Vaccinia virus (VACV) and has a major economic and public health effect in Brazil. Previous studies showed infectious VACV particles in milk from either experimentally or naturally infected cows and in fresh cheeses prepared with experimentally contaminated milk. Ripening is a process that leads to major changes in the physical and chemical characteristics of cheese, reducing contamination by spoilage, pathogenic microorganisms, or both. However, it is not known if VACV infectious particles persist after the ripening process. To investigate this issue, viral infectivity at different ripening times was studied in cheeses manufactured with milk experimentally contaminated with VACV strain Guarani P2 (GP2). Cheeses were analyzed at 1, 7, 14, 21, 45, and 60 d of ripening at 25°C. Viral DNA was quantified by real-time PCR, and VACV isolation and titration were performed in Vero cells. The whole experiment was repeated 4 times. Analysis of the mean viral DNA quantification and infectivity indicated a reduction of approximately 2 logs along the ripening process; however, infectious viral particles (1.7 × 10 pfu/mL) could still be recovered at d 60 of ripening. These findings indicate that the ripening process reduces VACV infectivity, but it was not able to inactivate completely the viral particles after 60 d.
牛痘是一种由牛痘病毒（VACV）引起的被忽视的人畜共患病，在巴西具有重大的经济和公共卫生影响。以前的研究表明，实验或自然感染牛的牛奶中存在传染性 VACV 颗粒，以及用实验污染牛奶制备的新鲜奶酪中存在传染性 VACV 颗粒。成熟是一个导致奶酪物理和化学特性发生重大变化的过程，可降低变质、致病性微生物或两者的污染。然而，目前尚不清楚 VACV 传染性颗粒在成熟过程后是否会持续存在。为了研究这个问题，研究了用实验污染的牛奶（Guarani P2 株）制造的奶酪在不同成熟时间的病毒感染性。在 25°C 下，在成熟 1、7、14、21、45 和 60 d 时分析奶酪。通过实时 PCR 定量病毒 DNA，并在 Vero 细胞中进行 VACV 分离和滴定。整个实验重复了 4 次。对平均病毒 DNA 定量和感染性的分析表明，在成熟过程中减少了约 2 个对数级；然而，在成熟 60 d 时仍能回收传染性病毒颗粒（1.7×10 pfu/mL）。这些发现表明，成熟过程降低了 VACV 的感染性，但在 60 d 后仍不能完全使病毒颗粒失活。
