Katzer Frank, Canton German, Burrells Alison, Palarea-Albaladejo Javier, Horton Ben, Bartley Paul M, Pang Yvonne, Chianini Francesca, Innes Elisabeth A, Benavides Julio
Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK; Instituto Nacional de Tecnología Agropecuaria (INTA), EEA Balcarce CC276, Argentina.
Vet Parasitol. 2014 Sep 15;205(1-2):46-56. doi: 10.1016/j.vetpar.2014.07.003. Epub 2014 Jul 10.
This study evaluates the influence of immunizing lambs with the incomplete S48 strain of Toxoplasma gondii, on parasite dissemination following a live oral challenge with a complete strain of T. gondii (M4). Lambs were culled at 14, 28 and 42 days post challenge. Parasite DNA was detected at significantly (p<0.0001) lower levels in samples from the vaccinated/challenged group (0% in heart and 5.9% in skeletal muscles), when compared to the non-vaccinated/challenged animals (75% heart, 87.9% skeletal muscle). S48 T. gondii DNA was found in muscle or lymph nodes until 42 days post infection, suggesting that parasite DNA or tachyzoites could persist longer after immunization than previously thought. Non-vaccinated/challenged animals showed more frequent lesions in muscles and central nervous system than the vaccinated animals. These results demonstrate that vaccination of lambs with the incomplete S48 T. gondii strain, can protect against establishment of tissue cysts following challenge with a complete strain of T. gondii. Consumption of undercooked meat containing T. gondii cysts is a major route of transmission to people, therefore vaccination of food animals may improve the safety of meat for human consumption.
本研究评估用刚地弓形虫不完全S48株免疫羔羊，对用刚地弓形虫完整株（M4）进行口服活攻毒后寄生虫传播的影响。在攻毒后14天、28天和42天宰杀羔羊。与未免疫/攻毒动物相比，接种/攻毒组样本中的寄生虫DNA水平显著降低（p<0.0001）（心脏中为0%，骨骼肌中为5.9%），未免疫/攻毒动物心脏中为75%，骨骼肌中为87.9%。在感染后42天之前，在肌肉或淋巴结中发现了S48刚地弓形虫DNA，这表明免疫后寄生虫DNA或速殖子可能比以前认为的持续时间更长。未免疫/攻毒动物在肌肉和中枢神经系统中出现病变的频率高于免疫动物。这些结果表明，用不完全S48刚地弓形虫株对羔羊进行疫苗接种，可以在受到完整刚地弓形虫株攻毒后防止组织囊肿的形成。食用含有刚地弓形虫囊肿的未煮熟肉类是人类感染的主要传播途径，因此对食用动物进行疫苗接种可能会提高供人类食用肉类的安全性。
