French Agency for Food, Environmental and Occupational Health and Safety (ANSES), INRAE, École Nationale Vétérinaire d'Alfort, UMR BIPAR, Animal Health Laboratory, 14 rue Pierre et Marie Curie, Maisons-Alfort 94700, France.
National Reference Centre on Toxoplasmosis, Toxoplasma Biological Reference Centre, CHU Reims and EA7510, SFR CAP-Santé, University of Reims Champagne-Ardenne, USC EpiToxo Anses, Reims 51095, France.
Parasite. 2022;29:3. doi: 10.1051/parasite/2022001. Epub 2022 Feb 1.
Consumption of raw or undercooked meat containing Toxoplasma gondii tissue cysts is one of the main sources of infection for humans worldwide. Among the various species intended for human consumption, sheep appear to be a high risk for human infection. The present study focused on the detailed anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs using fresh and frozen samples of various pieces of meat, from a public health perspective. The first objective was to rank the edible parts intended for human consumption according to the detectable parasite burden by real-time PCR targeting the 529-bp repeated element. The second objective was to evaluate the impact of freezing by comparing the detection efficiency of the quantitative PCR between fresh and frozen tissues, as imports of lamb carcasses/cuts may arrive frozen or chilled. The highest estimated parasite loads were observed in skeletal muscles, and more particularly in edible portions such as quadriceps femoris muscle, intercostal muscles, deltoid muscle and diaphragm, with a significant difference in detectable parasite burden between fresh and frozen samples (p < 0.0001) or natural and experimental infection (p < 0.0001). Thoracic and pelvic limbs (3278-1048 parasites/g muscle) were ranked at the top of the list. Toxoplasma gondii DNA was detected in all the edible parts of lamb studied. These results suggest that lamb meat represents a risk for consumers. Further investigations are needed in order to confirm these differences in larger numbers of animals and in different breeds.
食用含有弓形虫组织包囊的生的或未煮熟的肉是全世界人类感染的主要来源之一。在各种供人类食用的物种中，绵羊似乎是人类感染的高风险物种。本研究从公共卫生的角度出发，使用新鲜和冷冻的各种肉块样本，重点研究了天然和实验感染的羔羊中弓形虫的详细解剖分布。第一个目标是根据实时 PCR 检测到的 529-bp 重复元件，对人类食用的可食用部分进行寄生虫负担的排序。第二个目标是评估冷冻的影响，通过比较新鲜和冷冻组织的定量 PCR 检测效率，因为进口的羔羊胴体/切块可能是冷冻或冷藏的。在骨骼肌中观察到最高的估计寄生虫负荷，特别是在可食用的部分，如股四头肌、肋间肌、三角肌和膈肌，新鲜和冷冻样本之间（p<0.0001）或天然和实验感染之间（p<0.0001）的可检测寄生虫负担存在显著差异。胸和盆腔肢体（3278-1048 个寄生虫/g 肌肉）排在首位。在研究的所有羔羊可食用部分均检测到弓形虫 DNA。这些结果表明，羊肉对消费者构成了风险。需要进一步的调查，以便在更大数量的动物和不同品种中证实这些差异。
