School of Public Health & Zoonoses, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, 141004, India.
Sydney School of Veterinary Science, The University of Sydney, Camden, NSW, Australia.
Acta Parasitol. 2021 Mar;66(1):185-192. doi: 10.1007/s11686-020-00266-3. Epub 2020 Aug 28.
Toxoplasma gondii, an important food-borne parasite has been reported in a wide range of food animals globally. Poultry meat production is on rise in several developing nations including India. Several studies on status of T. gondii conducted globally had shown substantial risk of this parasite through poultry meat. Such information is lacking in the north India, where poultry meat is a preferred non-vegetarian food over other meats; therefore, this study determined the seroprevalence (based on detection of antibodies) and tissue prevalence (based on detection of DNA) of T. gondii in poultry meat intended for human consumption in north India.
Samples (skeletal muscle and/heart as well as blood) were collected from slaughter poultry intended for human consumption reared in Punjab state (n = 366), Himachal Pradesh (n = 44) state, and Chandigarh union territory (n = 112) in North India. Serum samples were tested using commercially available Chicken T. gondii IgG ELISA kit to determine the serostatus. The DNA of T. gondii was detected by nested PCR. To determine the agreement between ELISA and PCR, Kappa value was estimated.
Overall, study reports 2.3% (95% CI 1.3%-4.1%) tissue prevalence and 6.5% (95% CI 4.6%-9.1%) seroprevalence from chickens reared in north India. Backyard poultry had significantly higher proportion of T. gondii (24.4%, 10/41; p < 0.001) than caged (0%, 0/284) and deep litter poultry (16.2%, 32/197). The sequence alignment score of three sequences obtained in this study showed 97-100% nucleotide identity with Type I RH strain and VEG type III strain. The agreement between ELISA and PCR was poor (Kappa = 0.145; 95% CI 0.07-0.22). Thus, a combination of serological and molecular tests can improve the diagnosis of T. gondii.
A low prevalence indicates that T. gondii in poultry presents a lower food safety risk for public health in north India; however, this study recommend cooking of poultry meat before consumption. Further studies are required to check the viability of T. gondii in poultry meat intended for human consumption, and to determine the risk factors associated and the genotypes circulating in poultry in north India.
刚地弓形虫是一种重要的食源性寄生虫，在全球范围内广泛存在于各种食品动物中。在包括印度在内的几个发展中国家，家禽肉产量正在上升。在全球范围内进行的几项关于刚地弓形虫的研究表明，这种寄生虫通过家禽肉存在很大的风险。在印度北部，家禽肉是一种比其他肉类更受欢迎的非素食食品，因此缺乏此类信息；因此，本研究旨在确定印度北部用于人类消费的家禽肉中的刚地弓形虫血清流行率（基于抗体检测）和组织流行率（基于 DNA 检测）。
从印度北部旁遮普邦（n=366）、喜马偕尔邦（n=44）和昌迪加尔联合领土（n=112）饲养的供人类食用的屠宰家禽中采集肌肉和/或心脏以及血液样本。使用市售的鸡弓形虫 IgG ELISA 试剂盒检测血清样本，以确定血清状态。通过巢式 PCR 检测刚地弓形虫的 DNA。为了确定 ELISA 和 PCR 之间的一致性，估计了 Kappa 值。
总体而言，本研究报告称，来自印度北部饲养的鸡的组织流行率为 2.3%（95%CI 1.3%-4.1%），血清流行率为 6.5%（95%CI 4.6%-9.1%）。后院家禽的弓形虫比例明显高于笼养（0%，0/284）和深层垫料家禽（16.2%，32/197）（p<0.001）。本研究获得的三个序列的序列比对得分显示，与 Type I RH 株和 VEG 型 III 株的核苷酸同一性为 97-100%。ELISA 和 PCR 之间的一致性较差（Kappa=0.145；95%CI 0.07-0.22）。因此，联合使用血清学和分子检测可以提高对刚地弓形虫的诊断。
低流行率表明，印度北部家禽中的刚地弓形虫对公众健康的食品安全风险较低；然而，本研究建议在食用前将家禽肉煮熟。需要进一步研究以检查拟供人类食用的家禽肉中刚地弓形虫的生存能力，并确定与印度北部家禽中循环的基因型相关的风险因素。
