Department of Basic Medical Sciences, Khoy University of Medical Sciences, Khoy, Iran; Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran; Student of Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.
Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran; Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
Exp Parasitol. 2023 May;248:108480. doi: 10.1016/j.exppara.2023.108480. Epub 2023 Feb 28.
Toxoplasma gondii (T. gondii) is one of the most important foodborne pathogens that infects a large number of vertebrate species and has a cosmopolitan distribution. Birds as intermediate hosts are very important in the life cycle of T. gondii and they can be a main source of infection for humans and felids, as well as other animals. Most species of birds feed from the ground and are the best indicator for soil contamination with T. gondii oocysts. Hence, T. gondii strains isolated from birds can represent different genotypes circulating in the environment and their main predators and consumers. The recent systematic review tries to represent the population structure of T. gondii in birds around the world. Six English language databases were searched from 1990 to 2020 to find the related studies and overall, 1275 isolates of T. gondii were separated from the analyzed samples in birds. The results of our study revealed that atypical genotypes were predominant (58.8%, 750 out of 1275). Types II, III, and I had less frequency with prevalence rates of 23.4%, 13.8%, and 2%, respectively. No isolates of Type I were reported from Africa. Summarizing ToxoDB genotypes circulating in birds around the world manifested that ToxoDB #2 was the most common (101/875), followed by ToxoDB #1 (80/875), and #3 (63/875). Totally, the results of our review represented the high genetic diversity of T. gondii with circulating non-clonal strains in birds from South and North America, while clonal parasites with low genetic diversity were predominant in Europe, Asia, and Africa.
刚地弓形虫（Toxoplasma gondii）是最重要的食源性病原体之一，感染了大量的脊椎动物，分布范围广泛。鸟类作为中间宿主，在刚地弓形虫的生命周期中非常重要，它们是人类和猫科动物以及其他动物感染的主要来源。大多数鸟类从地面觅食，是刚地弓形虫卵囊污染土壤的最佳指示物。因此，从鸟类中分离出的刚地弓形虫株可以代表环境中循环的不同基因型，以及它们的主要捕食者和消费者。最近的系统综述试图代表世界各地鸟类中刚地弓形虫的种群结构。从 1990 年到 2020 年，检索了六个英文数据库，以查找相关研究，总共从鸟类分析样本中分离出 1275 株刚地弓形虫。我们的研究结果表明，非典型基因型占主导地位（58.8%，1275 株中的 750 株）。II 型、III 型和 I 型的频率较低，流行率分别为 23.4%、13.8%和 2%。非洲没有报告 I 型分离株。总结世界各地鸟类中循环的 ToxoDB 基因型表明，ToxoDB #2 是最常见的（875 株中的 101 株），其次是 ToxoDB #1（875 株中的 80 株）和 #3（875 株中的 63 株）。总的来说，本综述的结果表明，南、北美洲鸟类中的刚地弓形虫具有很高的遗传多样性，存在非克隆株循环，而欧洲、亚洲和非洲则以遗传多样性低的克隆寄生虫为主。
