Data on chicken samples from Amazon region.

Previous studies have reported high diversity between and within populations of Toxoplasma gondii in South America. In the present study, isolates of T. gondii from chickens were obtained from the Amazon region. Adult free-range chickens were acquired from 29 municipalities in the Brazilian Amazon region that included Acre (n = 9 municipalities), Amapá (n = 6), Amazonas (n = 6), Pará (n = 6), and Roraima (n = 2) states and from two municipalities in Peru, three in Bolivia, one in Guyana, and one in Venezuela. Heart, brain, and blood samples were collected from 401 chickens. Anti-T. gondii serum antibodies were detected in 273 (68.1%) chickens using the Modified Agglutination Test (MAT ≥ 5), and bioassays in mice were performed using 220 birds. Isolates were obtained from 116 (52.7%) chickens with antibody titers ≥ 20. Of these isolates, 93 (84.5%) led to acute sickness in more than 50% of the infected mice within 30 days post-inoculation. The 116 isolates were genotyped using multilocus nested polymerase chain reaction-restriction fragment length polymorphism (Mn-nPCR-RFLP) with 12 markers and 15 microsatellite (MS) markers. PCR-RFLP analysis revealed 42 genotypes from the 116 isolates. Of these, 20 (46.51%) genotypes are described for the first time. The most abundant genotype was ToxoDB PCR-RFLP genotype #7 with 40 isolates. A total of 83 genotypes were observed from the 116 isolates by MS analysis. The phylogenetic network constructed of T. gondii genotypes from current and previously reported isolates, using PCR-RFLP data, revealed five groups with clear indication of geographical separation of T. gondii population in the Amazon region versus the Southeastern region of Brazil. Such spatial diversity was also observed within the Amazon region. This study expands our knowledge of T. gondii population in South America and emphasizes the importance of genetic diversity and high mouse-virulence of the parasite in the Amazon region.

既往研究已报道，南美洲刚地弓形虫（Toxoplasma gondii）种群间及种群内部存在高度遗传多样性。本研究从亚马逊地区获取了鸡源刚地弓形虫分离株。研究样本采自巴西亚马逊地区的29个市县，涵盖阿克里州（n=9个市县）、阿马帕州（n=6）、亚马孙州（n=6）、帕拉州（n=6）及罗赖马州（n=2），同时采集自秘鲁的2个市县、玻利维亚的3个市县、圭亚那的1个市县及委内瑞拉的1个市县，对象均为成年散养肉鸡。研究人员从401只肉鸡体内采集了心脏、脑组织及血液样本。采用改良凝集试验（Modified Agglutination Test，MAT≥5）在273只（68.1%）肉鸡的血清中检出抗刚地弓形虫抗体；并对其中220只肉鸡的样本开展小鼠生物测定。最终从抗体滴度≥20的116只（52.7%）肉鸡中成功获得刚地弓形虫分离株。其中93株（84.5%）在接种后30天内，导致超过50%的感染小鼠出现急性发病症状。研究团队采用含12个标记的多位点嵌套聚合酶链反应-限制性片段长度多态性（multilocus nested polymerase chain reaction-restriction fragment length polymorphism，Mn-nPCR-RFLP）体系，以及15个微卫星（microsatellite，MS）标记，对这116株分离株进行基因分型。PCR-RFLP分析从116株分离株中鉴定出42种基因型，其中20种（46.51%）为首次报道。丰度最高的基因型为ToxoDB PCR-RFLP基因型#7，共包含40株分离株。而通过MS分析，则从116株分离株中鉴定出总计83种基因型。基于PCR-RFLP数据构建的刚地弓形虫基因型系统发育网络（涵盖本研究及既往已报道的分离株）显示，种群可分为5个类群，清晰体现出亚马逊地区与巴西东南部地区刚地弓形虫种群的地理分化特征；且在亚马逊地区内部，同样观测到了此类空间多样性。本研究拓展了学界对南美洲刚地弓形虫种群的认知，并强调了亚马逊地区该寄生虫的遗传多样性及高小鼠毒力的重要性。