Institute of Biotechnology, Department of Parasitology, University of Granada, Granada, Spain.
Center for Research and Diagnosis of Parasitic Diseases (CIDEP), Faculty of Medicine, University of Panama, Panama, Panama.
PLoS One. 2020 Nov 12;15(11):e0241921. doi: 10.1371/journal.pone.0241921. eCollection 2020.
Trypanosoma cruzi, the hemoparasite that causes Chagas disease, is divided into six Discrete Typing Units or DTUs: TcI-TcVI plus Tcbat. This genetic diversity is based on ecobiological and clinical characteristics associated with particular populations of the parasite. The main objective of this study was the identification of DTUs in patients with chronic chagasic infections from a mountainous rural community in the eastern region of Panama.
A total of 106 patients were tested for Chagas disease with three serological tests (ELISA, rapid test, and Western blot). Molecular diagnosis and DTU typing were carried out by conventional PCRs and qPCR targeting different genomic markers, respectively. As a control sample for the typing, 28 patients suspected to be chagasic from the metropolitan area of Panama City were included.
Results showed a positivity in the evaluated patients of 42.3% (33/78); high compared to other endemic regions in the country. In the control group, 20/28 (71.43%) patients presented positive serology. The typing of samples from rural patients showed that 78.78% (26/33) corresponded to TcI, while 9.09% (3/33) were mixed infections (TcI plus TcII/V/VI). Seventy-five percent (15/20) of the patients in the control group presented TcI, and in five samples it was not possible to typify the T. cruzi genotype involved.
These results confirm that TcI is the main DTU of T. cruzi present in chronic chagasic patients from Panama. However, the circulation of other genotypes (TcII/V/VI) in this country is described for the first time. The eco-epidemiological characteristics that condition the circulation of TcII/V/VI, as well as the immune and clinical impact of mixed infections in this remote mountainous region should be investigated, which will help local action programs in the surveillance, prevention, and management of Chagas disease.
引起恰加斯病的血液寄生虫克氏锥虫分为六个离散型单元或 DTU：TcI-TcVI 加 Tcbat。这种遗传多样性基于与寄生虫特定种群相关的生态生物学和临床特征。本研究的主要目的是鉴定来自巴拿马东部山区农村社区的慢性恰加斯病感染患者的 DTU。
对 106 名患者进行了三种血清学检测（ELISA、快速检测和 Western blot）以检测恰加斯病。通过常规 PCR 和 qPCR 分别针对不同的基因组标记进行分子诊断和 DTU 分型。作为分型的对照样本，纳入了来自巴拿马城大都市区的 28 名疑似恰加斯病患者。
评估患者的阳性率为 42.3%（33/78）；与该国其他流行地区相比，这一比例较高。在对照组中，20/28（71.43%）患者的血清学呈阳性。对农村患者样本的分型显示，78.78%（26/33）为 TcI，9.09%（3/33）为混合感染（TcI 加 TcII/V/VI）。对照组 75%（15/20）的患者为 TcI，5 个样本无法对涉及的克氏锥虫基因型进行分型。
这些结果证实 TcI 是巴拿马慢性恰加斯病患者中主要的 T. cruzi DTU。然而，该国首次描述了其他基因型（TcII/V/VI）的循环。应调查 TcII/V/VI 循环的生态流行病学特征，以及在这个偏远山区混合感染的免疫和临床影响，这将有助于地方行动方案在恰加斯病的监测、预防和管理方面采取行动。
