MIVEGEC (Université de Montpellier 1 et 2, CNRS 5290, IRD 224), Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle, Institut de Recherche pour le Développement (IRD), Representation in Bolivia, Av. Hernando Siles No. 5290, Esq Calle 7 Obrajes, CP 9214, La Paz, Bolivia.
Infect Genet Evol. 2013 Jan;13:116-23. doi: 10.1016/j.meegid.2012.09.014. Epub 2012 Oct 6.
In the Gran Chaco region the reinfestation by Triatoma infestans remains a major problem for control of Chagas disease. Trypanosoma cruzi the agent of the illness presents a broad genetic intraspecific variability which is poorly documented in the Bolivian Gran Chaco. This work presents the identification of the discrete typing units (DTUs) currently recognized for T. cruzi in T. infestans populations collected before and after residual insecticide spraying in four villages in this region. Before spraying, of 84 samples, the frequencies of the DTUs identified by using the multiplex PCR based on the non transcribed spacer of the mini-exon gene (MMPCR) were 0.21 for TcI, 0.70 for TcII/TcV/TcVI, and 0.17 for TcIII/TcIV and no significant difference was observed after spraying (76 samples). Moreover 13% of the total sample corresponds to T. infestans specimens with mixed infection of DTUs of which three were TcII/TcV/TcVI with TcIII/TcIV. The partial sequences of T. cruzi Gpi gene obtained from 14 PCR products agree the MMPCR DTU identification and allowed to precise the occurrence of TcIII, TcII and hybrid TcV/TcVI stocks which were not discriminated by the MMPCR. Given the high prevalence of hybrid stocks, the authors ask whether the recombination event at the origin of hybrids would have taken place in the Gran Chaco where the putative parents are also present.
在大查科地区，布氏锥虫的再感染仍然是控制恰加斯病的一个主要问题。引起这种疾病的克氏锥虫具有广泛的种内遗传变异性，但在玻利维亚大查科地区却鲜有记录。本研究介绍了在该地区四个村庄进行残留杀虫剂喷洒前后采集的感染锥蝽种群中，目前已识别的离散型基因分型单位（DTU）的鉴定情况。在喷洒前的 84 个样本中，基于 mini-exon 基因非转录间隔区（MMPCR）的多重 PCR 方法识别的 DTU 频率分别为 TcI 为 0.21、TcII/TcV/TcVI 为 0.70、TcIII/TcIV 为 0.17，喷洒后（76 个样本）没有观察到显著差异。此外，总样本的 13%对应于混合感染 DTU 的感染锥蝽标本，其中三种为 TcII/TcV/TcVI 与 TcIII/TcIV 的混合感染。从 14 个 PCR 产物中获得的克氏锥虫 Gpi 基因部分序列与 MMPCR DTU 鉴定一致，并能够精确确定 TcIII、TcII 和混合 TcV/TcVI 品系的发生情况，而 MMPCR 无法区分这些品系。鉴于混合品系的高流行率，作者询问这种杂种的重组事件是否发生在大查科地区，因为假定的亲本也存在于该地区。
