Jerez Puebla Luis Enrique, Núñez Fidel A, Santos Lissette Pérez, Rivero Lázara Rojas, Silva Isabel Martínez, Valdés Lucía Ayllón, Millán Iraís Atencio, Müller Norbert
Parasitology Department, Tropical Medicine Institute "Pedro Kourí", Autopista Novia del Mediodía Km 6½ e/Autopista Nacional y Carretera Central, La Habana, Cuba.
Virology Department, Tropical Medicine Institute "Pedro Kourí", Autopista Novia del Mediodía Km 6½ e/Autopista Nacional y Carretera Central, La Habana, Cuba.
Parasite Epidemiol Control. 2017 May 24;2(3):105-113. doi: 10.1016/j.parepi.2017.05.003. eCollection 2017 Aug.
Giardiasis is considered the most common intestinal parasitic disease in humans worldwide. In Cuba, this infection has particularly a strong clinical impact on the child population. is a highly diverse protozoan, which comprises a complex of eight morphologically identical genetic assemblages, further divided into sub-assemblages. The present study used triose phosphate isomerase () and small-subunit ribosomal RNA (SSU rRNA) genes as genetic markers for the identification of assemblages and sub-assemblages in correlation with clinical and epidemiological data in children attended at the Paediatric Hospital "William Soler" and at Pedro Kouri Institute, between 2015 and 2016. A prevalence of 8% of infection was recorded in stool samples after concentration techniques from 68 children out of 847 analysed. A 100% detection of DNA was achieved by a SSU-rRNA PCR, whereas DNA from 63 of 68 (92.6%) was successfully amplified by -PCR. By this assemblage-specific -PCR 32 (50.8%) assemblage B, 17 (27.0%) assemblage A and 14 (22.2%) mixed infection (A + B) were identified. Assemblage B was significantly ( < 0.02) more frequently found in children with diarrhoea. Sequence analysis of the gene of isolates from symptomatic children showed that assemblage A belonged to the sub-assemblage AII, and 4 sub assemblages BIV and 1 sub assemblage BIII were also recorded. Only 2 discordant genotyping results were observed by phylogenetic comparison of SSU-rRNA and sequences. Further studies with novel molecular tools for a better discrimination at the sub-assemblage level are needed to identify the dynamics of spread of giardiasis and to verify possible correlations between genetic diversity and clinical manifestation.
贾第虫病被认为是全球人类最常见的肠道寄生虫病。在古巴，这种感染对儿童群体尤其具有强烈的临床影响。贾第虫是一种高度多样化的原生动物，它由八个形态相同的遗传组合构成一个复合体，这些组合又进一步细分为亚组合。本研究使用磷酸丙糖异构酶（TPI）和小亚基核糖体RNA（SSU rRNA）基因作为遗传标记，以鉴定2015年至2016年期间在“威廉·索莱尔”儿童医院和佩德罗·库里研究所就诊的儿童中贾第虫的组合和亚组合，并将其与临床和流行病学数据相关联。在对847名儿童进行分析后，通过浓缩技术从68名儿童的粪便样本中记录到贾第虫感染率为8%。通过SSU - rRNA PCR实现了贾第虫DNA的100%检测，而68份样本中的63份（92.6%）的DNA通过TPI - PCR成功扩增。通过这种组合特异性TPI - PCR鉴定出32份（50.8%）组合B、17份（27.0%）组合A和14份（22.2%）混合感染（A + B）。组合B在腹泻儿童中显著更频繁地被发现（P < 0.02）。对有症状儿童的贾第虫分离株的TPI基因进行序列分析表明，组合A属于亚组合AII，还记录到4个亚组合BIV和1个亚组合BIII。通过SSU - rRNA和TPI序列的系统发育比较仅观察到2个不一致的基因分型结果。需要使用新的分子工具进行进一步研究，以便在亚组合水平上进行更好的区分，从而确定贾第虫病的传播动态，并验证贾第虫遗传多样性与临床表现之间可能存在的相关性。
