Féray Cyrille, Bouscaillou Julie, Falissard Bruno, Mohamed Mostafa K, Arafa Naglaa, Bakr Iman, El-Hoseiny Mostafa, Daly Mai El, El-Kafrawy Sherif, Plancoulaine Sabine, Abdel-Hamid Mohamed, Thiers Valérie, Fontanet Arnaud
Inserm 955, Hopital Henri Mondor, Créteil, France.
Institut Pasteur, Unité d'Epidémiologie des Maladies Emergentes, Paris, France.
PLoS One. 2014 Jan 23;9(1):e86098. doi: 10.1371/journal.pone.0086098. eCollection 2014.
We propose a new approach based on genetic distances among viral strains to infer about risk exposures and location of transmission at population level.
We re-analysed 133 viral sequences obtained during a cross-sectional survey of 4020 subjects living in a hepatitis C virus (HCV) endemic area in 2002. A permutation test was used to analyze the correlation between matrices of genetic distances in the NS5b region of all pairwise combinations of the 133 viral strains and exposure status (jointly exposed or not) to several potential HCV risk factors.
Compared to subjects who did not share the same characteristics or iatrogenic exposures, the median Kimura genetic distances of viral strains were significantly smaller between brothers and sisters (0.031 versus 0.102, P<0.001), mother and child (0.044 versus 0.102, P<0.001), father and child (0.045 versus 0.102, P<0.001), or subjects exposed to periodontal treatment (0.084 versus 0.102, P = 0.02). Conversely, viral strains were more divergent between subjects exposed to blood transfusions (0.216 versus 0.102, P = 0.04) or tooth filling or extraction (0.108, versus 0.097, P = 0.05), suggesting acquisition of the virus outside of the village.
This method provided insights on where infection took place (household, village) for several socio-demographic characteristics or iatrogenic procedures, information of great relevance for targeting prevention interventions. This method may have interesting applications for virologists and epidemiologists studying transmission networks in health-care facilities or among intravenous drug users.
我们提出了一种基于病毒株之间遗传距离的新方法，以推断人群水平上的风险暴露和传播地点。
我们重新分析了2002年在丙型肝炎病毒（HCV）流行地区对4020名受试者进行横断面调查期间获得的133个病毒序列。采用置换检验分析133个病毒株所有两两组合的NS5b区域遗传距离矩阵与暴露于几种潜在HCV风险因素的状态（共同暴露或未暴露）之间的相关性。
与没有相同特征或医源性暴露的受试者相比，兄弟姐妹之间（0.031对0.102，P<0.001）、母婴之间（0.044对0.102，P<0.001）、父子之间（0.045对0.102，P<0.001）或接受牙周治疗的受试者之间（0.084对0.102，P = 0.02）病毒株的中位木村遗传距离明显更小。相反，接受输血的受试者之间（0.216对0.102，P = 0.04）或补牙或拔牙的受试者之间（0.108对0.097，P = 0.05）病毒株差异更大，这表明病毒是在村外感染的。
该方法为几种社会人口统计学特征或医源性程序的感染发生地点（家庭、村庄）提供了见解，这对于确定预防干预目标具有重要意义。该方法可能对研究医疗保健机构或静脉吸毒者中传播网络的病毒学家和流行病学家有有趣的应用。
