Faculté des Sciences de la Nature et de la Vie, Université Kasdi Merbah Ouargla, Laboratoire des Bio Ressources Sahariennes, 30000 Ouargla, Algeria; Laboratoire d'Eco-épidémiologie Parasitaire et Génétique des Populations, Institut Pasteur d'Algérie, 16000 Algiers, Algeria.
Scientific and Technical Research Centre for Arid Areas (CRSTRA), 30002 Touggourt, Algeria.
Acta Trop. 2020 Jun;206:105443. doi: 10.1016/j.actatropica.2020.105443. Epub 2020 Mar 13.
Q fever is a widespread zoonotic disease caused by Coxiella burnetii that most commonly infects not only a variety of mammals but also arthropods and in particularly ticks. The aim of this study was to detect C. burnetii infection in camels including ixodid ticks using serological and molecular assays. Between July 2018 to June 2019, blood samples from 184 male and female camels (Camelus dromedarius) were collected from 3 regions of South-East Algeria and serum samples were tested for antibodies against Coxiella burnetii using indirect enzyme-linked immunosorbent assay (ELISA) kit. The positive sera and a total of 60 ticks were tested by quantitative PCR (qPCR) for detection of C. burnetii with primers and probes specific to the transposon-like repetitive region (IS1111 gene). Positive samples were genotyped by amplification and sequencing of partial sequences based on the IS1111 gene. The seroprevalence of antibodies against C. burnetii was 75.5%. Statistical analysis pointed out three potential risk factors associated with Q fever infection: geographic location, age class and season. No positive DNA of camel blood sample was observed. However, five Hyalomma dromedarii, one H. impeltatum and one H. excavatum tick species were detected positive for Coxiella burnetii DNA by qPCR, with an overall prevalence rate of 11.66% (7/60). The revealed Algerian strains by phylogenetic and comparative analysis of the IS1111 nucleotide sequences were clustered with several pathogenic C. burnetii strains isolated from ticks, human, and cattle located in Tunisia, Greece and in some Mediterranean countries, respectively. The study results clearly indicate that camels and their ticks in Algeria may play an important role as a reservoir for C. burnetii and can be considered as a significant source of Q fever transmission to other animal species and humans.
Q 热是一种由贝氏柯克斯体引起的广泛人畜共患病，最常见的感染源不仅包括多种哺乳动物，还包括节肢动物，尤其是蜱虫。本研究旨在使用血清学和分子检测方法检测骆驼（单峰驼）中的贝氏柯克斯体感染情况，包括蜱虫。2018 年 7 月至 2019 年 6 月，从阿尔及利亚东南部的 3 个地区采集了 184 只雄性和雌性骆驼（单峰驼）的血液样本，并通过间接酶联免疫吸附试验（ELISA）试剂盒检测了针对贝氏柯克斯体的抗体。对阳性血清和总共 60 只蜱虫进行了定量 PCR（qPCR）检测，以检测转座子样重复区（IS1111 基因）的 Coxiella burnetii。阳性样本基于 IS1111 基因的扩增和部分序列测序进行基因分型。针对 Coxiella burnetii 的抗体血清阳性率为 75.5%。统计分析指出了与 Q 热感染相关的三个潜在风险因素：地理位置、年龄类别和季节。未观察到骆驼血液样本的 Coxiella burnetii DNA 阳性。然而，通过 qPCR 检测到 5 只单峰驼血蜱、1 只 H. impeltatum 和 1 只 H. excavatum 蜱种的 Coxiella burnetii DNA 阳性，总体阳性率为 11.66%（7/60）。通过 IS1111 核苷酸序列的系统发育和比较分析揭示的阿尔及利亚株与从突尼斯、希腊和一些地中海国家分离的来自蜱、人类和牛的几种致病性 Coxiella burnetii 株聚类在一起。研究结果清楚地表明，阿尔及利亚的骆驼及其蜱虫可能在贝氏柯克斯体的储存中发挥重要作用，并且可以被认为是 Q 热向其他动物物种和人类传播的重要来源。
