PDF(Pubmed)
Abstract：
Cystic Echinococcosis (CE) as a prevalent tapeworm infection of human and herbivorous animals worldwide, is caused by accidental ingestion of Echinococcus granulosus eggs excreted from infected dogs. CE is endemic in the Middle East and North Africa, and is considered as an important parasitic zoonosis in Iran. It is transmitted between dogs as the primary definitive host and different livestock species as the intermediate hosts. One of the most important measures for CE control is dog deworming with praziquantel. Due to the frequent reinfection of dogs, intensive deworming campaigns are critical for breaking CE transmission. Dog reinfection rate could be used as an indicator of the intensity of local CE transmission in endemic areas. However, our knowledge on the extent of reinfection in the endemic regions is poor. The purpose of the present study was to determine E. granulosus reinfection rate after praziquantel administration in a population of owned dogs in Kerman, Iran. A cohort of 150 owned dogs was recruited, with stool samples collected before praziquantel administration as a single oral dose of 5 mg/kg. The re-samplings of the owned dogs were performed at 2, 5 and 12 months following initial praziquantel administration. Stool samples were examined microscopically using Willis flotation method. Genomic DNA was extracted, and E. granulosus sensu lato-specific primers were used to PCR-amplify a 133-bp fragment of a repeat unit of the parasite genome. Survival analysis was performed using Kaplan-Meier method to calculate cumulative survival rates, which is used here to capture reinfection dynamics, and monthly incidence of infection, capturing also the spatial distribution of disease risk. Results of survival analysis showed 8, 12 and 17% total reinfection rates in 2, 5 and 12 months following initial praziquantel administration, respectively, indicating that 92, 88 and 83% of the dogs had no detectable infection in that same time periods. The monthly incidence of reinfection in total owned dog population was estimated at 1.5% (95% CI 1.0-2.1). The results showed that the prevalence of echinococcosis in owned dogs, using copro-PCR assay was 42.6%. However, using conventional microscopy, 8% of fecal samples were positive for taeniid eggs. Our results suggest that regular treatment of the dog population with praziquantel every 60 days is ideal, however the frequency of dog dosing faces major logistics and cost challenges, threatening the sustainability of control programs. Understanding the nature and extent of dog reinfection in the endemic areas is essential for successful implementation of control programs and understanding patterns of CE transmission.
摘要：
囊性棘球蚴病（CE）作为一种普遍感染人类和食草动物的全球，是由于意外摄入从被感染的狗排泄的细粒棘球蚴卵引起的。CE在中东和北非很流行，并被认为是伊朗重要的寄生虫人畜共患病。它在作为主要最终宿主的狗和作为中间宿主的不同家畜物种之间传播。控制CE的最重要措施之一是用吡喹酮驱虫。由于狗经常再次感染，密集的驱虫运动对于打破CE传输至关重要。犬再感染率可作为流行区局部CE传播强度的指标。然而,我们对流行地区的再感染程度知之甚少。本研究的目的是确定在克尔曼的养犬种群中，吡喹酮给药后的细粒大肠杆菌再感染率。伊朗。招募了150只拥有的狗，吡喹酮给药前收集的粪便样本为5mg/kg的单次口服剂量。在初始吡喹酮给药后2、5和12个月时对所拥有的狗进行重新采样。使用Willis浮选法对粪便样品进行了显微镜检查。提取基因组DNA,和E.granulosussensulato特异性引物用于PCR扩增寄生虫基因组重复单元的133bp片段。生存分析采用Kaplan-Meier法计算累积生存率,它在这里用来捕捉再感染的动态，和每月的感染率，还捕获疾病风险的空间分布。生存分析结果显示，吡喹酮初始给药后2、5和12个月的总再感染率分别为8、12和17%，分别,表明在相同的时间段内，92、88和83％的狗没有可检测到的感染。所有犬只中的每月再感染发生率估计为1.5％（95％CI1.0-2.1）。结果表明,包虫病在养犬中的患病率,使用copro-PCR检测为42.6%。然而,使用传统的显微镜，8％的粪便样品对taeniid卵呈阳性。我们的结果表明，每60天使用吡喹酮定期治疗狗群是理想的，然而，狗给药的频率面临着重大的物流和成本挑战，威胁到控制项目的可持续性。了解流行地区狗再感染的性质和程度对于成功实施控制程序和了解CE传播模式至关重要。
