Chrono-environment, UMR UFC/CNRS 6249 aff. INRA, Université de Franche-Comté, Besançon, France.
Laboratory of Wildlife Management and Ecosystem Health, Yunnan University of Finance and Economics, Kunming, China.
PLoS Negl Trop Dis. 2019 Aug 30;13(8):e0007701. doi: 10.1371/journal.pntd.0007701. eCollection 2019 Aug.
Human alveolar echinococcosis caused by infection with Echinococcus multilocularis is one of the most potentially pathogenic helminthic zoonoses. Transmission occurs involving wildlife cycles typically between fox and small mammal intermediate hosts. In the late 1980s/early 1990s a large focus of human AE was identified in poor upland agricultural communities in south Gansu Province, China. More detailed investigations in 1994-97 expanded community screening and identified key risk factors of dog ownership and landscape type around villages that could support susceptible rodent populations. A crash of the dog population (susceptible domestic definitive host) in the early 1990s appeared to stop transmission.
METHODOLOGY/FINDINGS: We subsequently undertook follow-up eco-epidemiological studies based on human population screening and dog survey, in 2005/6 and in 2014/15. Our observations show a decrease in human AE prevalence, especially marked in the 11-30 year old age category. In 2015, although the dog population had recovered and in addition, forest protection and the reforestation of some areas may have favoured red fox (wild definitive host) population growth, there was no evidence of infection in owned dogs.
CONCLUSIONS/SIGNIFICANCE: Those observations suggest that over decades socio-ecological changes resulted in a cascade of factors that exacerbated and then interrupted parasite emergence, with probable elimination of peri-domestic transmission of E. multilocularis in this area, despite the relative proximity of large active transmission foci on the eastern Tibetan Plateau. This study case exemplifies how anthropogenic land use and behavioural changes can modify emergence events and the transmission of endemic zoonotic parasite infections, and subsequently the importance of considering processes over the long-term in a systems approach in order to understand pathogen and disease distribution.
由多房棘球绦虫感染引起的人类泡型包虫病是最具潜在致病性的寄生虫病之一。这种疾病的传播涉及野生动物循环，通常在狐狸和小型哺乳动物中间宿主之间进行。20 世纪 80 年代末/90 年代初，在中国甘肃省南部贫困的高地农业社区发现了一个大型人类泡型包虫病焦点。1994-97 年更详细的调查扩大了社区筛查范围，并确定了村庄周围的关键风险因素，包括养狗和景观类型，这些因素可以支持易感染的啮齿动物种群。20 世纪 90 年代初，狗（易感的终末宿主）数量的暴跌似乎阻止了传播。
方法/发现：随后，我们根据人口筛查和犬只调查，在 2005/6 年和 2014/15 年进行了后续的生态流行病学研究。我们的观察结果表明，人类泡型包虫病的患病率下降，尤其是在 11-30 岁年龄组中。2015 年，尽管狗的数量已经恢复，此外，森林保护和一些地区的重新造林可能促进了赤狐（野生终末宿主）种群的增长，但在犬只中没有发现感染。
结论/意义：这些观察表明，几十年来，社会生态变化导致了一系列因素的级联反应，加剧了寄生虫的出现，随后中断了寄生虫的出现，尽管在东部青藏高原上有相对较大的活跃传播焦点，但在该地区，可能已经消除了家庭周围传播多房棘球绦虫的途径。本研究案例说明了人为土地利用和行为变化如何改变出现事件和地方性人畜共患寄生虫感染的传播，随后强调了在系统方法中考虑长期过程以了解病原体和疾病分布的重要性。
