摘要
Zoonoses involve interactions between at least three species: the pathogen and two hosts, one of which is human and the other a non-human (vertebrate) animal. More than 60% of human infectious diseases are zoonotic, and many have a wildlife host. Urbanisation and human population growth have increased the demand for food and land resources, which have increased interaction between humans, domestic animals and wildlife and thus the potential for cross-species transmission of infections. Most studies of such systems take place in tropical and developing countries where population change and biodiversity makes the emergence of high profile infections (eg Ebola and SARS) more likely. This study, however, focuses on four well known infections within the UK: bovine tuberculosis, water-borne cryptosporidiosis and giardiasis, and campylobacteriosis. The aim of this study was to investigate, using four infectious diseases of economic and public health importance in the UK as study systems, the role of wildlife in the epidemiology of multihost, zoonotic infections.
Bovine tuberculosis (bTB) is an important zoonosis in many parts of the world, but human infection is rare in the UK owing to a policy of ‘test and cull’ in cattle and pasteurisation of milk. However, there has been an epidemic of bTB in British cattle in recent decades, the control of which is complicated by infection in badgers (Meles meles) and controversy over the control of wildlife infection. I investigated TB in badgers in the Cheshire area, located on the edge of the epidemic in England, in collaboration with various stakeholders. Using a road-kill survey, I found M. bovis in 20 of 94 badgers: the estimated prevalence of 21.3% (95% CI 14.2-30.6) is comparable to the county-level prevalence found at the core of the epidemic. That all isolates were spoligotype SP25, suggests this is an expansion of infection from neighbouring counties. The directionality of any cross-species transmission of bTB between wildlife and livestock cannot be ascertained from this project. However, it showed that using road-killed badgers is a valuable approach to sampling, especially if combined with the engagement of stakeholders.
Cryptosporidium spp and Giardia duodenalis are protozoa that can cause diarrhoea in many mammals including humans. Llyn Cowlyd, a major water reservoir in North Wales, had seen annual summer peaks of uncharacterised Cryptosporidium spp cysts, without human disease. My study aimed to determine the source(s) of the contamination and to investigate G. duodenalis in the same system. Water samples were collected from the reservoir and feeder streams, and faecal samples from livestock and wild rodents. In total, 97 rodents were sampled: 35 (35.7% CI 95% 26.9-45.6%) were positive for Cryptosporidium spp. and 11 (11.2% CI 95% 6.4-19%) for Giardia spp. Of cryptosporidia detected, 55% were novel genotypes and only 5% C. parvum (zoonotic). Of 11 livestock samples, only two samples were positive for C. parvum and G. duodenalis. All the rodent Giardia belonged to an apparently novel assemblage while livestock Giardia belonged to non-zoonotic assemblage E. The water samples contained C. ubiquitum, C. parvum, and G. duodenalis assemblages E, A (zoonotic), and the novel rodent assemblage.
Campylobacter jejuni and C. coli, are common causes of diarrhoeal disease in humans. Infection is common in a wide range of livestock and wildlife species, usually, however, without disease. The aim of this study was to investigate the potential role of wild birds in the epidemiology of campylobacteriosis on dairy and poultry units already studied in depth as part of a larger research programme. In total, 299 birds were sampled and 14 (4.7% CI 95% 2.8-7.7%) were positive for C. jejuni. Multi-locus sequence typing showed each isolate to be different, and many of these sequence types found in wild birds have not been associated with human disease.
Overall, these results show that while at first sight wildlife might be assumed to be potential sources of zoonotic infections, further characterisation of the agents involved often revealed separate cycles of infection in wildlife, livestock and humans.
摘要译文
Zoonoss涉及至少三种物种之间的相互作用：病原体和两个宿主，其中一个是人，另一个是非人（脊椎动物）动物。超过60％的人类传染病是一种人群，许多人都有野生动物主持人。城市化和人口增长增加了对食品和土地资源的需求，这些需求增加了人类，家畜和野生动物的互动，从而增加了感染的跨物种传播的可能性。大多数对这种系统的研究发生在热带和发展中国家，人口变化和生物多样性使得高型感染的出现（例如埃博拉和SARS）更有可能。然而，这项研究侧重于英国内部的四种众所周知的感染：牛结核病，水性密度症和胃肠病和脉动杆菌。本研究的目的是在英国使用四种经济和公共卫生的传染病作为研究制度，在多HOOTOST的流行病学中的野生动物的作用，从素质感染。核心核算（BTB）是许多重要的动物病世界各地，但由于牛的牛和巴氏杀菌的牛氏杀菌的政策，英国的人类感染是罕见的。然而，近几十年来，英国牛的BTB流行病，对其对獾（Meles Meles）的感染复杂化并对野生动物感染的控制争议。我调查了位于英格兰疫情边缘的柴郡地区的獾队中，与各种利益相关者合作。使用道路杀戮调查，我发现了94个獾20中的Bovis：估计的患病率为21.3％（95％CI 14.2-30.6）与陷入困境的核心普遍存在的县级普遍相当。所有分离物都是SpoliGotype SP25，表明这是来自邻近县的感染的扩展。从该项目确定野生动物和牲畜之间BTB之间任何跨物种传输的方向性。然而，它表明，使用道路杀死的獾是抽样的宝贵方法，特别是如果与利益相关者的参与相结合.Cryptosporidium spp和Giardia duodenalis是原生动物，可以在包括人类在内的许多哺乳动物中引起腹泻的原生动物。 Llyn Cowlyd是北威尔士的主要水库，每年夏季夏季峰的无特征性密码孢子SPP囊肿，没有人类疾病。我的研究旨在确定污染的来源，并在同一系统中调查G. Duodenalis。从储层和饲养物流中收集水样，来自牲畜和野生啮齿动物的粪便样品。总共有97个啮齿动物进行取样：35（35.7％CI 95％26.9-45.6％）对Cryptosporidium SPP呈阳性。 Giardia SPP 11（11.2％CI 95％6.4-19％）。检测到的Cryptosporidia，55％是新的基因型，只有5％C. parvum（动物园）。在11个牲畜样品中，只有两个样品对于C. parvum和G. duodenalis阳性。所有啮齿动物贾迪亚迪亚都属于一个明显的新组合，而牲畜贾纳迪亚属于非洲菌类化组合E.水样含有C. ubiquitum，C. parvum和G. duodenalis组装e，a（动物区）和新的啮齿动物组装。 Campylobacter Jejuni和C.Coli，是人类腹泻病的常见原因。感染在广泛的牲畜和野生动物种类中是常见的，然而，通常没有疾病。本研究的目的是调查野生鸟类在乳房和家禽单元的流行病流行病中的潜在作用，作为较大的研究计划的一部分已经研究过。总共有299只鸟类，14（4.7％CI 95％2.8-7.7％）对C. jejuni呈阳性。多基因座序列打字显示每个分离物不同，并且野生鸟类中发现的许多这些序列类型尚未与人类疾病有关。overall，这些结果表明，虽然乍一看野生动物可能被认为是潜在的人群来源感染，涉及的药剂的进一步表征通常揭示了野生动物，牲畜和人类的单独感染循环。