One Health,veterinarians and the nexus between disease and food security

Achieving ecologically sustainable food systems for people and animals is one of the greatest challenges facing our world today. Four interdisciplinary approaches that promote a holistic, systems approach to disease prevention and food security are introduced. Current domestic and international initiatives that link disease prevention with food and nutrition security are presented, with an emphasis on animal‐source food and examples from Australia, Tanzania and Timor‐Leste. Veterinarians are uniquely placed to use their training in comparative physiology in support of the production of sustainable, nutritious, ethical and safe food delivered with minimal waste to promote human, animal and environmental health.     

狂犬病及其防制措施

针对目前狂犬病在全世界流行日益严峻的形势，通过大量的数字详细列举了国内外人和动物狂犬病的流行现状、欧美等发达国家防制狂犬病的有效措施及我国防制措施，结合我国狂犬病流行现状，分析了狂犬病流行的原因，提出了我国防制狂犬病的几点建议。     

狂犬病病毒流行病学特征与实验室诊断技术的研究进展

狂犬病是由狂犬病病毒引起的以中枢神经系统感染为特征的一种人兽共患病。狂犬病病毒具有嗜神经性,能在人和多种哺乳动物中引起致死性感染,病死率几乎为100%。除常规的临床诊断外,狂犬病的确诊依赖于实验室诊断方法,方法主要有病原学诊断、血清学诊断和分子生物学诊断方法等。狂犬病作为一种人兽共患烈性传染病,呈全球分布的态势,中国每年因狂犬病病毒感染而导致死亡的人数居全球第2位。因此,加强对该病的病原学、流行病学特征的认识、加快实验室诊断方法的研究对其综合防控工作具有十分重要的意义。作者主要介绍了目前国内外狂犬病流行病学特征和诊断方法的研究进展,并比较了各种方法的优点和缺点,为狂犬病的临床快速诊断和深入研究提供科学依据。     

我国部分地区犬狂犬病免疫覆盖率的连续调查

本研究对我国部分城市或地区犬狂犬病的免疫覆盖率进行了连续3年以上的调查,结果显示,所调查的发达城市犬狂犬病免疫覆盖率总体水平有所提高,如深圳和北京已达到或接近70%的有效覆盖率;南方较发达城市的免疫覆盖率为20%~30%,但距离狂犬病免疫覆盖标准（≥70%）相差甚远;农村地区和狂犬病流行的北方城市,狂犬病免疫覆盖率仍很低,甚至不足5%。以上结果反映出,在未实行强制免疫的情况下,我国狂犬病的免疫覆盖率和经济发展水平呈正相关,欠发达城市和农村地区的犬仍未接受有效免疫,无法阻断狂犬病在动物之间传播,不利于我国狂犬病的控制。     

Epidemiological Characteristics of Human and Animal Rabies in Azerbaijan

The Caucasus is a region of geopolitical importance, in the gateway between Europe and Asia. This geographical location makes the region equally important in the epidemiology and control of transboundary infectious diseases such as rabies. Azerbaijan is the largest country in the Caucasus, and although rabies is notifiable and considered endemic, there is little information on the burden of human and animal rabies. Here, we describe a cross‐disciplinary international collaboration aimed at improving rabies control in Azerbaijan. Partial nucleoprotein gene sequences were obtained from animal rabies cases for comparison with those from surrounding areas. Reported human and animal rabies cases between 2000 and 2010 were also reviewed and analysed by region and year. Comparison of rabies virus strains circulating in Azerbaijan demonstrates more than one lineage of rabies virus circulating concurrently in Azerbaijan and illustrates the need for further sample collection and characterization. Officially reported rabies data showed an increase in human and animal rabies cases, and an increase in animal bites requiring provision of post‐exposure prophylaxis, since 2006. This is despite apparently consistent levels of dog vaccination and culling of stray dogs.     

Challenges to human rabies elimination highlighted following a rabies outbreak in bovines and a human in Punjab,India

In August 2015, a rabies outbreak occurred in bovines in a Punjab village, India; subsequently, a farmer in the same village died of rabies in October 2015. We surveyed farmers to describe the outbreak, the demographics and rabies prophylaxis administered to householders on case farms, and farmers’ knowledge of rabies prevention and treatment. We used multiple correspondence analysis to guide investigation of associations between demographics, farm status and rabies knowledge, attitudes and practices. The number of affected bovines was unusually high; 15 cattle and buffalo died on 13 smallholder farms (attack rate 4%). Post‐exposure vaccinations were administered to 24 people (median 2 doses). Affected farms had significantly larger households and were more likely to keep their livestock outside (therefore, accessible by stray dogs), suggesting that the impact of the outbreak was disproportionally borne by households of lower socio‐economic status. Primary sources of rabies information were friends and neighbours, not health authorities or media. Women who had not received formal education were less likely to have heard of rabies. Although case farm participants were more likely to have heard about rabies from a veterinarian, their knowledge and practices to prevent rabies did not reflect the level expected considering their contact with a health professional; they were more likely to believe that traditional remedies prevent rabies and less likely to tell their children to avoid playing with stray dogs than participants from other farms. This study highlights knowledge dissemination disparities that, if typical of rural locations, could obstruct attempts to eliminate canine‐mediated human rabies in India. Therefore, understanding the pervasiveness and influence of traditional medical beliefs on treatment‐seeking behaviour, communication structures within villages and the impact of local practices such as carcass disposal on dog populations will be essential to ensure that rabies control strategies are effective in rural India.     

The raccoon (Procyon lotor) as potential rabies reservoir species in Germany: a risk assessment

Terrestrial wildlife rabies has been successfully eliminated from Germany predominantly as a result of the distribution of oral rabies vaccine baits. In case that wildlife rabies would re-emerge among its known reservoir species in Germany, swift action based on previous experiences could spatially and temporally limit and subsequently control such an outbreak. However, if rabies emerged in the raccoon population in Germany (Procyon lotor), there are no tools or local experience available to cope with this situation. This is especially worrisome for urban areas like Kassel (Hesse) due to the extremely high raccoon population density. A rabies outbreak among this potential reservoir host species in these urban settings could have a significant impact on public and animal health.     

Review of Rabies Epidemiology and Control in South,South East and East Asia: Past,Present and Prospects for Elimination

Rabies is a serious public health problem in Asia. It causes substantial animal welfare, economic and human health impacts, with approximately 39 000 human deaths each year. Domestic dogs are the main reservoir and source of rabies in Asia. Common constraints for the control of rabies in the countries of Asia include inadequate resources; lack of political commitment to control programs; lack of consensus on strategy; weak intersectoral coordination and inadequate management structure; insensitive surveillance systems; limited accessibility to modern rabies vaccine and supply problems; lack of public awareness and public cooperation; and the existence of myths and religious issues. In this review, we summarize the epidemiology of rabies in both human and animals in each South and South East Asian country, the past and current approaches to control and the prospect for rabies elimination. We conclude that defining the cost of rabies to society and communicating this to decision‐makers might be the key to achieving such an advance.     

Challenges to controlling rabies in skunk populations using oral rabies vaccination: A review

Controlling rabies in skunk populations is an important public health concern in many parts of the United States due to the potential for skunk rabies outbreaks in urban centres and the possible role for skunks in raccoon rabies variant circulation. Oral rabies vaccination (ORV) programmes have supported wildlife rabies control efforts globally but using ORV to control rabies in skunk populations has proven more challenging than with other target species, like foxes, coyotes and raccoons. A review of published studies found that some ORV constructs are immunogenic in skunks and protect against virulent rabies virus challenges, especially when delivered by direct installation into the oral cavity. However, in field ORV programmes using currently available vaccine‐bait formats and distribution methods targeting other rabies reservoir species, skunks often fail to seroconvert. Field effectiveness of ORV in skunks appears to be limited by poor bait uptake or inadequate ingestion of vaccine rather than from poor vaccine efficacy. Observations of captive skunks revealed vaccine spillage when handling and biting into baits such that modification of bait formats might improve field effectiveness. In addition, a dose–response relationship between bait distribution density and post‐baiting seroconversion among skunks was observed across the limited number of field studies. Additional research is needed to identify opportunities to modify ORV baits and distribution strategies to improve the viability of ORV as a rabies control strategy in skunks.     

Rabies in kudu (Tragelaphus strepsiceros)

Cycles of terrestrial rabies are associated with carnivores. In non-carnivorous species, rabies typically occurs as a spill-over from the carnivore reservoir and quickly encounters a dead end in such species. One major exception to this scenario has been an ongoing epizootic of rabies in the Greater Kudu, an African antelope. These herbivores are found in high densities in southern Africa, but rabies cycles have only been described from Namibia, a vast country located in the South Western region of Africa. Epizootics were first noted in the late 1970's and losses of up to 50 000 animals were estimated by 1985. Between 2002 and 2011, Namibian conservancies again estimated kudu losses ranging from 30-70%, resulting in very significant economic losses to the farming and gaming industries of the country. The sheer magnitude of the epizootic, phylogenetic data and experimental evidence of the particular susceptibility of kudu to rabies infection via mucous membranes are factors in support of a hypothesis that suggests horizontal transmission and maintenance of a rabies cycle within this species. It has become critical to investigate pathways for effective rabies control in Namibia--including the development of a strategy to halt and reverse the devastating epizootic of kudu rabies.     

上海市犬只狂犬病认定免疫点主要管理做法分析

强化犬只狂犬病免疫工作是从源头控制狂犬病的最有效措施.近年来,上海市按照《上海市养犬管理条例》的要求,通过严把免疫资质准入、规范内部管理、落实疫情报告责任、推进免疫质量考核等举措,使犬只狂犬病认定免疫点的布局日趋合理,文明服务更加规范,这已成为上海市民犬只狂犬病免疫的主渠道,免疫数量和质量逐年提升,构筑了良好的免疫屏障...     

Polymerase chain reaction and other laboratory techniques in the diagnosis of long incubation rabies in Australia

SUMMARY Blood and post-mortem tissues from a 10-years-old girl were submitted to the Australian Animal Health Laboratory. Clinical signs and histopathological lesions had suggested a diagnosis of rabies, but, an unusually long incubation period of at least 5 years did not encourage such a diagnosis. Serological examinations by the rapid fluorescent focus inhibition test revealed a dramatic increase in rabies virus-neutralising antibody during the 10-day period of hospitalisation. The results of a fluorescent antibody test on brain smears, and an immunoperoxidase test on formalin-fixed sections of brain were also consistent with a diagnosis of rabies. Attempts to isolate virus were unsuccessful. Polymerase chain reactions (PCRs) were conducted on a 10% suspension of a post-mortem sample from the patient's brain, using primers based on the published sequence of the Pasteur virus strain of rabies virus. 413 and 513 bp fragments from the nucleoprotein gene and a 403 bp fragment from the glycoprotein gene were amplified. Subsequent sequencing of these fragments, and comparison with equivalent regions of known rabies viruses, confirmed that the fragments originated from a virus belonging to the rabies virus serotype. This case demonstrated the advantage of using a range of laboratory techniques to obtain a definitive diagnosis. In particular, a PCR-based test may allow a diagnosis, even in the face of conditions that preclude virus isolation such as apparently occurred in this case. Finally, this case demonstrated that an unusually long incubation period should not discourage a tentative clinical diagnosis of rabies.     

Use of Aspiration Method for Collecting Brain Samples for Rabies Diagnosis in Small Wild Animals

In developing countries such as Brazil, where canine rabies is still a considerable problem, samples from wildlife species are infrequently collected and submitted for screening for rabies. A collaborative study was established involving environmental biologists and veterinarians for rabies epidemiological research in a specific ecological area located at the Sao Paulo State, Brazil. The wild animals’ brains are required to be collected without skull damage because the skull’s measurements are important in the identification of the captured animal species. For this purpose, samples from bats and small mammals were collected using an aspiration method by inserting a plastic pipette into the brain through the magnum foramen. While there is a progressive increase in the use of the plastic pipette technique in various studies undertaken, it is also appreciated that this method could foster collaborative research between wildlife scientists and rabies epidemiologists thus improving rabies surveillance.     

Simultaneous Growth of Rabies and Canine Distemper Viruses in Chick Embryos

Rabies virus and canine distemper virus were grown simultaneously, and possibly symbiotically, in the same chick embryos. There seemed to be no adverse effect on either virus when cultured in such manner.

Bivalent vaccines for rabies and canine distemper were produced. The potencies and the virus titers of such vaccines were comparable to those of rabies vaccine and canine distemper vaccine produced separately.

     

Twenty year experience of the oral rabies vaccine SAG2 in wildlife: a global review

The SAG2 vaccine (RABIGEN® SAG2) is a modified live attenuated rabies virus vaccine, selected from the SAD Bern strain in a two-step process of amino acid mutation using neutralizing monoclonal antibodies. The strain is genetically stable and does not spread in vivo or induce a persistent infection. Its absence of residual pathogenicity was extensively demonstrated in multiple target and non target species (such as wild carnivores and rodent species), including non-human primates. The efficacy of SAG2 baits was demonstrated according to the EU requirements for the red fox and raccoon dog. The use of safe and potent rabies vaccines such as SAG2 largely contributed to the elimination of rabies in Estonia, France, Italy and Switzerland. Importantly, these countries were declared free of rabies after few years of oral vaccination campaigns with SAG2 baits distributed with an appropriate strategy. The excellent tolerance of the SAG2 vaccine has been confirmed in the field since its first use in 1993. No safety issues have been reported, and in particular no vaccine-induced rabies cases were diagnosed, after the distribution of more than 20 million SAG2 baits in Europe.     

Predictive qualitative risk model of bovine rabies occurrence in Brazil

Bovine rabies remains endemic in Brazil and despite control efforts, the disease still spreads insidiously. The main vector is the hematophagous bat, Desmodus rotundus. The present work aimed to create a predictive qualitative model of the occurrence of bovine rabies in each municipality in 25 of the 27 Brazilian States. The risk of rabies transmission from bats to bovine was estimated using decision-tree models of receptivity and vulnerability. Questionnaires, which covered a number of questions related to the surveillance of possible risk factors, such as bovine rabies outbreaks in the previous year, the presence of bat roosts, bat rabies positivity and environmental changes, were sent to the local veterinary units of each State. The bovine density and geomorphologic features were obtained from national databases and geographic information systems. Of the 433 municipalities presenting bovine rabies outbreaks in 2010, 178 (41.1%) were classified by the model as high risk, 212 (49.0%) were classified as moderate risk, 25 (5.8%) were classified as low risk, whereas the risk was undetermined in 18 municipalities (4.1%). An ROC curve was built to determine if the risk evaluated by the model could adequately discriminate between municipalities with and without rabies occurrence in future years. The risk estimator for the year 2011 was classified as moderately accurate. In the future, these models could allow the targeting of rabies control efforts, with the adoption of control measures directed to the higher risk locations and the optimization of the field veterinary staff deployment throughout the country. Additionally, efforts must be made to encourage continuous surveillance of risk factors.     

Prevention and Control of Rabies in an Age of Global Travel: A Review of Travel‐ and Trade‐Associated Rabies Events – United States, 1986–2012

Rabies prevention and control efforts have been successful in reducing or eliminating virus circulation regionally through vaccination of specific reservoir populations. A notable example of this success is the elimination of canine rabies virus variant from the United States and many other countries. However, increased international travel and trade can pose risks for rapid, long‐distance movements of ill or infected persons or animals. Such travel and trade can result in human exposures to rabies virus during travel or transit and could contribute to the re‐introduction of canine rabies variant or transmission of other viral variants among animal host populations. We present a review of travel‐ and trade‐associated rabies events that highlight international public health obligations and collaborative opportunities for rabies prevention and control in an age of global travel. Rabies is a fatal disease that warrants proactive coordination among international public health and travel industry partners (such as travel agents, tour companies and airlines) to protect human lives and to prevent the movement of viral variants among host populations.     

A Conceptual Model for the Impact of Climate Change on Fox Rabies in Alaska, 1980–2010

The direct and interactive effects of climate change on host species and infectious disease dynamics are likely to initially manifest\ at latitudinal extremes. As such, Alaska represents a region in the United States for introspection on climate change and disease. Rabies is enzootic among arctic foxes (Vulpes lagopus) throughout the northern polar region. In Alaska, arctic and red foxes (Vulpes vulpes) are reservoirs for rabies, with most domestic animal and wildlife cases reported from northern and western coastal Alaska. Based on passive surveillance, a pronounced seasonal trend in rabid foxes occurs in Alaska, with a peak in winter and spring. This study describes climatic factors that may be associated with reported cyclic rabies occurrence. Based upon probabilistic modelling, a stronger seasonal effect in reported fox rabies cases appears at higher latitudes in Alaska, and rabies in arctic foxes appear disproportionately affected by climatic factors in comparison with red foxes. As temperatures continue a warming trend, a decrease in reported rabid arctic foxes may be expected. The overall epidemiology of rabies in Alaska is likely to shift to increased viral transmission among red foxes as the primary reservoir in the region. Information on fox and lemming demographics, in addition to enhanced rabies surveillance among foxes at finer geographic scales, will be critical to develop more comprehensive models for rabies virus transmission in the region.