Transboundary Spread Research Articles

First Report of bla CTX-M-15-Type ESBL-Producing Klebsiella pneumoniae in Wild Migratory Birds in Pakistan

We investigated wild migratory birds faecal swabs for extended-spectrum β-lactamases-producing Klebsiella pneumoniae (ESBL-K. pneumoniae) from wetland habitats in Pakistan. ESBL-K. pneumoniae were analysed for MDR phenotype, ESBL genotype and genetic diversity. A total of 13 (8.6%) ESBL-K. pneumoniae were recovered. Of these, 8 (61%) isolates were MDR. DNA sequencing confirmed bla CTX-M-15 as the dominant ESBL genotype. BOX-PCR fingerprints showed most of the isolates are unrelated. This study is the first to report the wildlife contamination of CTX-M-15-producing K. pneumoniae in Pakistan. Due to long-range migration, these birds could be responsible for trans-boundary spread of multidrug-resistant bacteria.

Global monitoring of drivers of animal disease outbreaks to inform local risks of disease introduction

Purpose: Tools are needed by decision-makers to enhance understanding of global disease transmission dynamics and facilitate timely risk analyses. Additionally, there is a need to include situational awareness of the presence of potential drivers of disease emergence and transmission when making early projections on transboundary risks of animal disease outbreak spread. We conducted a pilot study of an approach to bring diverse data on social and environmental drivers of animal disease emergence and spread together with data on animal populations and outbreaks. Information is presented geographically to visually communicate potential risks of disease emergence and potential spread. Methods & Materials: Our use cases for this approach were lumpy skin disease and avian influenza. Variables collected daily from systematic searches of global biosurveillance data on unexplained increases in animal morbidity and mortality, as well as confirmed findings of diseases in livestock and poultry populations are layered with social and environmental data layers, such as climate, flood and drought, and civil unrest. Using GIS coordinates for area centroids, a time-series geospatial presentation of outbreaks and findings is developed. Data is layered on estimated population density of susceptible livestock or poultry for an initial understanding of risk potential for direct transmission and movement of the disease agent geospatially. In addition, based on knowledge of the known drivers of each disease agent, additional data are included to reflect variables associated with animal disease emergence and transboundary spread. Results: Using this simple data visualization tool, the emergence and transboundary spread of lumpy skin disease and avian influenza viruses are visualized and used for situational awareness and analysis of the possible forecasted risks of local emergence of these diseases. Conclusion: Data gathered to monitor and estimate local risks of emerging animal diseases are analyzed using a readily updated data visualization tool and used to visually communicate potential risks of animal disease emergence and potential spread to risk analysts. Such a tool can assist decision-makers assess local risks of disease emergences based on global drivers of animal disease transmission, as reported by open sources.

Identification of Associations between Clinical Signs and Hosts to Monitor the Web for Detection of Animal Disease Outbreaks

In a context of intensification of international trade and travels, the transboundary spread of emerging human or animal pathogens represents a growing concern. One of the missions of the national veterinary services is to implement international epidemiological intelligence for a timely and accurate detection of emerging animal infectious diseases (EAID) worldwide, and take early actions to prevent their introduction on the national territory. For this purpose, an efficient use of the information published on the web is essential. The authors present a comprehensive method for identification of relevant associations between terms describing clinical signs and hosts to build queries to monitor the web for early detection of EAID. Using text and web mining approaches, they present statistical measures for automatic selection of relevant associations between terms. In addition, expert elicitation is used to highlight the most relevant terms and associations among those automatically selected. The authors assessed the performance of the combination of the automatic approach and expert elicitation to monitor the web for a list of selected animal pathogens.

A Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Confers Full Protection against Rift Valley Fever Challenge in Sheep

Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing disease outbreaks in Africa and the Arabian Peninsula. The virus has great potential for transboundary spread due to the presence of competent vectors in non-endemic areas. There is currently no fully licensed vaccine suitable for use in livestock or humans outside endemic areas. Here we report the evaluation of the efficacy of a recombinant subunit vaccine based on the RVFV Gn and Gc glycoproteins. In a previous study, the vaccine elicited strong virus neutralizing antibody responses in sheep and was DIVA (differentiating naturally infected from vaccinated animals) compatible. In the current efficacy study, a group of sheep (n = 5) was vaccinated subcutaneously with the glycoprotein-based subunit vaccine candidate and then subjected to heterologous challenge with the virulent Kenya-128B-15 RVFV strain. The vaccine elicited high virus neutralizing antibody titers and conferred complete protection in all vaccinated sheep, as evidenced by prevention of viremia, fever and absence of RVFV-associated histopathological lesions. We conclude that the subunit vaccine platform represents a promising strategy for the prevention and control of RVFV infections in susceptible hosts.

GMS Regional Trade in Livestock: Animal Flows and Disease Risk--A Preliminary Assessment of the Movement of Livestock and Livestock Products

Background:The official and unofficial movement of livestock and livestock products is a major risk factor in the spread of disease. Specifically in the Greater Mekond Sub-Region (GMS), where borders are extensive and powerful market forces move livestock across and within countries, the potential for trans-boundary spread of disease is great. However, with limited enforcement of regulation and information on these cross-border movements of livestock and their products, several challenges to proper disease management arise.Methods and data:Governmental departments collect data on the official movements of livestock and their products. These sources include the Ministry of Commerce and the Department of Livestock Development in Thailand, the Lao PDR Statistics Bureau, the General Statistics Office of Vietnam and the National Institute of Statistics of Cambodia. FAOSTAT was also used as a supplement for official data. Interviews were conducted with traders and anecdotal evidence was collected in certain provinces of Thailand to obtain information on unofficial livestock movements.Results:The majority of the available information on livestock and livestock product trade within the GMS is centered on Thailand (Tables 5-14). While data on livestock production is available for Thailand, Lao PDR, Vietnam and Cambodia, only the Thai government has truly invested in broad data collection thus far. This is evident in the trade statistics between Thailand and other GMS member countries provided in this report.Conclusions and recommendations:Thai trade data can assist in inferring trade movements into other countries within the GMS, and these current trends are provided in the discussion and conclusion section. However, this is not sufficient for cost-effective disease risk management.Because of these large information gaps on livestock trade within the GMS, more investment into surveillance and information gathering is necessary. Without this information, both governments and related organizations are unable to fully assess and manage the trans-boundary disease risk posed by livestock and animal product movements.

Peste Des Petits Ruminants in Benin: Persistence of a Single Virus Genotype in the Country for Over 42Years.

Peste des petits ruminants (PPR) is a contagious and often fatal disease affecting sheep and goats. Currently, it is endemic in Africa, the Middle and Near East, the Indian subcontinent and China. Understanding the molecular epidemiology and evolution of PPR virus (PPRV) can assist in the control of the transboundary spread of this economically important disease. We isolated PPRV from pathological and swab samples collected 42years apart (1969 and 2011) in Benin, West Africa, and sequenced the full genome of two isolates (Benin/B1/1969 and Benin/10/2011). Phylogenetic analysis showed that all of the characterized isolates clustered within viral lineage II and that the 2011 isolates fell into two distinct subgroups. Comparison of the full genome sequences revealed a 95.3% identity at the nucleotide level, while at the protein level, the matrix protein was the most conserved between the two viruses with an identity of 99.7% and only one amino acid substitution over the 42-year sampling period. An analysis of specific amino acid residues of known or putative function did not identify any significant changes between the two viruses. A molecular clock analysis of complete PPRV genomes revealed that the lineage II viruses sampled here arose in the early 1960s and that these viruses have likely persisted in Benin since this time.

Detection of dwarf gourami iridovirus (Infectious spleen and kidney necrosis virus) in populations of ornamental fish prior to and after importation into Australia, with the first evidence of infection in domestically farmed Platy (Xiphophorus maculatus)

The movement of ornamental fish through international trade is a major factor for the transboundary spread of pathogens. In Australia, ornamental fish which may carry dwarf gourami iridovirus (DGIV), a strain of Infectious spleen and kidney necrosis virus (ISKNV), have been identified as a biosecurity risk despite relatively stringent import quarantine measures being applied. In order to gain knowledge of the potential for DGIV to enter Australia, imported ornamental fish were sampled prior to entering quarantine, during quarantine, and post quarantine from wholesalers and aquatic retail outlets in Australia. Samples were tested by quantitative polymerase chain reaction (qPCR) for the presence of megalocytivirus. Farmed and wild ornamental fish were also tested. Megalocytivirus was detected in ten of fourteen species or varieties of ornamental fish. Out of the 2086 imported gourami tested prior to entering quarantine, megalocytivirus was detected in 18.7% of fish and out of the 51 moribund/dead ornamental fish tested during the quarantine period, 68.6% were positive for megalocytivirus. Of fish from Australian wholesalers and aquatic retail outlets 14.5% and 21.9%, respectively, were positive. Out of 365 farmed ornamental fish, ISKNV-like megalocytivirus was detected in 1.1%; these were Platy (Xiphophorus maculatus). Megalocytivirus was not detected in free-living breeding populations of Blue gourami (Trichopodus trichopterus) caught in Queensland. This study showed that imported ornamental fish are vectors for DGIV and it was used to support an import risk analysis completed by the Australian Department of Agriculture. Subsequently, the national biosecurity policy was revised and from 1 March 2016, a health certification is required for susceptible families of fish to be free of this virus prior to importation.

The Influence of International Law upon ASEAN Approaches in Addressing Transboundary Haze Pollution in Southeast Asia

Transboundary haze pollution is the Association of Southeast Asian Nation's (ASEAN) greatest environmental challenge to date. (1) Haze pollution from land and forest fires, largely in Indonesia, has repeatedly caused havoc in Malaysia and Singapore. These fires have far-reaching impacts, from causing significant damage to biodiversity, health and local economies to contributing to global climate change. (2) The worst forest fires were during 2013 and 1997-98, yet occur annually during the dry season with varied intensity. Humans are responsible for most of the fires, by clearing forest and lands for plantations and agricultural activity, especially in peatland areas. (3) Given the ongoing threat of transboundary haze pollution, its management and prevention has been listed as one of ten priority areas of regional importance for environmental cooperation for 2009 to 2015. (4) Finding a solution to transboundary pollution requires international and regional environmental law mechanisms, in addition to domestic legal systems that are more effective. (5) As international law provides frameworks and mechanisms for an appropriate response to transboundary haze, this article addresses two frameworks: customary international law and treaties. (6) The former involves the state responsibility principle, which comprises the duty to prevent transboundary pollution and to compensate accordingly. Implementation of the state responsibility principle is particularly problematic in Southeast Asia, as state sovereignty is strongly embedded in the Charter. (7) A further complication is the so-called ASEAN Way, a term that describes the preference of countries for non-interference in each other's domestic affairs, the use of consensus decision-making and cooperative programmes, and national implementation rather than reliance on a strong region-wide agency or bureaucracy. (8) The second framework for addressing haze pollution is Multilateral Environment Agreements or MEAs, namely treaties on atmosphere and biodiversity. These include the United Nations Framework Convention on Climate Change (UNFCCC), (9) and its Kyoto Protocol, (10) the Convention on Biodiversity (CBD), (11) and the Ramsar Convention. (12) MEAs are international frameworks, which can indirectly support the efforts in combating forest fires at the national level. However, there are constraints on the domestic implementation of MEAs in Southeast Asia, namely, overlapping domestic legal frameworks, lack of financial and human resources, and capacity building. Based on the two international legal frameworks mentioned above, this article will firstly examine the extent to which international law has influenced approaches in addressing transboundary pollution in the region. Secondly, it will assess whether international law has successfully contributed to regional environmental solutions. This article argues that further implementation of international law at the regional level is a necessary step forward. International Legal Regime Addressing Transboundary Air Pollution Transboundary air pollution has long been a concern of international law. (13) It has remained high on the environmental agenda in many regions including Europe, North America and Southeast Asia. (14) As transboundary air pollution is now a global threat that is contributing to issues such as ozone depletion and climate change, addressing it requires international cooperation. International law has responded to this threat by developing customary international law and MEAs on atmosphere and biodiversity as respective frameworks for its management. For customary environmental law, the principle of state responsibility for transboundary environmental harm, or the no harm principle, is particularly significant. Treaties also play an important role, especially those relating to atmosphere and biodiversity. Although these MEAs do not directly address land and forest fires, they can help to provide a framework for countries to protect their natural resources, prevent the transboundary spread of pollution and avoid international conflict. …

Detection and Genetic Characterization of Lineage IV Peste Des Petits Ruminant Virus in Kazakhstan.

Peste des petits ruminant (PPR) is endemic in many Asian countries with expansion of the range in recent years including across China during 2013-2014 (OIE, 2014). Till the end of 2014, no cases of PPR virus (PPRV) were officially reported to the Office Internationale des Epizooties (OIE) from Kazakhstan. This study describes for the first time clinicopathological, epidemiological and genetic characterization of PPRV in 3 farm level outbreaks reported for the first time in Zhambyl region (oblast), southern Kazakhstan. Phylogenetic analysis based on partial N gene sequence data confirms the lineage IV PPRV circulation, similar to the virus that recently circulated in China. The isolated viruses are 99.5-99.7% identical to the PPRV isolated in 2014 from Heilongjiang Province in China and therefore providing evidence of transboundary spread of PPRV. There is a risk of further maintenance of virus in young stock despite vaccination of adult sheep and goats, along livestock trade and pastoral routes, threatening both small livestock and endangered susceptible wildlife populations throughout Kazakhstan.

Introduction to the Special Issue: Nuclear Power in East Asia

Asian Perspective 39 (2015), 555-558 Introduction to the Special Issue: Nuclear Power in East Asia Tilman Ruff Nearly five years after the Fukushima nuclear disaster, with the largest planned share of new nuclear power reactors antici­ pated to be built in Asia, it is timely to survey the status and chal­ lenges of nuclear power in East Asia. The articles in this special issue of Asian Perspective grew out of the international,work­ shop, Nuclear Power in East Asia: The Costs and Benefits, con­ vened by Peter Van Ness at the Australian National University in Canberra on August 12-14, 2014. The workshop aimed to identify what is really at stake in the vitally important decisions being made in many countries with respect to nuclear power. This spe­ cial issue, like the workshop, provides perspectives from various disciplines, key to a comprehensive assessment and evidencebased policy. Andrew Blakers provides an inspiring current overview of sus­ tainable energy options. He describes the uniquely vast and ubiq­ uitous nature of solar energy, and its minimal security, military, environmental, and accident risks. He underlines the rapid and continuing price reductions in photovoltaics (PV) and wind energy that have seen renewables become the majority of new generation capacity installed in recent years. A feasible threefold increase in the 2015 deployment rate of PV and wind alone could turn current world electricity production completely renewable by 2035. Tatsujiro Suzuki reviews nuclear power policy issues in Japan after the 2011 Fukushima nuclear disaster, identifying key chal­ lenges that must be addressed, whatever the future direction of nuclear power in Japan. The challenges include decommissioning the Fukushima site and restoring affected people’s lives and liveli­ hoods; enhancing safety and security; spent fuel and plutonium stockpile management; waste disposal; human resource develop­ ment; and, above all, restoring public trust. 555 556 Introduction to the Special Issue Amy King and M. V. Ramana examine the conflicts and com­ promises involved in China’s record of implementation of nuclear safety measures in the years since the Fukushima disaster. These are of global importance not only because of the transboundary spread of any uncontrolled release of radioactivity but also because China plans the most rapid construction anywhere of nuclear power reactors and hopes to export nuclear technology to boot. Across the Taiwan Strait, Kuang-Jung Hsu examines the poorly documented and murky history of nuclear power in Tai­ wan. She explains how many of the accidents, neglect of public safety, regulatory failures, and current dilemmas have roots in a secret nuclear weapons program undertaken, with assistance prin­ cipally from Israel, starting in the early 1960s. Richard Tanter analyzes nuclear power plans in Indonesia— the plethora of proposals and announcements, many with scant basis in reality, promoted over four decades by the national nuclear power agency BATAN. He lays out the domestic and international alliances that have enabled this “permanently failing organization” to survive. Here again we have a murky, disturbing, and not widely known nuclear history, this time linking Indone­ sia with Slovakia. As Tanter describes it, the history is entwined with an “informational fog of fantasy” that deflects attention from the substantial domestic opposition to Indonesian nuclear power reactors. Mely Caballero-Anthony and Julius Cesar Trajano explain the state of nuclear power plans in Vietnam (furthest advanced), Malaysia, and Indonesia, and the norms, framework, and opportu­ nities provided by the Association of Southeast Asian Nations (ASEAN) in the fields of nuclear power and nonproliferation. They highlight the need to fill substantial gaps that exist in vari­ ous combinations in all three countries regarding the institutions and capacity needed for each aspect of nuclear power, from assessment and planning, construction and operation, and disas­ ter preparedness to decommissioning and waste management. Humanity is facing a perfect storm—needing to drastically and rapidly curtail climate disruption, and remove from our increasingly resource-strained and cyber-wired world the daily Tilman Ruff 557 possibility of nuclear war. Achieving both objectives is not optional but preconditional if we are to survive and enable future generations to share any kind of healthy, sustainable future. Pre­ venting nuclear war requires achieving and sustaining the eradi­ cation of nuclear weapons. And this means ceasing the...

Molecular Epidemiology ofPasteurella multocidaCirculating in India by Multilocus Sequence Typing

Multilocus sequence typing (MLST), a sequence-based typing method for bacterial pathogens, is currently the best method for long-term epidemiological study and to understand the population structure of the bacteria. This investigation was carried out to study the diversity of Pasteurella multocida isolates circulating in India. Ten different sequence types (ST) identified in this study are ST 122 from cattle, goat, mithun and pig; ST 50 from pig; ST 9 from cattle and sheep; ST 229 from cattle and goat; ST 71 and ST 277 from cattle; and ST 129, ST 280, ST 281 and ST 282 from avian species. Of these, ST 277, ST 280, ST 281 and ST 282 were identified for the first time. The analysis of results provides novel epidemiological information on the circulation of multiple STs across India. The majority of STs or their variants identified in this study have already been reported from different parts of the globe. This suggests that probably transboundary spread of strains across countries and continents has occurred across evolutionary time and is still happening. The isolation of ST 122 from small ruminants and pigs suggests that these species may be included in the preventive vaccination policy for effective control of haemorrhagic septicaemia in India.

Incursions of Cyprinid herpesvirus 2 in goldfish populations in Australia despite quarantine practices

The international trade in ornamental fish is considered a major factor for the transboundary spread of aquatic pathogens that can affect both wild and farmed fish populations. Nearly 18 million ornamental fish were imported into Australia in 2007, including approximately 3.9 million goldfish. Despite quarantine regulations during importation, there have been several incidents in Australia where exotic pathogens from ornamental fish have become established in farmed or free-living fish species. The exotic virus Cyprinid herpesvirus 2 (CyHV2) was first found in Australia in 2003 in goldfish, suggesting that sub-clinically infected goldfish were passing through quarantine regardless of health certification and three weeks of quarantine. Repeated cross sectional surveys were conducted to determine whether CyHV2 has already established in farmed or wild ornamental fish in Australia. Goldfish populations were tested to OIE standard to detect 2% prevalence with 95% confidence assuming a test of 100% sensitivity and specificity. CyHV2 was found at retail outlets, farms and in several populations of wild goldfish in the ACT and Victoria. The prevalence and moderate to high viral loads in sub-clinically infected goldfish from different domestic populations suggested the introduction was not a recent event. This study demonstrated that CyHV2 has established in Australia and informed quarantine policy to revoke the requirement for goldfish exported to Australia to be certified free of CyHV2. The results provided clear evidence that an aquatic pathogen from imported ornamental fish can become established in farmed and wild populations. This is of particular significance to Australia as there are many endemic and ecologically sensitive populations of fish that may be severely affected by exotic pathogens. The incursion of CyHV2 in Australia should be considered a case study to inform pathway analysis for pathogen establishment.

Efficiency indices and indicators of poor performance among emerging small-scale pig farmers in the Limpopo Province, South Africa.

Limpopo is a very important area for pig production in terms of animal populations and contributions to transboundary animal disease spread. Emerging small-scale pig farmers (ESSPF) are being encouraged to establish operations and spread in South Africa; however, for these farmers to perform optimally, they need to understand the basics of animal agriculture and contribute to enhancing biosecurity and efficient production systems. In the present study, the limitations to efficient production amongst ESSPF were evaluated and some improvements were suggested. It was found that the ESSPF are dominated by males and include a large percentage of older persons. A total of 26.54% of these farmers have post-matriculation qualifications. Undefined and indigenous breeds still dominate their animal genetics. The animal health technicians are the preferred channels by which farmers report diseases to the authorities (52.47%) and only one out of five (20.37%) will preferably report a disease situation direct to a veterinarian. These farmers do not vaccinate their stock, and knowledge of biosecurity is poor. Antimicrobials, especially tetracyclines, are abused. Animals that are slaughtered within the community or sold at local sale points, pension pay stations and auction markets are likely candidates for disease spread. It is recommended that the younger generations are retained and incentivised in animal agriculture. Improved training on management, health, biosecurity and better market access must be provided for the ESSPF, whilst efforts should made to consolidate these farmers into small cooperatives. The current government agricultural support system will need to be reworked to benefit the resource-poor farmers. Collaborative efforts in disease reporting and management among veterinarians, animal health technicians and extension officers will become necessary. Finally, the creation of a progressive quality grading system for ESSPF should be planned by the industry and this should be attached to a reward system that will encourage these farmers to target good farming practice.

Genetic diversity of serotype A foot-and-mouth disease viruses in Kenya from 1964 to 2013; implications for control strategies in eastern Africa

Serotype A is the most genetically and antigenically diverse of the foot-and-mouth disease virus (FMDV) serotypes. Records of its occurrence in Kenya date back to 1952 and the antigenic diversity of the outbreak viruses in this region is reflected by the current use of two different vaccine strains (K5/1980 and K35/1980) and previous use of two other strains (K18/66 and K179/71). This study aimed at enhancing the understanding of the patterns of genetic variation of serotype A FMDV in Kenya. The complete VP1 coding region sequences of 38 field isolates, identified as serotype A FMDV, collected between 1964 and 2013 were determined. Coalescent-based methods were used to infer times of divergence of the virus strains and the evolutionary rates alongside 27 other serotype A FMDV sequences from Genbank and the World Reference Laboratory (WRL). This study represents the first comprehensive genetic analysis of serotype A FMDVs from Kenya. The study detected four previously defined genotypes/clusters (termed G-I, G-III, G-VII and G-VIII), within the Africa topotype, together with a fifth lineage that has apparently emerged from within G-I; these different lineages have each had a countrywide distribution. Genotypes G-III and G-VIII that were first isolated in 1964 are now apparently extinct; G-VII was last recorded in 2005, while G-I (including the new lineage) is currently in widespread circulation. High genetic diversity, widespread distribution and transboundary spread of serotype A FMDVs across the region of eastern Africa was apparent. Continuous surveillance for the virus, coupled to genetic and antigenic characterization is recommended for improved regional control strategies.

Virome Profiling of Bats from Myanmar by Metagenomic Analysis of Tissue Samples Reveals More Novel Mammalian Viruses

Bats are reservoir animals harboring many important pathogenic viruses and with the capability of transmitting these to humans and other animals. To establish an effective surveillance to monitor transboundary spread of bat viruses between Myanmar and China, complete organs from the thorax and abdomen from 853 bats of six species from two Myanmar counties close to Yunnan province, China, were collected and tested for their virome through metagenomics by Solexa sequencing and bioinformatic analysis. In total, 3,742,314 reads of 114 bases were generated, and over 86% were assembled into 1,649,512 contigs with an average length of 114 bp, of which 26,698 (2%) contigs were recognizable viral sequences belonging to 24 viral families. Of the viral contigs 45% (12,086/26,698) were related to vertebrate viruses, 28% (7,443/26,698) to insect viruses, 27% (7,074/26,698) to phages and 95 contigs to plant viruses. The metagenomic results were confirmed by PCR of selected viruses in all bat samples followed by phylogenetic analysis, which has led to the discovery of some novel bat viruses of the genera Mamastrovirus, Bocavirus, Circovirus, Iflavirus and Orthohepadnavirus and to their prevalence rates in two bat species. In conclusion, the present study aims to present the bat virome in Myanmar, and the results obtained further expand the spectrum of viruses harbored by bats.

African Swine Fever Virus, Tanzania, 2010–2012

African Swine Fever Virus, Tanzania, 2010–2012

Developing vaccines against foot-and-mouth disease and some other exotic viral diseases of livestock

Vaccines remain the main tool for the control of livestock viral diseases that pose a serious threat to animal and occasionally human health, reduce food security, distort trade in animals and their products, and undermine agricultural development in poor countries. Globalization and climate change increase the likelihood for new patterns of emergence and spread of livestock viruses. Conventionally attenuated and killed virus products have had spectacular success, and recent examples include the global eradication of rinderpest and the control of bluetongue in the UK and northern Europe. However, in many cases, livestock vaccines could benefit from improvement in some properties (e.g. stability, speed of onset and duration of immunity, and breadth of cross-protection to different serotypes or strains) and in some cases are not available at all. Compared with human vaccines, uptake of livestock products is highly cost-sensitive and their use may also need to be compatible with post-vaccination screening methods to determine whether or not animals continue to be infected. Requirements and prospects for new or improved vaccines are described for some priority viral diseases with potential for transboundary spread, particularly for foot-and-mouth disease.

The spread of pathogens through trade in aquatic animals and their products

It is well known that the transboundary spread of infectious diseases is aided by trade in live animals and the consequences can be severe if, as a result, a pathogen broadens its host range to new species. Trade in aquatic animal species is increasing, and aquaculture is also expanding to meet the growing human population's demands for animal protein. Moreover, it is clear that aquaculture has created potential new pathways by which pathogens and diseases may be introduced or spread to new areas. The risk of pathogen transfer is generally considered greater for the movement of live aquatic animals than for the movement of processed and dead products. The currently available health standards support the concept of minimising the risk of disease and pathogen incursion while, at the same time, avoiding unjustifiable or unnecessary impediments to trade. Nevertheless, the international spread of diseases through the movement of animals still occurs, despite these standards. Consequently, this paper considers the evidence linking international trade in aquatic animals and aquatic animal-derived products with the transmission and spread of diseases. The authors provide examples of pathogen transfer leading to disease spread and considerthe situation of emerging diseases, as well as the need for a holistic approach to deal with risk-based threats at their source.

Transboundary spread of highly pathogenic avian influenza through poultry commodities and wild birds

The extensive circulation of the H5N1 highly pathogenic avian influenza (HPAI) virus in animals and the human health implications which it poses have led to extensive research in unexplored fields and thus a re-assessment of our understanding of this infection. Moreover, widespread infection of poultry has raised concerns about the food safety and trade implications of this infection, necessitating revised international trade regulations. The role of wild birds has been much debated and resources have been invested to clarify the role that they may play in the spread of infection. It is now clear that wild birds may be responsible for primary introduction in a previously free area. To date it is still unclear whether HPAI infection may be maintained in wild bird populations for extended periods of time. This paper reviews existing knowledge on the transboundary spread of HPAI through poultry and poultry commodities and summarises evidence of spread through wild birds.

Phylogenetic Analysis of Rabies Viruses from Burkina Faso, 2007

Genetic characterization of 32 canine rabies viruses circulating in Burkina Faso in 2007 identified two clades both belonging to the Africa 2 lineage. Sequence homology data suggest that transboundary spread is the most likely means of introduction, highlighting an evolving epidemiological situation.