Reconstruction and analysis of the transmission network of African swine fever in People's Republic of China, August 2018-September 2019.

Introduction of African swine fever (ASF) to China in mid-2018 and the subsequent transboundary spread across Asia devastated regional swine production, affecting live pig and pork product-related markets worldwide. To explore the spatiotemporal spread of ASF in China, we reconstructed possible ASF transmission networks using nearest neighbour, exponential function, equal probability, and spatiotemporal case-distribution algorithms. From these networks, we estimated the reproduction numbers, serial intervals, and transmission distances of the outbreak. The mean serial interval between paired units was around 29 days for all algorithms, while the mean transmission distance ranged 332 -456 km. The reproduction numbers for each algorithm peaked during the first two weeks and steadily declined through the end of 2018 before hovering around the epidemic threshold value of 1 with sporadic increases during 2019. These results suggest that 1) swine husbandry practices and production systems that lend themselves to long-range transmission drove ASF spread; 2) outbreaks went undetected by the surveillance system. Efforts by China and other affected countries to control ASF within their jurisdictions may be aided by the reconstructed spatiotemporal model. Continued support for strict implementation of biosecurity standards and improvements to ASF surveillance is essential for halting transmission in China and spread across Asia.

Investigative and Diagnostic Toxicology and Feed-Related Outbreaks.

Incidences of feed contamination are rare even though enormous amounts of animal feed are manufactured. However, there are still some cases of feed-related illness in horses. Veterinarians play a crucial role in recognizing and mitigating these events and in assessing the severity of risks. Due to these risks, proper reporting and consultation with government and state agencies are crucial. Accurate diagnosis and identification of the source of poisoning are promising when a thorough case workup is performed and agencies such as veterinary diagnostic laboratories and the US Food and Drug Administration Center for Veterinary Medicine are used effectively.

Modelling livestock infectious disease control policy under differing social perspectives on vaccination behaviour.

The spread of infection amongst livestock depends not only on the traits of the pathogen and the livestock themselves, but also on the veterinary health behaviours of farmers and how this impacts their implementation of disease control measures. Controls that are costly may make it beneficial for individuals to rely on the protection offered by others, though that may be sub-optimal for the population. Failing to account for socio-behavioural properties may produce a substantial layer of bias in infectious disease models. We investigated the role of heterogeneity in vaccine response across a population of farmers on epidemic outbreaks amongst livestock, caused by pathogens with differential speed of spread over spatial landscapes of farms for two counties in England (Cumbria and Devon). Under different compositions of three vaccine behaviour groups (precautionary, reactionary, non-vaccination), we evaluated from population- and individual-level perspectives the optimum threshold distance to premises with notified infection that would trigger responsive vaccination by the reactionary vaccination group. We demonstrate a divergence between population and individual perspectives in the optimal scale of reactive voluntary vaccination response. In general, minimising the population-level perspective cost requires a broader reactive uptake of the intervention, whilst optimising the outcome for the average individual increased the likelihood of larger scale disease outbreaks. When the relative cost of vaccination was low and the majority of premises had undergone precautionary vaccination, then adopting a perspective that optimised the outcome for an individual gave a broader spatial extent of reactive response compared to a perspective wanting to optimise outcomes for everyone in the population. Under our assumed epidemiological context, the findings identify livestock disease intervention receptiveness and cost combinations where one would expect strong disagreement between the intervention stringency that is best from the perspective of a stakeholder responsible for supporting the livestock industry compared to a sole livestock owner. Were such discord anticipated and achieving a consensus view across perspectives desired, the findings may also inform those managing veterinary health policy the requisite reduction in intervention cost and/or the required extent of nurturing beneficial community attitudes towards interventions.

Epidemiology-driven approaches to surveillance in HPAI-vaccinated poultry flocks aiming to demonstrate freedom from circulating HPAIV.

Incursion pressure of high pathogenicity avian influenza viruses (HPAIV) by secondary spread among poultry holdings and/or from infected migratory wild bird populations increases worldwide. Vaccination as an additional layer of protection of poultry holdings using appropriately matched vaccines aims at reducing clinical sequelae of HPAIV infection, disrupting HPAIV transmission, curtailing economic losses and animal welfare problems and cutting exposure risks of zoonotic HPAIV at the avian-human interface. Products derived from HPAIV-vaccinated poultry should not impose any risk of virus spread or exposure. Vaccination can be carried out with zero-tolerance for infection in vaccinated herds and must then be flanked by appropriate surveillance which requires tailoring at several levels: (i) Controlling appropriate vaccination coverage and adequate population immunity in individual flocks and across vaccinated populations; (ii) assessing HPAI-infection trends in unvaccinated and vaccinated parts of the poultry population to provide early detection of new/re-emerged HPAIV outbreaks; and (iii) proving absence of HPAIV circulation in vaccinated flocks ideally by real time-monitoring. Surveillance strategies, i.e. selecting targets, tools and random sample sizes, must be accommodated to the specific epidemiologic and socio-economic background. Methodological approaches and practical examples from three countries or territories applying AI vaccination under different circumstances are reviewed here.

The second coming of urban yellow fever in the Americas: looking the past to see the future.

Yellow fever (YF) epizootics in South America during the 21st century have an unprecedented recorded magnitude and geographical dispersion. The YF spread progressively involved areas considered previously free of risk reaching the edge of cities with large unvaccinated populations, and urban outbreaks were frequently forecasted. We critically reviewed the initial stages and enhancing contexts of YF urban epidemics since the 17th century in the Americas, and the modeling attempts of YF epidemic risk by of Aedes-Human transmission, to find common factors that increase the probability of these events in the current scenarios. The YF urban outbreaks of the past showed as necessary conditions the multiple introduction by viremic carriers clustered in time and space, coincident with population peaks of Aedes. These conditions are not met in the current outbreaks in the Americas by sylvatic YF cycles, besides the protective impact of vector control campaigns, vaccination coverage, improved surveillance, and case management. Therefore, urban Aedes-Human YF outbreaks in the Americas are still possible but with low probability or very focal transmission, while the conditions reported in the past were avoided, and the surveillance and control measures sustained, including the vaccination of the population at risk.

Ongoing rabies outbreak in dogs of unprecedented scale and human cases in Nelson Mandela Bay Municipality, South Africa, up to 13 February 2022.

More than 430 cases of rabies have been confirmed in dogs in the Nelson Mandela Bay Metropolitan Municipality of South Africa since July 2021. We describe the ongoing outbreak, its geographical spread and six related human deaths that have occurred. Further investigation of the outbreak and vaccination of the dog population is required. Raising awareness among healthcare providers, the public, and among international travellers planning to visit the region, is key for action to protect human and animal health.

Teaching Outbreak Investigations with an Interactive Blended Learning Approach.

Public health is a central but often neglected component of veterinary education. German veterinary public health (VPH) education includes substantial theory-focused lectures, but practical case studies are often missing. To change this, we combined the advantages of case-based teaching and blended learning to teach these topics in a more practical and interactive way. Blended learning describes the combination of online and classroom-based teaching. With it, we created an interdisciplinary module for outbreak investigations and zoonoses, based on the epidemiology, food safety, and microbiology disciplines. We implemented this module within the veterinary curriculum of the seventh semester (in the clinical phase of the studies). In this study, we investigated the acceptance of this interdisciplinary approach and established a framework for the creation of interactive outbreak investigation cases that can serve as a basis for further cases. Over a period of 3 years, we created three interactive online cases and one interactive in-class case and observed the student-reported evaluation of the blended learning concept and self-assessed learning outcomes. Results show that 80% (75-89) of students evaluated the chosen combination of case-based and blended learning for interdisciplinary teaching positively and therefore accepted it well. Additionally, 76% (70-98) of students evaluated their self-assessed learning outcomes positively. Our results suggest that teaching VPH through interdisciplinary cases in a blended learning approach can increase the quality of teaching VPH topics. Moreover, it provides a framework to incorporate realistic interdisciplinary VPH cases into the curriculum.

Bird flu outbreak amidst COVID-19 pandemic in South Africa: Efforts and challenges at hand.

Over the months of April and May 2021, South Africa has witnessed several outbreaks of highly infective avian influenza (H5N1) in different poultry farms. This came as a shock to a country that was already battling with the deadly COVID-19 pandemic. The emergence of the virus has spurred import bans and massive culls in the poultry business. Local experts have also called for a restriction on the movement of people and cars in and out of their chicken farms. Employees have also been encouraged to shower in the mornings when they arrive at the farms and wear fresh clothes, as the flu spreads very quickly. In a country that is already facing the economic implications of the COVID-19, this has the potential to cause a significant dent in the economy, as well as severely impact people's day-to-day life. Bird flu-also called avian influenza-is a viral infection that can infect not only birds but also humans and other animals. The threat of a new influenza pandemic has prompted countries to draft national strategic preparedness plans to prevent, contain and mitigate the next human influenza pandemic. This paper describes the South African burden, current efforts, and preparedness against the avian influenza virus.

The contribution of extensive chicken production systems and practices to Newcastle disease outbreaks in Kenya.

Newcastle disease (ND) poses a challenge especially for farmers rearing indigenous chicken under the extensive system. This is due to the lack of uniformity in practices, favoring the introduction and spread of the disease. This is worsened by the lack of information on how management practices contribute to the spread of ND. The current study assessed the role of extensive chicken production systems and management practices on the frequency of ND outbreaks in Kenya using a Poisson regression model (PRM) on primary survey data from 332 farmers in Kakamega and Machakos counties. Descriptive results showed a low access to institutional support services like extension, training, credit, and vaccination services for both male and female farmers. Results from the PRM analysis show that flock size, isolated and confined housing, multi-aged flock mixture, screening of birds, access to ND vaccination, ND awareness, distance to agro-veterinary service providers, and access to animal health training and extension services had significant effects on the frequency of ND outbreaks. The findings underscore the need for innovative extension approaches that facilitate the use of information communication technologies to create more awareness on disease detection and mitigation measures. Use of farmer groups as innovation platforms for enhanced skill sharing and as key peer monitoring channels would also improve compliance with prescribed disease control methods. Further, there is a need for partnerships between local-level county governments, vaccine producers, and agro-veterinary service providers to ensure the development of low-cost vaccines and requisite storage facilities, and their timely delivery to the male and female resource-poor smallholder extensive chicken farmers.

Best practices for after-action review: turning lessons observed into lessons learned for preparedness policy.

All-hazards preparedness and response planning requires ongoing individual, organisational and multi-jurisdictional learning. Disaster after-action reviews are an established emergency management practice to acquire knowledge through a process of analysing what happened and why, to improve the emergency response before the next crisis. After-action reviews help individuals and organisations learn, and are an essential step in the preparedness cycle. Human and animal health authorities have begun to employ after-action reviews for disaster preparedness and response among public health and Veterinary Services. The World Organisation for Animal Health (OIE) encourages Members to establish after-action reviews and share best practice. The adoption of afteraction review is an essential step for all provincial, national and multinational emergency management authorities to mitigate the impact of disasters on human and animal health. Emerging and re-emerging infectious diseases with pandemic potential pose unique preparedness challenges, requiring high-level policy attention to close long-standing gaps. A review of after-action reports from the 2001 anthrax bioterror attacks and of naturally occurring infectious disease crises, from the 2003 outbreak of severe acute respiratory syndrome (SARS) to the 2014 Ebola epidemic, reveal a similar pattern of repeated weakness and failures. These phenomena are described as 'lessons observed but not lessons learned'. Most infectious disease outbreaks with pandemic potential are zoonotic and require a One Health approach to prevent, prepare for and respond to global health security crises. After-action reviews in a One Health security context are essential to improve the pandemic preparedness of public health and Veterinary Services. After-action reviews can also provide the evidence-based 'feedback loop' needed to galvanise public policy and political will to translate lessons observed into sustained and applied lessons learned.

La planification de la préparation et de la réponse à tous les risques est un processus qui exige un apprentissage permanent tant à l'échelle des individus que des organisations et des différentes autorités compétentes. Les retours d'expérience (ou « revues après action¼) suite à une catastrophe constituent un exercice éprouvé de gestion des urgences visant à acquérir de nouvelles connaissances en procédant à l'analyse de ce qui est arrivé et des raisons pour lesquelles c'est arrivé, dans le but d'améliorer les capacités d'intervention d'urgence avant que ne survienne la prochaine crise. Les individus et les organisations trouvent dans ces retours un cadre pour tirer des enseignements de leur expérience, ce qui constitue une étape essentielle du cycle de préparation. Les autorités en charge de la santé humaine et de la santé animale ont commencé à utiliser les retours d'expérience pour planifier la préparation et la réponse au sein des Services de santé publique et des Services vétérinaires. L'Organisation mondiale de la santé animale (OIE) encourage ses Membres à mettre en place des retours d'expérience et à partager les meilleures pratiques en la matière. L'analyse des retours d'expérience est une étape cruciale pour que les autorités en charge de la gestion des urgences à l'échelle provinciale, nationale et internationale puissent atténuer l'impact des catastrophes sur la santé humaine et animale. Les maladies émergentes et ré-émergentes ayant un potentiel pandémique posent des défis exceptionnels en termes de préparation et exigent des prises de décision de haut niveau afin de pallier des lacunes souvent anciennes. L'examen des retours d'expérience datant des attentats terroristes à l'anthrax de 2001 et des crises sanitaires dues à des maladies infectieuses d'origine naturelle (depuis l'épidémie du syndrome respiratoire aigu sévère [SRAS] en 2003 jusqu'à l'épidémie d'Ebola en 2014) révèle des caractéristiques toujours similaires, avec à chaque fois les mêmes faiblesses et les mêmes écueils. Ce phénomène correspond à ce que l'on peut appeler des « leçons observées mais non apprises ¼. Compte tenu de la nature zoonotique de la plupart des foyers de maladies infectieuses ayant un potentiel pandémique, c'est l'approche Une seule santé qui doit prévaloir en matière de prévention, de préparation et de réponse aux crises de sécurité sanitaire d'envergure mondiale. Les retours d'expérience dans un contexte de sécurité Une seule santé sont essentiels pour améliorer la préparation des Services de santé publique et des Services vétérinaires aux pandémies. En outre, les « boucles de réaction¼ fondées sur des éléments factuels résultant des retours d'expérience apportent un éclairage indispensable pour inciter les pouvoirs publics à élaborer des mesures appropriées et pour créer la volonté politique de traduire les leçons observées en leçons durablement apprises et appliquées.

La planificación de las labores de preparación y respuesta ante toda clase de peligros exige un permanente aprendizaje tanto personal como institucional y desde múltiples competencias. El examen de las intervenciones tras un desastre constituye un arraigado proceder de gestión de emergencias que sirve para aprender de la experiencia analizando el cómo y el porqué de lo sucedido y, a partir de ahí, mejorar los procesos de respuesta de emergencia antes de que advenga la siguiente crisis. Estos exámenes posteriores a las intervenciones, que ayudan a las personas y organizaciones a aprender, son una etapa fundamental del ciclo de preparación. Las autoridades sanitarias y zoosanitarias han empezado a utilizarlos en los servicios de salud pública y los Servicios Veterinarios con fines de preparación y respuesta para casos de desastre. La Organización Mundial de Sanidad Animal (OIE) alienta a sus Miembros a que establezcan este tipo de exámenes y pongan en común prácticas óptimas al respecto. La implantación del examen posterior a las intervenciones es un paso esencial para que todas las autoridades provinciales, nacionales e internacionales de gestión de emergencias estén en condiciones de mitigar los efectos sanitarios y zoosanitarios de un desastre. Las enfermedades infecciosas emergentes y reemergentes con potencial pandémico plantean singulares problemas de preparación, que requieren una atención y una labor normativa de alto nivel para solventar carencias históricas. El examen de los informes posteriores a las actuaciones de respuesta a los ataques bioterroristas perpetrados en 2001 con bacterias de carbunco (ántrax) y a crisis infecciosas de origen natural, desde el brote registrado en 2003 de síndrome respiratorio agudo severo (SRAS) hasta la epidemia causada por el virus del Ébola en 2014, revela un parecido patrón de fallos y carencias que se van repitiendo, fenómeno que se describe como «hechos observados sin enseñanzas extraídas¼. La mayoría de los brotes de enfermedades infecciosas con potencial pandémico son zoonóticos y exigen la aplicación de la lógica de Una sola salud para prevenir crisis sanitarias de dimensión mundial, prepararse para ellas y darles respuesta. Los exámenes posteriores a una intervención inscritos en el contexto de seguridad sanitaria de Una sola salud son esenciales para mejorar la preparación de los servicios de salud pública y los Servicios Veterinarios para episodios de pandemia. Estos procesos de examen también pueden alimentar con datos científicos el «ciclo de retroalimentación¼ que se requiere para galvanizar las políticas públicas y la voluntad política de traducir los hechos observados en enseñanzas extraídas que sean duraderas y se apliquen en la práctica.

Teaching Wildlife Disease Outbreak Response Through a Collaborative One Health Workshop.

Issues in the fields of wildlife disease and One Health are often difficult to address by single research groups because of the many disciplines and areas of expertise required to effectively solve complex problems. Although collaborations are becoming increasingly prevalent in the professional realm, many undergraduate, graduate, and professional students are merely introduced to the idea of collaboration without fully understanding how team-based approaches function. In this report, we describe the framework for a one-day workshop hosted by the Colorado State University student chapter of the Wildlife Disease Association (CSU WDA), where we gathered students and professionals to collectively investigate a simulated wildlife disease outbreak. CSU WDA student members designed the workshop and recruited professionals who are experts in their respective fields to run an outbreak simulation during the event. Based on pre- and post-event evaluation responses, this workshop was effective in increasing participants' knowledge of disease ecology, pathology, genetics, and microbiology, as well as the importance of collaboration among disciplines as it pertains to wildlife disease outbreaks.

Containment of Highly Pathogenic Avian Influenza A(H5N1) Virus, Lebanon, 20161.

A preparedness plan for avian influenza A(H5N1) virus infection was activated in Lebanon in 2016 after reported cases in poultry. Exposed persons were given prophylaxis and monitored daily. A total of 185 exposed persons were identified: 180 received prophylaxis, 181 were monitored, and 41 suspected cases were reported. All collected specimens were negative for virus by PCR.

Animal pathogens and their impact on animal health, the economy, food security, food safety and public health.

Animal pathogens attract attention in both the livestock and public health sectors for their impacts on socio-economics, food safety and security, and human health. These impacts are felt at the household, national, regional and global levels. Whereas the World Organisation for Animal Health (OIE) has identified 118 animal diseases as notifiable, based on their potential for impact on trade, there is a selected subset that have been classified as posing a greater threat to countries due to unique characteristics, such as being highly transmissible, spreading rapidly within and between countries, and requiring cooperation between several countries to control their spread or exclude them. While these 'transboundary diseases' are endemic in much of the world, particularly the developing nations, many countries are classified as disease free. Following the terrorist events of 11 September 2001 in the United States, a small group of zoonotic pathogens and a group of animal-specific pathogens (those that cause what are referred to as `high-consequence foreign animal diseases'), were classified as high-risk, biothreat 'select agents'. Rather than providing a comprehensive review of all animal pathogens, the authors briefly review the impact of these high-risk biothreat agents on animal health, the economy, food security and safety, and public health, using highly pathogenic avian influenza, foot and mouth disease and brucellosis as examples. They focus on the impact of these diseases in the context of high-income countries and low- and middle-income countries, comparing and contrasting their impact at the national and individual household levels.

Les agents pathogènes d'origine animale revêtent une grande importance tant pour le secteur de l'élevage que pour celui de la santé publique, en raison de leurs conséquences sur la société et l'économie, sur la sécurité alimentaire, sur la sécurité sanitaire des aliments et sur la santé publique. Ces impacts sont perceptibles à l'échelle des ménages, des pays, des régions et du monde. L'Organisation mondiale de la santé animale (OIE) a établi une liste de 118 maladies animales à déclaration obligatoire en se basant principalement sur leurs conséquences potentielles pour le commerce ; néanmoins, un sous-ensemble de la liste concerne les maladies qui font peser un risque élevé sur les pays, de par leurs caractéristiques uniques, par exemple leur contagiosité, la rapidité de leur potentiel de propagation dans le territoire national ou d'un pays à l'autre, ou la nécessité de mettre en place une coopération internationale en vue de maîtriser leur propagation ou de les éliminer. Ces « maladies transfrontalières ¼ sont présentes à l'état endémique dans une grande partie du monde, en particulier dans les pays en développement, tandis que d'autres pays sont considérés comme « indemnes ¼. Suite aux attaques terroristes du 11 septembre 2001 aux États-Unis d'Amérique, les maladies animales dites « exotiques ¼ ainsi qu'un petit nombre d'agents pathogènes zoonotiques ont été classés dans la catégorie des « agents biologiques à haut risque ¼. Plutôt que de fournir un inventaire exhaustif des agents pathogènes d'origine animale, les auteurs résument l'impact de ces agents biologiques à haut risque sur la santé animale, l'économie, la sécurité alimentaire, la sécurité sanitaire des aliments et la santé publique, en illustrant leur propos avec les exemples de l'influenza aviaire hautement pathogène, la fièvre aphteuse et la brucellose. Ils examinent l'impact de ces maladies dans le contexte des pays à revenus élevés, mais aussi des pays à revenus faibles ou intermédiaires, en comparant et en détaillant les impacts respectifs à l'échelle nationale ainsi qu'à l'échelle des ménages.

Por su influencia en factores socioeconómicos y en temas como la higiene de los alimentos, la seguridad alimentaria o la salud humana, los patógenos animales atraen la atención de los sectores de la producción animal y la salud pública. Dicha influencia se deja sentir tanto a nivel de los hogares como a escala nacional, regional y mundial. Aunque la Organización Mundial de Sanidad Animal (OIE) tiene catalogadas 118 enfermedades animales como «de declaración obligatoria¼, atendiendo a sus posibles consecuencias para el comercio, hay un pequeño subconjunto de ellas que se consideran especialmente peligrosas para los países porque revisten características singulares, como el hecho de ser muy transmisibles, propagarse con gran rapidez entre los países y dentro de ellos o exigir cooperación entre varias naciones para combatir su propagación o atajarlas. Estas «enfermedades transfronterizas¼ son endémicas en gran parte del mundo, especialmente en las naciones en desarrollo, pero también hay muchos países que están considerados «libres¼ de ellas. Después de los atentados terroristas que sufrieron los Estados Unidos el 11 de septiembre de 2001, las llamadas enfermedades animales «extranjeras¼, junto con un pequeño grupo de patógenos zoonóticos, fueron catalogadas como «agentes selectos¼ de alto riesgo de amenaza biológica. En lugar de ofrecer una panorámica completa de todos los patógenos animales, los autores repasan brevemente el impacto de estos agentes calificados de alto riesgo y portadores de una amenaza biológica en la sanidad animal, la economía, la seguridad alimentaria, la higiene de los alimentos y la salud pública, valiéndose para ello de los ejemplos de la influenza aviar altamente patógena, la fiebre aftosa y la brucelosis. Centrándose en el impacto de estas enfermedades en el contexto de los países de renta alta y en el de los países de renta baja o media, comparan y contrastan tal impacto a escala nacional y en el ámbito de los hogares.

Outbreaks of avian influenza A (H5N2), (H5N8), and (H5N1) among birds--United States, December 2014-January 2015.

During December 15, 2014-January 16, 2015, the U.S. Department of Agriculture received 14 reports of birds infected with Asian-origin, highly pathogenic avian influenza A (HPAI) (H5N2), (H5N8), and (H5N1) viruses. These reports represent the first reported infections with these viruses in U.S. wild or domestic birds. Although these viruses are not known to have caused disease in humans, their appearance in North America might increase the likelihood of human infection in the United States. Human infection with other avian influenza viruses, such as HPAI (H5N1) and (H5N6) viruses and (H7N9) virus, has been associated with severe, sometimes fatal, disease, usually following contact with poultry.

Emergence and pandemic potential of swine-origin H1N1 influenza virus.

Influenza viruses cause annual epidemics and occasional pandemics that have claimed the lives of millions. The emergence of new strains will continue to pose challenges to public health and the scientific communities. A prime example is the recent emergence of swine-origin H1N1 viruses that have transmitted to and spread among humans, resulting in outbreaks internationally. Efforts to control these outbreaks and real-time monitoring of the evolution of this virus should provide us with invaluable information to direct infectious disease control programmes and to improve understanding of the factors that determine viral pathogenicity and/or transmissibility.

Rift Valley fever.

Rift Valley fever (RVF) is a mosquito-borne zoonotic viral disease affecting domestic and wild ruminants, camels and humans. The causative agent of RVF, the RVF virus (RVFV), has the capacity to cause large and severe outbreaks in animal and human populations and to cross significant natural geographic barriers. Rift Valley fever is usually inapparent in non-pregnant adult animals, but pregnant animals and newborns can be severely affected; outbreaks are characterised by a sudden onset of abortions and high neonatal mortality. The majority of human infections are subclinical or associated with moderate to severe, non-fatal, febrile illness, but some patients may develop a haemorrhagic syndrome and/or ocular and neurological lesions. In both animals and humans, the primary site of RVFV replication and tissue pathology is the liver. Outbreaks of RVF are associated with persistent high rainfalls leading to massive flooding and the emergence of large numbers of competent mosquito vectors that transmit the virus to a wide range of susceptible vertebrate species. Outbreaks of RVF have devastating economic effects on countries for which animal trade constitutes the main source of national revenue. The propensity of the virus to spread into new territories and re-emerge in traditionally endemic regions, where it causes large outbreaks in human and animal populations, presents a formidable challenge for public and veterinary health authorities. The presence of competent mosquito vectors in RVF-free countries, the wide range of mammals susceptible to the virus, altering land use, the global changes in climate, and increased animal trade and travel are some of the factors which might contribute to international spread of RVF.

Current status and future needs in diagnostics and vaccines for high pathogenicity avian influenza.

Since 1959, 32 epizootics of high pathogenicity avian influenza (HPAI) have occurred in birds. Rapid detection and accurate identification of HPAI has been critical to controlling such epizootics in poultry. Specific paradigms for the detection and diagnosis of avian influenza virus (AIV) in poultry vary somewhat among different countries and industry compartments depending on specific needs and resources. Importantly, since HPAI and low pathogenicity (LP) AI of the H5 and H7 subtypes are reportable to the World Organization for Animal Health (OIE), diagnostic procedures are implemented for regulatory purposes and are harmonized to some degree. Most current tests are adequate and have been in use for some time, therefore they have been well validated and presently there is no reported new technology that will completely replace the current tests. However, some modifications, updates or additional tests could be beneficial. The element of AIV diagnostics that is most in need of improvement is in determining the hemagglutinin and neuraminidase subtype specificity of antibody to AIV. Most HPAI epizootics have been eradicated using traditional stamping-out programs, but beginning in 1995, five epizootics have added vaccination as an additional, interim control tool. From 2002-2010, >113 billion doses of AI vaccine have been used in poultry; 95.5% as oil-emulsified, inactivated whole AIV vaccines and 4.5% as live vectored vaccines. The majority of vaccine has been used in the four H5N1 HPAI enzootic countries (China [91%], Egypt [4.7%], Indonesia [2.3%], and Vietnam [1.4%]) where vaccination programs are directed to all poultry. The 10 other countries/regions have used less than 1% of the vaccine, administered in a focused, risk- based approach. Some vaccine "failures" have resulted from antigenic drift of field viruses away from the vaccine viruses, but most have resulted from failures in the vaccination process; i.e. failure to adequately administer the vaccine to at risk poultry resulting in lack of population immunity. China, as the major AIV vaccine user, will drive innovation and commercialization of new vaccine technologies, but because of the low-cost to manufacture the current high quality inactivated whole AIV vaccines, such vaccines will continue to dominate the market for the next 10 years.