Epidemiology Of Avian Influenza Viruses

Avian influenza is a highly contagious viral disease, characterized by intense circulation in the wild waterbird reservoirs, with periodical introductions into the domestic poultry sector. AI viruses have been the source of devastating economic losses in the poultry industry over the last three decades, and have become a major veterinary and public health concern due to their zoonotic potential. The most emblematic illustration of this impact has been the emergence of the HPAI H5N1 virus in southern China in the mid-1990s, followed by its continental spread across East and Southeast Asia, and the unprecedented epidemics recorded in 2003–2004. More recently (from 2014 to 2017), several subtypes of HPAI (including H5N1, H5N6, H5N8) emerged in East Asia and spread intercontinentally, stressing the crucial role of this geographical hotspot as a source of new HPAI subtypes. The international dimension and the difficulty to effectively control those epidemics highlight the need for a global approach to HPAI surveillance and a comprehensive knowledge on epidemiology and patterns of the disease. This Research Topic aims at contributing to fill this gap. It includes ten papers which supplement the knowledge of the epidemiology of AI and offer new approaches on control strategies in various regions of the world.

This book focuses on the "Bird Flu: the new emerging infectious disease", a new health problem, and the aspects relating to the use of tropical medicine. It specifically covers the clinical aspects, scientific laboratory, public health, as well as the social sciences relating to this new important infectious disease. Mainly, the book presents summative data from the molecular to the population scales, as well as additional metanalysis for important topics. In addition, the diagnostic guideline and clinical practice guidelines of the mentioned conditions are detailed. There is still limited knowledge on this topic while the wider distribution of the disorder due to the globalisation can be expected.

Because of its high impact on both animal and human health, avian influenza has become a matter of increasing public concern and growing scientific interest within the last decade. This volume gives an overview of the most important results of these research efforts and provides information about the ecology and epidemiology of avian influenza with particular emphasis on recent H5N1 outbreaks in China, Siberia and Europe. Several articles deal with new vaccination strategies, the use of antivirals and other control measures to combat outbreaks of avian influenza. Further chapters illustrate that molecular biology, culminating in the generation of influenza viruses by recombinant DNA technology, was instrumental in unravelling the roles of the viral hemagglutinin and polymerase as well as cellular signalling pathways and innate immunity in pathogenesis and interspecies transmission. Finally, the threat of a pandemic originating from avian influenza viruses is illustrated by the example of the Spanish influenza of 1918.This comprehensive publication on avian influenza viruses and their relevance for human influenza will be of great value to all influenza virologists, molecular biologists, public health scientists, veterinary virologists, ecologists, and scientists engaged in drug design and vaccine development.

Avian influenza, sometimes avian flu, and commonly called bird flu, refers to "influenza caused by viruses adapted to birds". Of greatest concern is highly pathogenic avian influenza (HPAI). These influenza viruses occur naturally among birds. Wild birds world-wide carry the viruses in their intestines, but usually do not get sick from them. However, avian influenza is very contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very ill. Infected birds shed influenza virus in their saliva, nasal secretions, and faeces. Susceptible birds become infected when they have contact with contaminated secretions or excretions or with surfaces that are contaminated with secretions or excretions from infected birds. The risk from avian influenza is generally low for most people, because the viruses do not usually infect humans. However, confirmed cases of human infection from several subtypes of avian influenza infection have been reported since 1997. The spread of avian influenza viruses from one ill person to another has been reported very rarely, and has been limited, inefficient and unsustained. This important book gathers the latest research from around the globe in this field.

Avian influenza, or 'bird flu', is a contagious disease of animals caused by viruses that normally infect only birds and, less commonly, pigs. Avian influenza viruses are highly species-specific, but have, on rare occasions, crossed the species barrier to infect humans. In domestic poultry, infection with avian influenza viruses causes two main forms of disease, distinguished by low and high extremes of virulence. The so-called 'low pathogenic' form commonly causes only mild symptoms (ruffled feathers, a drop in egg production) and may easily go undetected. The highly pathogenic form is far more dramatic. It spreads very rapidly through poultry flocks, causes disease affecting multiple internal organs, and has a mortality that can approach 100%, often within 48 hours.

Avian influenza (AI) is caused by Influenza A viruses, and are single stranded, segmented RNA viruses of the family Orthomyxoviridae. Influenza A viruses continue to pose a major threat to the poultry industry and to the public. Wild aquatic birds are considered the primary hosts of influenza A, in which the virus is enzootic. In these birds, influenza viruses usually replicate in the intestinal tract, cause no disease, and spread by fecal contamination of the water habitat. This book discusses the epidemiology, global patters, and clinical management of Avian Influenza. It also examines the symptoms, treatment and clinical outcomes of Severe Acute Respiratory Syndrome (SARS), which is a highly contagious respiratory disease caused by a SARS coronavirus.

Asia, Africa and Europe have in the recent years witnessed outbreaks of Avian Influenza resulting in the deaths and culling of over 200 million poultry resulting in huge economic losses besides adversely affecting farmers, households, the poultry industry, tourism and trade relations countries and nations. Many countries in the South-East Asia region are on the flight paths of migrating birds, some of which could be carrying Avian Influenza virus. In view of the epidemiological situation, all countries in the region are vulnerable to the influenza pandemic. Threat of world influenza pandemic has never been imminent. To combat this grave threat, it is essential for countries to be well prepared. Experts predict it is only a matter of time before a bird flu strain will mutate and become transmissible between humans. Once that happens, a pandemic like the Spanish flu that resulted in over 50 million deaths, overwhelming hospital and medical services could be inevitable. This book includes a detailed glossary of terms and a comprehensive index to clarify all the technical and general concepts about this deadly virus. WHO guidelines are provided in detail. The prevention and preparedness of activities that facilitate the response and recovery during and after influenza pandemic are important aspects that are included in this book.

THE PLAGUE YEARS Mankind has always been fascinated by "origins," and biologists are no exception. Darwin is our most famous example. What is the origin of mankind, of species, of infectious diseases? In the last few years we have seen the emergence and spread of some apparently "new" viruses, such as HIV -1 and the virus causing bovine spongiform encephalomyelopathy. But are these, in fact, entirely new agents, or mutated forms of "old" viruses that have evolved along with us for eons? Edgar Hope-Simpson could not have written this book at a more opportune moment. He is a firm believer in gradual evolution, rather than the sudden arrival of new agents. I suspect that he would also have a naturalist's Darwinian approach for the origin of AIDS. It has been a source of some amazement to me over the years how even the most innovative scientists conform to a current hypothesis. Pioneer thinking comes more easily to persons outside the scientific mainstream. Edgar Hope Simpson has always struck me as a modem-day naturalist of the classic style, observant and perhaps a little maverick in line of thought. Certainly, the central hypothesis propounded in this book will be controversial to many scientists. From his unique citadel, the Epidemiological Research Unit in Cirencester, he has carefully reexamined mortality data from old records as well as new.