Caister Academic Press

Porcine Viruses: From Pathogenesis to Strategies for Control | Book

Publisher: Caister Academic Press
Edited by: Hovakim Zakaryan
Institute of Molecular Biology NAS RA, Yerevan, Armenia
Pages: c. 230
Paperback:
Publication date: January 2019Buy book
ISBN: 978-1-910190-91-3
Price: GB £159 or US $319
Ebook:
Publication date: January 2019
ISBN: 978-1-910190-92-0
Price: GB £159 or US $319
DOI: https://doi.org/10.21775/9781910190913

The global population has quadrupled over the last century leading to an increased demand for affordable safe food. Satisfying this demand will not be easy and will require even more widespread use of intensive farming practices. However intensive farming practices can lead to higher probabilities of outbreaks of a variety of viral diseases, a critical concern in terms of food protection and food security. In the case of the pig industry there are several important viruses. One example is African swine fever virus (ASFV) which causes a devastating disease with enormous socio-economic consequences in affected countries, mostly in Africa. No ASFV vaccine currently exists. An understanding of the molecular biology, pathogenesis, host-virus interaction and epidemiology of these viruses is critical for their prevention and control.

This book provides a comprehensive review of the current knowledge of the most important porcine viruses written by prominent scientists who have made great contributions in their respective fields of expertise. Topics include: African swine fever virus, classical swine fever virus, foot-and-mouth disease virus, porcine circovirus, porcine epidemic diarrhea virus, porcine parvovirus, porcine reproductive and respiratory syndrome virus, and swine vesicular disease virus. Each chapter covers the current knowledge on epidemiology, pathogenesis, virus biology, diagnosis, and prevention and control strategies.

This book is essential reading for everyone working with porcine viruses from the PhD student to the experienced scientist, in academia, the pharmaceutical or biotechnology industries and for those working in clinical environments.

Table of contents
1. African Swine Fever Virus
E. Arabyan, A. Kotsinyan, A. Hakobyan and Hovakim Zakaryan
African swine fever virus (ASFV) is a large DNA virus belonging to the family Asfarviridae. It is the causative agent of an acute haemorrhagic fever in domestic pigs and wild boar with high fatality rates, up to 100%, in the acute forms. The disease is currently present in Africa and Europe, where it causes a high socio-economic impact. In this chapter we have addressed different aspects of ASFV including the biology of virus which is relevant for understanding the viral disease. We have also discussed the pathological changes caused by highly and low virulent ASFV strains. Finally, this chapter addresses the current approaches for ASFV diagnosis, as well as presents an overview of research efforts toward the development of effective vaccines during the past decades. As an alternative to vaccine development, the current state in antiviral research is also presented.
2. Classical Swine Fever Virus
Sandra Blome
Classical swine fever (CSF) remains one of the most important threats to profitable and sustainable pig production world-wide and its occurrence in domestic and wild pigs has to be reported to the World Organization for Animal Health (OIE). The causative agent, CSF virus (CSFV), is a small enveloped RNA virus of the genus Pestivirus in the Flaviviridae virus family. The clinical picture of CSF depends on virus and host factors and is highly variable. It can range from an almost inapparent infection to a hemorrhagic fever-like illness with high mortality. An immunopathogenesis with dysregulated cytokine responses is suggested for many lesions. After implementation of strict control measures, several countries with industrialized pig production succeeded in eradicating CSF. These control measures often included mandatory vaccination with live attenuated vaccines that have proven to be safe and highly efficacious. Nevertheless, in most parts of the world, CSF is at least sporadically present in either domestic pigs or wild boar. Endemicity can be assumed in several countries of South and Central America, parts of Eastern Europe and neighboring countries, as well as Asia, including India. The chapter summarized virus properties, pathogenesis and clinical picture as well as control options.
3. Foot-and-Mouth Disease Virus
Francisco Sobrino, F. Caridi, R. Cañas-Arranz and M. Rodríguez-Pulido
Foot-and-mouth disease virus (FMDV) is the prototypic member of the Aphthovirus genus within the Picornaviridae family. This virus causes an acute systemic vesicular disease, foot-and-mouth disease (FMD), which affects livestock worldwide and causes one of the most feared animal diseases. Here we have addressed different aspects dealing with the biology of this highly variable and transmissible virus that are relevant to understand the viral infectious cycle, including its genome organization, its control of gene expression, the proteins encoded by the FMDV RNA and their known functions, as well as the role they play on cell entry and virus replication and pathogenesis. The characteristics of virus particles and the innate and adaptive responses elicited by this virus are also discussed, as well as current and new strategies for FMD control by vaccination and other antiviral strategies. This chapter also addresses the lesions and clinical signs FMD produce, the current approaches for virus diagnosis and characterization, as well as an overview regarding FMDV control and epidemiology.
4. Porcine Circoviruses
Sheela Ramamoorthy and P. Pineyro
Porcine circoviruses are small, single stranded DNA viruses belonging to the Circoviridae family. Two major open reading frames (ORF), ORF1 and ORF2, which run in opposing directions on the 1700bp genome, code for the capsid and replicase proteins respectively. Transmission of PCV2 occurs both horizontally via contaminated feed, water or contact and vertically from mother to fetus. Porcine circovirus strain 2 (PCV2) was initially identified as the causative agent of post weaning multi-systemic wasting syndrome in weanling pigs, which is characterized by severe weight loss and lymphadenopathy. Subsequently, a wide range of clinical syndromes such as reproductive failure, respiratory signs and diarrhea were associated with PCV2 infections and are now recognized as a part of porcine circovirus associated diseases or PCVAD. Post-mortem diagnosis of PCVAD requires a combination of the presence of clinical signs and demonstration of PCV2 antigen in tissues or lymph nodes. Ante-mortem diagnosis could involve serological testing for antibodies or detection of viral DNA by PCR in combination with the herd history. Commercial vaccines against PCV2 are effective in preventing clinical signs. They are administered at 3 weeks of age and prior to farrowing in sows. Both vaccination and strict biosecurity measures are critical for the control of PCV2. However, periodical emergence of new viral strains due to mutation and recombination in the field continue to render PCV2 an economically important pathogen of swine.
5. Porcine Epidemic Diarrhea Virus
Changhee Lee
A novel enteric disease of swine recognized in Europe in the early 1970s was initially named "epidemic diarrhea", and is now called "porcine epidemic diarrhea (PED)". A new coronavirus referred to as PED virus (PEDV) was determined as the etiologic agent of this disease in the late 1970s. PEDV has since plagued Europe and Asia; however, the most severe outbreaks with the greatest economic impact have occurred in Asian swine-producing countries. PED first emerged in the United States in early 2013, caused unprecedented devastating to the pork production industry, and further spread to Canada and Mexico, as well as to South American countries. Promptly thereafter, massive PED epidemics recurred in South Korea, Japan, and Taiwan. Thus, these recent global emergences and re-emergences of PED requires urgent attention, and a deeper and concrete understanding of the molecular biology and pathogenic mechanisms underlying PEDV is required to develop effective vaccines and control strategies. This chapter will emphasize the importance of basic, applied, and translational studies and encourage collaboration among swine producers, researchers, and veterinarians to provide answers that improve our knowledge of PEDV in efforts to prevent and eliminate this economically significant viral disease, as well as to prepare for future epizootics or panzootics of PED.
6. Porcine Parvovirus
A.F. Streck and Uwe Truyen
Porcine parvovirus (PPV) is considered the main cause of reproductive disorders in Pigs which are summerized under the acronym SMEDI (stillbirth, mummification, embryonic death, and infertility). In the chapter the biology of the virus, its structure, pathogenic potential and strain variation, as well as the disease induced by the virus are described. Known aspects of pathogenesis, diagnosis and prevention particularly by vaccination are summarized. In recent years "new" parvoviruses (PPV2 through 7) have been described in pigs. Although they were detected in pigs from various parts of the world, no association to clinical signs or a disease entity could be established.
7. Porcine Reproductive and Respiratory Syndrome Virus
Alexander N. Zakhartchouk, S. K. Pujhari and J.C.S. Harding
Porcine reproductive and respiratory syndrome virus (PRRSV) is a swine arterivirus responsible for reproductive failure and respiratory problems in sows and piglets, respectively. It is one of the most economically devastating diseases of pigs and continues to result in major health challenges in the swine industry worldwide. The virus is continuously evolving and emerges episodically in different regions of the world with increased virulence. In this chapter, we briefly summarize the current understanding of PRRSV from the perspectives of the virus molecular biology, virus-host cell interactions, pathogenesis, diagnostic procedures and epidemiology. We also provide an overview of currently available vaccines and a novel vaccine development.
8. Swine Vesicular Disease Virus
E. Escribano-Romero, M.A. Martín-Acebes, A. Vazquez-Calvo, E. Brocchi, G. Pezzoni, Francisco Sobrino and B. Borrego
Swine vesicular disease (SVD) virus (SVDV) belongs to the Enterovirus genus within the Picornaviridae family. This virus is genetically and antigenically highly related to the human coxsackie virus B5 (CVB5). Indeed, it has been shown that SVDV is a subspecies of CVB5 that arose as a result of an adaptation to swine. SVDV causes a vesicular disease that affects pigs resulting in lesions and clinical signs similar to those of foot-and-mouth disease (FMD). In this chapter we have addressed different aspects relevant to understand the infectious cycle of SVDV, including its genome organization and the control of gene expression, the proteins encoded by the SVDV RNA and their known functions, as well as the role they play on cell entry and virus replication and pathogenesis. In addition, the characteristics of the virus particles and the adaptive response elicited by this virus, as well as current strategies for SVDV control by vaccination and other antiviral strategies are discussed. The clinical signs and lesions characteristic of SVD are also addressed, as well as the current approaches to its diagnosis, with special emphasis in its differentiation from FMD. Finally, an overview regarding SVDV control and epidemiology is also presented.

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(EAN: 9781910190913 9781910190920 Subjects: [medical microbiology] [microbiology] [molecular microbiology] [virology] )