Animal virology - AbsoluteAstronomy.com

The study of animal

Animal

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

virus

Virus

A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

es is important from a veterinary

Veterinary medicine

Veterinary Medicine is the branch of science that deals with the prevention, diagnosis and treatment of disease, disorder and injury in non-human animals...

viewpoint and many of these viruses cause diseases that are economically devastating. Many animal viruses are also important from a human medical perspective. The emergence of the SARS virus in the human population, coming from an animal source, highlights the importance of animals in bearing infectious agents; avian influenza viruses can directly infect humans. In addition research into animal viruses has made an important contribution to our understanding of viruses in general, their replication, molecular biology

Molecular biology

Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

, evolution

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

and interaction with the host.

Foot-and-Mouth Disease Virus

Foot-and-mouth disease virus

The foot-and-mouth disease virus is the pathogen that causes foot-and-mouth disease. It is a picornavirus, the prototypical member of the Aphthovirus genus...

(FMDV) is the prototypic member of the Aphthovirus

Aphthovirus

Aphthovirus is a viral genus of the family Picornaviridae. Aphthoviruses infect vertebrates, and include the causative agent of foot-and-mouth disease. Foot-and-mouth disease virus is the prototypic member of the genus Aphthovirus...

genus in the Picornaviridae family. This picornavirus

Picornavirus

A picornavirus is a virus belonging to the family Picornaviridae. Picornaviruses are non-enveloped, positive-stranded RNA viruses with an icosahedral capsid. The genome RNA is unusual because it has a protein on the 5' end that is used as a primer for transcription by RNA polymerase...

is the etiological agent of an acute systemic vesicular disease that affects cattle worldwide, foot-and-mouth disease

Foot-and-mouth disease

Foot-and-mouth disease or hoof-and-mouth disease is an infectious and sometimes fatal viral disease that affects cloven-hoofed animals, including domestic and wild bovids...

. FMDV is a highly variable and transmissible virus. It enters the body through inhalation. Soon after infection, the single stranded positive RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

that constitutes the viral genome

Genome

In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

is efficiently translated using a cap-independent mechanism driven by the internal ribosome

Ribosome

A ribosome is a component of cells that assembles the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule....

entry site element (IRES). This process occurs concomitantly with the inhibition of cellular protein synthesis, caused by the expression of viral proteases. Processing of the viral polyprotein is achieved cotranslationally by viral encoded protease

Protease

A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....

s, giving rise to the different mature viral proteins. Viral RNA as well as viral proteins interact with different components of the host cell, acting as key determinants of viral pathogenesis

Pathogenesis

The pathogenesis of a disease is the mechanism by which the disease is caused. The term can also be used to describe the origin and development of the disease and whether it is acute, chronic or recurrent...

. In depth knowledge of the molecular basis of the viral cycle is needed to control viral pathogenesis and disease spreading.

Pestiviruses

Pestivirus

Pestivirus is a genus of viruses that belong to the family Flaviviridae. Viruses in the genus Pestivirus infect mammals, including members of the family Bovidae and the family Suidae .-Virus Genetics and Structure:Pestivirus viruses have a single strand of...

es account for important diseases in animals such as Classical swine fever

Classical swine fever

Classical swine fever or hog cholera is a highly contagious disease of pigs and wild boar.-Clinical Signs:...

(CSF) and Bovine viral diarrhea / Mucosal disease (BVD/MD). According to the current O.I.E. list CSF and BVD/MD are notifiable diseases and eradication programs are administered in many countries worldwide. The molecular biology

Molecular biology

of pestiviruses shares many similarities and peculiarities with the human hepacivirus

Hepacivirus

Hepacivirus is a genus of the Flaviviridae family of viruses. The only member of the genus is the type species, Hepatitis C virus. Hepaciviruses, like other Flaviviridae, infect mammals.-External links:* *...

es. Genome organisation and translation strategy are highly similar for the members of both genera. One hallmark of pestiviruses is their unique strategy to establish persistent infection during pregnancy. Persistent infection with pestiviruses often goes unnoticed; for BVDV frequently nonhomologous RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

recombination events lead to the appearance of genetically distinct viruses that are lethal to the host.

Arteriviruses

In 1996, the family Arteriviridae
Arterivirus
Arterivirus is a genus of virus, with type species equine arteritis virus. In 1996, the family Arteriviridae was included within the order Nidovirales. Arteriviruses are small, enveloped, animal viruses with an icosahedral core containing a positive-sense RNA genome...

was included within the order Nidovirales
Nidovirales
The Nidovirales are an order of viruses with animal hosts. It includes the families Coronaviridae, Arterivirus and Roniviridae.-Virology:...

. Arteriviruses are small, enveloped, animal viruses with an icosahedral core containing a positive-sense RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

genome. The family includes equine arteritis virus

Equine viral arteritis

Equine viral arteritis is a disease of horses caused by an RNA virus of the genus Arterivirus. The virus which causes EVA was first isolated from horses in Ohio in 1953 but the disease has afflicted equine animals worldwide for centuries. It has been more common in some breeds of horses in the...

(EAV), porcine reproductive and respiratory syndrome virus

Porcine Reproductive and Respiratory Syndrome Virus

Porcine reproductive and respiratory syndrome virus , also known as blue-ear pig disease , is a virus that causes a disease of pigs, called porcine reproductive and respiratory syndrome . This economically important, pandemic disease causes reproductive failure in breeding stock and respiratory...

(PRRSV), lactate dehydrogenase elevating virus

Lactate dehydrogenase elevating virus

Lactate dehydrogenase elevating virus, or LDV for short, belongs to part of the arteriviridae family and the nidovirales order. Also included in the nidovirales order are the coronaviridae. The arteriviridae infect macrophages in animals and cause a variety of diseases...

(LDV) of mice and simian haemorrhagic fever virus (SHFV). Three of these viruses were first discovered and characterized in the 1950/60s, whereas PRRSV was first isolated in Europe and in North America in the early 1990s. The arteriviruses are highly species specific, but share many biological and molecular properties, including virion morphology, a unique set of structural proteins, genome organization and replication strategy, and the ability to establish prolonged or true persistent infection in their natural hosts. However, the epidemiology

Epidemiology

Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...

and pathogenesis

Pathogenesis

of the infection caused by each virus is distinct, as are the diseases they cause.

Coronaviruses

Coronavirus

Coronaviruses are species in the genera of virus belonging to the subfamily Coronavirinae in the family Coronaviridae. Coronaviruses are enveloped viruses with a positive-sense single-stranded RNA genome and a helical symmetry. The genomic size of coronaviruses ranges from approximately 16 to 31...

(CoV) genome

Genome

replication takes place in the cytoplasm

Cytoplasm

The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

in a membrane-protected microenvironment, and starts with the translation of the genome to produce the viral replicase. CoV transcription involves a discontinuous RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

synthesis (template switch) during the extension of a negative copy of the subgenomic mRNAs. The requirement for basepairing during transcription has been formally demonstrated in arterivirus

Arterivirus

Arterivirus is a genus of virus, with type species equine arteritis virus. In 1996, the family Arteriviridae was included within the order Nidovirales. Arteriviruses are small, enveloped, animal viruses with an icosahedral core containing a positive-sense RNA genome...

es and CoVs. CoV N protein is required for coronavirus RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

synthesis, and has RNA chaperone activity that may be involved in template switch. Both viral and cellular proteins are required for replication and transcription. CoVs initiate translation by cap-dependent and cap-independent mechanisms. Cell macromolecular synthesis may be controlled after CoV infection by locating some virus proteins in the host cell nucleus. Infection by different coronaviruses cause in the host alteration in the transcription and translation patterns, in the cell cycle, the cytoskeleton

Cytoskeleton

The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...

, apoptosis

Apoptosis

Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...

and coagulation

Coagulation

Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...

pathways, inflammation

Inflammation

Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

, and immune and stress responses. The balance between gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

s up- and down-regulated could explain the pathogenesis caused by these viruses. Coronavirus expression systems based on single genome constructed by targeted recombination, or by using infectious cDNAs, have been developed. The possibility of expressing different genes under the control of transcription regulating sequences (TRSs) with programmable strength, and engineering tissue and species tropism indicates that CoV vectors are flexible. CoV based vectors have emerged with high potential for vaccine development and, possibly, for gene therapy.

Influenza

Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...

is caused by RNA viruses of the family Orthomyxoviridae

Orthomyxoviridae

The Orthomyxoviridae are a family of RNA viruses that includes five genera: Influenzavirus A, Influenzavirus B, Influenzavirus C, Isavirus and Thogotovirus. A sixth has recently been described...

and affects birds and mammals.

Avian Influenza

Wild aquatic birds are the natural hosts for a large variety of influenza

Influenza

Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...

A viruses. Occasionally viruses are transmitted from this reservoir to other species and may then cause devastating outbreaks in domestic poultry or give rise to human influenza pandemic

Pandemic

A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic...

s. Proteolytic activation of the hemagglutinin

Hemagglutinin

Influenza hemagglutinin or haemagglutinin is a type of hemagglutinin found on the surface of the influenza viruses. It is an antigenic glycoprotein. It is responsible for binding the virus to the cell that is being infected...

is an important determinant for pathogenicity

Pathogenicity

Pathogenicity is the ability of a pathogen to produce an infectious disease in an organism.It is often used interchangeably with the term "virulence", although virulence is used more specifically to describe the relative degree of damage done by a pathogen, or the degree of pathogenicity caused by...

and adaptation of the receptor binding specificity of the hemagglutinin and adaptation of the polymerase to new hosts play important roles in interspecies transmission.

Bluetongue virus

Bluetongue disease

Bluetongue disease or catarrhal fever is a non-contagious, non-zoonotic, insect-borne, viral disease of ruminants, mainly sheep and less frequently cattle, goats, buffalo, deer, dromedaries and antelope...

(BTV), a member of Orbivirus

Orbivirus

The genus Orbivirus is a member of the Reoviridae family. This genus currently contains 22 species and at least 130 different serotypes. Orbiviruses can infect and replicate within a wide range of arthropod and vertebrate hosts...

genus within the Reoviridae

Reoviridae

Reoviridae is a family of viruses that can affect the gastrointestinal system and respiratory tract. Viruses in the family Reoviridae have genomes consisting of segmented, double-stranded RNA...

family causes serious disease in livestock (sheep, goat, cattle). Partly due to this BTV has been in the forefront of molecular studies for the last three decades and now represents one of the best understood viruses at the molecular and structural levels. BTV, like the other members of the family is a complex non-enveloped virus with seven structural proteins and a RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

genome

Genome

consisting of 10 double-stranded (ds) RNA segments of different sizes. It has been possible to determine the complex nature of the virion through 3D structure reconstructions (diameter ~ 800 Å); the atomic structure of proteins and the internal capsid

Capsid

A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...

(~ 700 Å, the first large highly complex structure ever solved); the definition of the virus encoded enzymes required for RNA replication; the ordered assembly of the capsid shell and the protein sequestration required for it; and the role of host proteins in virus entry and virus release. These areas are important for BTV replication but they also indicate the pathways that may be used by related viruses, which include viruses that are pathogenic to man and animals, thus providing the basis for developing strategies for intervention or prevention.

Porcine Circoviruses

Porcine Circovirus

Porcine circovirus

Porcine circovirus is a single-stranded DNA virus , that is nonenveloped with an unsegmented circular genome. The viral capsid is icosahedral and approximately 17 nm in diameter. PCV is a member of the virus family Circoviridae....

es (PCV) are the smallest viruses replicating autonomously in eukaryotic cells. The virions are non-enveloped and spherical with a diameter of 16-18 nm and the covalently closed and single-stranded DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

genome

Genome

s comprise less than 1800 nucleotide

Nucleotide

Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...

s. The genomes encode only two major open reading frame

Open reading frame

In molecular genetics, an open reading frame is a DNA sequence that does not contain a stop codon in a given reading frame.Normally, inserts which interrupt the reading frame of a subsequent region after the start codon cause frameshift mutation of the sequence and dislocate the sequences for stop...

s. The gene

Gene

products Rep, Rep' and Cap are involved in viral replication, regulation of transcription and capsid formation. Due to their highly limited coding capacity, circoviruses are supposed to rely principally on the host's machinery for synthesis of macromolecule

Macromolecule

A macromolecule is a very large molecule commonly created by some form of polymerization. In biochemistry, the term is applied to the four conventional biopolymers , as well as non-polymeric molecules with large molecular mass such as macrocycles...

s. Two types of PCV are known, which differ with respect to their pathogenicity. Porcine circovirus type 1 (PCV1) is not linked with a disease, while porcine circovirus type 2 (PCV2) is the etiological agent of Postweaning Multisystemic Wasting Syndrome (PMWS), a new emerging and multifactorial disease in swine. PCV1 and PCV2 show a high degree of sequence homology and a similar genomic organisation; nevertheless, the basis of the distinct pathogenicity has not yet been unravelled.

Herpesviruses

Herpesviridae

The Herpesviridae are a large family of DNA viruses that cause diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word herpein , referring to the latent, recurring infections typical of this group of viruses...

are highly successful pathogens infecting animals and man. Although there is a wide variety of different herpesviruses with different biological characteristics, they have in common basic properties such as morphology of the virion, highly regulated transcription and establishment of latency. In animal virology the most important herpesviruses belong to the Alphaherpesvirinae

Alphaherpesvirinae

Alphaherpesvirinae is a subfamily of Herpesviridae primarily distinguished by reproducing more quickly than other subfamilies of Herpesviridae. In animal virology the most important herpesviruses belong to the Alphaherpesvirinae...

. Research on pseudorabies virus, the causative agent of Aujeszky's disease in pigs, has pioneered animal disease control with genetically modified vaccines. PrV is now extensively studied as a model for basic processes during lytic herpesvirus infection, and for unravelling molecular mechanisms of herpesvirus neurotropism, whereas bovine herpesvirus 1, the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis, is analyzed to elucidate molecular mechanisms of latency. The avian infectious laryngotracheitis virus

Gallid herpesvirus 1

Gallid herpesvirus 1 is a virus of the family Herpesviridae that causes avian infectious laryngotracheitis. It was originally recognized as a disease of chickens in the United States in 1926...

is phylogenetically distant from these two viruses and serves to underline similarity and diversity within the Alphaherpesvirinae.

African Swine Fever Virus

African swine fever virus

African swine fever virus is the causative agent of African swine fever . ASFV is a large, double-stranded DNA virus which replicates in the cytoplasm of infected cells, and is the only member of the Asfarviridae family. ASFV infects domestic pigs, warthogs and bushpigs, as well as soft ticks ,...

(ASFV) is a large double-stranded DNA

DNA

virus which replicates in the cytoplasm

Cytoplasm

of infected cells and is the only member of the Asfarviridae

Asfarviridae

Asfarviridae is a family of viruses that primarily infects swine, resulting in an onset of African swine fever. There is a single genus in this family: Asfivirus. The name of this family and genus are derived from the acronym: African swine fever and related viruses...

family. In common with other viral haemorrhagic fevers, the main target cells for replication are those of monocyte

Monocyte

Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...

, macrophage

Macrophage

Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...

lineage. The virus causes a haemorrhagic fever with high mortality rates in pigs, but persistently infects its natural hosts, warthogs, bushpigs and soft ticks of the Ornithodoros

Ornithodoros

Ornithodoros is a genus in the soft-bodied tick family, Argasidae. The Linnean name derives from ornithos and doros , meaning "bird" and "gift," respectively...

species with no disease signs. The virus encodes enzymes required for replication and transcription of the genome

Genome

, including elements of a base excision repair system, structural proteins and many proteins that are not essential for replication in cells but have roles in virus survival and transmission in its hosts. Virus replication takes place in perinuclear factory areas. Assembly of the icosahedral capsid

Capsid

occurs on modified membranes from the endoplasmic reticulum

Endoplasmic reticulum

The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...

. Products from proteolytically processed polyproteins form the core shell between the internal membrane and the nucleoprotein

Nucleoprotein

A nucleoprotein is any protein that is structurally associated with nucleic acid .Many viruses harness this protein, and they are known for being host-specific...

core. An additional outer membrane is gained as particles bud from the plasma membrane. The virus encodes proteins that inhibit signalling pathways in infected macrophages and thus modulate transcriptional activation of immune response genes. In addition the virus encodes proteins which inhibit apoptosis

Apoptosis

of infected cells to facilitate production of progeny virions. Viral membrane proteins with similarity to cellular adhesion proteins modulate interaction of virus-infected cells and extracellular virions with host components.

Lentivirus

Lentivirus is a genus of slow viruses of the Retroviridae family, characterized by a long incubation period...

es comprise a genus of diverse viruses in the Retroviridae family which are united in their ability to infect and persist in macrophage

Macrophage

s. Infections are characterized by immune system dysfunctions following sometimes lengthy incubation periods. The viruses in this genus include primate lentiviruses such as HIV

HIV

Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

as well as animal lentiviruses including equine infectious anemia virus (EIAV). A feature of lentiviruses is their ability to hijack macrophages so that they are simultaneously involved in the dissemination and control of virus spread throughout the host, leading to disease induction and/or transmission to a new host. Despite the devastating infections that lentiviruses cause, they also have enormous potential as research tools due to their ability to integrate into the host genome and are being exploited for use as delivery vehicles in gene therapy.

Flaviviruses

Flavivirus

Flavivirus is a genus of the family Flaviviridae. This genus includes the West Nile virus, dengue virus, tick-borne encephalitis virus, yellow fever virus, and several other viruses which may cause encephalitis....

es constitute a family of linear, single-stranded RNA(+) viruses. Flaviviruses include the West Nile virus

West Nile virus

West Nile virus is a virus of the family Flaviviridae. Part of the Japanese encephalitis antigenic complex of viruses, it is found in both tropical and temperate regions. It mainly infects birds, but is known to infect humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, domestic...

, dengue virus

Dengue virus

Dengue virus in one of four serotypes is the cause of dengue fever. It is a mosquito-borne single positive-stranded RNA virus of the family Flaviviridae; genus Flavivirus...

, Tick-borne Encephalitis Virus, Yellow Fever

Yellow fever

Yellow fever is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family....

Virus, and several other viruses. Many flavivirus species can replicate in both mammalian and insect cells. Most flaviviruses are arthropod

Arthropod

An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

borne and multiply in both vertebrates and arthropods.

Paramyxoviruses

Paramyxovirus

Paramyxoviruses are viruses of the Paramyxoviridae family of the Mononegavirales order; they are negative-sense single-stranded RNA viruses responsible for a number of human and animal diseases.-Genera:*Subfamily Paramyxovirinae**Genus Avulavirus Paramyxoviruses (from Greek para-, beyond, -myxo-,...

es are a diverse family of non-segmented negative strand RNA viruses that include many highly pathogenic viruses affecting humans, animals, and birds. In recent years the advent of reverse genetics has led to a greater understanding of the genomics, molecular biology and viral pathogenesis. Paramyxoviruses cause a range of diseases in animal species: canine distemper virus (dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

s), phocine distemper virus

Phocine distemper virus

Phocine distemper virus is a paramyxovirus of the genus morbillivirus that is pathogenic for pinniped species, particularly seals. Clinical signs include laboured breathing, fever and nervous symptoms....

(seals), cetacean morbillivirus (dolphin

Dolphin

Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s and porpoise

Porpoise

Porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen...

s) Newcastle disease virus (birds) and rinderpest virus (cattle

Cattle

Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

). Some paramyxoviruses such as the henipaviruses are zoonotic

Zoonosis

A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...

pathogens, occurring naturally in an animal host, but also able to infect humans.

Hendra and Nipah Virus

Over the past decade, the previously unknown paramyxovirus

Paramyxovirus

es Hendra virus (HeV) and Nipah virus (NiV) have emerged in humans and livestock in Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

and Southeast Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

. Collectively they are known as henipavirus

Henipavirus

Henipavirus is a genus of the family Paramyxoviridae, order Mononegavirales containing two established species, Hendra virus and Nipah virus. The henipaviruses are naturally harboured by Pteropid fruit bats , and some microbat species...

es. Both viruses are contagious

Contagious disease

A contagious disease is a subset category of infectious diseases , which are easily transmitted by physical contact with the person suffering the disease, or by their secretions or objects touched by them....

, highly virulent, and capable of infecting a number of mammalian species and causing potentially fatal disease. Due to the lack of a licensed vaccine

Vaccine

A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

or antiviral therapies, HeV and NiV are designated as biosafety level

Biosafety level

A biosafety level is the level of the biocontainment precautions required to isolate dangerous biological agents in an enclosed facility. The levels of containment range from the lowest biosafety level 1 to the highest at level 4 . In the United States, the Centers for Disease Control and...

4 agents. The genomic structure of both viruses is that of a typical paramyxovirus. However, due to limited sequence homology and little immunological cross-reactivity with other paramyxoviruses, HeV and NiV have been classified into a new genus within the family Paramyxoviridae named Henipavirus

Henipavirus

Insect viruses

Viruses that are pathogenic to insects cause millions of dollars worth of damage to industries such as sericulture

Sericulture

Sericulture, or silk farming, is the rearing of silkworms for the production of raw silk.Although there are several commercial species of silkworms, Bombyx mori is the most widely used and intensively studied. According to Confucian texts, the discovery of silk production by B...

, apiculture and aquaculture

Aquaculture

Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...

(e.g. infection of honeybees and silk worms). On the other hand, viruses that are pathogenic to insect pests can be exploited as biological control agents. Some insect viruses, e.g. baculovirus

Baculovirus

The baculoviruses are a family of large rod-shaped viruses that can be divided to two genera: nucleopolyhedroviruses and granuloviruses . While GVs contain only one nucleocapsid per envelope, NPVs contain either single or multiple nucleocapsids per envelope. The enveloped virions are further...

, have been commercially exploited for use as gene expression

Gene expression

Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA , transfer RNA or small nuclear RNA genes, the product is a functional RNA...

and delivery vectors in both insect and mammalian cells.

Interferon

Interferons (IFNs) play pivotal roles in shaping the immune responses in mammals and are particularly important for the control of viral infections and cell growth, and immune regulation. These proteins rapidly induce an "anti-viral state" in cells that surround infected cells. In order to survive, viruses have evolved multiple strategies to evade the anti-viral effects of IFNs. Elucidating the molecular and cellular biology of the virus-interferon interaction is key to understanding issues such as viral pathogenesis, latency, and the development of novel antivirals.

Foot-and-Mouth Disease Virus

Pestiviruses

Arteriviruses

Coronaviruses

Influenza

Avian Influenza

Bluetongue virus

Porcine Circoviruses

Herpesviruses

African Swine Fever Virus

Lentivirus

Flaviviruses

Paramyxoviruses

Hendra and Nipah Virus

Insect viruses

Interferon

See also