Pestivirus
Encyclopedia
Pestivirus is a genus of virus
es that belong to the family
Flaviviridae
. Viruses in the genus Pestivirus infect mammals, including members of the family Bovidae (which includes, but is not limited to, cattle, sheep, and goats) and the family Suidae
(which includes various species
of swine).
RNA
(i.e. RNA which can be directly translated
into viral proteins) which is around 12.5 kilobases (kb) long (equal to the length of 12,500 nucleotide
s). Sometimes virions (individual virus particles) contain sections of an animal's genome
which have been duplicated, though this is not normally the case. There is no Poly-A
on the 3' end of the genome. (This means that these viruses have no post-transcriptional modification
s, and have simple RNA genomes.) The genome contains RNA to encode both structural and non-structural proteins.
The molecular biology
of pestiviruses shares many similarities and peculiarities with the human hepacivirus
es. Genome organisation and translation strategy are highly similar for the members of both genera. For BVDV frequently nonhomologous RNA
recombination events lead to the appearance of genetically distinct viruses that are lethal to the host.
Each virion is approximately 40-60 nanometers (nm) in diameter, and consists of a nucleocapsid
envelope
d with the cytoplasm
of infected cells.
, mainly in cattle. Some adult cattle are immune to the disease, while others are life-long carriers. If a foetus becomes infected within the first three to four months of gestation
then it will fail to develop antibodies
towards the virus. In these cases the animals often die before birth or shortly after. It is spread very easily among feedlot cattle as nasal secretions and close contact spread the disease, and animals with infected mucous membrane
s give off millions of particles of BVDV a day.
Symptoms of Pestivirus infection include diarrhoea, respiratory
problems and bleeding disorders.
Pestivirus vaccines exist and the correct vaccine strain should be given, depending on the herd's location and the endemic strain in that region. This vaccination must be given regularly to maintain immunity.
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 that belong to the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Flaviviridae
Flaviviridae
The Flaviviridae are a family of viruses that are primarily spread through arthropod vectors . The family gets its name from Yellow Fever virus, a type virus of Flaviviridae; flavus means yellow in Latin...
. Viruses in the genus Pestivirus infect mammals, including members of the family Bovidae (which includes, but is not limited to, cattle, sheep, and goats) and the family Suidae
Suidae
Suidae is the biological family to which pigs belong. In addition to numerous fossil species, up to sixteen extant species are currently recognized, classified into between four and eight genera...
(which includes various species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of swine).
Virus Genetics and Structure
Pestivirus viruses have a single strand of positive-senseSense (molecular biology)
In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...
RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
(i.e. RNA which can be directly translated
Translation (genetics)
In molecular biology and genetics, translation is the third stage of protein biosynthesis . In translation, messenger RNA produced by transcription is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein...
into viral proteins) which is around 12.5 kilobases (kb) long (equal to the length of 12,500 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). Sometimes virions (individual virus particles) contain sections of an animal's 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....
which have been duplicated, though this is not normally the case. There is no Poly-A
Polyadenylation
Polyadenylation is the addition of a poly tail to an RNA molecule. The poly tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In eukaryotes, polyadenylation is part of the process that produces mature messenger RNA for translation...
on the 3' end of the genome. (This means that these viruses have no post-transcriptional modification
Post-transcriptional modification
Post-transcriptional modification is a process in cell biology by which, in eukaryotic cells, primary transcript RNA is converted into mature RNA. A notable example is the conversion of precursor messenger RNA into mature messenger RNA , which includes splicing and occurs prior to protein synthesis...
s, and have simple RNA genomes.) The genome contains RNA to encode both structural and non-structural proteins.
The 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...
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. 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.
Each virion is approximately 40-60 nanometers (nm) in diameter, and consists of a nucleocapsid
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...
envelope
Viral envelope
Many viruses have viral envelopes covering their protein capsids. The envelopes typically are derived from portions of the host cell membranes , but include some viral glycoproteins. Functionally, viral envelopes are used to help viruses enter host cells...
d with 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...
of infected cells.
Transmission and Prevention
Pestivirus is widespread in AustraliaAustralia
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...
, mainly in cattle. Some adult cattle are immune to the disease, while others are life-long carriers. If a foetus becomes infected within the first three to four months of gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....
then it will fail to develop antibodies
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
towards the virus. In these cases the animals often die before birth or shortly after. It is spread very easily among feedlot cattle as nasal secretions and close contact spread the disease, and animals with infected mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
s give off millions of particles of BVDV a day.
Symptoms of Pestivirus infection include diarrhoea, respiratory
Respiratory system
The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...
problems and bleeding disorders.
Pestivirus vaccines exist and the correct vaccine strain should be given, depending on the herd's location and the endemic strain in that region. This vaccination must be given regularly to maintain immunity.
Potential species
Several additional isolates have been reported and may be recognised as species- Border disease virus 2 (BDV-2)
- Bovine viral diarrhea virus 3 (BVDV-3) (HoBi group)
- Bungowannah.
- Giraffe
- Pronghorn