A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds.
Selective breeding is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, cultivars, or breeds. Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids. Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals.
Whiteleg shrimp, also known as Pacific white shrimp or King prawn, is a species of prawn of the eastern Pacific Ocean commonly caught or farmed for food.
Poxviridae is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated with this family include smallpox.
Birnaviridae is a family of double-stranded RNA viruses. Salmonid fish, birds and insects serve as natural hosts. There are currently 11 species in this family, divided among seven genera. Diseases associated with this family include infectious pancreatic necrosis in salmonid fish, which causes significant losses to the aquaculture industry, with chronic infection in adult salmonid fish and acute viral disease in young salmonid fish.
Marine shrimp farming is an aquaculture business for the cultivation of marine shrimp or prawns for human consumption. Although traditional shrimp farming has been carried out in Asia for centuries, large-scale commercial shrimp farming began in the 1970s, and production grew steeply, particularly to match the market demands of the United States, Japan and Western Europe. The total global production of farmed shrimp reached more than 1.6 million tonnes in 2003, representing a value of nearly 9 billion U.S. dollars. About 75% of farmed shrimp is produced in Asia, in particular in China and Thailand. The other 25% is produced mainly in Latin America, where Brazil, Ecuador, and Mexico are the largest producers. The largest exporting nation is India.
White spot syndrome (WSS) is a viral infection of penaeid shrimp. The disease is highly lethal and contagious, killing shrimp quickly. Outbreaks of this disease have wiped out the entire populations of many shrimp farms within a few days, in places throughout the world.
Taura syndrome (TS) is one of the more devastating diseases affecting the shrimp farming industry worldwide. It was first described in Ecuador during the summer of 1992. In March 1993, it returned as a major epidemic and was the object of extensive media coverage. Retrospective studies have suggested a case of Taura syndrome might have occurred on a shrimp farm in Colombia as early as 1990 and the virus was already present in Ecuador in mid-1991. Between 1992 and 1997, the disease spread to all major regions of the Americas where whiteleg shrimp is cultured. The economic impact of TS in the Americas during that period might have exceeded US$2 billion by some estimates.
Necrotising hepatopancreatitis (NHP), is also known as Texas necrotizing hepatopancreatitis (TNHP), Texas Pond Mortality Syndrome (TPMS) and Peru necrotizing hepatopancreatitis (PNHP), is a lethal epizootic disease of farmed shrimp. It is not very well researched yet, but generally assumed to be caused by a bacterial infection.
Penaeus monodon, commonly known as the giant tiger prawn, Asian tiger shrimp, black tiger shrimp, and other names, is a marine crustacean that is widely reared for food.
Simian foamy virus (SFV) is a species of the genus Spumavirus that belongs to the family of Retroviridae. It has been identified in a wide variety of primates, including prosimians, New World and Old World monkeys, as well as apes, and each species has been shown to harbor a unique (species-specific) strain of SFV, including African green monkeys, baboons, macaques, and chimpanzees. As it is related to the more well-known retrovirus human immunodeficiency virus (HIV), its discovery in primates has led to some speculation that HIV may have been spread to the human species in Africa through contact with blood from apes, monkeys, and other primates, most likely through bushmeat-hunting practices.
Drosophila X virus (DXV) belongs to the Birnaviridae family of viruses. Birnaviridae currently consists of three genera. The first genus is Entomobirnavirus, which contains DXV. The next genus is Aquabirnavirus, containing infectious pancreatic necrosis virus (IPNV). The last genus is Avibirnavirus, which contains infectious bursal disease virus (IBDV). All of these genera contain homology in three specific areas of their transcripts. The homology comes from the amino and carboxyl regions of preVP2, a small 21-residue-long domain near the carboxyl terminal of VP3, and similar small ORFs sequences.
Infectious hematopoietic necrosis virus (IHNV), is a negative-sense single-stranded, bullet-shaped RNA virus that is a member of the Rhabdoviridae family, and from the genus Novirhabdovirus. It causes the disease known as infectious hematopoietic necrosis in salmonid fish such as trout and salmon. The disease may be referred to by a number of other names such as Chinook salmon disease, Coleman disease, Columbia River sockeye disease, Cultus Lake virus disease, Oregon sockeye disease, Sacramento River Chinook disease and sockeye salmon viral disease. IHNV is commonly found in the Pacific Coast of Canada and the United States, and has also been found in Europe and Japan. The first reported epidemics of IHNV occurred in the United States at the Washington and the Oregon fish hatcheries during the 1950s. IHNV is transmitted following shedding of the virus in the feces, urine, sexual fluids, and external mucus and by direct contact or close contact with the surrounding water. The virus gains entry into fish at the base of the fins.
Snakehead rhabdovirus (SHRV) is a novirhabdovirus that affects warm water wild and pond-cultured fish of various species in Southeast Asia, including snakehead for which it is named.
Marnaviridae is a family of positive-stranded RNA viruses in the order Picornavirales that infect various photosynthetic marine protists. Members of the family have non-enveloped, icosahedral capsids. Replication occurs in the cytoplasm and causes lysis of the host cell. The first species of this family that was isolated is Heterosigma akashiwo RNA virus (HaRNAV) in the genus Marnavirus, which infects the toxic bloom-forming Raphidophyte alga, Heterosigma akashiwo. As of 2021, there are twenty species across seven genera in this family, as well as many other related virus sequences discovered through metagenomic sequencing that are currently unclassified.
Turkeypox virus is a virus of the family Poxviridae and the genus Avipoxvirus that causes turkeypox. It is one of the most common diseases in the wild turkey population. Turkeypox, like all avipoxviruses, is transmitted either through skin contact or by arthropods acting as mechanical vectors.
Nudiviruses are a family of animal viruses that constitute the family Nudiviridae. Insects and marine crustaceans serve as natural hosts. There are 11 species in this family, assigned to 4 genera. Diseases associated with this family include: death in larvae, chronic disease in adults.
Infectious pancreatic necrosis virus (IPNV) is a double-stranded RNA virus from the family Birnaviridae, in the genus Aquabirnavirus. Causing the highly infectious disease Infectious pancreatic necrosis, the virus primarily affects young salmonids resulting in high mortality, occasionally surpassing 90 percent in the early stages. IPNV or IPNV-like viruses have been isolated worldwide from at least 32 families of saltwater and freshwater salmonids and non-salmonids fish including salmon, flatfish, pike, eels and others. Other aquatic organisms infected include 11 molluscs and 4 species of crustaceans. Due to its wide host range and high mortality, the virus is of great concern to global aquaculture. In addition to persistence in hosts, IPNV is also perpetual in the environment, surviving across a range of conditions and capable of infecting fish with as little as 101TCID50/ml of the virus. Found in Europe, North America, South America, Africa, Asia, and Australia, the virus has led to significant losses in the mariculture of Atlantic salmon, brook trout, and rainbow trout.
Astroviridae is a family of non-enveloped ssRNA viruses that cause infections in different animals. The family name is derived from the Greek word astron ("star") referring to the star-like appearance of spikes projecting from the surface of these small unenveloped viruses. Astroviruses were initially identified in humans but have since been isolated from other mammals and birds. This family of viruses consists of two genera, Avastrovirus (AAstV) and Mamastrovirus (MAstV). Astroviruses most frequently cause infection of the gastrointestinal tract but in some animals they may result in encephalitis, hepatitis (avian) and nephritis (avian).
Biofloc technology (BT) is a fish farming system that recycles waste nutrients as fish food. Biofloc, specifically cultured microorganisms, are introduced into the water to form microbial protein from toxic fish waste and other organic matter. This maintains water quality as well as lowering costs. Candidate species must be resistant to environmental changes, tolerate high stocking density, adapt to changes in dissolved oxygen, and take microbial protein as food. BT is used in large-scale shrimp and finfish farms, mainly in Asia.
