Common Viral fish diseases
Grass carp hemorrhage (hemorrhage of grass carp) is most grass carp Fingerling rearing stage of the disease, as early as 1978, the hydrobiology Institute to study the pathogen of this report. , Chinese Academy of Sciences, Wuhan University, Wuhan Institute of Virology, CAFS, the Yangtze River Fisheries Research Institute in China, and many units have also conducted in-depth research to this pathogen. International grass carp hemorrhage virus found in China, and the first was reported. Research personnel on grass carp bleeding disease virus of form structure and physico-chemical characteristics, and virus of nucleic acid nature, and virus and host between of mutual role, and virus of organization pathology, and different virus separation strains of nature features, and virus of serum learn nature, and immune control, many carried out has research (Chen Yanxin,, 1983; Deng summer,, 1985; Min Shuqin,, 1986; Fang Qin,, 1989; Ke Lihua,, 1990; Ding Qingquan,, 1990; Jiang Yulin,, 1991a).
Pathogenic viruses for 20 solid particles, diameter 50~80nm, vary because of different isolates, such as Chen Yanxin, (1983) reported the virus particle diameter is 53nm; Ke Lihua et al (1990) reported the virus particle diameter is 71nm. No lipoprotein envelope of the virus, had a double capsid. Viral genomic nucleic acid is RNA, made up of 11 segments of total molecular weight of about 15×10-6. Virus in rostral cell line ZC7901 in grass carp, grass carp, cell line, CIK, GCK84, fish fin Minnow cell proliferation in CF84.
Epidemic disease and harm hemorrhage in FRY, viruses mainly carp, herring also makes artificial infection of diseases. With up to 2.5~15cm of fish disease is the most common, and often caused the death of a large number of grass carp fingerlings. 25 ℃ below fish is a latent infection, when water temperature exceeds 27 ℃, the disease can be widely popular, high mortality rates, often up to 90% or more. Fish virus infection can have different symptoms, such as “red muscle” symptoms as muscle blood red gills are often anemic and pale, this small fish found in 7~10cm; “Red fin red gills” symptoms as the fin base and the gills congestion, disease-prone in the larger fish (13cm) and “diarrhea” symptoms are characterized by intestinal serious congestion, small and large grass carp may occur. These three symptoms can occur alone or both.
Pathological changes in small blood vessels extensively damaged the wall, the formation of microthrombi and infarct-like lesions cause tissues and organs. In liver cells, such as intracytoplasmic Eosinophilic inclusion bodies can be seen. Percentage amount of white blood cells, lymphocytes, red blood cells and haemoglobin was significantly lower than fish, monocyte percentage is significantly higher than that of fish. Serum alanine aminotransferase, isocitrate dehydrogenase, lactate dehydrogenase activity increased plasma levels of total protein, cholesterol-lowering. Intestinal bleeding is the main symptom of sick fish to swelling of the intestinal epithelial cells, Goblet cells increases intestinal epithelium and lamina propria stripping, lumen has a large number of red blood cells and pieces fall off the intestinal epithelium.
Detection and prevention of fish Reovirus antiserum was prepared on the basis of, through discontinuous EP and enzyme-linked immunosorbent assay (ELISA) methods on early diagnosis of disease, but also by Staphylococcus protein a coagglutination test, histopathological and electron microscopic observation of the preliminary diagnosis of grass carp haemorrhage. Through the artificial immune system can effectively control grass carp haemorrhage. Tissue pulp inactivated vaccine and inactivated vaccines can be used in the production of cell culture practice, supplemented by using immune booster (such as hyoscyamine) can enhance the immune effect. Certain herbs, the rational use of antibiotics and, to some extent, slow the effects of the illness.
Referred to research on the virus disease of grass carp Reovirus outer in detail, there are other relevant reports. Mao Shujian (1989) isolated from grass carp in the pathogenesis of Zhejiang reported a small virus particles, diameter 20~30nm, genome as a single strand of RNA, no envelope, after the preliminary appraisal is a small RNA virus.
Viral disease of carp have been found and reported the main spring carp Viremia, carp Gill of smallpox disease, necrosis, and following a brief introduction, respectively.
Spring carp Viremia
Spring carp Viremia virus (Spring Viraemia of carp virus,SVCV) are pathogens that can cause acute infections in carp. After infection by the virus of carp in the pathogenesis of water temperature below 15 ° c in spring, and severe bladder inflammation symptoms are severe abdominal edema syndrome, and can often lead to secondary bacterial infections. Debate about the origin of the problem some, originally thought to be bacteria, until 1972 Fijan reported issued by the separation of infectious virus to be determined. SVCV genus rhabdoviridae family, this virus particles were rod and (or) bullet-shaped, long 135~380nm of mature virus particles, with a diameter of 45~95nm. Nuclear protein nucleocapsid consists of spiral wound (minus-strand single-stranded RNA and the n protein). Spring carp Viremia of outbreaks of water-related, and the optimum temperature for 16~17℃. Viruses can be spread by susceptible fish feces in the water, or some blood sucking parasites such as Lei Shi (Argulus Foliaceus) and inchworm fish leech (Piscicola geometrica Linnaeus) spread. In a State of nature, other fish besides carp, grass carp can also be infected. SVCV cells in some fishes such as FHM, effects of the EPC, and cause cell lesions. The pathogen by serological methods for diagnosis. May refer to several methods to control the SVCV: avoid the incoming virus source; Vigorously carry out drug cultivation of seedlings; Artificial control of water temperature (20 ℃ farmed fish); Immunization.
Necrosis of common carp Gill disease
Necrosis of common carp Gill (Gill necrosis of CARP) by Soviet scholars Shchelkunov and Shchelkunova (1981) reported that from a disease characterized by necrosis of Gill fish gills and kidney were isolated in virus, the virus can replicate FHM cells and infected fish disease. Preliminary judgment that the virus belongs to iridovirus.
CARP smallpox disease
Smallpox disease of carp (fish POX) smallpox disease is carp common diseases before and after winter, fashion is very broad. Main round belly Chub and carp, crucian carp, effects on fish growth and the value of goods. Fijan, (1983) isolated from diseased fish herpes virus (Herpesvirus). Jiang Yulin (1991b) reported the results of electron microscopic observation of carp smallpox pathogen. The typical symptoms of varying size in fish body surface is covered with massive white mucus, wax-like increase of biological, namely smallpox. These smallpox combined with the body surface of the fish is firm and can be scratched off with a knife. Remove smallpox into thin slices, electron microscope, there are a large number of virus particles present in the cytoplasm. Virus core 20 facets of Herpesviridae. Virus particle diameter 140~160nm, capsid diameter is 80~100nm. Virus nucleocapsid formed in the cell nucleus, get when the capsid bud through the nuclear membrane envelope, and gains the ability to infect cells. The viruses in epithelial cells of carp (EPC) cells, form a syncytium. After artificial infection test vaccinations to health carp virus suspensions in vivo, in 10~15℃ conditions 1 month later was get smallpox by inoculating the body surface of the fish. Pocked suspension with scratch after inoculation with Lei Yue Mun can be copied out in the laboratory with the same natural onset of symptoms, and by changing some of the environmental factors that control the occurrence of smallpox and disappeared. Under natural conditions, the virus can spread through mucous membrane exposure and contamination on the surface of the water. In addition to viruses, but Jeney (1995) on carp’s other diseases such as bacteria, fungi and parasites, a more comprehensive review of the progress, and control of fish diseases of great value.
Eel virus disease
Both at home and abroad have reported on eel virus, see the research.
Virus disease of eel type: virus of European eel (eel virus european,EVE), eel virus (eel virus,EV), eel Bush virus (cauliflower disease of eels virus), eel slug virus (rhabdovirus of eels), eel blisters virus (vesiculo virus ofeels). There is popular among other fish and infections viruses such as infectious pancreatic necrosis virus (infectious pancreatic nerosisvirus,IPNS), herpes viruses (herpeslike virus), Viral Hemorrhagic Septicemia virus (viral haemorrhagic septicaemia virus,VHSV) can also be infected eels (Castric, 1992).
Eel virus disease symptoms and pathogenic nature eel virus pathogen of the earlier study was EVE. Japan imported from European eel FRY in the 2nd year (1969), outbreaks of disease, and about half of eel deaths deaths a year in the same place only eels reach 2 700T. Only in 1973 on the eel from kidney disease viruses isolated. This double-stranded RNA virus of the genus eel virus pathogen, serology and infectious pancreatic necrosis virus (IPNV) close to the Ab strain, physical and chemical properties are identical to the IPNV. By EVE caused disease occurs mainly in winter, in Japan and China’s Taiwan caused Japan eel dead. 8~14℃, 4~26G 55% of the elver 20D mortality after infection. Main symptoms and pathological changes are: dying eel in temporary muscle spasms, or eels local rigid body, anal and some eels abdominal congestion, renal enlargement, ascites, Glomerular seriously damaged, some eels spleen necrosis of large areas. In naturally infected eels, Gill lamellae and hyperplasia of fusion phenomena (Huang Qiyan, 1993).
SchwantzPeitzner (1976) isolated from patients suffering from cutaneous Papilloma eel blood out of the EV. Viruses are round, with a diameter of 46~54nm. After viral inoculation of eels, do not produce any symptoms, but the virus particles in the cytoplasm of the host. Nagabayashi et al (1979) from the eel are ill isolated another virus in the blood, known as the eel Bush virus (cauliflower disease of eels virus). This virus, orthomyxovirus family (Orthomyxoviridae), type, diameter 90~140nm, 10nm long protrusions on the surface structure. Disease of eel head and lips clearly covered with hyperplasia of squamous cells, forming cauliflower-like head. Viruses are sensitive to ether, poisoning at 4 ℃ for 3 weeks, chickens and sheep red blood cell lectin. Virus on FHM cell culture cultivation temperature is 15 degrees Celsius.
In addition to the eels serological relationships of different isolates studied (Ahne, 1987). Jorgensen et al (1994) reported that scientists from several countries, such as 1977-1992 in Denmark and the United Kingdom, and France and the Sudan on 2 092 Man Chi virus test result. They got 91 virus samples, analysis showed that, of which 44 eel rhabdoviridae (eel rhabdovirus EVEX/EVA) genus Vesiculovirus (vesiculo group); 3 eel elastic-like virus belongs to the genus of rabies virus (Lyssa group); 38 infectious pancreatic necrosis virus (IPNS); 5 types of herpes virus, and Viral Hemorrhagic Septicemia virus 1. Visible, eel virus disease of harm exists and has caught the attention of scientists.
About the research profile of the first reports of eel eel virus virus disease is Chen Yanxin, (1992), suffering from a bloody opening of eel virus was found in blood cells. Virus particles 20 dodecahedral symmetry, consisting of a core and wrapped in film composition, particles with an average diameter of 70nm, inner core to 40nm. Mouth disease of eel in red blood cells and white blood cells, are seen under the electron microscope virus particles, but in the form of the virus found in the two size difference: virus 70nm in diameter in the red blood cells, capsule; In the white blood cells of diameter up to 40nm, not capsule. Fish is the main symptom mouth open not closed, in addition to sick fish is dark grey, head up, membrane bleeding in the mouth, and pectoral, pelvic and abdominal bleeding bit. Infected cells had abnormalities, such as wider or forming irregular folds of nuclear envelope; Round the swelling of mitochondria were vacuolated, and some contain Flocculent particles; Rough endoplasmic reticulum threshing and vacuolation. Recently, such as Tao Zengsi (1997) reported on eel “swim” pathogens research results show that the disease is caused by the “coronavirus-like virus” causes. Their condition is a disease of eel down in the water ran, spin crazy tour, muscle cramps, chest bruises; At necropsy liver enlargement. Histopathological examination showed liver, kidney and nervous cell degeneration and necrosis of the heart.
Viral diseases of rainbow trout
Rainbow Trout for cold water fish (cold water fishes), natural distribution in the United States, and Canada, and Mexico and other places. Trout began in 1959, but since intensive farming in 1983 from the United States, and Japan began only after the introduction of fine varieties of trout. Has been studied in detail in several important virus diseases of fish, at least three serious threats to farming of rainbow trout, which is infectious pancreatic necrosis (infectiouspanereatic necrosis,IPN), Viral Hemorrhagic Septicemia (viral haemorragic septicemia,VHS) and infectious hematopoietic necrosis disease (infectious hematopoietic necrosis,IHN)。
Infectious pancreatic necrosis disease
Rainbow Trout research on infectious pancreatic necrosis and viral pathogens is the Wolf (1959) began after reports this is a viral disease. Wolf (1988a) reviewed more than 200 articles in the literature based on the history of study of infectious pancreatic necrosis virus of fish, host and geographic distributions of, physicochemical properties, separation, identification, immunity and control aspects are described in detail. Since this virus serious, popular, as a first class national fish quarantine and quarantine objects. Main symptoms of infectious pancreatic necrosis is perpendicular to the fish swim, fish blackened, proptosis, swelling of the abdomen, anus and often drag cable-like mucus. Infectious pancreatic necrosis virus (IPNV) sensitive many fish, such as some varieties of salmon, trout, salmon, mainly against day-old FRY and 14-17 species, mortality rates of up to 80%~100% when the water temperature 10~12℃; Other fish from 20 families also in detecting IPNV and most poisonous fish illness did not appear. Studies have shown that, IPNV levels can not only spread poison led to vertical transmission through the egg. The most visible pathological changes of pancreatic necrosis, cell nuclear pyknosis and fractured, some of the inclusions in the cytoplasm of the cell. IPNV belongs to the double-stranded RNA viruses, with 20 grain, about 60nm in diameter, there are RNA-dependent RNA transcriptase. IPNV RTG2, R1, PG and CHSE cold-water fish cell lines cell proliferation and caused varying degrees of lesions. In Rainbow Trout imported in 1987 from the isolation of IPNV, and serological identification of IPNV rapid detection method of rainbow trout was also established (Jiang Yulin, 1989, 1990).
Viral Hemorrhagic Septicemia
Viral Hemorrhagic Septicemia virus (VHSV) is a bullet-shaped virus, can cause acute and subacute infection of rainbow trout mortality as high as 80%. Histopathological characteristics of the hematopoietic organs such as the spleen, kidney, and pancreatic necrosis. Acute type characterized by proptosis, bleeding and rapid death; Chronic infection characterized by slow movement disorders, anemia, and death. Epidemic in late winter and early spring, water temperatures below 14 c during outbreaks. Pathogenic diagnosis can be formed by taking the sick fish entrails, blood, or ascites for virus isolation, inoculated tissue homogenate or body fluids of sick fish to RTG2, CHSE, FHM, EPC or PG cells, 15 training 1~2D lesions can occur, complemented by neutralization test or fluorescent antibody technique can be used for isolation of strains for identification.
Infectious hematopoietic necrosis disease
Infectious hematopoietic necrosis virus (IHNV) rhabdoviridae, Huang Qiyan (1993) on the virus and the disease has been introduced. Infectious hematopoietic necrosis disease initially in the United States occurred, found in North America and Japan as well. Zhao Zhizhuang et al (1993), reported that the China’s Benxi rainbow trout virus IHNVB separation of hybridoma cell lines, monoclonal antibodies and ELISA detection method. Leng (1995) wrote that with IHNV from broodstock to eggs or sperm can be virus progeny, and a descendant of fish can survive a few individuals, these fish survive once it can no longer be IHNV infections cause disease, electron microscopy and molecular techniques (PCR) showed that, in those still surviving fish can be found in the presence of RNA of IHNV. Why the surviving fish disease but also against IHNV infection? Drolet et al (1995) studies have solved the mystery: the original flawed virus particles in these fish (DI), and DI for IHNV interfere with infectious, which shows the fish a molecular mechanism of resistance to viral infections, also explore the treatment of fish disease provides a new way of thinking. In addition in recent years has reported on other viral diseases of rainbow trout (Nylund, and others, 1995).
Mandarin fish siniperca chuatsi virus edit this paragraph
The Mandarin fish siniperca chuatsi [Siniperca chuats (Basilewsky)] virus abroad about the Mandarin fish siniperca chuatsi virus disease research are yet to see, but in recent years the Mandarin fish siniperca chuatsi diseases in Guangdong and other places popular with serious, illnesses mainly Mandarin fish skin bleeding point, Gill pale; Anatomical visible damage caused by a lot of bleeding, liver, spleen, gall bladder and bowel congestion and significantly enlarged. And harm of the disease in 1993, occurred only in a small number of farms, but extremely fierce, against the 1994-1995 of the same diseases, and in the Pearl River Delta is widespread. Incidence of tens of thousands of hectares of fish ponds 60%, serious disease of fish mortality than 90%. Use medications such as antibiotics, to no avail; Bacteria pathogenic bacteria could not be found. Researchers at the Institute of hydrobiology of the Mandarin fish siniperca chuatsi in fulminant epidemic of liver, spleen and heart tissue thin section electron microscopy, found in the cytoplasm, nucleus and cell gap distribution there are viral particles in. Virus morphology is spherical, its diameter is about to 280nm. Filtration and degerming crude after virus vaccination to fish cells in monolayer culture can make cells lesion; Healthy sauce using crude extract of virus or amplification of the virus infection in cultured cells, could cause the morbidity and mortality of the Mandarin fish siniperca chuatsi. Mandarin fish siniperca chuatsi on health (both artificial and natural infection of fish) were dissected, and the gills, liver, spleen, heart and renal histopathological observation 5 organs, confirmed the 5 organs of the Mandarin fish siniperca chuatsi diseases have taken place, and artificial infection of fish and fish in the pathogenesis of disease in natural state consistent with the pathological condition. These results show that of Mandarin fish siniperca chuatsi viruses discovered by (siniperca chuatsi virus,SCV) is the Mandarin fish siniperca chuatsi fulminant epidemic disease (such as Zhang qiya, 1996a).
Spotted catfish channel catfish virus disease
Spotted cross channel catfish virus disease (channelcatfishvirusdisease,CCVD) spotted catfish channel catfish virus (CCV) is a herpes virus, which can cause spots cross channel catfish (IctaluruspunctatusRafinesque) FRY and young fish acute hemorrhagic diseases, mortality is as high as 100%. Fijan, (1970) reported the first results of CCV. Wolf (1988b) study reviews the progress of the CCV, introduced the history of CCV, infection caused by illnesses and pathological changes, physical and chemical properties, diagnosis and isolation, such as immunization and prevention. CCV as spherical particles, the capsule of a virus particle diameter 175~200nm, capsid diameter of about 100nm, genome for double-stranded DNA. CCVD outbreak is related to water temperature and fish age, when water temperature at 25 ℃, when the fish susceptible to, the incubation period is only 7~10d and acute onset. Disease characterized by uncoordinated spiral swim fins and bleeding at the base of the tail. Anatomical visible disease of kidney, spleen enlargement, internal bleeding, and pathological examination and hematopoietic necrosis, nuclear pyknosis and vacuolation. Spotted catfish channel catfish farming in some parts in China has taken shape, with the promotion of intensive farming techniques, more and more serious diseases, to establish awareness is very important. Serological and molecular biological diagnostic techniques have been successfully used in diagnosis of CCV (Wise, 1985), application for reference. Also worthy of special mention is the world’s first virus recombinant gene and its expression in fishes have been successful (such as Zhang, 1996), which is aimed at the CCV made an important study. This development heralded hopes to use genetically engineered vaccines to prevent viral diseases of fish.