Classical swine fever (CSF) or hog cholera (also sometimes called pig plague based on the German word ) is a highly contagious disease of
swine (
Old World
The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...
and
New World pigs).
[ It has been mentioned as a potential ]bioweapon
A biological agent (also called bio-agent, biological threat agent, biological warfare agent, biological weapon, or bioweapon) is a bacterium, virus, protozoan, parasite, fungus, or toxin that can be used purposefully as a weapon in bioterrorism ...
.
Clinical signs
Swine fever causes fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
, skin lesions
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this sy ...
, convulsion
A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is sometimes used as a s ...
s, splenic infarction
Infarction is tissue death (necrosis) due to inadequate blood supply to the affected area. It may be caused by artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as an infarct
(from the ...
s and usually (particularly in young animals) death
Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
within 15 days.
The disease has acute and chronic forms, and can range from severe, with high mortality, to mild or even unapparent.
In the acute form of the disease, in all age groups, there is fever, huddling of sick animals, loss of appetite, dullness, weakness, conjunctivitis, constipation followed by diarrhoea, and an unsteady gait. Several days after the onset of clinical signs, the ears, abdomen and inner thighs may show a purple discoloration. Animals with acute disease die within 1–2 weeks. Severe cases of the disease appear very similar to African swine fever. With low-virulence strains, the only expression may be poor reproductive performance and the birth of piglets with neurologic defects such as congenital tremor.
Immunization
A small fraction of the infected pigs may survive and are rendered immune. Artificial immunization procedures were first developed by Marion Dorset.
Epidemiology
The disease is endemic in much of Asia, entral and South America, and parts of Europe and Africa. It was believed to have been eradicated in the United Kingdom by 1966 (according to the Department for Environment, Food and Rural Affairs), but an outbreak occurred in East Anglia in 2000. On January 31, 1978 United States Department of Agriculture, USDA Secretary Bob Bergland declared that the United States was free of the disease. The appearance of CSF in Italy and Spain was traced by in a retroactive genetic analysis. Greiser-Wilke ''et al.'', 2000 traced these to shipments of piglets from the Netherlands.
Other regions believed free of CSF include Australia, Belgium (1998), Canada (1962), Ireland, New Zealand, and Scandinavia.
Virus
The infectious agent responsible is a virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
CSFV (previously called hog cholera virus) of the genus ''Pestivirus
''Pestivirus'' is a genus of viruses, in the family ''Flaviviridae''. Viruses in the genus ''Pestivirus'' infect mammals, including members of the family Bovidae (which includes cattle, sheep, and goats) and the family Suidae (which includes var ...
'' in the family ''Flaviviridae
''Flaviviridae'' is a family of enveloped positive-strand RNA viruses which mainly infect mammals and birds. They are primarily spread through arthropod vectors (mainly ticks and mosquitoes). The family gets its name from the yellow fever virus ...
''.[Classical Swine Fever]
The Center for Food Security and Public Health / The Institute for International Cooperation in Animal Biologics, College of Veterinary Medicine, Iowa State University
Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the n ...
, update September 2009. CSFV is closely related to the ruminant pestiviruses that cause bovine viral diarrhoea and border disease.
The effect of different CSFV strains varies widely, leading to a wide range of clinical signs. Highly virulent strains correlate with acute, obvious disease and high mortality, including neurological
Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal ...
signs and hemorrage
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
s within the skin.
Less virulent strains can give rise to subacute or chronic infections that may escape detection, while still causing abortions and stillbirths. In these cases, herds in high-risk areas are usually serologically tested on a thorough statistical basis.
Infected piglets born to infected but subclinical sows help maintain the disease within a population. Other signs can include lethargy, fever, immunosuppression, chronic diarrhoea, and secondary respiratory infections. The incubation period of CSF ranges from 2 to 14 days, but clinical signs may not be apparent until after 2 to 3 weeks. Preventive state regulations usually assume 21 days as the outside limit of the incubation period. Animals with an acute infection can survive 2 to 3 months before their eventual death.
Eradicating CSF is problematic. Current programmes revolve around rapid detection, diagnosis, and slaughter. This may possibly be followed by emergency vaccination (ATCvet
The Anatomical Therapeutic Chemical (ATC) Classification System is a drug classification system that classifies the active ingredients of drugs according to the organ or system on which they act and their therapeutic, pharmacological and chemical p ...
codes: for the inactivated viral vaccine, for the live vaccine). Vaccination is only used where the virus is widespread in the domestic pig population and/or in wild or feral pigs. In the latter case, a slaughter policy alone is usually impracticable. Instead, countries within the EU have implemented hunting restrictions designed to limit the movement of infected boars, as well as using marker and emergency vaccines to inhibit the spread of infection. Possible sources for maintaining and introducing infection include the wide transport of pigs and pork products, as well as endemic CSF within wild boar and feral pig populations.
Strains
* 1 including 1.1, 1.2, 1.3, 1.4, the unassigned 1.x
* 2 including 2.1, 2.2, 2.3
* 3 including 3.1, 3.2, 3.3, 3.4
Diagnosis
Standard diagnostic tests include:
* Fluorescent antibody test (FAT) detection of viral protein using fluorescent labelled antibodies in tissue
* Serum Enzyme-linked-immunosorbent assay (ELISA
The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence ...
) detection of host animal antibody response in serum samples.
* Antigen ELISA
The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence ...
detection of viral protein (antigen) in serum samples.
* RT-qPCR
A real-time polymerase chain reaction (real-time PCR, or qPCR) is a laboratory technique of molecular biology based on the polymerase chain reaction (PCR). It monitors the amplification of a targeted DNA molecule during the PCR (i.e., in real ...
test detection of viral RNA in samples, especially useful to differentiate strains. Direct genetic typing for CSF was first developed by Greiser-Wilke ''et al.'', 2000 to trace descendants of the 1997-1998 EU epizootic
In epizoology, an epizootic (from Greek: ''epi-'' upon + ''zoon'' animal) is a disease event in a nonhuman animal population analogous to an epidemic in humans. An epizootic may be restricted to a specific locale (an "outbreak"), general (an "epi ...
.
* Virus isolation isolation of virus in cell culture.
Histopathological examination:
* Histology of the brain shows vasculoendothelial proliferation and perivascular cuffing (cuffing is highly suggestive when accompanied by other signs, but is not pathognomonic for the disease).
See also
* 2007 Central Luzon hog cholera outbreak
* Animal viruses
Veterinary virology is the study of viruses in non-human animals. It is an important branch of veterinary medicine.
Rhabdoviruses
Rhabdoviruses are a diverse family of single stranded, negative sense RNA viruses that infect a wide range of ho ...
References
External links
CSF page of Pig Disease Information Centre (UK)
Current status of Classical Swine Fever worldwide
at OIE. WAHID Interface – OIE World Animal Health Information Database
Technical Disease card
World Organisation for Animal Health
European Commission Animal Health & Welfare on CSF
Classical swine fever: how to spot and report the disease
United Kingdom Department for Environment, Food & Rural Affairs
Animal and Plant Health Inspection Service: Classical Swine Fever
United States Department of Agriculture
(Bloomington, Illinois newspaper)
Center for Food Security and Public Health: Classical Swine Fever
Iowa State University
Species Profile – Classical Swine Fever
National Invasive Species Information Center, United States National Agricultural Library
The United States National Agricultural Library (NAL) is one of the world's largest agricultural research libraries, and serves as a national library of the United States and as the library of the United States Department of Agriculture. Located ...
.
{{DEFAULTSORT:Classical Swine Fever
Swine diseases
Animal viral diseases
Pestiviruses
Biological anti-agriculture weapons
Flaviviridae