Classic swine fever
The classical swine fever ( CSF ) (also European swine fever (ESP), Swine Fever , Hog Cholera ) than since 1833 infection skrankheit known. This viral infection occurs worldwide with the exception of North America, Australia, New Zealand and parts of Europe and South America. It is one of the most dangerous pig diseases of all and is still difficult to control and not eradicated. Classic swine fever is to be differentiated from African swine fever (ASF). Despite the similar symptoms, ASF and KSP pathogens are not closely related.
In Germany, swine fever is considered an animal disease and must be reported. Control after an outbreak is generally carried out by the veterinary authorities in accordance with the Swine Fever Ordinance.
Cause of illness
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The swine fever pathogen is pestivirus C, also called classic swine fever virus . Pestivirus C , formerly Classical swine fever virus (CSFV) or Hog cholera virus . Although they are related to pathogens in other diseases, no other animal species (including humans) are susceptible.
The wild boar can be regarded as a permanent reservoir of pathogens . In addition to contact with wild boars, the purchase of pigs that are already infected but not visibly sick is often a source of infection. In addition, the virus can also be transmitted through so-called vectors (contaminated vehicles and equipment, clothing or food waste - feeding is therefore prohibited in Germany). Infection within a herd then takes place directly from animal to animal, mainly perorally or via the respiratory tract. The incubation time depends on the virulence of the particular pathogen. It can range from 2 days to over 5 weeks. The virus initially multiplies in the tonsils and the lymph nodes of the pharynx. The pathogen is already in the bloodstream after 24 hours and reaches its maximum concentration within a week. If the pathogen is in the blood, it is constantly excreted in urine, saliva, feces, eye and nasal secretions (until the animal dies). This is also the reason for the epidemic spread of the disease; large herds of several thousand pigs can be completely infected within a week.
Clinical symptoms and course
Swine fever is a disease that is influenced by numerous factors in the sick animal and by the virus. Because of this, the symptoms can be quite complex. Roughly, one can differentiate between two forms: the acute (also classic) form and the atypical (chronic) variant. All pig species are susceptible .
Acute form
This variant is characterized by a high fever (41 ° C), which can drop and rise again in phases as the disease progresses; central nervous disorders (unsteady gait, paresis , ataxia ); pronounced tendency to bleed ( haemorrhages ); cyanotic ( blue-red ) discoloration of the snout, ears and abdomen; frequent occurrence of abortions and noise . Typical changes found in the dissection of sick animals are massive, punctiform bleeding ( petechiae ), altered (clay-colored) kidneys and lymph nodes (“marbled”), damage to the urinary bladder mucosa and the spleen. The direct detection then takes place via immunofluorescence on tissue parts or via direct cultivation of pathogens from the blood.
In the further course of the disease, lung lesions , sometimes vomiting, diarrhea or constipation and severe vascular damage, which lead to disorders of the blood circulation, often join . Death usually occurs from circulatory failure or as a result of secondary bacterial infections.
Chronic form
In contrast to the acute form, the chronic form is relatively mild. The cause of this are often weakly virulent viruses that do not kill the host organism and can therefore reproduce longer and better ( selection advantage, biological selection ). In some places the disease even runs without any visible clinical symptoms, so that the disease is very difficult to identify and, if suspected, can only be diagnosed using (EU-standardized) serological blood tests. Fever (around 40 ° C), gastrointestinal ulcers ( ulcers ), inflammation of the oral mucous membranes, conjunctivitis ( conjunctivitis ) and increased infertility, stillbirths, the birth of mummified or life-weak, trembling piglets occur preferentially . During the dissection, there are solid deposits ( diphtheroid - necrotizing inflammation ) mainly on the mucous membranes of the large intestine and in the area of the oral mucous membranes and in some cases extensive ulcerations (so-called boutons ).
The chronic variant of swine fever is usually survived by the older animals and sometimes leads to complete recovery. Affected piglets care for and usually survive for a maximum of one year.
Prenatal course and late onset of the disease ("late onset disease")
The KSP virus can overcome the placental barrier and infect the fetuses (carrier sow syndrome) in pregnant animals that show only a mild course of the disease (transient infection). Depending on the stage of pregnancy, embryonic or fetal death, abortion and stillbirth, mummification and malformations can occur and can lower the farm's fertility index. However, healthy, persistently viremic piglets can also be born, especially if they are infected before the 90th day of gestation.
prophylaxis
For reasons of trade policy and pharmacological reasons, prophylaxis is not used in the EU .
The only possibility of prophylaxis is vaccination . This was practiced with success in the former Eastern Bloc countries . While the limiting factor at the time was due to the fact that there were no vaccines that were pharmacologically labeled in such a way that they could have been distinguished from the actual virus in a blood test, marker vaccines have been approved in the EU since 2000 . With such a serum, sick pigs could be distinguished from vaccinated pigs. However, in two large-scale trials in Mecklenburg and Brandenburg, neither the eradication of the virus nor the reliable traceability of the antibodies after vaccination with a marker vaccine could be demonstrated. Every vaccination is also associated with problems when the pigs or their carcasses or other products are exported. Since the International Office of Epizootics extends the swine fever status of a country from six to twelve months in the event of a vaccination and this status is of great importance for trade, especially with non-EU countries, many countries still resort to culling infected herds instead of this to vaccinate ( see control).
After a catastrophic outbreak of swine fever in wild boar populations in many parts of Germany in 2003, appropriate vaccination baits were laid out to protect wild boars . These consisted of corn flour, starch, binding agents and other additives and contain a small capsule with the vaccine inside, mostly weakened antigens .
Combat
In Germany, swine fever is notifiable. This means that if there is the slightest suspicion, a report must be made to the appropriate veterinary authority. After notification, the responsible veterinary office takes on the further measures. In accordance with the relevant EU directives, the Animal Disease Act and the ordinance against classic and African swine fever (swine fever ordinance), a first restricted area (around 3 km radius) around the affected population and a further restricted area (observation area) in a larger radius (about 10 km). All pig herds that are within the first restricted area are killed ( culled ) to prevent the disease from spreading further. All pigs within the second barrier ring are constantly examined. Approximately 30 days after the pigs have been killed and disinfected in the first restricted area, blood tests are carried out according to a sample key specified by the EU in order to lift the restricted area.
Cases of swine fever
The epidemic last raged nationwide in the mid-1990s, and there have been isolated cases since then. The 1997 swine fever in the Netherlands killed more than twelve million pigs.
On March 1, 2006, a swine fever test did not yield a clearly negative result for the first time since the 1990s in a fattening farm in Haltern in the Recklinghausen district , North Rhine-Westphalia . Further investigations confirmed the suspicion of swine fever. The outbreak of the KSP was officially confirmed on March 3, 2006, in the course of which more than 92,000 pigs were culled by order of the EU after it spread on other farms, including in the Borken district .
In the edition of the Rhein-Zeitung of February 10, 2009 No. 34 it was reported that the first case of swine fever occurred in a wild boar on the right bank of the Rhine in Rhineland-Palatinate. Laboratory tests confirmed that a dead rookie found in the community of Wissen (Altenkirchen district) had become infected with the ESP virus (European swine fever virus). This means that the Altenkirchen district as well as the Neuwied district and parts of the Westerwaldkreis will be designated as endangered districts by the Koblenz state investigation office.
literature
- Heinrich Liebermann: Textbook of the veterinary virology . Gustav Fischer, Jena and Stuttgart 1992, ISBN 3-334-60360-1
- Hans Plonait, Klaus Bickhardt (starter): Textbook of pig diseases . 4th edition. Parey, Stuttgart 2004, ISBN 3-8304-4104-5
- Diana-Kerstin Schwarz: Swine fever. A contribution to the history of animal diseases . Mensch-und-Buch-Verlag, Berlin 2006, ISBN 3-89820-958-X ( plus dissertation, FU Berlin 2005) - full text
- Erwin Sieverding: Handbook of Healthy Pigs . Kamlage, Osnabrück 2000, ISBN 3-9806688-1-9
- Alarm plan of the state government of Mecklenburg-Western Pomerania regarding the KSP of July 6, 2001
- Today in the Bundestag, message 203/2000 ( Memento from May 13, 2003 in the Internet Archive )
Individual evidence
- ↑ Welcome to the district of Amberg Sulzbach / swine fever. In : kreis-as.de. Retrieved April 6, 2016 .
- ^ Rostock district -. In: landkreis-rostock.de. Retrieved April 6, 2016 .
- ↑ African swine fever - is there a new risk of epidemics for wild boars? In: jagd-freising.de. Retrieved April 6, 2016 .
- ↑ ICTV Master Species List 2018b.v2 . MSL # 34, March 2019
- ↑ a b c d ICTV: ICTV Taxonomy history: Yellow fever virus , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
- ↑ ICTV as of November 2018 according to Smith DB et al : Proposed revision to the taxonomy of the genus Pestivirus, family Flaviviridae
- ↑ The fight against classic swine fever (KSP) in wild boars in the state of Brandenburg Diss. Brigitte Kern
- ↑ Oral immunization of wild boar against classic swine fever in Mecklenburg-Western Pomerania. Diss. Utta Schurig
Web links
Wikinews: Swine Fever - In The News
