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AFRICAN SWINE FEVER, THE VIRUS

The African swine fever virus originates in African countries.

Here, warthogs are particularly affected, but they do not become ill.

The virus was probably introduced into Europe via the disposal of infectious food waste to which wild boar had access.

 

Infection with African swine fever (ASF) causes severe disease in both domestic pigs and wild boar, and is almost always fatal.

African swine fever is notifiable and cannot be clinically distinguished from classical swine fever (CSF).

Currently, no vaccine against ASF is available. Because infection occurs primarily through blood, blood-bearing fluids, and blood-bearing tissues, infection often spreads very slowly.

However, very small amounts of blood are sufficient for infection.

The ASF virus is exceptionally resistant to environmental factors and is therefore difficult to control. 

 

The life span of the ASF virus (maximum values):

* 3 hours at 50° C heating

5 weeks in refrigerated meat

* 6 weeks in preserved ham

* 70 days in blood (room temperature)

* 18 months in refrigerated blood

* many years in frozen carcasses.

 

The spread of the virus

African swine fever (ASF) is endemic in many sub-Saharan African countries.

Since 2007, it has also been spreading in feral pig populations in many regions of Eastern Europe, (Hungary, Poland, Baltic States, Moldova, Romania, Bulgaria, Belarus, Russian Federation, Ukraine, Georgia, Armenia and Azerbaijan). 

In many cases, domestic pig herds were also infected with ASF in these countries.

 

In September 2018, the virus was detected in wild swine herds in Belgium, and in November 2019, it was detected in western Poland, less than 50 km from the German border.

 

ASF infections in these countries are caused by virus strains originating from a genotype 2 virus introduced into Georgia in 2007.

In some cases, the infection is spreading massively in the affected countries.

 

On the Italian island of Sardinia, African swine fever has been present for decades.

The outbreak there is caused by a different virus strain (genotype 1) and is therefore not related to the outbreaks mentioned above.

 

In Germany, ASF was officially detected in domestic pigs in Brandenburg in July 2021 and in Mecklenburg-Vorpommern in November 2021. This was followed by another case in a domestic pig farm in Baden-Württemberg in May 2022 and two more in Niedersachsen and Brandenburg in July 2022.

 

Disease pattern

The clinical picture of ASF is non-specific, (high fever, loss of appetite, respiratory and gastrointestinal symptoms, skin discoloration, movement disorders, recumbency) and can be confused with many other infectious diseases of pigs.

Death usually occurs within 7-10 days of onset.

A definite diagnosis can only be made in the laboratory.

Therefore, if the herd is characterized by highly febrile animals and increased mortality, you should contact your veterinarian immediately.

Early sampling with exclusion diagnostics in the laboratory could quickly detect a disease and quickly contain a possible epidemic.

 

There is currently no vaccination against ASF.

Therefore, prevention against ASF is the most important approach. 

 

Transmission

ASF is transmitted either by direct animal-to-animal contact or indirectly by contact with virus-contaminated persons, clothing, feed, slaughterhouse/food waste, food, slurry/manure, and other equipment or vehicles (livestock transporters).

A major risk of infection is posed in particular by the blood of infected animals or objects contaminated with the infected blood.

 

The European Food Safety Authority (EFSA) has released an English-language educational film titled

"African Swine Fever:  how to stay one step ahead"