Detection Workflow African Swine Fever Virus

How to detect African Swine Fever virus

African swine fever poses a significant risk to wild boar populations and agricultural meat production. Currently the disease, which is caused by the African Swine Fever (ASF) virus, is spreading more and more in Europe. In Germany, the first case of an ASF infected wild boar was detected in the federal state of Brandenburg in September 2020. The need for safe and rapid detection solutions is constantly increasing. The following article will explain which methods exist and how laboratories can cope with increasing detection requirements.

What is African swine fever?

African swine fever (Pestis Africana Suum) is a viral infection that affects wild and domestic pigs and occurs mainly in Africa. The pathogen settles in the lymph nodes of the animals, multiplies there, then spreads throughout the entire body via the bloodstream and attacks the body organs. The incubation period is between two and 14 days depending on the animal. Affected animals sometimes develop very severe symptoms. The symptoms are similar to those of classical european swine fever, but the two pathogens are not genetically related. Hence, the differentiation between the classical european and the ASF virus can only be made using laboratory diagnostic methods. African swine fever is transmitted by direct contact via secretions, blood or semen of infected animals or via parasites such as ticks carrying infected blood. Indirect transmission via contaminated food waste, utensils, clothing or other equipment is also possible. African swine fever can only be transmitted from animal to animal. For humans and other animal species the disease is harmless. A vaccine does not exist and therapeutic intervention of ASP sick animals is not allowed. African swine fever has been raging in Eastern Europe for some time and has already caused great economic damage as infected animals are killed and trade flows from not disease-free countries to third countries are tightly restricted. However, it is spreading more and more to other regions.

Detection methods

For the detection of an ASF virus infection different methods can be used. Besides virus cultivation in leukocyte cultures, ELISA-based detection of the antigen itself or serological antibody detection, Real-time PCR plays a decisive role due to its enormous specificity and time savings. For this purpose, samples must first be collected. Serum, (EDTA) blood and tissue samples from spleen, lungs and kidneys are suitable as sample material. Then the DNA must be extracted from the starting material. Special extraction kits are used to purify the genetic material of the pathogen from the sample. In order to be able to reliably detect the pathogen sequence in the extracted nucleic acid mixture, only the ASF virus-characteristic sequences are amplified in a highly specific way using primers and enzymes. This amplification is performed by a PCR method (polymerase chain reaction). Fluorescence-labeled probes are used for the detection of the amplification products.

For the molecular biological detection based on PCR or quantitative real-time PCR the general workflow looks the following:

Due to the increasing number of samples to be tested for the ASF pathogen, automation of the detection workflow is often indicated. Automation of workflow routines not only has the advantage of being able to process more samples in less time, automation also increases the reproducibility of results and minimizes the risk of having to repeat measurements.

Workflow solutions from Analytik Jena

Analytik Jena offers various solutions to make the detection workflow more efficient and reliable - from nucleic acid extraction to PCR/real-time PCR and detection.

Sampling

Suitable sample materials include serum, EDTA-stabilized whole blood, tissue samples from spleen, lungs or kidneys.

Nucleic acid extraction

Analytik Jena's portfolio includes extraction platforms and corresponding kits for the extraction of viral DNA from swabs, cell-free body fluids (e.g. serum, plasma, cerebrospinal fluid), tissues, stool samples and more. The kits of the innuPREP AniPath product line are particularly suitable for use with a wide variety of starting materials. They allow the simultaneous extraction of bacterial and viral DNA and/or RNA from the respective starting materials. A detailed overview of the available solutions is shown in the following table.

* launch planned for November 2020