How strong is the adhesion of swine fever virus? How strong is the ability of items that come into direct contact with or carry the virus to spread again? Not yet clear. At present, it is known that swine fever is a highly contagious acute disease, mainly transmitted through contact or ingestion of items contaminated with swine fever virus, as well as through insect blood sucking. This disease can be indirectly transmitted over short distances through airborne transmission, contaminated feed, swill, leftovers and meat scraps, fences, vehicles, utensils, and clothing. Today we will mainly introduce the confirmation method of the window period in swine fever detection.
There are many methods to confirm whether pigs are in the window period, but the currently mature method is still qualitative or quantitative polymerase chain reaction (PCR).
The selection of test samples is based on research data. Both oral and nasal swabs can be used as window period test samples, but fresh secreted saliva often has significant detection advantages, as its virus content is much higher than that of oral and nasal swabs. The average value of African swine fever virus in freshly secreted saliva is about 5 lower than that in mouth and nose swabs.
Pigs in the window period of saliva sample processing still have strong specific and non-specific immune abilities, and the body has a strong ability to clear viruses. The two are in a state of confrontation, mainly due to the high activity of enzymes (lysozyme, nuclease, alkaline phosphatase, etc.) in saliva. If the amount of African swine fever virus collected in saliva is too low, the virus will be quickly degraded by saliva. Therefore, the collected saliva should be protected with nucleic acid.
Saliva sample testing requires strict testing conditions due to the low content of African swine fever virus in saliva samples during the window period. It is recommended to compare and evaluate the testing environment (temperature, air, water, operating table), testing reagent kit, and testing instruments, and choose carefully. In order to obtain a good saliva sample, animals need to be fasted for 12 hours before sampling.
Research has confirmed that the virus content of African swine fever virus in saliva from test tubes is much higher at the bottom than in the supernatant of the test tube when in a static or centrifuged state. Therefore, it is recommended to take samples from the bottom of the test tube for testing.
Before implementing laboratory testing work, it is recommended to provide scientific sampling and sampling training to operators. Only after passing the training can they be allowed to engage in testing work.
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