How is FIPV produced? How does it develop in the body?

Unfortunately, the pathogenesis of Feline Abdominal Virus is still not fully understood.

According to the currently known research, there are three key features in the development of feline diarrhoea: systemic infection with a virulent strain of FCoV (i.e., FIPV), efficient and sustained replication of FIPV in macrophages, and macrophages infected with FIPV. activation.

Let me tell you about the “speaking people” version.

We all know that when our body is infected with a virus, the immune system will start to work, produce antibodies, and eliminate the virus. The macrophages just mentioned are part of the immune system.

Normally, macrophages can swallow pathogens, and then the internal enzymes will decompose the pathogens, and macrophages will send instructions to other departments of the immune system at the same time, when the virus comes, quickly activate the immune system to eliminate the virus. In simple terms, macrophages are not only the first charge of the army, but also a herald.

Steps for macrophages to ingest pathogens: a. Ingest pathogen 1 through phagocytosis to form phagosome 2. b. Lysosome 3 integrates into phagosome and forms phagosome 4. c. Pathogens are broken down by enzymes and waste materials are excreted or assimilated (the latter is not pictured)

 一个位于老鼠体内的巨噬细胞，正在延伸其假足以吞没两粒可能是病原体的颗粒。

But after encountering Feline Abdominal Virus (FIPV), the situation is different. After FIPV is engulfed by macrophages, not only is it not broken down, but it also uses macrophages to hitchhike into various organs of the human body, and keeps replicating, increasing in number. Of course, the macrophages are not idle, and they are constantly expanding their team to try to kill the virus, but it is useless at all. In this way, the body will produce a large number of ineffective macrophages and immune proteins (this process is also called an inflammatory response), and these things become pyogenic granulomas and effusions (commonly known as ascites).

If Feline Abdominal Virus infects the whole body, macrophages will also form pyogranuloma and effusion in the organs of the whole body, which is why when cats with Feline Abdominal Virus were autopsied, it was found that their organs were commonly Pyogranuloma and ascites effusion.

显微镜下，可以观察到湿性 FIP 患猫积液中含有中性粒细胞 ，巨噬细胞和淋巴细胞