(1) Microsporidiosis is a common disease of crayfish, because after the occurrence of this disease, the diseased crayfish muscles show obvious clinical symptoms of albinism, which is easy to be identified. Of course, the above speculation needs to be supported by test results, and there is no successful test report so far. By feeding the tissues of crayfish infected with microspores to the same kind of healthy crayfish, it is proved that microspores can be successfully transmitted and infected, especially the diseases belonging to microsporidia, especially Tethys and similar Tethys. In Europe, the common microsporidia of crayfish mainly include Thelohania and some Pleistocene species, and Thelohaniacontejeani is the most common microsporidia.

(2) Coccidiosis Recently, the results of genetic analysis of parasites by using molecular biology technology show that coccidiosis is a relatively primitive protozoa, which is closely related to other protozoa that have been studied more in aquatic animal pathology, such as tunicates, ichthyozoites and osetteagent. In Europe, the species of crayfish infected with Psorospermiumhaeckeli are obviously different from those infected with Australian crayfish and American crayfish. Although cryptosporidium is not highly pathogenic to crayfish, it is often found that a large number of cryptosporidium can be detected in dead shrimp during crayfish culture. In a large number of dead crayfish, most individuals who can detect cryptosporidium parasitism exist in the tactile gland of eyeball necrosis.

(3) Tetrahymena is the conditional pathogen of crayfish. Crayfish may also be infected when conditions are suitable. Ciliates may invade the blood cavity of crayfish through epidermal wounds and feed on crayfish blood cells and their tissues. Histological observation shows that crayfish infected with Tetrahymena pyriformis usually have a surprising number of ciliates in the blood cavity, and this phenomenon can also be found in gill tissue. In fresh gill tissue, it can also be observed that parasites move rapidly by cilia, and the gill tissue of crayfish is destroyed with the circular movement of its cilia.

(4) Infection of Oral Worms In the United States, crayfish have been reported to be infected with Hyalophysalwoffi. However, compared with other species, this parasite is very harmless to crayfish.

The content of this article comes from: China Agricultural Development Report by China Agricultural Publishing House.