CATDOLL : CATDOLL: What are the diagnostic procedures for crayfish diseases and common disease diagnosis methods?

What are the diagnostic procedures for crayfish diseases and common disease diagnosis methods?

Comprehensive judgment of disease diagnosis results

1. Determination of parasitic diseases

If green hair, yellow hair and black dirt are observed on the carapace and tail of crayfish, and protozoa or fungi such as dactyls are found in microscopic examination, it can be determined to be a parasitic disease. If a parasitic disease occurs, the anthelmintic drug Scico can be used.

2. Judgment of black gills

Open the cephalothorax of the crayfish. If you observe that the gill filaments are black or yellow, it can be judged as black gills.

3. Diagnosis of enteritis

The intestine is extracted from the tail segment. If it is observed that there is no food in the intestine, there are vacuoles, congestion (blue blood cells), and the intestine is blue, then the spinal disturbance can be judged as enteritis.

4. Diagnosis of Vibrio disease

If you observe that the crayfish has broken whiskers and claws, black or yellow tips, water accumulation in the tissues at the edge of the tail fan, whitish liver, black gills, low vitality of the stools, and only the large crayfish die, it can be judged that it is Vibrio disease and it is best to do a Vibrio test.

5. Judgment of Vitiligo Syndrome

When peeling off the cephalothorax of crayfish, if you observe spots on the cephalothorax and large areas of death on the shrimp body, it can be diagnosed as white spot syndrome.

Saike Aquatic Animal Health Manufacturer targets various diseases of various aquatic animals.

What protozoa may cause diseases in crayfish?

(1) Microsporidiosis Microsporidiosis is a disease that frequently occurs in crayfish. After the disease occurs, the muscles of the infected crayfish show obvious clinical symptoms of whitening, which can be easily identified. Of course, the above speculation still needs to be supported by experimental results, and no successful experimental reports have been reported so far. By feeding crayfish tissues infected with microsporidia to healthy crayfish of the same species, it has been proven that microsporidia can be successfully transmitted, especially diseases belonging to microsporidia, especially Tehania and Tehania-like. In Europe, the common microsporidia in crayfish are mainly some species of Thelohania and Pleistophora, and Tehania (Thelohania contejeani) is the most common microsporidia.

(2) Gloeosporiasis Recently, the results of the analysis of parasite genes using molecular biological techniques have shown that gloeosporia is a relatively primitive protozoan, and is closely related to other protozoans that are more studied in aquatic animal pathology, such as Dermocystidium, Ichthyophonus, and osetteagent. In Europe, the gloeosporia (Psorospermium haeckeli) that infects crayfish is significantly different from the species that infect Australian crayfish and American crayfish. Although gloeosporia is not highly pathogenic to crayfish, it is often found in large numbers in dead crayfish during crayfish farming. Chang et al. found that among the large number of dead crayfish, all individuals that could be parasitized by gloeosporia were mostly found in the tactile glands accompanied by eye necrosis.

(3) Tetrahymena disease Tetrahymenapyriformis is an opportunistic pathogen of crayfish. It may also infect crayfish when conditions are suitable. Ciliates may invade the hemocoel of crayfish through epidermal wounds and live on the blood cells and tissues of crayfish. Histological observations show that there are usually an astonishing number of ciliates in the hemocoel of crayfish infected with Tetrahymenapyriformis, and this phenomenon can also be found in the gill tissue. In fresh gill tissue, it can also be observed that the parasites move rapidly by relying on cilia, and the circular movement of their cilia damages the gill tissue of crayfish.

(4) Hyalostomycete infection: There have been reports of crayfish being infected with Hyalophysalwoffi on their gills in the United States; however, this parasite is less harmful to crayfish than to other species.

This article is from: China Agricultural Press "China Agricultural Development Report"