1. Pathogen: Crab slaves, also known as *Aercus* sp., are parasitic organisms that infect Chinese mitten crabs. These parasites are microscopic and can cause serious health issues in the host. 2. Symptoms: The disease caused by crab slaves is commonly referred to as "crab slave disease." Affected crabs show slight swelling in the abdominal area, and when the navel is opened, small, milky or translucent granular bodies can be observed. Infected crabs often have difficulty distinguishing between males and females. Male crabs typically have an oval-shaped navel, smaller chelae (claws), and less hair on their legs. Diseased crabs grow slowly, lose reproductive ability, and may develop a peculiar taste, making them inedible. In severe cases, the crabs become weak and unmarketable. 3. Epidemic Situation: This disease is prevalent in provinces such as Shanghai, Hubei, and Anhui, with a particularly high incidence rate among Chinese mitten crabs in coastal areas. When infected crabs are raised in inland freshwater environments, the crab slaves can only form endosomes and exosomes, but they cannot reproduce larvae after infection. Within the same water body, female crabs tend to have a higher infection rate than males. The disease becomes more common starting in July, peaks in September, and gradually declines after October. As the infection progresses, the outer shell of the crabs softens, and eventually, only black spots remain after the crab slaves detach from the host. 4. Diagnosis: A preliminary diagnosis can be made based on the visible symptoms. For confirmation, a microscope is used to examine the granular bodies found inside the crab's abdomen. This helps distinguish the presence of crab slaves from other potential causes of similar symptoms. 5. Treatment: Currently, there is no effective treatment for crab slave disease. Prevention is the most important strategy. Some key preventive measures include: (1) Introducing healthy crab seedlings from non-infected regions or selecting only healthy crabs for artificial breeding programs.
(2) Raising Chinese mitten crabs in clean, fresh water to reduce the risk of parasite transmission.
(3) Manually removing white-point crab exosomes using a fine needle. After removal, 0.8 grams of copper sulfate per cubic meter of water can be applied for about 30 minutes. This method has shown a more noticeable improvement in affected crabs. It’s crucial for farmers and aquaculture operators to remain vigilant and implement strict biosecurity measures to prevent the spread of this disease. Regular monitoring and early detection are essential to maintaining healthy crab populations and ensuring sustainable production. rosehip tea,organic rose petals,rose petal tea ZHONGSHAN G.H.L. TRADING CO., LTD. , https://www.ghltrade.com