Grass carp farming bosses know that "grass carp hemorrhagic disease has a wide range of transmission, great harm, high mortality rate, and has a great impact on grass carp farming"!
Pathogenesis of grass carp hemorrhagic disease
The causative agent of grass carp bleeding disorder is grass carp reovirus, which is mainly transmitted by water bodies and parasites. The onset is most severe at water temperatures of 25-30 °C. Grass carp hemorrhagic disease has two obvious peak periods throughout the year: the first peak period is from the beginning of June to the beginning of July, when the water temperature exceeds 25 ° C, and the grass carp hemorrhagic disease is serious, mainly endangering the second-instar grass carp; The second peak period is from September to October, when the water temperature drops below 30°C, mainly affecting first-in-year grass carp, and the mortality rate is as high as 90%.
Grass carp hemorrhagic disease symptoms:
Sick fish will appear black in color, especially the head is most obvious. Some fish will have a loss of appetite, while others will eat normally, but they will die every day.
