Analysis of fish disease pathogen

Disease of freshwater fishes in China has more than 100, and the shrimp disease, disease frog, turtle disease and aquaculture fish disease, kinds is more, the pathogens are viruses, bacteria, fungi, algae, protozoa and trematodes, nematodes, Acanthocephala, tapeworm, leeches, the Glochidia larvae, crustaceans and other. Some of these pathogens often make the fish sick, causing many diseases, common diseases,
In aquaculture water, if there is no pathogen, or at least pathogens control in the degree of damage to the extent of the following, fish and aquatic animal diseases will not occur, the pathogen is parasitic organisms, they can not survive or thrive in the environment of the outside world, and must be in the main body of the breeding. Source of infection of pathogenic diseases come from the fish, especially parasitic pathogens and not a moment in the pathogenesis of carry pathogens, pathogenic spread faster and more subtle. Some parasitic diseases infectious bird. Animals and humans, such as export trematodes, ligulosis source of infection is of European birds, herons and other birds, fish Clonorchis vampire disease to infect a source are cats, dogs and other mammals, the human body is also infected with the disease, the original Hugh reports, some fish parasites, the developmental stage of the larval stage is spent in birds, animals or humans, so bird, animal or human has become some fish parasitic disease to infect a source,
Fish pathogens discharged into the water, with water irrigation and drainage into other aquaculture water, the waters of the original pathogen becomes foci.
Contagious pathogens and the strength of the pathogen in the host settle, reproduction and discharged from the host number has a close relationship, is conducive to the parasite growth and reproduction of the environment, the infectious force will be very strong; on the contrary, the drugs to kill and ecological methods inhibition of pathogen activity make it infectious reduction or elimination of pathogens, is not conducive to the parasite growth and reproduction, fish has a chance of less.
The virulence of the pathogen is the ability of the pathogen to cause disease, and it is determined by the number of pathogens. The number of species in the living environment, the virulence of pathogenic bacteria and the strong and weak points. Larger number of pathogens in fish, fish disease symptoms of more serious, such as more than 10 Chinese) parasitic in 2nd instar gill of grass carp, grass carp and no significant response to the disease; and when hundreds of parasites in strontium grass carp, it will cause the gill filaments to inflammation of the end, pale and swollen, bending deformation, anemia, sick fish irritability, but also in wound bacterial infection, concurrent disease caused by bacteria, serious will cause mass mortality of grass carp.
The pathogen is the result of a prerequisite for the occurrence of fish diseases. Cut off pathogens in aquaculture water route of infection, or according to the characteristics of pathogen infectivity and pathogenicity, targeted for ecological control, drug prevention and immune prevention, reduce fish, its control below the extent of damage, in order to reduce economic losses.