What is pathogens and disease?

Answer 1

Farmed aquatic animals are subject to the same diseases that occur naturally in wild aquatic animals. Unfortunately, knowledge about the interaction between pathogens of wild aquatic animals and aquacultured animals is poor. Because aquacultured animals receive considerably more scrutiny than their wild counterparts, more is known about diseases under aquaculture conditions. Wild fishes are often the source of pathogens causing disease in domesticated species. There are several protozoan parasites, for example, that are resident or endemic in wild fish. These fish may seed parasites into the water that supply an aquaculture facility. The cause of "Ich" (Ichthyopthirius multifiliis) is a classic example. Almost anyone who has a home aquarium has seen Ich breakout when a new fish or aquarium plant is brought in. Birds or other animals may seed the facility with a new pathogen. Similar concerns occur in agriculture where wild bison or elk may serve as a potential reservoir for the organisms causing brucellosis in hoofed domesticated animals. It is because the aquacultured animals are closely confined, that disease may move through a population quickly. The US Fish and Wildlife Service (USFWS) has recently set out to determine the prevalence of various fish pathogens in wild fish populations. This effort is required to increase knowledge about the interaction of aquatic animal pathogens between wild and aquacultured animals and provide a better accounting of where pathogens occur naturally. The NAA supports these efforts. Treatment of aquatic animal diseases is difficult. The FDA closely regulates availability of drugs used by aquaculturists. There are only two antibacterial drugs available (Terramycin® and Romet-30®) in the US and these cannot be used for all aquatic species. Several microbicides can be used by aquaculturists including salt (NaCl), iodine (to treat eggs), and copper (EPA approved to treat algae). It is incumbent on each aquaculturist to use these compounds according to state or federal toxics criteria. Various efforts are underway, supported by the FDA, USDA, public and commercial interests to alleviate the lack of drugs or chemicals, but it is a formidable task. The high cost of drug approval is a significant barrier and there is a considerable disparity in the availability of aquatic animal drugs between the US and other countries. Additional efforts are being directed at harmonizing use of drugs internationally. These efforts are being encouraged by the FDA and the NAA. Because drugs should only be used as a last resort, enhanced husbandry (integrated fish health management) and vaccination of aquatic animals against specific pathogens are used for disease prevention. The NAA supports additional efforts directed toward these important farming practices. The commercial aquaculture industry is concerned about the importation of exotic pathogens into the US. Current regulation of imported animals, including pathogens, under 50 CFR Part 16 and the Lacey Act may not be adequate to protect our resources nor to foster US aquaculture. The NAA, in association with the National Association of State Aquaculture Coordinators (NASAC), is coordinating efforts to further minimize the importation of injurious pathogens. These two groups are working closely to help establish a coherent national aquatic animal health management program. The commercial aquaculture industry expects to work closely with the US Department of Agriculture Animal Plant Health Inspection Service (USDA-APHIS) and the Office of International Epizootics (OIE) in this effort.

Answer 2

Pathogens are the smallest microscopic form of life