Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection.
A pest is any animal or plant detrimental to humans or human concerns, including crops, livestock, and forestry. The term is also used of organisms that cause a nuisance, such as in the home. An older usage is of a deadly epidemic disease, specifically plague. In its broadest sense, a pest is a competitor of humanity.
In biology and medicine, a host is an organism that harbours a parasitic, a mutualistic, or a commensalist guest (symbiont), the guest typically being provided with nourishment and shelter. Examples include animals playing host to parasitic worms, cells harbouring pathogenic (disease-causing) viruses, a bean plant hosting mutualistic (helpful) nitrogen-fixing bacteria. More specifically in botany, a host plant supplies food resources to micropredators, which have an evolutionarily stable relationship with their hosts similar to ectoparasitism. The host range is the collection of hosts that an organism can use as a partner.
Ichthyophthirius multifiliis is an ectoparasite of freshwater fish which causes a disease commonly known as white spot disease, or Ich. Ich is one of the most common and persistent diseases in fish. It appears on the body, fins and gills of fish as white nodules of up to 1 mm, that look like white grains of salt. Each white spot is an encysted parasite. It is easily introduced into a fish pond or home aquarium by new fish or equipment which has been moved from one fish-holding unit or pond to another. When the organism gets into a large fish culture facility, it is difficult to control due to its fast reproductive cycle and its unique life stages. If not controlled, there is a 100% mortality rate of fish. With careful treatment, the disease can be controlled but the cost is high in terms of lost fish, labor, and cost of chemicals.
Trematoda is a class within the phylum Platyhelminthes. It includes two groups of parasitic flatworms, known as flukes.
Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life. This means it forms a synthesis of other disciplines, and draws on techniques from fields such as cell biology, bioinformatics, biochemistry, molecular biology, immunology, genetics, evolution and ecology.
Monogeneans are a group of ectoparasitic flatworms commonly found on the skin, gills, or fins of fish. They have a direct lifecycle and do not require an intermediate host. Adults are hermaphrodites, meaning they have both male and female reproductive structures. Monogeneans have a series of hooks which are used to attach onto fish, and as a result, could lead to infections.
Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an animal cell. Coccidian parasites infect the intestinal tracts of animals, and are the largest group of apicomplexan protozoa.
Myxobolus cerebralis is a myxosporean parasite of salmonids that causes whirling disease in farmed salmon and trout and also in wild fish populations. It was first described in rainbow trout in Germany a century ago, but its range has spread and it has appeared in most of Europe, the United States, South Africa, Canada and other countries. In the 1980s, M. cerebralis was found to require a tubificid oligochaete to complete its life cycle. The parasite infects its hosts with its cells after piercing them with polar filaments ejected from nematocyst-like capsules.
Ceratonova shasta is a myxosporean parasite that infects salmonid fish on the Pacific coast of North America. It was first observed at the Crystal Lake Hatchery, Shasta County, California, and has now been reported from Idaho, Oregon, Washington, British Columbia and Alaska.
Tetracapsuloides bryosalmonae is a myxozoan parasite of salmonid fish. It is the only species currently recognized in the monotypic genus Tetracapsuloides. It is the cause of Proliferative Kidney Disease (PKD), one of the most serious parasitic diseases of salmonid populations in Europe and North America that can result in losses of up to 90% in infected populations.
Babesia, also called Nuttallia, is an Apicomplexan parasite that infects red blood cells, transmitted by ticks. Originally discovered by the Romanian bacteriologist Victor Babeș, over 100 species of Babesia have since been identified.
Protozoan infections are parasitic diseases caused by organisms formerly classified in the Kingdom Protozoa. They include organisms classified in Amoebozoa, Excavata, and Chromalveolata.
Nanophyetus salmincola is a food-borne intestinal trematode parasite prevalent on the Pacific Northwest coast. The species may be the most common trematode endemic to the United States.
Dermocystidium is a genus of cyst forming parasitic eukaryotes of fish, which are the causative agents of dermocystidiosis.
Like humans and other animals, fish suffer from diseases and parasites. Fish defences against disease are specific and non-specific. Non-specific defences include skin and scales, as well as the mucus layer secreted by the epidermis that traps microorganisms and inhibits their growth. If pathogens breach these defences, fish can develop inflammatory responses that increase the flow of blood to infected areas and deliver white blood cells that attempt to destroy the pathogens.
Lernaeocera branchialis, sometimes called cod worm, is a parasite of marine fish, found mainly in the North Atlantic. It is a marine copepod which starts life as a small pelagic crustacean larva. It is among the largest of copepods, ranging in size from 2–3 millimetres when it matures as a copepodid larva to more than 40 millimetres (1.6 in) as an adult.
This article is about diseases and parasites in salmon, trout and other salmon-like fishes of the Salmonidae family.
Scuticociliatosis is a severe and often fatal parasitic infection of several groups of marine organisms. Species known to be susceptible include a broad range of teleosts, seahorses, sharks, and some crustaceans. The disease can be caused by any one of about 20 distinct species of unicellular eukaryotes known as scuticociliates, which are free-living marine microorganisms that are opportunistic or facultative parasites. Scuticociliatosis has been described in the wild, in captive animals in aquariums, and in aquaculture. It is best studied in fish species that are commonly farmed, in which typical effects of infection include skin ulceration, hemorrhage, and necrosis, with post-mortem examination identifying ciliates in the skin, gills, blood, and internal organs including the brain.
