Kinetoplastida is a group of flagellated protists belonging to the phylum Euglenozoa, and characterised by the presence of a distinctive organelle called the kinetoplast, a granule containing a large mass of DNA. The group includes a number of parasites responsible for serious diseases in humans and other animals, as well as various forms found in soil and aquatic environments. The organisms are commonly referred to as "kinetoplastids" or "kinetoplasts".
The peritrichs are a large and distinctive group of ciliates.
Ichthyophthirius multifiliis, often termed "Ich", is a parasitic ciliate described by the French parasitologist Fouquet in 1876. Only one species is found in the genus which also gave name to the family. The name literally translates as "the fish louse with many children". The parasite can infect most freshwater fish species and, in contrast to many other parasites, shows low host specificity. It penetrates gill epithelia, skin and fins of the fish host and resides as a feeding stage inside the epidermis. It is visible as a white spot on the surface of the fish but, due to its internal microhabitat, it is a true endoparasite and not an ectoparasite.
Monogeneans, members of the class Monogenea, 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.
Stylonychia is a genus of ciliates, in the subclass Hypotrichia. Species of Stylonychia are very common in fresh water and soil, and may be found on filamentous algae, surface films, and among particles of sediment. Like other Hypotrichs, Stylonychia has cilia grouped into membranelles alongside the mouth and cirri over the body. It is distinguished partly by long cirri at the posterior, usually a cluster of three. The largest can just be seen at a 25x magnification, and the smallest can just be seen at a 450x magnification.
Vorticella is a genus of bell-shaped ciliates that have stalks to attach themselves to substrates. The stalks have contractile myonemes, allowing them to pull the cell body against substrates. The formation of the stalk happens after the free-swimming stage.
Cryptocaryon irritans is a species of ciliates that parasitizes marine fish, causing marine white spot disease or marine ich. It is one of the most common causes of disease in marine aquaria.
The Cymothoidae are a family of isopods in the suborder Cymothoida found in both marine and freshwater environments. Cymoithoids are ectoparasites, usually of fish, and they include the bizarre "tongue-biter", which attaches to a fish's tongue, causing it to atrophy, and replaces the tongue with its own body. Ceratothoa oestroides is one of the most devastating ectoparasites in Mediterranean aquaculture. Around 40 genera and more than 380 species of cymothoid are recognised. Species of the Cymothoidae are generally found in warmer waters and rarely in the cool and cold climates.
Dactylogyrus vastator is a species of monoic flatworms of class Monogenea. It is an ectoparasite of fish which infests the gills. It is problematic on fish farms. It is otherwise non-hazardous to humans.
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group and are variously used in swimming, crawling, attachment, feeding, and sensation.
Trichodinidae is a family of ciliates of the order Mobilida, class Oligohymenophorea. Members of the family are ectoparasites of a wide variety of aquatic organisms, including fish, amphibians, hydrozoans, molluscs and crustaceans.
Mobilida is a group of parasitic or symbiotic peritrich ciliates, comprising more than 280 species. Mobilids live on or within a wide variety of aquatic organisms, including fish, amphibians, molluscs, cnidarians, flatworms and other ciliates, attaching to their host organism by means of an aboral adhesive disk. Some mobilid species are pathogens of wild or farmed fish, causing severe and economically damaging diseases such as trichodinosis.
Cothurnia is a genus of freshwater and marine peritrichs in the family Vaginicolidae. It is characterised by living in a transparent tubular lorica. During the feeding or vegetative phase of its life cycle, Cothurnia attaches to submerged surfaces through a short stalk — mostly on the surfaces of fishes, crustaceans and aquatic plants. It is commonly studied for its epibiotic relationship with the host that it is attached to.
Licnophora is a genus of ciliates in the family Licnophoridae. They typically have an hourglass-like shape and live as ectocommensals on marine animals.
Miamiensis avidus is a species of unicellular marine eukaryote that is a parasite of many different types of fish. It is one of several organisms known to cause the fish disease scuticociliatosis and is considered an economically significant pathogen of farmed fish. M. avidus is believed to be the cause of a 2017 die-off of fish and sharks in the San Francisco Bay.
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.
Zoothamnium is a genus of ciliate protozoan.
Neobodo are diverse protists belonging to the eukaryotic supergroup Excavata. They are Kinetoplastids in the subclass Bodonidae. They are small, free-living, heterotrophic flagellates with two flagella of unequal length used to create a propulsive current for feeding. As members of Kinetoplastids, they have an evident kinetoplast There was much confusion and debate within the class Kinetoplastid and subclass Bodonidae regarding the classification of the organism, but finally the new genera Neobodo was proposed by Keith Vickerman. Although they are one of the most common flagellates found in freshwater, they are also able to tolerate saltwater Their ability to alternate between both marine and freshwater environments in many parts of the world give them a “cosmopolitan” character. Due to their relatively microscopic size ranging between 4–12 microns, they are further distinguished as heterotrophic nanoflagellates. This small size ratio limits them as bacterivores that swim around feeding on bacteria attached to surfaces or in aggregates.
Stentor roeselii is a free-living ciliate species of the genus Stentor, in the class Heterotrichea. It is a common and widespread protozoan, found throughout the world in freshwater ponds, lakes, rivers and ditches.
Sparicotyle chrysophrii is a species of monogenean, parasitic on the gills of the marine fish. It belongs to the family Microcotylidae. Its type-host is the gilt-head seabream.
