Cercaria

Last updated

A cercaria (plural cercariae) is the larval form of the trematode class of parasites. It develops within the germinal cells of the sporocyst or redia. [1] A cercaria has a tapering head with large penetration glands. [2] It may or may not have a long swimming "tail", depending on the species. [1] The motile cercaria finds and settles in a host where it will become either an adult, or a mesocercaria, or a metacercaria, according to species.

The term Cercaria is also used as a genus name in descriptions of species when only the larval form is known. [3]

Rotifers ( Rotaria rotatoria) produce a chemical, Schistosome Paralysis Factor, suppressing cercaria swimming and reducing infections. [4]

Related Research Articles

<span class="mw-page-title-main">Acanthocephala</span> Phylum of parasitic thorny-headed worms

Acanthocephala is a phylum of parasitic worms known as acanthocephalans, thorny-headed worms, or spiny-headed worms, characterized by the presence of an eversible proboscis, armed with spines, which it uses to pierce and hold the gut wall of its host. Acanthocephalans have complex life cycles, involving at least two hosts, which may include invertebrates, fish, amphibians, birds, and mammals. About 1420 species have been described.

<span class="mw-page-title-main">Rotifer</span> Phylum of pseudocoelomate invertebrates

The rotifers, commonly called wheel animals or wheel animalcules, make up a phylum of microscopic and near-microscopic pseudocoelomate animals.

Veterinary parasitology is a branch of veterinary medicine that deals with the study of morphology, life-cycle, pathogenesis, diagnosis, treatment, and control of eukaryotic invertebrates of the kingdom Animalia and the taxon Protozoa that depend upon other invertebrates and higher vertebrates for their propagation, nutrition, and metabolism without necessarily causing the death of their hosts. Modern parasitology focuses on responses of animal hosts to parasitic invasion. Parasites of domestic animals,, as well as wildlife animals are considered. Data obtained from parasitological research in animals helps in veterinary practice and improves animal breeding. The major goal of veterinary parasitology is to protect animals and improve their health, but because a number of animal parasites are transmitted to humans, veterinary parasitology is also important for public health.

<span class="mw-page-title-main">Digenea</span> Class of flukes

Digenea is a class of trematodes in the Platyhelminthes phylum, consisting of parasitic flatworms with a syncytial tegument and, usually, two suckers, one ventral and one oral. Adults commonly live within the digestive tract, but occur throughout the organ systems of all classes of vertebrates. Once thought to be related to the Monogenea, it is now recognised that they are closest to the Aspidogastrea and that the Monogenea are more closely allied with the Cestoda. Around 6,000 species have been described to date.

<i>Fasciola gigantica</i> Species of fluke

Fasciola gigantica is a parasitic flatworm of the class Trematoda, which causes tropical fascioliasis. It is regarded as one of the most important single platyhelminth infections of ruminants in Asia and Africa. Estimates of infection rates are as high as 80–100% in some countries. The infection is commonly called fasciolosis.

<span class="mw-page-title-main">Trematode life cycle stages</span>

Trematodes are parasitic flatworms of the class Trematoda, specifically parasitic flukes with two suckers: one ventral and the other oral. Trematodes are covered by a tegument, that protects the organism from the environment by providing secretory and absorptive functions.

Schistosoma japonicum is an important parasite and one of the major infectious agents of schistosomiasis. This parasite has a very wide host range, infecting at least 31 species of wild mammals, including 9 carnivores, 16 rodents, one primate (human), two insectivores and three artiodactyls and therefore it can be considered a true zoonosis. Travelers should be well-aware of where this parasite might be a problem and how to prevent the infection. S. japonicum occurs in the Far East, such as China, the Philippines, Indonesia and Southeast Asia.

<i>Schistosoma mansoni</i> Species of fluke

Schistosoma mansoni is a water-borne parasite of humans, and belongs to the group of blood flukes (Schistosoma). The adult lives in the blood vessels near the human intestine. It causes intestinal schistosomiasis. Clinical symptoms are caused by the eggs. As the leading cause of schistosomiasis in the world, it is the most prevalent parasite in humans. It is classified as a neglected tropical disease. As of 2021, the World Health Organization reports that 236.6 million people have schistosomiasis and most of it is due to S. mansoni. It is found in Africa, the Middle East, the Caribbean, Brazil, Venezuela and Suriname.

<span class="mw-page-title-main">Swimmer's itch</span> Medical condition

Swimmer's itch, cercarial dermatitis or schistosome dermatitis is a short-term allergic contact dermatitis occurring in the skin of humans that have been infected by water-borne schistosomes, a type of flatworm. It is common in freshwater, brackish and marine habitats worldwide. The incidence of this condition may be increasing, although this may be attributed to better monitoring and reporting. Nevertheless, the condition is considered to be an emerging infectious disease.

Opisthorchis viverrini, common name Southeast Asian liver fluke, is a food-borne trematode parasite from the family Opisthorchiidae that infects the bile duct. People are infected after eating raw or undercooked fish. Infection with the parasite is called opisthorchiasis. O. viverrini infection also increases the risk of cholangiocarcinoma, a cancer of the bile ducts.

<span class="mw-page-title-main">Thelaziasis</span> Medical condition

Thelaziasis is the term for infestation with parasitic nematodes of the genus Thelazia. The adults of all Thelazia species discovered so far inhabit the eyes and associated tissues of various mammal and bird hosts, including humans. Thelazia nematodes are often referred to as "eyeworms".

Schistosoma mekongi is a species of trematodes, also known as flukes. It is one of the five major schistosomes that account for all human infections, the other four being S. haematobium, S. mansoni, S. japonicum, and S. intercalatum. This trematode causes schistosomiasis in humans.

<i>Biomphalaria pfeifferi</i> Species of gastropod

Biomphalaria pfeifferi is a species of air-breathing freshwater snail, an aquatic animal pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.

Echinostoma cinetorchis is a species of human intestinal fluke, a trematode in the family Echinostomatidae.

<i>Clinostomum marginatum</i> Species of fluke

Clinostomum marginatum is a species of parasitic fluke. It is commonly called the "yellow grub". It is found in many freshwater fish in North America, and no fish so far is immune to this parasite. It is also found in frogs. Clinostomum marginatum can also be found in the mouth of aquatic birds such as herons and egrets. They are commonly present in the esophagus of fish-eating birds and reptiles. Eggs of these trematodes are shed in the feces of aquatic birds and released into water. Aquatic birds become hosts of this parasite by ingesting infected freshwater fish. The metacercariae are found right beneath the skin or in the muscles of host fish.

<i>Philophthalmus gralli</i> Species of fluke

Philophthalmus gralli, commonly known as the Oriental avian eye fluke, parasitises the conjunctival sac of the eyes of many species of birds, including birds of the orders Galliformes and Anseriformes. In Brazil this parasite was reported in native Anseriformes species. It was first discovered by Mathis and Leger in 1910 in domestic chickens from Hanoi, Vietnam. Birds are definitive hosts and freshwater snail species are intermediate hosts. Human cases of philophthalmosis are rare, but have been previously reported in Europe, Asia, and America.

<i>Lernaeocera branchialis</i> Species of crustacean

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 to 3 millimetres when it matures as a copepodid larva to more than 40 mm as a sessile adult.

Microphallus turgidus is a widespread and locally common flatworm parasite in New Zealand lakes and streams. Multilocus allozyme genotype data show that Microphallus turgidus is a single outbred species with high levels of gene flow among South Island populations. Microphallus turgidus is commonly found in the abdominal muscles of grass shrimp.

Acanthoparyphium tyosenense is a species of digenetic trematodes in the family Himasthlidae.

<i>Pseudoterranova</i> Genus of roundworms

Pseudoterranova is a genus within the family Anisakidae of parasitic nematodes with an aquatic life cycle. The lifecycle of Pseudoterranova spp. involves marine mammals, pinnipeds as definitive hosts, planktonic or benthic crustaceans as intermediate hosts and fish which act as second intermediate or paratenic hosts. In some regions, the rise in seal numbers has prefaced a significant increase in fish infected with P. decipiens which is of concern for fish health. Infection with Pseudoterranova may affect the health and swimming ability of the fish host and is therefore of concern for the survival of wild caught and farmed species. Species belonging to this genus have been demonstrated to cause illness of varying exigency in humans if raw or under cooked infected fish is consumed. Cases of human infection have been reported from consuming partially cooked fish infected with Pseudoterranova decipiens, Pseudoterranova cattani and Pseudoterranova azarasi. The propensity of P. decipiens to encyst in the edible portion of fish musculature may make this parasite a considerable threat to human health in undercooked fish.

References

  1. 1 2 "Glossary". VPTH 603 Veterinary Parasitology. University of Pennsylvania School of Veterinary Medicine. Archived from the original on 2011-07-18. Retrieved 2019-05-22.
  2. "Schistosoma". Australian Society for Parasitology. Retrieved 19 February 2011.
  3. "Cercaria Müller, 1773". WoRMS. World Register of Marine Species. 2023. Retrieved 2023-02-26.
  4. Gao, Jiarong; Yang, Ning; Lewis, Fred A.; Yau, Peter; Collins, James J.; Sweedler, Jonathan V.; Newmark, Phillip A. (2019). Khosla, Chaitan (ed.). "A rotifer-derived paralytic compound prevents transmission of schistosomiasis to a mammalian host". PLOS Biology. 17 (10): e3000485. doi: 10.1371/journal.pbio.3000485 . ISSN   1545-7885. PMC   6797223 . PMID   31622335.