Eimeria falciformis | |
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Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Alveolata |
Phylum: | Apicomplexa |
Class: | Conoidasida |
Order: | Eucoccidiorida |
Family: | Eimeriidae |
Genus: | Eimeria |
Species: | E. falciformis |
Binomial name | |
Eimeria falciformis Eimer, 1870 | |
Synonyms | |
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Eimeria falciformis is an obligate intracellular parasite that primarily infects the mouse species Mus musculus . [1] As part of the Apicomplexa phylum, it has a complex life cycle within its host, causing tissue necrosis and inflammation, particularly in the cecum. This leads to coccidiosis, a disease characterized by symptoms like diarrhoea and weight loss. E. falciformis is one of over 1,700 species in the Eimeria genus, which infects the intestinal epithelial cells of various animals, including poultry and livestock.
Transmission occurs via oocysts, which are shed in faeces. Under suitable environmental conditions—such as proper temperature, humidity, and oxygen levels—these oocysts sporulate. [2] When a new host ingests sporulated oocysts, sporozoites are released and invade the cecal epithelial cells. Inside the host, sporozoites develop into trophozoites and then merozoites, which undergo rounds of asexual reproduction (schizogony), leading to host cell rupture. Some merozoites become sexual gametes, which fuse to form unsporulated oocysts. These are excreted in faeces, completing the life cycle. [3]
Infected mice develop coccidiosis, which manifests through diarrhoea and weight loss due to cecal epithelial destruction. Disease severity depends on factors such as infection dose, the host's age, and immune status. The short, single-host (monoxenous) life cycle of E. falciformis makes it a valuable model for studying parasitic infections and host-parasite interactions in vivo. [4]
The Eimeria falciformis–mouse model is widely used to study intracellular parasitism, including schizogony, gametogenesis, and oocyst formation. It provides valuable insights into coccidiosis in poultry and livestock caused by other Eimeria species. Researchers also use this model to study host-pathogen interactions, mucosal immunity, and immune responses to parasitic infections. [5]
With a relatively small genome of 44 Mb across 14 chromosomes, E. falciformis has been the focus of genomic studies that reveal its adaptation to a single host. Research shows that it exploits host metabolic pathways, such as tryptophan catabolism, to sustain its life cycle. The E. falciformis model remains central to efforts aimed at developing antiparasitic treatments for coccidiosis in economically important animals. [6]
Isosporiasis, also known as cystoisosporiasis, is a human intestinal disease caused by the parasite Cystoisospora belli. It is found worldwide, especially in tropical and subtropical areas. Infection often occurs in immuno-compromised individuals, notably AIDS patients, and outbreaks have been reported in institutionalized groups in the United States. The first documented case was in 1915. It is usually spread indirectly, normally through contaminated food or water (CDC.gov).
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.
Eimeria tenella is a species of Eimeria that causes hemorrhagic cecal coccidiosis in young poultry. It is found worldwide.
Eimeria is a genus of apicomplexan parasites that includes various species capable of causing the disease coccidiosis in animals such as cattle, poultry and smaller ruminants including sheep and goats. Eimeria species are considered to be monoxenous because the life cycle is completed within a single host, and stenoxenous because they tend to be host specific, although a number of exceptions have been identified. Species of this genus infect a wide variety of hosts. Thirty-one species are known to occur in bats (Chiroptera), two in turtles, and 130 named species infect fish. Two species infect seals. Five species infect llamas and alpacas: E. alpacae, E. ivitaensis, E. lamae, E. macusaniensis, and E. punonensis. A number of species infect rodents, including E. couesii, E. kinsellai, E. palustris, E. ojastii and E. oryzomysi. Others infect poultry, rabbits and cattle. For full species list, see below.
Cryptosporidium parvum is one of several species that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract.
Eimeria stiedae is a species of Eimeria that causes hepatic coccidiosis in rabbits. It was observed for the first time by Antonie van Leeuwenhoek in 1674.
Megaloschizonts are large schizonts that produce extremely high numbers of merozoites. They are found in various species of the Phylum Apicomplexa. The Apicomplexa phylum contains several parasitic protozoans. They have a very complex life cycle that includes several stages. Megaloschizonts and the smaller schizonts are the part of the life cycle that takes place inside the infected host organism and operates as an asexually reproductive cell. Megaloschizonts appear as grey-white nodules found in the smooth muscle of major organs, such as the heart, liver, lung or spleen.
Karyolysus is a genus of coccidia. With the exception of K. sonomae whose vertebrate host is the yellow-legged frog, species in this genus only infect lizards of the genus Lacerta.
Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism is typified by a cellular variety with a distinct morphology and biochemistry.
Isospora hammondi is an apicomplexan parasite of the genus Isospora that infects the marsh rice rat. It was discovered at Tuskegee National Forest, Macon County, Alabama, and formally described in 1971. The specific name honors Dr. Datus M. Hammond of Utah State University.
Polychromophilus is a genus of obligate intracellular eukaryotic parasites that infect bats from every continent except Antarctica. They are transmitted by bat flies, which act as an insect vector as well as the parasite’s site of sporogeny. Polychromophilus follows a fairly typical Haemospororidian lifecycle, with gametocytes and gametes restricted to the bloodstream of the host and meronts infecting organs – most notably the lungs and the liver. The type species is Polychromophilus melanipherus, and was described by Dionisi in 1898.
Dactylosoma is a genus of parasitic alveolates of the phylum Apicomplexa.
The genus Schellackia comprises obligate unicellular eukaryotic parasites within the phylum Apicomplexa, and infects numerous species of lizards and amphibians worldwide. Schellackia is transmitted via insect vectors, primarily mites and mosquitoes, which take up the parasite in blood meals. These vectors then subsequently infect reptilian and amphibian which consume the infected insects. The parasites deform erythrocytes of the host into crescents, and can be visualized using a blood smear.
Epieimeria is a genus of parasitic alveaolates of the phylum Apicomplexa.
Nephroisospora is a genus of parasites that infects bats
Cystoisospora belli, previously known as Isospora belli, is a parasite that causes an intestinal disease known as cystoisosporiasis. This protozoan parasite is opportunistic in immune suppressed human hosts. It primarily exists in the epithelial cells of the small intestine, and develops in the cell cytoplasm. The distribution of this coccidian parasite is cosmopolitan, but is mainly found in tropical and subtropical areas of the world such as the Caribbean, Central and S. America, India, Africa, and S.E. Asia. In the U.S., it is usually associated with HIV infection and institutional living.
Cystoisospora canis, previously known as Isospora canis, is a microscopic, coccidian parasite that causes an intestinal tract infection in dogs. The intestinal tract infection is coccidiosis caused by a protozoa called coccidia.
Plasmodium cynomolgi is an apicomplexan parasite that infects mosquitoes and Asian Old World monkeys. In recent years, a number of natural infections of humans have also been documented. This species has been used as a model for human Plasmodium vivax because Plasmodium cynomolgi shares the same life cycle and some important biological features with P. vivax.
Eimeria zuernii is a species of the parasite Eimeria that causes diarrheic disease known as eimeriosis in cattle, and mainly affects younger animals. The disease is also commonly referred to as coccidiosis. The parasite can be found in cattle around the globe.
Eimeria bovis is a parasite belonging to the genus Eimeria and is found globally. The pathogen can cause a diarrheic disease in cattle referred to as either eimeriosis or coccidiosis. The infection predominantly cause disease in younger animals.