Cystoisospora belli | |
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stained oocyst of Cystoisospora belli | |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Alveolata |
Phylum: | Apicomplexa |
Class: | Conoidasida |
Order: | Eucoccidiorida |
Family: | Sarcocystidae |
Genus: | Cystoisospora |
Species: | C. belli |
Binomial name | |
Cystoisospora belli (Wenyon, 1923) | |
Synonyms | |
Isospora belli |
Cystoisospora belli, previously known as Isospora belli, is a parasite that causes an intestinal disease known as cystoisosporiasis. [1] This protozoan parasite is opportunistic in immune suppressed human hosts. [2] It primarily exists in the epithelial cells of the small intestine, and develops in the cell cytoplasm. [2] 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. [3]
A fully mature (sporulated) oocyst of genus Isospora is a spindle-shaped body that has two sporocysts that contain four sporozoites each. [4] The oocysts of Cystoisospora belli are long and oval shaped. They measure between 20 and 33 micrometers in length and between 10 and 19 micrometers wide. [5]
The sporulation time of this parasite's egg is usually 1–4 days, and the entire life cycle takes about 9–10 days. [7] The infective stage found in stool is the mature oocyst. [1] The mature oocyst for Cystoisospora belli can remain infective in the environment for months. [8]
Immune competent individuals are usually asymptomatic to this parasite's infection. But clinical symptoms such as mild diarrhea, abdominal discomfort, and low grade fever for approximately one week has been observed in some individuals. [2]
Immunocompromised people are more severely affected by Cystoisospora belli and can experience extreme diarrhea that can lead to weakness, anorexia, and weight loss. Other symptoms of cystoisosporiasis include abdominal pain, cramps, loss of appetite, nausea, vomiting, and fever, that can last from weeks to months. [1] [5] [9]
Cystoisospora belli is diagnosed by identification of the oocyst through examining a stool sample under a microscope. The diagnostic stage is the immature oocyst that contains a spherical mass of protoplasm. In other words, the oocyst that is diagnosed in the stool sample is unsporulated, and contains only one sporoblast. [2] For stool diagnosis, direct smear, concentration smear, microscopic wet mount, or iodine stains of fecal smears are adequate. But for easy screening, acid-fast stains is recommended. [2] [3] If stool test is negative, and biopsies of the small intestine is performed, different stages of schizogony and sporogony should exist in the epithelial cells, but the alteration of the villi is not necessarily present. [2]
Eosinophilia may also be seen unlike in the case of other protozoal infections. [3]
This infection is easily treated with antibiotics. The most common antibiotic that is prescribed is co-trimoxazole (trimethoprimsulfamethoxazole), more commonly known as Bactrim, Septra, or Cotrim. [1]
In AIDS patients, treatments can result in the disappearance of the symptoms, but recurrence of symptoms is common. [2] In order prevent the recurrence, medication is continued in AIDS patients and other immunosuppressed patients. [10]
Cystoisospora belli does not require an intermediate host and currently is only known to transmit from person to person. [11] The method of transmission is ingesting food or water that has been contaminated with feces from someone who is infected. [1] Washing your hands with soap and warm water after using the toilet, changing diapers, and before handling food is vital. Also, educating children the importance of hand-washing and good hygiene practice is important. [1] Because HIV-AIDS patients will have higher risk of symptomatic intestinal parasitic infections, and pathogenic burden can increase disease progression and contributes to early death, routine screening of parasites especially in patients with lower CD4 count should be emphasized. [12]
Isospora belli was discovered by Rudolf Virchow in 1860 and was named by Charles Morley Wenyon in 1923. The parasite is now known as Cystoisospora belli. [5]
Cryptosporidiosis, sometimes informally called crypto, is a parasitic disease caused by Cryptosporidium, a genus of protozoan parasites in the phylum Apicomplexa. It affects the distal small intestine and can affect the respiratory tract in both immunocompetent and immunocompromised individuals, resulting in watery diarrhea with or without an unexplained cough. In immunosuppressed individuals, the symptoms are particularly severe and can be fatal. It is primarily spread through the fecal-oral route, often through contaminated water; recent evidence suggests that it can also be transmitted via fomites contaminated with respiratory secretions.
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).
A trophozoite is the activated, feeding stage in the life cycle of certain protozoa such as malaria-causing Plasmodium falciparum and those of the Giardia group. The complementary form of the trophozoite state is the thick-walled cyst form. They are often different from the cyst stage, which is a protective, dormant form of the protozoa. Trophozoites are often found in the host's body fluids and tissues and in many cases, they are the form of the protozoan that causes disease in the host. In the protozoan, Entamoeba histolytica it invades the intestinal mucosa of its host, causing dysentery, which aid in the trophozoites traveling to the liver and leading to the production of hepatic abscesses.
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.
Sarcocystis is a genus of protozoan parasites, with many species infecting mammals, reptiles and birds. Its name is dervived from Greek sarx = flesh and kystis = bladder.
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.
Dactylosoma is a genus of parasitic alveolates of the phylum Apicomplexa.
Cystoisospora is a genus of parasitic alveolates belonging to the phylum Apicomplexa.
Atoxoplasma is a genus of parasitic alveolates in the phylum Apicomplexa. The species in this genus infect birds. They are spread by the orofaecal route.
Merogregarina is a genus of parasitic alveolate in the phylum Apicomplexa. Species in this genus infect marine invertebrates.
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.
Sarcocystis neurona is primarily a neural parasite of horses and its management is of concern in veterinarian medicine. The protozoan Sarcocystis neurona is a protozoan of single celled character and belongs to the family, Sarcocystidae, a group called coccidia. The protozoan, S. neurona, is a member of the genus Sarcocystis, and is most commonly associated with equine protozoal myeloencephalitis (EPM). The protozoan, S. neurona, can be easily cultivated and genetically manipulated, hence its common use as a model to study numerous aspects of cell biology.
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