Cryptosporidium

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Cryptosporidium
Cryptosporidium muris.jpg
Oocysts of C. muris found in human feces
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Alveolata
Phylum: Apicomplexa
Class: Conoidasida
Order: Eucoccidiorida
Suborder: Eimeriorina
Family: Cryptosporidiidae
Genus: Cryptosporidium
Tyzzer, 1907
Species

See § Species

Cryptosporidium, sometimes called crypto, is an apicomplexan genus of alveolates which are parasites that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea (intestinal cryptosporidiosis), sometimes with a persistent cough (respiratory cryptosporidiosis). [1] [2]

Contents

Treatment of gastrointestinal infection in humans involves fluid rehydration, electrolyte replacement, and management of any pain. For cryptosporidiosis, supportive treatment and symptom management are the primary treatments for immunocompetent individuals. [3] Anti-diarrheal medication, such as Loperamide, may be effective in slowing the rate of diarrhea. Nitazoxanide is the only drug approved for the treatment of cryptosporidiosis in immunocompetent persons. [4] Supplemental zinc may improve symptoms, [5] particularly in recurrent or persistent infections or in others at risk for zinc deficiency. Cryptosporidium oocysts are 4–6  μm in diameter and exhibit partial acid-fast staining. They must be differentiated from other partially acid-fast organisms including Cyclospora cayetanensis .

General characteristics

Cryptosporidium causes cryptosporidiosis, an infection that may present as a diarrhea, sometimes with a persistent cough in immunocompetent hosts.[ clarification needed ] [1] Other apicomplexan pathogens of humans include the malaria parasite Plasmodium and the toxoplasmosis parasite Toxoplasma . Unlike Plasmodium, which transmits via a mosquito disease vector, and Toxoplasma which needs a feline as definitive host, [6] Cryptosporidium does not use a vector, and is capable of completing its lifecycle within a single host. It results in cyst stages that are excreted in feces or through inhalation of coughed on fomites and are capable of transmission to a new host. [1] [7] [8]

A number of species infect mammals. In humans, the main causes of disease are C. parvum and C. hominis (previously C. parvum genotype 1). C. canis , C. felis , C. meleagridis , and C. muris can also cause disease in humans. [7]

Cryptosporidiosis is typically an acute, short-term infection, but can recur through reinfection in immunocompetent hosts, or become severe or life-threatening in immunocompromised individuals. In humans, it remains in the lower intestine and may remain for up to five weeks. [7] The parasite is transmitted by environmentally hardy cysts (oocysts) that, once ingested, exist in the small intestine and result in an infection of intestinal epithelial tissue. [7] Transmission by ingestion or inhalation of coughed-on fomites is a second, less likely route of infection. [1]

The genome of C. parvum, sequenced in 2004, was found to be unusual amongst eukaryotes in that the mitochondria seem not to contain DNA. [9] A closely related species, C. hominis, also has its genome sequence available. [10]

Life cycle

Cryptosporidiosis 01.png

Cryptosporidium has three developmental stages: meronts, gamonts and oocysts. [11] They reproduce within the intestinal epithelial cells. [12] The Cryptosporidium spore phase (oocyst) can survive for lengthy periods outside a host. It can also resist many common disinfectants, including chlorine-based disinfectants. [13]

Water treatment and detection

Many treatment plants that take raw water from rivers, lakes, and reservoirs for public drinking water production use conventional filtration technologies. Direct filtration, which is typically used to treat water with low particulate levels, includes coagulation and filtration but not sedimentation. Other common filtration processes including slow sand filters, diatomaceous earth filters, and membranes will remove 99% of Cryptosporidium. [14] Membranes and bag- and cartridge-filter products remove Cryptosporidium specifically.

Cryptosporidium is highly resistant to chlorine disinfection; [15] but with high enough concentrations and contact time, Cryptosporidium inactivation will occur with chlorine dioxide and ozone treatment. In general, the required levels of chlorine preclude the use of chlorine disinfection as a reliable method to control Cryptosporidium in drinking water. Ultraviolet light treatment at relatively low doses will inactivate Cryptosporidium. [16] [17]

One of the largest challenges in identifying outbreaks is the ability to verify the results in a laboratory. The oocytes may be seen by microscopic examination of a stool sample, but they may be confused with other objects or artifacts similar in appearance. [18] Most cryptosporidia are 3–6 μm in size, although some reports have described larger cells. [18]

Boiling is believed to be the safest option for water contaminated by Cryptosporidium. [19] [20] [21]

Epidemiology

Exposure risks

Dealing with stabilized compost - i.e. composting material that has gone through the phases where micro-organisms are digesting the organic matter and the temperature inside the composting pile has reached temperature up to 50–70 °C – poses very little risk as these temperatures kill pathogens and even make oocysts unviable. [23]

Like many fecal-oral pathogens, the disease can also be transmitted by contaminated food, poor hygiene or turning compost in a local compost site. Testing of water, as well as epidemiological study, are necessary to determine the sources of specific infections. Cryptosporidium typically does not cause serious illness in healthy people. It may chronically sicken some children, as well as adults exposed and immunocompromised.

Species

See also

Related Research Articles

<span class="mw-page-title-main">Apicomplexa</span> Phylum of parasitic alveolates

The Apicomplexa are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an apicoplast—with an apical complex membrane. The organelle's apical shape is an adaptation that the apicomplexan applies in penetrating a host cell.

<span class="mw-page-title-main">Cryptosporidiosis</span> Parasitic disease

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.

<span class="mw-page-title-main">Isosporiasis</span> Human intestinal disease

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).

<span class="mw-page-title-main">Coccidia</span> Subclass of protists

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.

Coccidiosis is a parasitic disease of the intestinal tract of animals caused by coccidian protozoa. The disease spreads from one animal to another by contact with infected feces or ingestion of infected tissue. Diarrhea, which may become bloody in severe cases, is the primary symptom. Most animals infected with coccidia are asymptomatic, but young or immunocompromised animals may suffer severe symptoms and death.

<i>Cryptosporidium parvum</i> Species of single-celled organism

Cryptosporidium parvum is one of several species that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract.

Wilderness-acquired diarrhea is a variety of traveler's diarrhea in which backpackers and other outdoor enthusiasts are affected. Potential sources are contaminated food or water, or "hand-to-mouth", directly from another person who is infected. Cases generally resolve spontaneously, with or without treatment, and the cause is typically unknown. The National Outdoor Leadership School has recorded about one incident per 5,000 person-field days by following strict protocols on hygiene and water treatment. More limited, separate studies have presented highly varied estimated rates of affliction that range from 3 percent to 74 percent of wilderness visitors. One survey found that long-distance Appalachian Trail hikers reported diarrhea as their most common illness. Based on reviews of epidemiologic data and literature, some researchers believe that the risks have been over-stated and are poorly understood by the public.

<i>Cyclospora cayetanensis</i> Species of single-celled organism

Cyclospora cayetanensis is a coccidian parasite that causes a diarrheal disease called cyclosporiasis in humans and possibly in other primates. Originally reported as a novel pathogen of probable coccidian nature in the 1980s and described in the early 1990s, it was virtually unknown in developed countries until awareness increased due to several outbreaks linked with fecally contaminated imported produce. C. cayetanensis has since emerged as an endemic cause of diarrheal disease in tropical countries and a cause of traveler's diarrhea and food-borne infections in developed nations. This species was placed in the genus Cyclospora because of the spherical shape of its sporocysts. The specific name refers to the Cayetano Heredia University in Lima, Peru, where early epidemiological and taxonomic work was done.

The 1993 Milwaukee cryptosporidiosis outbreak was a significant distribution of the Cryptosporidium protozoan in Milwaukee, Wisconsin, and the largest waterborne disease outbreak in documented United States history. It is suspected that The Howard Avenue Water Purification Plant, one of two water treatment plants in Milwaukee at the time, was contaminated. It is believed that the contamination was due to an ineffective filtration process. Approximately 403,000 residents were affected resulting in illness and hospitalization. Immediate repairs were made to the treatment facilities along with continued infrastructure upgrades during the 25 years since the outbreak. The total cost of the outbreak, in productivity loss and medical expenses, was $96 million. At least 69 people died as a result of the outbreak. The city of Milwaukee has spent upwards to $510 million in repairs, upgrades, and outreach to citizens.

<span class="mw-page-title-main">Nitazoxanide</span> Broad-spectrum antiparasitic and antiviral medication

Nitazoxanide, sold under the brand name Alinia among others, is a broad-spectrum antiparasitic and broad-spectrum antiviral medication that is used in medicine for the treatment of various helminthic, protozoal, and viral infections. It is indicated for the treatment of infection by Cryptosporidium parvum and Giardia lamblia in immunocompetent individuals and has been repurposed for the treatment of influenza. Nitazoxanide has also been shown to have in vitro antiparasitic activity and clinical treatment efficacy for infections caused by other protozoa and helminths; evidence as of 2014 suggested that it possesses efficacy in treating a number of viral infections as well.

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

Blastocystosis refers to a medical condition caused by infection with Blastocystis. Blastocystis is a protozoal, single-celled parasite that inhabits the gastrointestinal tracts of humans and other animals. Many different types of Blastocystis exist, and they can infect humans, farm animals, birds, rodents, amphibians, reptiles, fish, and even cockroaches. Blastocystosis has been found to be a possible risk factor for development of irritable bowel syndrome.

Cryptosporidium hominis, along with Cryptosporidium parvum, is among the medically important Cryptosporidium species. It is an obligate parasite of humans that can colonize the gastrointestinal tract resulting in the gastroenteritis and diarrhea characteristic of cryptosporidiosis. Unlike C. parvum, which has a rather broad host range, C. hominis is almost exclusively a parasite of humans. As a result, C. hominis has a low zoonotic potential compared to C. parvum. It is spread through the fecal-oral route usually by drinking water contaminated with oocyst laden feces. There are many exposure risks that people can encounter in affected areas of the world. Cryptosporidium infections are large contributors of child death and illness in heavily affected areas, yet low importance has been placed on both identifying the species and finding more treatment options outside of nitazoxanide for children and AIDS patients.

<span class="mw-page-title-main">Protozoan infection</span> Parasitic disease caused by a protozoan

Protozoan infections are parasitic diseases caused by organisms formerly classified in the kingdom Protozoa. These organisms are now classified in the supergroups Excavata, Amoebozoa, Harosa, and Archaeplastida. They are usually contracted by either an insect vector or by contact with an infected substance or surface.

Cryptosporidium muris is a species of coccidium, first isolated from the gastric glands of the common mouse. Cryptosporidium does originate in common mice, specifically laboratory mice. However, it also has infected cows, dogs, cats, rats, rabbits, lambs, and humans and other primates.

The 1987 Carroll County cryptosporidiosis outbreak was a significant distribution of the Cryptosporidium protozoan in Carroll County, Georgia. Between January 12 and February 7, 1987, approximately 13,000 of the 65,000 residents of the county suffered intestinal illness caused by the Cryptosporidium parasite. Cryptosporidiosis is characterized by watery diarrhea, stomach cramps or pain, dehydration, nausea, vomiting and fever. Symptoms typically last for 1–4 weeks in immunocompetent individuals.

Cryspovirus is a genus of viruses, in the family Partitiviridae. Protists serve as natural hosts. There is only one species in this genus: Cryptosporidium parvum virus 1.

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

A feline zoonosis is a viral, bacterial, fungal, protozoan, nematode or arthropod infection that can be transmitted to humans from the domesticated cat, Felis catus. Some of these diseases are reemerging and newly emerging infections or infestations caused by zoonotic pathogens transmitted by cats. In some instances, the cat can display symptoms of infection and sometimes the cat remains asymptomatic. There can be serious illnesses and clinical manifestations in people who become infected. This is dependent on the immune status and age of the person. Those who live in close association with cats are more prone to these infections, but those that do not keep cats as pets can also acquire these infections as the transmission can be from cat feces and the parasites that leave their bodies.

Cryptosporidium varanii is a protozoal parasite that infects the gastrointestinal tract of lizards. C. varanii is often shed in the feces, and transmission is primarily via fecal-oral route. Unlike Cryptosporidium serpentis, C. varanii does not colonize the stomach, but rather the intestines of most infected lizards, such as geckos. An exception to this rule are monitor lizards, as gastric (stomach) lesions have been found in those species. Oocysts of lizard Cryptosporidium are larger than the snake counterpart.

Cryptosporidium serpentis is a protozoal parasite that infects the gastrointestinal tract of snakes. Sporated oocysts of C. serpentis are intermittently shed in the feces, and transmission is primarily via fecal-oral route. C. serpentis is a gastric parasite, primarily colonizing the stomach. Unlike mammalian Cryptosporidium - that is usually self-limiting - C. serpentis remains chronic and in most cases, eventually lethal in snakes once an animal has become symptomatic. However, recent advancements in detection have led to the identification of healthy carrier animals some of which have thus far remained in good health for years and cast doubt on previous assumptions about the lethality of the parasite, though it remains to be seen how many carriers will remain healthy and for how long as most such animals are euthanized immediately. Cryptosporidiosis infection has been documented in a variety of snake species worldwide, such as North American Corn snakes and Australian Taipans, both free-living and captive. Necropsy examinations of expired captive snakes infected with C. serpentis note characteristic gastric mucosal hypertrophy that, in time, narrows the gastric lumen, resulting in classic symptoms of repetitive regurgitation and anorexia. Due to the enlargement of the stomach lining, a noticeable midbody bulge can be palpable and commonly visible. Frequent mucoid stools have been reported. However, some snakes will display no external symptoms at all throughout their lifetime, yet still remain infectious to counterparts.

References

  1. 1 2 3 4 Sponseller JK, Griffiths JK, Tzipori S (July 2014). "The evolution of respiratory Cryptosporidiosis: evidence for transmission by inhalation". Clinical Microbiology Reviews. 27 (3): 575–86. doi:10.1128/CMR.00115-13. PMC   4135895 . PMID   24982322. Recent evidence indicates that respiratory cryptosporidiosis may occur commonly in immunocompetent children with cryptosporidial diarrhea and unexplained cough. Findings from animal models, human case reports, and a few epidemiological studies suggest that Cryptosporidium may be transmitted via respiratory secretions, in addition to the more recognized fecal-oral route. ... Upper respiratory cryptosporidiosis may cause inflammation of the nasal mucosa, sinuses, larynx, and trachea, accompanied by nasal discharge and voice change (54, 61, 62). Cryptosporidiosis of the lower respiratory tract typically results in productive cough, dyspnea, fever, and hypoxemia (63,–66). ... While fecal-oral transmission is indisputably the major route of infection, transmission via coughing and fomites is also possible in situations of close contact (20). ... Because they lacked gastrointestinal symptoms and oocyst excretion, the latter cases establish the possibility of primary respiratory infection with Cryptosporidium, which may have been acquired by inhalation of expectorated droplets or by contact with fomites. ... This finding suggests that respiratory cryptosporidiosis may occur commonly in immunocompetent individuals.
  2. ↑ Chalmers, Rachel M.; Davies, Angharad P.; Tyler, Kevin (1 May 2019). "Cryptosporidium". Microbiology. 165 (5): 500–502. doi: 10.1099/mic.0.000764 . ISSN   1350-0872. PMID   31268415. S2CID   243706992.
  3. ↑ Leder, Karin. "Cryptosporidiosis: Treatment and Prevention". UpToDate. Retrieved 4 August 2023.
  4. ↑ Love, MS; Choy, RKM (1 October 2021). "Emerging treatment options for cryptosporidiosis". Current Opinion in Infectious Diseases. 34 (5): 455–462. doi:10.1097/QCO.0000000000000761. PMC   7611666 . PMID   34261904.
  5. ↑ Cabada MM, White AC, Venugopalan P, Sureshbabu J (18 August 2015). Bronze MS (ed.). "Cryptosporidiosis Treatment & Management". Medscape. WebMD. Retrieved 8 January 2016. Infection may improve with nutritional supplementation, particularly with regimens including zinc or glutamine. ... Nitazoxanide significantly shortens the duration of diarrhea and can decrease the risk of mortality in malnourished children.[22] Trials have also demonstrated efficacy in adults.[26, 27] ... Symptomatic therapy includes replacement of fluids, provision of appropriate nutrition, and treatment with antimotility agents. ... Replacement of fluids and electrolytes is the critically important first step in the management of cryptosporidiosis, particularly in patients with large diarrheal losses. Fluids should include sodium, potassium, bicarbonate, and glucose.
  6. ↑ "Toxoplasmosis". www.cdc.gov. Atlanta, GA: U.S. Centers for Disease Control and Prevention. 5 May 2022.
  7. 1 2 3 4 "Parasites – Cryptosporidium (also known as "Crypto")". Centers for Disease Control and Prevention. 20 February 2015.
  8. ↑ Widmer, Giovanni; Carmena, David; Kváč, Martin; Chalmers, Rachel M.; Kissinger, Jessica C.; Xiao, Lihua; Sateriale, Adam; Striepen, Boris; Laurent, Fabrice; Lacroix-Lamandé, Sonia; Gargala, Gilles; Favennec, Loïc (2020). "Update on Cryptosporidium spp.: highlights from the Seventh International Giardia and Cryptosporidium Conference". Parasite. 27: 14. doi: 10.1051/parasite/2020011 . ISSN   1776-1042. PMC   7069357 . PMID   32167464. Open Access logo PLoS transparent.svg
  9. ↑ Abrahamsen MS, Templeton TJ, Enomoto S, Abrahante JE, Zhu G, Lancto CA, Deng M, Liu C, Widmer G, Tzipori S, Buck GA, Xu P, Bankier AT, Dear PH, Konfortov BA, Spriggs HF, Iyer L, Anantharaman V, Aravind L, Kapur V (April 2004). "Complete genome sequence of the apicomplexan, Cryptosporidium parvum". Science. 304 (5669): 441–5. Bibcode:2004Sci...304..441A. doi:10.1126/science.1094786. PMID   15044751. S2CID   26434820.
  10. ↑ Xu P, Widmer G, Wang Y, Ozaki LS, Alves JM, Serrano MG, Puiu D, Manque P, Akiyoshi D, Mackey AJ, Pearson WR, Dear PH, Bankier AT, Peterson DL, Abrahamsen MS, Kapur V, Tzipori S, Buck GA (October 2004). "The genome of Cryptosporidium hominis". Nature. 431 (7012): 1107–12. Bibcode:2004Natur.431.1107X. doi: 10.1038/nature02977 . PMID   15510150.
  11. ↑ "Cryptosporidium". The Australian Society for Parasitology Inc. Retrieved 7 August 2019.
  12. ↑ Ash, Lawrence; Orihel, Thomas (2007). Ash & Orihel's Atlas of Human Parasitology (5th ed.). American Society for Clinical Pathology Press.
  13. ↑ "Chlorine Disinfection of Recreational Water for Cryptosporidium parvum". CDC. Retrieved 6 May 2007.
  14. ↑ "The Interim Enhanced Surface Water Treatment Rule – What Does it Mean to You?" (PDF). USEPA. Retrieved 6 May 2007.
  15. ↑ Korich DG, Mead JR, Madore MS, Sinclair NA, Sterling CR (May 1990). "Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability". Applied and Environmental Microbiology. 56 (5): 1423–8. Bibcode:1990ApEnM..56.1423K. doi:10.1128/aem.56.5.1423-1428.1990. PMC   184422 . PMID   2339894.
  16. ↑ Bolton, JR, Dussert, B, Bukhari, Z, Hargy, TM, Clancy, JL (1998). "Inactivation of Cryptosporidium parvum by Medium-Pressure Ultraviolet Light in Finished Drinking Water". Proc. AWWA 1998 Annual Conference, Dallas, TX. A: 389–403.
  17. ↑ Bukhari Z, Hargy TM, Bolton JR, Dussert B, Clancy JL (1999). "Medium Pressure UV Light for Oocyst Inactivation". Journal of the American Water Works Association. 91 (3): 86–94. doi:10.1002/j.1551-8833.1999.tb08602.x. S2CID   87880510.
  18. 1 2 Casemore DP, Armstrong M, Sands RL (December 1985). "Laboratory diagnosis of cryptosporidiosis". Journal of Clinical Pathology. 38 (12): 1337–41. doi:10.1136/jcp.38.12.1337. PMC   499488 . PMID   2416782.
  19. ↑ "Boil water warning 'precaution'". BBC News. 2 September 2008.
  20. ↑ "Boil water 'into January' warning". BBC News. 30 November 2005.
  21. ↑ "Devon residents urged to boil water after parasite found". BBC News. 15 May 2024. Retrieved 16 May 2024.
  22. ↑ Walker MD (2018). "Reducing the risk of zoonotic infection". Conservation Land Management. 16 (2): 19–22. Archived from the original on 25 October 2020. Retrieved 14 July 2018.
  23. 1 2 Gerba, C. (1 August 1995). "Occurrence of enteric pathogens in composted domestic solid waste containing disposable diapers". Waste Management & Research. 13 (4): 315–324. Bibcode:1995WMR....13..315G. doi:10.1016/S0734-242X(95)90081-0. ISSN   0734-242X.

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