Cryptosporidium parvum
Cryptosporidium parvum | |
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Immunofluorescence image of C. parvum oocysts | |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Alveolata |
Phylum: | Apicomplexa |
Class: | Conoidasida |
Order: | Eucoccidiorida |
Family: | Cryptosporidiidae |
Genus: | Cryptosporidium |
Species: | C. parvum
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Binomial name | |
Cryptosporidium parvum Tyzzer, 1912
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Cryptosporidium parvum is one of several species that cause
Primary symptoms of C. parvum infection are acute, watery, and nonbloody
Infection is caused by ingestion of
Infection is generally
Detection
Cryptosporidium parvum oocysts are very difficult to detect; their small size means they are difficult to detect in fecal samples. A fecal ELISA could detect the presence of the parasite. A serological ELISA is unable to distinguish between past and present infections.[2]
Cryptosporidium parvum is considered to be the most important waterborne pathogen in developed countries. The protozoa also caused the largest waterborne-disease outbreak ever documented in the United States, making 403,000 people ill in
Prevention
The most effective way to prevent the spread of C. parvum is to avoid contact with contaminated feces. Avoiding this contact, especially with young children, is important, as they are more likely to come into oral contact and have the parasite transferred into the body. Hygiene is the most effective way to combat this difficult-to-prevent parasite.[5] Those visiting areas, such as petting zoos, where they might access affected animals should ensure good hygiene measures such as hand washing.[6]
Oocyst stage
The C. parvum oocysts are incredibly durable, which can cause extended problems when attempting to control the spread of the parasite. The oocyst stage can tolerate a vast number of environmental pressures. The oocyst can tolerate temperatures as low as −22 °C and for long periods of time, which means fecal contamination is possible even after going through deep freezing. The oocysts can also tolerate shifts in pH that are found in some water treatment processes, and careful attention to detail must be done to prevent the possibility of infection. The oocysts in fecal material are immediately infective and have the potential to find a new host if contamination occurs.[2][5]
Genome
The genome of C. parvum (sequenced in 2004) is of relatively small size and simple organization of 9.1 Mb, which is composed of eight chromosomes ranging from 1.04 to 1.5 Mb.[7] The genome is very compact, and is one of the few organisms without transposable elements. Unlike other apicomplexans, C. parvum has no genes in its plastids or mitochondria.[7][8]
Treatment
Treatment of gastrointestinal infection in humans involves
Important C. parvum proteins and drug targets
Lipid metabolism
C. parvum is incapable of
Surface glycoproteins
Cryptosporidium parvum possesses numerous surface
In vitro, hyperimmune sera, as well as antibodies directed at specific epitopes on the GP900 protein, inhibit the invasion of C. parvum sporozoites into MDCK cell monolayers. Additionally, competitive inhibition using native GP900 or purified GP900 fragments reduces cell invasion.[10]
Further experiments have confirmed the importance of the mucin-like glycosylations. Lectins directed at GP900 carbohydrate moieties (alpha-N-galactosamine) were able to block adhesion and prevent C. parvum invasion.[11]
Cryptosporidium parvum glycoproteins have the characteristics of attractive vaccine candidates. Many are
References
- ^ "DPDx - Cryptosporidiosis". Centers for Disease Control and Prevention. 5 December 2017. Retrieved 2018-03-18.
- ^ PMID 7870140.
- ^ "Surveillance for Waterborne-Disease Outbreaks --United States, 1993-1994". Centers for Disease Control and Prevention. Retrieved 2018-03-18.
- PMID 14711592.
- ^ PMID 1482175.
- ^ Walker, M.D. (2018) Cryptosporidiosis. Conservation Land Management, 16(2),19-22. Accessed from: http://sites.google.com/site/cryptosporidiosisukanimal/ Archived 2020-06-05 at the Wayback Machine
- ^ S2CID 26434820.(subscription required)
- ISBN 978-3-540-76733-6.
- ^ 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.
- PMID 9851610.
- PMID 10948140.