Cryptosporidiosis , also known as crypto , is a parasitic disease caused by Cryptosporidium , a genus of parasitic protozoa in Apicomplexa phyla. This affects the distal intestine and may affect the respiratory tract in both immunocompetent (ie, individuals with normal functioning immune systems) and immune disorders (eg, people with HIV/AIDS or autoimmune disorders) individuals, resulting in watery diarrhea with or without a cough that is not can be explained. In individuals with impaired immune systems, the symptoms are very severe and can be fatal. It mainly spreads through the fecal-oral route, often through contaminated water; recent evidence suggests that it can also be transmitted through fomites in respiratory secretions.
Cryptosporidium is generally isolated in HIV-positive patients with diarrhea. Although not identified until 1976, it is one of the most common waterborne diseases found worldwide. These parasites are transmitted by environmentally-resistant microbial cysts (oocysts) which, after digestion, sporozoites in oocysts excyst (ie, released) and result in intestinal epithelial tissue infections.
Video Cryptosporidiosis
Signs and symptoms
Cryptosporidiosis may occur as an asymptomatic infection, an acute infection (ie, duration shorter than 2 weeks), as a recurrent acute infection in which symptoms reappear after a short recovery period of up to 30 days, and as a chronic infection (ie, duration longer than 2 weeks ) where the symptoms are severe and persistent. This can be fatal in individuals with very disturbed immune systems. Symptoms usually appear 5-10 days after infection (range: 2-28 days) and usually last up to 2 weeks in immunocompetent individuals; symptoms are usually more severe and persist longer in individuals with the immune system. After the resolution of diarrhea, symptoms may recur after a few days or weeks due to reinfection. The likelihood of re-infection is high in immunocompetent adults, and low in those with normal immune systems.
In immunocompetent individuals, cryptosporidiosis is primarily localized to the distal intestine and sometimes respiratory tract as well. In people with immune disorders, cryptosporidiosis may spread to other organs, including the hepatobiliary system, the pancreas, the upper gastrointestinal tract, and the bladder; Pancreatic and biliary infections may involve cholecytic akalkulus, sclerosing cholangitis, papillary stenosis, or pancreatitis.
Intestinal Cryptosporidiosis
Common signs and symptoms of intestinal cryptosporidiosis include:
- Medium to severe watery diarrhea, sometimes containing mucus and rarely blood or leukocytes
- In very severe cases, diarrhea can be overwhelming and cholera-like with malabsorption and hypovolemia
- Low quality fever
- Abdominal pain cramps
- Dehydration
- Weight
- Fatigue
- Nausea and vomiting - shows upper gastrointestinal involvement and may cause respiratory cryptosporidiosis
- Epigastric pain or right upper quadrant
Less common or rare signs and symptoms include:
- Reactive arthritis (may affect the hands, knees, ankles, and feet)
- JaundiceÃ, - indicates hepatobiliary involvement
- Asites - shows pancreatic involvement
Respiratory cryptosporidiosis
Symptoms of upper respiratory cryposporidiosis include:
- Inflammation of the nasal mucosa, sinuses, larynx, or trachea
- Disposal of the nose
- Sound changes (e.g., hoarseness)
The symptoms of lower respiratory cryptosporidiosis include:
- Cough
- Shortness of breath
- Fever
- Hypoxemia
Maps Cryptosporidiosis
Cause
Cryptosporidium is a genus of pathogenic protozoans categorized under Apicomplexa phyla. Other apicomplexan pathogens include the malaria parasite Plasmodium , and Toxoplasma , the causative agent of toxoplasmosis. A number of Cryptosporidium infect mammals. In humans, the leading cause of disease is C. parvum and C. hominis (formerly C. parvum genotype 1). C. canis , C. felis , C. meleagridis , and C. muris can also cause disease in humans. Cryptosporidium is able to complete its life cycle in a single host, resulting in a stage of microbial cyst excreted in the feces and capable of being transmitted to a new host via the fecal-oral route. Other vectors of disease transmission also exist.
The life cycle pattern Cryptosporidium fits perfectly with other homogeneous coccidian genera of the suborder of Eimeriina : macro and microgamont develop independently; mikrogamont gives rise to many male gametes; and oocysts serve the spread of parasites in the environment. Electron microscopic studies made from the 1970s have been shown to be intracellular, despite the localization of extrusion of the Cryptosporidium species.
This species has a number of unusual features:
- an endogenous developmental phase in surface epithelial microvilli
- two types of morphofunctional oocyst
- the smallest number of sporozoites per oocyst
- multi-membrane "feeder" organelle
DNA studies show association with gregarines rather than coccidia. The group's taxonomic position has not been approved yet.
The Cryptosporidium parvum genome was sequenced in 2004 and found unusual among Eukaryotes where mitochondria do not appear to contain DNA. The closely related species, C. hominis , also have available genome sequences. CryptoDB.org is a NIH funded database that provides access to the Cryptosporidium genomic data set .
Transmission
Infection is through contaminated materials such as soil, water, uncontaminated or cross contaminated foods that have come into contact with impurities from infected individuals or animals. The contact should be moved to the mouth and swallowed. It is especially prevalent among those who are associated regularly with freshwater bodies including recreational water such as swimming pools. Other potential sources include inadequate water supply, contaminated food, or dirt exposure. The high resistance of Cryptosporidium oocysts to disinfectants such as chlorine bleach allows them to survive for long periods of time and still remain infective. Some outbreaks have occurred in child care related to diaper changes.
The following groups are at high risk for Cryptosporidium :
- Child worker
- Parents of infected children
- The person caring for others with cryptosporidiosis
- International travelers
- Backpackers, pedestrians, and campers drinking unfiltered, untreated water
- People, including swimmers, swallow water from contaminated sources
- The person handling the infected livestock
- People exposed to human waste through sexual contact
Cases of cryptosporidiosis can occur even in cities with well-contaminated water supplies. In cities with clean water, cryptosporidiosis cases may have other origins. Water testing, as well as epidemiological studies, is needed to determine the source of specific infections. Cryptosporidium causes more serious illness more frequently in immunocompromised than in seemingly healthy individuals. It can thicken children chronically, as well as adults exposed and impaired immunity. Part of the immunocompromised population is people with AIDS. Some sexual behaviors can transmit parasites directly.
Life cycle
Cryptosporidium spp. there are as several types of cells corresponding to different stages in an infection (eg, sexual and asexual stages). As an oocyst - a type of hard and thick-walled spore - it can survive in the environment for months and is resistant to many common disinfectants, especially chlorine-based disinfectants. Once ingested, sporozoites in the excyst oocysts (ie, released) in the small intestine. The sporozoit is then attached to the microvilial cells of the small bowel epithelium. From there they become trophozoites that reproduce asexually by double fission, a process known as schizogony. Trofozoit develops into type 1 meront [1] containing 8 child cells.
This child cell is a type 1 merozoit, released by meronts. Some of these merozoites can cause autoinfection by attaching to epithelial cells. Other merozoites are a type II meronts, which contain 4 types of merozoites II. This merozoit is released and attached to the epithelial cells. From there they become macrogamonts or microgamonts. These are the sexual forms of women and men, respectively. This stage, when the sexual forms appear, is called gametogony.
Zygote is formed by microgametes from microgamont that penetrates macrogamonts. Zygote evolved into oocysts of two types. 20% of oocysts have thin walls and can infect hosts by breaking and releasing sporozoites that begin the process again. Oocyst thick-walled excreted into the environment. Oocyst is mature and infective after excretion.
Pathogenesis
Ookista is oval or round and measuring 5 to 6 micrometers. When in flotation preparation they look very refractile. Ookista contains up to 4 sporozoit-shaped bow.
As few as 2 to 10 oocysts can start an infection. The parasite is located at the border of the brush of small bowel epithelial cells. They are mainly located in jejunum. When sporozoites attach the cells to the epithelial cells that envelop them. Thus, they are "intracellular but extracytoplasmic". The parasite can cause damage to the microvilli where it is attached. Infected humans secrete most oocysts during the first week. Oocysts can be excreted for weeks after diarrhea subsides from infection by C. parvum or C. hominis ; however, immunocompetent individuals with C. muris infections have been observed to excrete oocysts for seven months.
The immune system reduces the formation of type 1 merozoites and the number of thin-walled oocysts. This helps prevent autoinfection. Cell B does not help with the initial response or the fight to remove parasites. Previous infections in immunocompetent individuals produce less resistance to future infections, but may decrease the severity of the disease and the number of oocysts excreted.
Diagnosis
There are many diagnostic tests for Cryptosporidium . They include microscopy, staining, and antibody detection. Microscopy can help identify oocysts in the feces. To increase oocysts' chances of finding oocysts, diagnostics should check at least 3 stool samples. There are several techniques for centralizing stool samples or oocysts. The method of concentration of formalin-ethyl acetate (FEA) concentrates on the stool. Both modified sodium centrifugal flotation techniques and the Sheather sugar flotation procedure can concentrate oocysts by causing them to float. Another form of microscopy is fluorescence microscopy performed by staining with auramine.
Other staining techniques include fast-acid staining, which will color the oocysts to red. One type of acid-fast stain is Kinyoun stain. Giemsa staining can also be done. Part of the small intestine can be stained with hematoxylin and eosin (H & E), which will show the oocysts attached to the epithelial cells.
Detecting antigens is another way to diagnose illness. This can be done with direct fluorescent antibody (DFA) techniques. This can also be achieved through indirect immunofluorescence testing. The assay-linked immunosorbent enzyme (ELISA) also detects antigens.
Polymerase chain reaction (PCR) is another way to diagnose cryptosporidiosis. It can even identify specific species Cryptosporidium . If the patient is considered to have biliary cryptosporidiosis, then the proper diagnostic technique is ultrasound. If it returns a normal result, the next step is to perform endoscopic retrograde cholangiopancreatography.
Prevention
Many processing plants are taking raw water from rivers, lakes, and reservoirs for public drinking water production using conventional filtration technology. It involves a series of processes, including coagulation, flocculation, sedimentation, and filtration. Direct filtration, which is usually used to treat water with low particulate content, including coagulation and filtration, but not sedimentation. Other common filtering processes, including slow sand filters, diatomaceous soil filters and membranes will remove 99% of Cryptosporidium . Membranes and bags and filter cartridges remove special Cryptosporidium products.
While Cryptosporidium is highly resistant to chlorine disinfection, with high concentrations and contact times, Cryptosporidium will be disabled by chlorine dioxide and ozone treatment. The required level of chlorine generally precludes the use of chlorine disinfectants as a reliable method for controlling Cryptosporidium in drinking water. Ultraviolet light treatment with a relatively low dose will disable Cryptosporidium . Research funded by the Water Research Foundation initially found the effectiveness of UV in disabling Cryptosporidium .
One of the biggest challenges in identifying outbreaks is the ability to identify Cryptosporidium in the laboratory. Real-time monitoring technology can now detect Cryptosporidium with the online system, unlike spot testing methods and batches used in the past.
The most reliable way to decontaminate drinking water that might be contaminated by Cryptosporidium is to boil it.
In the US the law requires doctors and laboratories to report cases of cryptosporidiosis to the local or state health department. These departments then report to the Centers for Disease Control and Prevention. The best way to prevent and spread cryptosporidiosis is to have good hygiene and sanitation. Examples are hand washing. Prevention is to wash your hands carefully after going to the bathroom or contact the bench, and before eating. One should avoid contact with animal waste. They should also avoid food and water that may be contaminated. In addition, people should refrain from engaging in sexual activity that may expose them to the feces.
Standard water filtration may not be sufficient to eliminate Cryptosporidium ; boiling at least 1 minute (3 minutes above 6,500 feet (2,000 m) from the height) will decontaminate it. Heating milk at 71.7 Â ° C (161 Â ° F) for 15 seconds pasteurization and can destroy the oocyst's ability to infect. Water can also be made safe by filtering with a filter with a pore size no larger than 1 micrometer, or with an approved filter for "cyst removal" by the NSF International National Sanitation Foundation. Bottled drinking water is less likely to contain Cryptosporidium , especially if water comes from an underground source.
People with cryptosporidiosis should not swim in communal areas because pathogens can be in the anal and genital areas and cleaned. They should wait at least two weeks after diarrhea stops before entering a public water source, since oocysts can still be shed for a while. Also, they should stay away from immunosuppressed people. People who do not have immunity should be careful to protect themselves from water in lakes and rivers. They should also stay away from animal waste and wash their hands after touching the animals. To be safe, they must boil or filter their water. They should also wash and cook their vegetables.
The CDC USA notes the recommendations of many public health departments to soak contaminated surfaces for 20 minutes with 3% hydrogen peroxide (99% murder rate) and then rinse thoroughly, with a warning that no disinfectant is fully effective against Cryptosporidium.. However, hydrogen peroxide is more effective than standard bleach solutions.
Treatment
Symptomatic treatment mainly involves fluid rehydration, electrolyte replacement (sodium, potassium, bicarbonate, and glucose), and antimotility agents (eg, loperamide). Additional zinc may improve symptoms, especially in recurrent or persistent infections or in others at risk for zinc deficiency.
Incompetent
Individuals incompetent with cryptosporidiosis usually suffer briefly (ie, duration less than 2 weeks) limit self-diarrhea that may require symptomatic treatment and end in spontaneous recovery; in some circumstances, antiparasitic drugs may be necessary (eg, recurrent, severe, or persistent symptoms); However, reinfection is common.
By 2015, nitazoxanide is the only proven antiparasitic drug treatment for cryptosporidiosis in immunocompetent individuals; However, it has no efficacy in patients with severe immune system disorders. Certain agents such as paromomycin and azithromycin are sometimes used as well, but they only have partial efficacy.
Immunocompromised
In immunocompromised individuals, such as AIDS patients, cryptosporidiosis resolves slowly or completely, and often causes a very severe and persistent form of watery diarrhea coupled with a profoundly decreased ability to absorb major nutrients through the intestinal tract. As a result, infected individuals may experience severe dehydration, electrolyte imbalances, malnutrition, wasting, and potentially death. In general, the mortality rate for infected AIDS patients is based on the number of CD4 markers. Patients with CD4 cell counts greater than 180 cells/mm recovered with supportive care and treatment in hospitals; however, in patients with a CD4 cell count below 50 cells/mm 3, the effect is usually fatal within 3 to 6 months. During the epidemic of Milwaukee cryptosporidiosis (the largest of its kind), 73% of AIDS patients with CD4 cell counts were lower than 50 and 36% of those with between 50 and 200 cells/mmÃ,³ died within the first year of infection.
The best treatment approach is to improve immune status in people with immunodeficiency using highly active antiretroviral therapy that includes HIV protease inhibitors along with ongoing use of antiparasitic drugs. Treatment of antiparasitic drugs for individuals with impaired immune systems usually involves a combination of nitazoxanide, paromomycin, and azithromycin together; these drugs are only partially active in HIV/AIDS patients compared with their effect on immunocompetent people. Cochrane Collaboration reviews recommend that nitazoxanide be considered for use in treatment although its effectiveness is reduced in individuals with impaired immune systems.
Currently, research is being conducted in molecular-based immunotherapy. For example, synthetic isoflavone derivatives have been shown to counter both cryptosporidium parvum both in vitro and in animal studies. The nitazoxanide derivatives, known as thiazolides, have also shown promising results in vitro .
Epidemiology
Cryptosporidiosis is found worldwide. This causes 50.8% of water-borne diseases associated with parasites. In developing countries, 8-19% of diarrheal diseases can be attributed to Cryptosporidium . Ten percent of the population in the developing world issues oocysts. In developed countries, the number is lower at 1-3%. The most affected age groups are children from 1 to 9 years old.
About 30% of adults in the United States are seropositive to cryptosporidiosis, which means that they contract infections at some point in their lives.
History
The organism was first described in 1907 by Tyzzer, who admitted it was a coccidian.
Research
Recombinant vaccine Cryptosporidium parvum surface oocyst protein (rCP15â € <60) has resulted in an antibody response in a large group of cows as well as antibody response in calves given colostrum rCP15 ​​â € <â € kDa protein (CP15) located on the surface of the organism. This protein is a good candidate for use as a molecular vaccine because previous research has shown that monoclonal antibodies to CP15 provide passive immunity in mice. Currently, there is no fully effective vaccine or drug therapy against Cryptosporidium parvum in HIV/AIDS individuals.
Other animals
- Cryptosporidiosis - Centers for Disease Control and Prevention
- Aquatics International Article Regarding Infection through Spray Parks
- CryptoDB: The Cryptosporidium Genome Resource
Source of the article : Wikipedia
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