Watery diarrhea is the most common sign of CP. Others include:
CP might present with no symptoms at all. The most affected area is the small intestine, but frequently Cryptosporidium infection might spread to other anatomical areas which include other gastrointestinal tracts and even respiratory tracts. Symptoms appear after a an incubation period of 2 to 10 days. In immunocompetent subjects Cryptosporidium infection is not life-threatening and might last no more than 2 weeks. However, in immunocompromised subjects infection lasts much longer, tends to reappear numerous times, and might lead to the death of the patient.
Stool examination is the mainstay in the diagnosis of Cryptosporidium infection. However, the detecting process might be difficult, and frequently patients are asked to provide several stool samples taken over a period of several days. Stool specimens are examined with different techniques like acid-fasting staining and direct fluorescent antibody, before reaching the final diagnosis. Molecular tests have become increasingly important in the diagnosis of CP, as they allow to identify the specific species which is responsible for the infection and consequently increase the efficiency of the treatment. Unfortunately, tests for Cryptosporidium infection are not routine procedures in many laboratories, and have to be specifically required by the healthcare providers  .
Treatment of CP is based on the regulation of fluids and electrolytes using antimotility agents, nutritional support, antiparasitic drugs, and immunosuppression reversal strategies .
Avoiding the potential fatal side effects of malnutrition is paramount in the treatment of CP and can be achieved with correct diet choices. For example, one of the features of the clinical presentation of CP is secondary lactose intolerance. This condition is the consequence of the loss of a great number of mature epithelial cells on the tips of the intestinal villi and the enzymes expressed by them, including lactase, which is necessary to digest lactose. Therefore, supportive care for patients affected by CP should include a lactose-free diet. Infections can also be reduced with diet modifications and nutritional supplementation, especially if zinc or glutamine rich regimes are taken into consideration.
If surgery is taken into consideration, it is advised to consult the following specialists:
Nitazoxanide is a mainstay in the treatment of CP, as it reduces the duration of diarrhea and the risk of mortality in malnourished children.
According to many trials, the effects of antiparasitic drugs in patients affected by AIDS are disappointing, and drugs such as nitazoxanide, paromomycin, and azithromycin have proven to be only partially active. However, drastic improvement in many cases has been observed when CP treatment is combined with antiretroviral therapy which includes the use of an HIV protease inhibitor . This improvement can be either the result of immune reconstruction or the antiparasitic activity of the HIV protease inhibitor. In any case, the combination of partially active antiparasitic drugs like nitazoxanide or paromomycin with antiretroviral therapy appears to be the best clinical option.
It should be noted that in patients affected by AIDS positive treatment response is seen only after restoration of the CD4 cell count following the combined antiretroviral therapy. Therefore, an early phase of immune reconstitution can be recognized for clinical purposes, during which patients should continue antiparasitic therapy and antimotility agents administration as required.
Symptoms may be alleviated with a series of key measurements which include appropriate nutrition, fluid replacement, and antimotility agent administration. If mild agents fail to achieve a positive response, more potent opiates like morphine can be taken into consideration. Furthermore, watery diarrhea can be suppressed by the somatostatin analogue octreotide.
Fluid and electrolyte loss
Since CP is mainly characterized by severe fluid loss through diarrhea, replacement of fluid and electrolytes proves to be an important step for its treatment. The administered fluids should contain essential electrolytes like sodium, potassium, or bicarbonate. Several administration routes may be chosen, but usually oral rehydration is the preferred choice.
Acalculous cholecystitis can be serious a complication of CP and should be treated with cholecystectomy. Similarly, sclerosing cholangitis might be associated with CP and requires ERCP.
In the majority of the cases the diarrhea caused by Cryptosporidium infection is usually self-limited and lasts for several days, and only in few cases extends to 1 or 2 weeks. However, in immunocompromised subjects diarrhea can become chronic and severe, and may occur in combination with other extra-intestinal manifestations . Patients with AIDS frequently develop chronic symptoms that might show a fatal course. In these cases, antiretroviral treatment is strongly suggested.
Children are frequently affected by CP, even though the clinical course of the treatment is good. They usually experience persistent abdominal pain, loose feces and a sequence of other extra-intestinal signs such as eye pain, headache and fatigue.
After excretion, Cryptosporidium oocysts are immediately highly infectious. The parasite produces several forms which might infect the intestine in the different stages of invasion. A Cryptosporidium infection is very resistant to treatment due to the extracytoplasmic localization of the parasite, which allows it to frequently elude detection. The excreted oocysts show a high resiliency even in hostile environments, such as high chlorine levels employed in water treatment .
The main sign of Cryptosporidiosis is watery diarrhea, which is seen as a consequence of the particular response of the pathogen to infection, largely based on increased intestinal permeability, chloride secretion, and malabsorption working as combined factors. The pathology is usually limited to the area of the small intestine, but it may spread to the biliary tract in particularly exposed subjects like immunocompromised patients.
CP develops when a subject is exposed to Cryptosporidium in any particular circumstance. However, the risk of infection is substantially increased in case the exposed person is immunocompromised, either due to a congenital condition or as a consequence of some other factor such as HIV, malnutrition, cancer therapy, bone marrow transplantation, or diabetes mellitus.
The following list indicates the types of individuals that are at a higher risk of acquiring a Cryptosporidium infection:
Infection in hospital and health-care centers has also been frequently reported, together with occurrence in pregnant women due to the debilitated conditions.
Prevalence of CP is undoubtedly higher in developing countries due to poor hygienic standards and a lack of clean water along with close proximity of animals and humans.
Tests for Cryptosporidium are not routinely conducted in US laboratories or show an insufficient sensitivity to the pathogen. Thus, the frequency of CP has not been clearly defined in the United States.
However, the number of the cases reported has risen in the last years, due to an increased awareness of the problem and better diagnostic tests. For example, in the 2006-2010 period the reported number of affected individuals lay between 2.3 and 3.9 cases in every 100,000 persons, with a peak registered in 2007, while in 2010 alone 8951 cases in total were reported, with a related rate of 2.9 cases in every 100,000 persons. Recent studies suggest that Cryptosporidium species in the United Stets are present in about 4% of the stools sent to the laboratories for examination, while seroprevalence tests performed by using antibody assays indicate that around 25-35% of the population in industrialized countries might have been exposed to Cryptosporidium infection sometime during their life. This trend is further underlined by frequent Cryptosporidium related outbreaks.
Despite the fact that Cryptosporidium is ubiquitous in all continents, its appearance is particularly frequent in warm and moist climates. In the United States incidence peaks in summer, between July and September. Wastewater (e.g. from sewage) may contaminate water sources and lead to outbreaks of CP infection . Furthermore, incidence is particularly high in daycare centers, where it can even reach a rate ranging from 30 to 60%. Immunocompromised subjects are at an especially high risk for infection.
Large-scale surveys made from samples of fecal oocysts underline a prevalence rate for the developed countries which ranges between 1% to 3%. This rate is especially high among children under 2 years of age , perhaps as consequence of the weaker state of their immune system.
CP is a notifiable disease in Europe whose related data can be collected through the so called European Basic Surveillance Network. The incidence reported for the European continent is similar to the one observed in the United States, although significant differences have been observed between one country and the other. For example, in the majority of the countries the peak of incidence takes place in autumn, especially in the period between August and November. However, in Ireland and Spain this peak occurs earlier, between spring and summer. The cases reported are largely caused by Cryptosporidium hominis in men and Cryptosporidium parvum in cattle. Incidence appears to be particularly high in August in countries like Germany, England, Wales, Scotland, and the Netherlands. The reason behind this particular trend remains still unknown.
In the developing countries, CP is responsible for 10-15% of the cases of acute diarrhea, but if molecular tests are used this rate can be even higher . Accordingly, high CP rates are also observed in international travelers, due to the high risk conditions to which these people are exposed. Unfortunately, also in these countries the most affected people are children, especially those younger than 5 years as many of them still live in slums under bad hygienic conditions, or immunocompromised subjects infected by HIV virus.
Regardless of the continent, the incidence of CP usually peaks in children younger than 5 years or in women in childbearing age, perhaps due to frequent contact with infected infants. Children under 2 years of age turn out to be particularly exposed , perhaps for the typical increase in fecal-oral transmission or for their immune system which is still not fully effective. In industrialized countries, CP appears in any age in the cases of waterborne epidemics or in immunocompromised subjects.
The infection of Cryptosporidium usually takes place through fecal-oral transmission. Once ingested, oocysts release sporozoites which in turn enter the epithelial cells lining the small intestine, where they further develop into trophozoites. The trophozoites allow the development of merozoites which once released can either infect nearby epithelial cells or develop into sexual gametes. Lastly, sexual gametes can join to give rise other oocysts, which then exit outside the host's body through the feces. The entire life cycle of Cryptosporidium takes place in the small intestine, over the surface of the microvilli present throughout this anatomical site .
Unfortunately, there is no effective method to disinfect drinking water against Cryptosporidium species, and water filtration remains the only viable solution at the moment. The following recommendations may reduce the risk of an CP infection:
When it was discovered back in 1907, the genus Cryptosporidium was thought to be a group of commensal protozoa which live in symbiosis with the human body. After the 1950s a series of outbreaks of diarrhea in turkeys and cows could be associated with the infection by the protozoa of Cryptosporidium. Today, this genus is considered as an important pathogen infecting livestock and human beings, as well as a common cause of acute and self-limiting forms of gastroenteritis in immunocompromised subjects. To date, more than 20 species have been recognized on the basis of the animal host infected, although this criterion of characterization is debated among experts due to the absence of a sound scientific basis. Therefore, a new approach has recently been developed which takes into consideration the molecular aspects of a species as means for its characterization. At the moment, 18 valid species have been recognized which include Cryptosporidium hominis and Cryptosporidium parvum, the two spieces that affect humans. In addition, 40 genotypes have been discovered, and some of them are likely to become recognized as new species as research progresses.
The primary sign of cryptosporidiosis (CP) is watery diarrhea, which is frequently combined with evident signs of gastrointestinal distress. The infection is self-limiting in immunocompetent individuals, but might appear as a severe and persistent pathology in immunocompromised patients. Diagnosis is largely based on the identification of the organism or its associated antigens in stool, especially by employing molecular methods such as polymerase chain reaction, restriction fragment length polymorphism and DNA sequencing. This molecular approach has led to the discovery of sequence-based differences in a series of key genes such as ribosomal RNAs and heat shock proteins, which now requires a detailed revision of the host-based taxonomy and classification that has been developed in the past   .
Cryptosporidiosis is an infection caused by the species belonging to the genus Cryptosporidium. These parasites can be found in water, food, and soil or on contaminated waste. The main clinical symptom of cryptosporidiosis is watery diarrhea, which might be combined with:
Many patients may recover without treatment. However, people with compromised immune systems, like those affected by AIDS, might experience severe clinical problems. Cryptosporidiosis can be prevented by following some general measures, like frequently washing hands, avoiding infected water, and washing food which might be contaminated before eating.