Cryptosporidiosis overview

# Overview
Cryptosporidiosis is a parasitic disease affecting the intestines of mammals that is caused by Cryptosporidium, a protozoan parasite in the phylum Apicomplexa. It is a disease spread through the fecal-oral route; the main symptom is self-limiting diarrhea in people with intact immune system. In immunocompromised individuals, such as AIDS patients, infection can cause permanent & life-threatening diarrhea. Despite not being identified until 1976 it is one of the most common waterborne diseases and is found worldwide.

# Historical Perspective
Cryptosporidium was first described by Tyzzer in 1910. In the 1970s, it was determined to be a significant cause of gastrointestinal disease in humans. In 1995, the UK had the largest outbreak of cryptosporidia with 575 people falling ill. Recently, outbreaks of cryptosporidiosis have been reported in 2005 and 2007 in the UK and the US and have been linked with contaminated water supplies and water recreation parks.In 2017, there was a rise in the cases of cryptosporidiosis in the United States following swimming pool exposure.

# Classification
Cryptosporidiosis may be classified according to the affected organ system. In immunocompetent individuals, cryptospyoridiosis primarily affects the gastrointestinal system. Immunocompromised patients infected with cryptosporidiosis often have extragastrointestinal manifestions such as meningitis, encephalitis, pneumonia, or cholecystitis.

# Pathophysiology
Cryptosporidiosis is a zoonotic disease, humans could be infected by contact with contaminated water and through inhalation of the spores. Following transmission, white blood cells phagocyte the pathogen and transports it via hematologic or lymphatic route to different organs.

# Causes
A number of species of Cryptosporidium 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.

# Differential Diagnosis
Cryptosporidiosis primarily presents with diarrheasandhould bethus  differentiated from other causes of diarrhea which can be viral, bacterial or parasitic.

# Epidemiology and Demographics
Cryptosporidium parasites are found in every region of the United States and throughout the world. Travelers to developing countries may be at greater risk for infection because of poorer water treatment and food sanitation, but cryptosporidiosis occurs worldwide. In the United States, an estimated 748,000 cases of cryptosporidiosis occur each year.

# Risk Factors
The risk factors of cryptosporidiosis include malnutrition, HIV infection and unhygienic environments. Cryptosporidiosis can also affect cancer and transplant patients and those at risk of exposure to contaminated materials.

# Screening
Theere are no guidelines for screening for cryptosporidiosis according to United States Preventive Services Task Force (USPSTF).

# Natural History, Complications, and Prognosis
Cryptosporidiosis causes short term illness in healthy individuals. While in immunocompromized individuals it can cause prolonged diarrhea. Cholangitis, malabsorption, pancreatitis and weight loss are some common complications of cryptosporidiosis.

# History and Symptoms
The symptoms of cryptosporidiosis are seen 2-10 days after infection. The common manifestations include watery diarrhea, abdominal pain, nausea, vomiting and fever.

# Physical Examination
Physical examination findings in cryptosporidiosis include fever, fatigue, weakness, dehydration, hypotension and tachycardia.

# Laboratory Findings
Diagnosis of cryptosporidiosis is made by microscopic identification of the oocysts in stool or tissue with acid-fast staining or direct immunofluorescence.

# CT
There are no CT scan findings associated with Cryptosporidiosis.

# MRI
There are no MRI findings associated with Cryptosporidiosis.

# Other Diagnostic Studies
Diagnosis of cryptosporidiosis is made by microscopic identification of the oocysts in stool or tissue with acid-fast staining or direct immunofluorescence. Other diagnostic tests useful for the diagnosis of cryptosporidiosis include the ELISA and PCR.

# Medical Therapy
Medical management of Cryptosporidium infection includes supportive care, symptomatic management and prompt initiation of antiretroviral therapy.

# Surgery
The role of surgical intervention for cryptosporidiosis is reserved for cases of biliary cryptosporidiosis causing acalculous cholecystitis.

# Primary Prevention
Cryptosporidiosis is primarily transmitted via fecal oral route and dwells in water resevoirs. Primary prevention of cryptosporidiosis lies in appropriate hygiene after contact with sources or environments that may be contaminated with fecal material such as: after using the toilet, after contact with animals, after contact with children, after gardening or outdoor activities, after engaging in anal sex. Other primary preventive measures include avoidance public swimming areas or water recreation parks for two weeks after resolution of an episode of diarrhea, avoidance of contact with someone who has diagnosed cryptospiroidosis, and caution when traveling in countries where the safety of the food or water supply is unknown or in question. People who are immunocompromised should be particularly cautious to follow these prevention strategies. A cryptosporidiosis infection may have serious and possibly life-threatening sequelae in immune compromised patients.

# Secondary Prevention
Secondary prevention strategies for cryptosporidiosis are the same as primary prevention strategies.