Causes
Cryptosporidiosis is caused by Cryptosporidium a microscopic protozoan parasite. Both the parasite and the disease are commonly known as “Crypto.”
Cryptosporidium passes through your mouth into your digestive system, where it reproduces and causes symptoms. It is a single-celled organism that are only visible with a microscope. It usually infects animals and humans. Cryptosporidium hominis and Cryptosporidium parvum are the forms of crypto that usually infect people.
Symptoms of Crypto usually include:
• Watery diarrhea.
• Stomach cramps.
• Loss of appetite.
• Weight loss.
• Slight fever.
• Vomiting.

Transmission
Crypto is passed in the stool of an infected person or animal. Cryptosporidiosis is spread through the fecal-oral route, which means one can get infected from it accidentally by swallowing poop (feces) that has parasites in it. The parasite is protected by an outer shell that allows it to survive outside the body for long periods of time, and is highly resistant to chlorine.
Crypto can be transmitted by:
• Swallowing contaminated water while swimming or drinking.
• Having contact with animals, especially calves and goats, and their environment.
• Having contact with people who are sick with Crypto, especially in child care settings.
• Swallowing Crypto oocysts picked up from contaminated surfaces, like changing tables, door handles, or toys.
• Eating unwashed fruits and vegetables,
• Drinking unpasteurized apple cider, unpasteurized milk or eating food made with unpasteurized milk.
Pathogenesis:
The life cycle of Cryptosporidium can be broken down into the following steps:
1. Ingestion of sporulated oocysts: The life cycle of Cryptosporidium begins with the ingestion of sporulated oocysts, which are found in the feces of infected hosts. These oocysts contain four sporozoites.
2. Release of sporozoites: Upon ingestion, the oocysts are dissolved in the stomach and the sporozoites are released.
3. Parasitization of epithelial cells: The sporozoites parasitize epithelial cells of the gastrointestinal tract or other tissues such as the respiratory tract.
4. Asexual multiplication: In these cells, the parasites undergo asexual multiplication, producing multiple copies of themselves.
5. Sexual multiplication: After asexual multiplication, the parasites undergo sexual multiplication, producing male (microgamonts) and female (macrogamonts) gametes.
6. Fertilization: Upon fertilization of the macrogamonts by the microgametes, oocysts develop.
7. Sporulation: The oocysts mature and sporulate in the infected host, producing two different types of oocysts: thick-walled oocysts, which are commonly excreted from the host, and thin-walled oocysts, which are primarily involved in autoinfection.
8. Excretion and transmission: Oocysts are infective upon excretion, thus permitting direct and immediate fecal-oral transmission.
This life cycle allows Cryptosporidium to infect a wide range of hosts and to persist in the environment through the resistant oocyst stage.
Diagnosis of cryptosporidiosis is made by examination of stool samples.
The detection of Cryptosporidium can be difficult, therefore, doctors may ask patients to submit several stool samples over several days.
Most often, stool specimens are examined microscopically using different techniques (e.g., acid-fast staining, direct fluorescent antibody [DFA], and/or enzyme immunoassays for detection of Cryptosporidium sp. antigens).
Molecular methods like polymerase chain reaction PCR are increasingly used in reference diagnostic labs, since they can be used to identify Cryptosporidium at the species level.
Tests for Cryptosporidium are not routinely done in most laboratories; therefore, healthcare providers should specifically request testing for this parasite.
Prevention
One can reduce the risk of getting Crypto by following these recommendations:
• Wash your hands often and with soap and water. Alcohol-based sanitizers are not effective against Crypto.
• Do not swallow water while swimming.
• Wash your hands after contact with farm animals, pets, animal poop, and animal environments.
• Do not drink untreated water from lakes, rivers, springs, ponds, and streams.
• Do not drink raw (unpasteurized) milk or cider.
• Use caution when traveling in countries with minimal water treatment and sanitation systems by avoiding tap water, fountain drinks, ice, and raw foods.