Cryptosporidiosis is an infection caused by a tiny parasite called Cryptosporidium. This parasite is often found in contaminated water, especially in swimming pools or lakes. People can get infected by swallowing water that contains the parasite, leading to symptoms like diarrhea, stomach cramps, and nausea. The illness can be particularly serious for those with weakened immune systems, such as individuals with HIV/AIDS or those undergoing chemotherapy. While most healthy people recover without treatment, it's essential to stay hydrated and seek medical advice if symptoms persist. Good hygiene practices, like washing hands and avoiding contaminated water, can help prevent the infection.