Coccidiosis refers to gastrointestinal infections caused by microscopic, spore-forming parasites known as coccidia. These parasites are obligate intracellular, meaning they live inside host cells. While commonly associated with various animals, coccidiosis can also affect humans.
Coccidiosis in Humans
Humans can contract coccidiosis, primarily through infection with Cystoisospora belli. Other coccidian parasites like Toxoplasma gondii and Cryptosporidium can also infect humans, causing conditions such as toxoplasmosis and cryptosporidiosis. These parasites infect intestinal epithelial cells, leading to various symptoms.
Human transmission occurs when individuals ingest food or water contaminated with the parasite’s oocysts, which are microscopic, environmentally resistant spores shed in the feces of infected hosts. Direct fecal-oral transmission is less common for Cystoisospora belli because its oocysts are not immediately infectious when shed and require time to mature. This maturation process makes the oocysts capable of infecting a new host.
Symptoms of coccidiosis in humans often include watery diarrhea, which is often non-bloody, along with abdominal pain and cramping. Nausea, vomiting, loss of appetite, fatigue, and weight loss are also common. While healthy individuals may experience self-limiting illness that resolves within weeks, those with weakened immune systems can suffer from more severe, prolonged diarrhea, potentially leading to dehydration and malnutrition.
Management and Prevention
Diagnosing coccidiosis in humans involves laboratory analysis of stool samples to detect characteristic oocysts under a microscope. Multiple stool specimens may be necessary due to intermittent shedding. Specialized staining techniques can assist in identifying Cystoisospora oocysts. In some instances, if stool tests are inconclusive, diagnosis might require detecting intracellular parasite stages in intestinal tissue biopsies.
Treatment for coccidiosis involves antiparasitic medications. For Cystoisospora belli infections, a common treatment is trimethoprim-sulfamethoxazole (TMP/SMX), administered orally. Supportive care is also important, particularly rehydration to replace fluids lost due to diarrhea and vomiting, and electrolyte replacement to address imbalances. A bland, easily digestible diet can help reduce gastrointestinal irritation.
Preventing coccidiosis involves reducing exposure to infectious oocysts. Practicing good hygiene, such as frequent and thorough handwashing with soap and water, is important, especially after using the toilet, handling animals, or before preparing food. Ensuring access to safe, treated drinking water is also important; if water safety is uncertain, boiling it for at least one minute can eliminate potential parasites. Proper food handling, including thoroughly washing fruits and vegetables and cooking food to recommended temperatures, helps prevent transmission. Proper disposal of human and animal waste is also a measure to prevent environmental contamination.