Isosporiasis, also known as cystoisosporiasis, is a human intestinal disease caused by the parasite Cystoisospora belli (previously known as Isospora belli). It is found worldwide, especially in tropical and subtropical areas. Infection often occurs in immuno-compromised individuals, notably AIDS patients, and outbreaks have been reported in institutionalized groups in the United States. The first documented case was in 1915. It is usually spread indirectly, normally through contaminated food or water (CDC.gov). Signs and symptoms
Infection causes acute, non-bloody diarrhea with crampy abdominal pain, which can last for weeks and result in malabsorption and weight loss. In immunodepressed patients, and in infants and children, the diarrhea can be severe. Eosinophilia may be present (differently from other protozoan infections). Cause
The coccidian parasite Cystoisospora belli infects the epithelial cells of the small intestine, and is the least common of the three intestinal coccidia that infect humans (Toxoplasma, Cryptosporidium, and Cystoisospora). Transmission
People become infected by swallowing the mature parasite; this normally occurs through the ingestion of contaminated food or water. The infected host then produces an immature form  of the parasite in their feces, and when the parasite matures, it is capable of infecting its next host, via food or water containing the parasite. Life cycle
At time of excretion, the immature oocyst contains usually one sporoblast (more rarely two). In further maturation after excretion, the sporoblast divides in two, so the oocyst now contains two sporoblasts. The sporoblasts secrete a cyst wall, thus becoming sporocysts; and the sporocysts divide twice to produce four sporozoites each.
Patients without active bleeding, but diagnosed aneurysms should have strict blood pressure control with antihypertensive drugs to decrease the risk of aneurysm rupture. Epidemiology
Since it was first reported in 1976 there have been 101 documented cases of Segmental Arterial Mediolysis. Although typically seen in older patients with an average age of 57 years old, it can affect patients of any age and does not favor one gender or the other. == References ==