Contents
Isosporosis is an invasive disease of the gastrointestinal tract caused by Isospora belli, a coccidial protozoan. In people with a weakened immune system, the infection manifests itself as intense diarrhea with abdominal pain and fever.
The incidence of isosporosis
Isosporosis is a cosmopolitan parasitosis, although it is much more common in regions with a tropical climate. Faecal oocysts are an invasive form of the parasite. Isosporosis is spread by the fecal-oral route. The source of infection is water or food contaminated with the pathogen.
Isosporosis – causes
Isospora belli, a protozoan belonging to coccidia, is the etiological factor of isosporosis.
The mechanism of the development of the disease
In the duodenum and small intestine, sporozoites are released from the oocyst and the mucosa is invaded. Isospora belli is parasitic in the epithelial cells of the duodenum and small intestine. The invasion causes flattening and then atrophy of the intestinal villi, intestinal gland hyperplasia (Lieberkühn’s crypt), infiltration of mononuclear cells in the epithelial stroma (in the lamina propria – lamina propria). Inflammation leads to diarrhea and other malabsorption symptoms.
Isosporosis – clinical symptoms
Isospora belli invasion is characterized by:
- watery diarrhea of varying severity,
- diffuse abdominal pain
- lack of appetite,
- general weakness,
- weight reduction,
- high body temperature or fever
- dehydration,
- electrolyte disturbances and eventually cachexia.
Isosporosis can be acute or chronic, sometimes lasting many months. During the invasion, fatty stools may occur as a sign of the malabsorption syndrome. There have been reports of cholecystitis and reactive arthritis. In HIV-infected people, isosporosis is an opportunistic infection. Recurrent invasion is less frequently observed in patients successfully treated with cART.
How to recognize isosporosis?
In diagnostics it is used microscopic examination of feces (direct examination, staining of preparations by the Ziehl-Neelsen method), which is the basis for the diagnosis of this disease. The invasion is confirmed by finding Isospora belli oocysts in the stool. It is also helpful staining with brilliant green in the Kinyouna modification – it is a method revealing vivid red staining of Isospora belli oocysts. Repeated microscopic examination of the stool also plays an important role due to the irregularity of oocyst excretion.
Isosporosis should be differentiated from:
- giardiasis,
- cryptosporidiosis,
- other protozoal invasions,
- diarrhea of bacterial etiology,
- celiac disease (celiac disease),
- functional disorders of the intestines.
Isosporosis and treatment
The therapeutic effects of isosporosis are obtained after the administration of co-trimoxazole (Biseptol, Bactrim forte) 2 times 960 mg for 3 weeks. In patients with immune deficiencies, it is recommended to double the daily dose (4 times 960 mg) for the first 10 days of treatment, and then 3 times 4 mg for 2-960 weeks. In the course of treatment of isosporosis, nitazoxanide, ciprofloxacin, pyrimethamine with sulfadoxine and folinic acid are also used. Supportive treatment – secondary prophylaxis – is quite common in AIDS patients.
Can isosporosis be prevented?
Preventive management in isosporosis consists in following the basic rules of hygiene, consuming water and food free from contamination with the oocysts of this protozoan.
Prognosis
The prognosis is favorable in immunocompetent patients. In turn, in HIV-infected patients, it depends on effective cART.
Source: J. Cianciara, J. Juszczyk, Infectious and parasitic diseases; Czelej Publishing House