Isosporosis

Introduction to isosporosis Isopporiasis is a parasitic protozoan disease caused by parasitic coccidia in the intestinal mucosal epithelium, causing intestinal mucosal damage. Clinical manifestations include diarrhea, nausea, vomiting, and abdominal tenderness. There are two types of Isospora parasitic in humans: lsosporabelli and I. natalensis. Isoflavans infected by humans are mainly spores of the genus Bemis, and Neisseria elegans is very rare. basic knowledge The proportion of illness: 0.002% Susceptible people: no special people Mode of transmission: insect vector transmission complication:

Etiology of isosporosis

(1) Causes of the disease

Isospora is parasitic in the terminal duodenum and proximal jejunal epithelial cells. The patient's feces contain oocysts, which are in the stage of infection. The oocysts are oblong and the size is about (20-33). Mm × (10 ~ 19) m, one end is slightly narrow, bottle-shaped, the inner and outer layers of the capsule wall are smooth and transparent, the inner layer is thin film, the outer layer is hard and the permeability is relatively low, and the freshly discharged oocyst usually contains one Spore cells, but sometimes there are two. When the feces are discharged, the spore cells are divided into two and secrete the wall of the capsule, forming sporangia of about 7 to 9 m × (12 to 14) m. The sporangia divides twice, eventually forming 4 sporozoites and a pellet of residual bodies. The sporozoites are slender as a crescent, so each mature oocyst contains two sporangia, each containing 4 sporozoites (Figure 1).

The life history of Isospora, including schizophrenia, gamete reproduction and sporulation (Fig. 2). The first two are carried out in the host. After eating food or drinking water contaminated by mature oocysts, the oocysts are in the small intestine. It is ruptured by the action of digestive juice, and the sporozoites escape and enter the intestinal mucosal epithelial cells to develop into trophozoites. After several schizophrenia, the trophozoites produce a large number of merozoites, and the schizonts rupture to release merozoites and invade adjacent ones. The epithelial cells continue their cleavage process. After about 1 week, part of the merozoites develop into females in the epithelial cells or in the intestinal lumen. Male gametocytes and female and male gametes form a zygote and secrete the sacs after mating. It develops into an oocyst, which is excreted in the body or with the feces and continues to develop.

(two) pathogenesis

The pathogenesis of this disease has not been elucidated. Invasion of the intestinal mucosal epithelium and repeated division can lead to intestinal mucosal damage and erosion, absorption function decline, and the parasite metabolites may also have toxic effects. Biopsy can be seen in small intestinal mucosal epithelial cells, mucosa The villi atrophy, and some patients showed fluff elongation and apical thickening or focal cilia low, the lamina propria had more collagen deposition, and a large number of eosinophils, monocytes and lymphocytes infiltrated, mucosal epithelium A large number of worms can be found at different stages of development. In the chronic patients, the intestinal mucosa is often shortened and the crypts are deepened; in addition to the eosinophils, the lamina propria can also be seen.

Isosporosis prevention

1, do not drink cold water, do not eat raw food and unclean fruits;
2, wash hands before and after meals, cut nails;
3. Cook the food thoroughly, especially when grilling or eating hot pot.
4, educate children to change the habit of eating fingers and biting nails;
5, it is best to wear children to wear dead pants to sleep, to prevent them from scratching the anus;
6. Wash the toys regularly or scrub the toys with 0.05% iodine solution;
7. Strengthen water source management to avoid water pollution;

Isosporosis complications Complication

Can cause chronic diarrhea, water and electrolyte disorders, persistent or fatty diarrhea, weight loss, etc., and can even cause death. Due to intestinal mucosal damage, leading to diarrhea, vomiting, etc., water and electrolyte disorders can occur, if the condition is not treated in time, or severe cases can lead to fatty diarrhea and malnutrition.

Symptomosis symptoms Common symptoms Mucus, abdominal discomfort, low heat, loss of appetite, nausea and diarrhea

Isospora infection can last for weeks or even years, most of the symptoms are mild, diarrhea is its main symptom, stool is more common with mucus, eosinophils are often present in large numbers, but neutrophils are rare, diarrhea several times a day However, there are reports that it lasts for more than 20 times a day for 3 to 4 days, and the periodic episodes last for several months. In addition, patients often have abdominal cramps, fever, nausea, vomiting, loss of appetite, weight loss, etc. A few patients have Intestinal malabsorption, especially fat malabsorption, large fat particles in the stool, foreign "volunteer" experimental infection or accidental infection of laboratory workers, symptoms are abdominal discomfort, low fever, diarrhea is more common, diarrhea begins with infection After 1 week, it can be self-healing for 5 to 10 days, but the oocyst discharge in the stool can continue for 10 to 20 days. There is an asymptomatic worm in the disease, but the oocysts are often missed in the stool, accurate asymptomatic The number of insects cannot be determined.

Isosporosis check

Microscopic examination can improve the detection rate of oocysts after floating stools with zinc sulphate. The spore coccidia oocysts have high transparency and are easily missed in the direct smear. At this time, the microscope aperture can be reduced until the smear The other protozoa or bacteria in the outline are clear.

Diagnosis and identification of isosporosis

The diagnosis of this disease depends on the discovery of isofoclay oocysts in the stool, taking fresh stool and floating concentration after zinc sulfate floating, the microscopic examination can improve the detection rate of oocysts, and the spore coccidia oocysts have higher transparency, in direct smear It is easy to miss. At this time, the microscope aperture can be reduced until the other protozoa or bacteria in the smear are clearly defined, which is helpful for identification. The identification is mainly based on the size of the oocyst, the number of sporozoites, and whether there are sporangia around the sporozoites. In addition to stool examination, small intestinal mucosal biopsy and intestinal contents examination, may also find the various stages of the development of isospores, duodenal drainage, some patients may also get positive results.

The disease should be distinguished from other diarrhea. Isospores are widely distributed in the tropics and subtropics, especially in the differences between amoebic dysentery, intestinal trichomoniasis, giardiasis, and cryptosporidiosis. However, this patient's body infection is quite rare.

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