Strongyloidiasis

Introduction to roundworm disease Strongyloidiasis is an infectious disease caused by the invasion of Strongyloidesstercoralis. The pathogen mainly infects the human body and can also be parasitic on animals such as cats and dogs. Most of them are chronic asymptomatic infections, diffuse ( Heavy cases invading the organs outside the intestines are often life-threatening. basic knowledge Sickness ratio: 0.05% Susceptible people: no special people Mode of infection: digestive tract spread Complications: shock, respiratory failure, bronchial pneumonia, sepsis

Etiology of roundworm disease

Form (30%):

The two life stages, the parasitic stage and the auto-living stage, are only females in the parasitic period, parthenogenesis, and male and female in the spontaneous period.

The parasitic female is 2.2 to 2.5 mm long and 0.03 to 0.05 mm wide. It has a funnel-shaped oral cavity, a cylindrical long esophagus (1/3 to 2/5 of the body length), a sharp end, and an anus The ventral surface of the ventral surface is in the ventral surface of the posterior 1/3 of the body. The ovary, fallopian tube, and uterus are connected to the vagina and the vulva. The egg shell is thin and transparent. After the output is 70m × 43m, it can rapidly develop into a larva and hatch. (5 ~ 6h), in addition to severe diarrhea or laxatives, it is usually not easy to find eggs in the feces.

The male and female adults in the spontaneous period are smaller than the females in the parasitic period, the esophagus is short, and it is double-spherical. The auto-living male is 0.7 mm × (0.035-0.05) mm, and there are two brown crosses. Connected, female 1.0mm × 0.05mm, the tip of the tail, the vulva opening in the middle of the body, the eggs are similar to those in the parasitic period.

Life history (30%):

Parasitic females mainly parasitize in the small intestine (especially the duodenum), and can also be found in the large intestine, bile duct, pancreatic duct, lung, urinary tract, esophagus, etc., spawning in the deep mucosa, rapidly hatching into rod-shaped sputum In the intestinal lumen, the sputum develops in the intestine, grows and grows longer, excretes with the feces, develops in the soil, and the molt becomes an infectious filamentous mites, which invade human skin at appropriate opportunities. Or mucous membrane, enters the bloodstream to the lungs, enters the intestine through the trachea, pharynx, esophagus, and stomach, and develops into females in the mucosa (the human body has a period of about 7 days), and some rod-shaped mites are released before being discharged from the human body. It becomes a filamentous sputum and directly invades the intestinal mucosa or anal skin to cause self-infection. If the rod-shaped scorpion in the parasitic period reaches the outside of the body and does not develop into a filamentous sputum and develops into a self-born female and male, it participates in the spontaneous period. In the life ring, the male and female adults in the self-breeding period mate to lay eggs, hatch into rod-shaped mites, and then turn the scorpion into adult worms... and start to live spontaneously in the camp. When the conditions are unfavorable, they can become infected with the filaments and infect the human body and enter the parasitic period ( figure 1).

Other (20%):

The pathogenicity of A. faecalis is composed of three factors including the damage stimulation of the intestinal mucosa and the inflammatory reaction of the host and the ulceration of the bacteria in the digestive tract. The intestinal mucosal lesions can be divided into catarrhalis. Sexual, edematous and ulcerative, catarrhal enteritis is the most common, due to more infections, the lesions will increase, edema and ulcers, granuloma formation or fibrosis at the edge of the ulcer, stomach and colon of critically ill patients Can also be affected, colonic ulcers are multiple, patients with chronic wasting diseases, immunocompromised patients and long-term use of hormones and other immunosuppressive therapy patients, often induced filamentous sputum spread to all organs of the body, resulting in diffuse circle Nematode disease, multiple organ damage.

Roundworm disease prevention

The prevention principle of this disease is similar to hookworm disease, and the fecal harmless treatment and individual skin protection should be done well. Patients should be thoroughly treated to avoid repeating their own infection.

Some scholars have immunized mice with soluble proteins extracted from infected larvae to obtain protective IgG antibodies, which laid the experimental foundation for the preparation of specific immune vaccines.

Roundworm disease complications Complications, respiratory failure, bronchopneumonia sepsis

Mainly in critically ill patients, complications are often the cause of death, such as shock, respiratory failure, bronchial pneumonia, sepsis, etc., the mortality rate is about 26%, up to 50% to 86% in patients with systemic disseminated infection.

Symptoms of roundworm disease common symptoms weak upper abdominal pain sepsis abdominal pain nausea and vomiting acute abdomen depression circulatory failure maculopapular bloating

About 2/3 of the infected patients were asymptomatic. It was reported that there were asymptomatic infections of the insects for 40 years, and the dominant manifestations of the disease were different.

1. larval (juvenile) migration symptoms

For the most common early manifestations, 66% to 84% of patients have maculopapular or rash around the anus of the buttocks or other infected areas. About 5% of patients have cough caused by lung infiltration, asthma, hypothermia or allergic pneumonia, only Very few patients have severe respiratory symptoms such as difficulty breathing, cyanosis, hemoptysis and complicated bacterial bronchopneumonia.

2. Gastrointestinal symptoms

Moderate and severe patients often have abdominal pain, diarrhea, vomiting, anorexia or constipation. The abdominal pain is different. It is usually a burning or cramping of the upper abdomen. Sometimes it is confused with ulcer disease or acute abdomen. The diarrhea is often watery or thin. However, bloody mucinous diarrhea may occur, and some may have paralytic ileus, abdominal distension and electrolyte imbalance, dehydration, and circulatory failure.

3. Other

Different symptoms appear, such as meningitis, urinary tract infection, etc., some patients suffer from fever due to disintegration of worm body metabolites or worms, general malaise, irritability, depression, insomnia and other neurasthenia Syndrome, some complicated by bacterial or fungal sepsis, when the patient is in low immune function, such as AIDS patients, the roundworm can cause disseminated hyperinfection, causing multiple organ failure or death.

Examination of roundworm disease

1. When leukocytes and eosinophils increase acute infection, white blood cells can reach (8 ~ 30) × 109 / L, eosinophil ratio is often between 0.25 ~ 0.35, even up to 0.85, after the acute phase returns to normal, Eosinophils in severely infected patients may be normal or reduced, indicating poor prognosis.

2. Fecal pathogen examination For patients with diarrhea, the eggs produced by the larvae may be found, but the larvae are mainly investigated, but the cause of the larvae is small, and the larval discharge is not regular. With the conventional stool test method, the missed diagnosis rate can be as high as 70%. The methods for checking larvae in feces are:

1 Direct smear to find larvae.

2 aldehyde ether centrifugation.

3Baermann funnel separation method, take a round copper wire yarn, four sides folded into a basket shape, bottom lining gauze two layers, placed in a funnel with a diameter of 15cm, a funnel outlet connected to a control rubber tube, the patient's feces in the appropriate amount of gauze On the layer, add appropriate amount of warm water of 40 ~ 46 °C to infiltrate the feces, the larvae can move to the water and concentrate on the bottom of the funnel. After a few hours, the tube can be opened for microscopic examination (anatomical mirror or low power microscope).

4 Agar plate incubation method, the detection rate of larvae in the feces can reach 96.8%, and the unique larval trace phenomenon can be found on the agar plate, and the larvae can be collected by duodenal liquid fluoroscopy.

3. Serological IgE levels were elevated in more than half of patients with pathological serology, but the specific IgE levels in patients with systemic disseminated infection were significantly lower than those in non-dispersive infections. About 90% of patients had serum fibroblast antigens. IgG and IgE antibodies, US CDC using enzyme-linked immunosorbent assay (ELISA) to detect 76 patients diagnosed by fecal larvae, the sensitivity of 94.6%.

4. Adult intradermal and indirect fluorescence tests can aid diagnosis.

5. Other inspections of C. elegans invading the central nervous system can cause protein in the cerebrospinal fluid, increase in cells, and occasionally find larvae of C. elegans. This disease can also cause liver damage.

Diagnosis and identification of roundworm disease

diagnosis

Diagnosis is based primarily on epidemiological history, clinical manifestations, and detection of fecal larvae.

Differential diagnosis

The disease should be differentiated from other intestinal parasitic diseases and other causes of eosinophilic pneumonia, and identification with hookworm disease, ulcer disease, amebiasis.

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