What is Trichinosis?

Trichinellosis is a zoonotic disease caused by Trichinella spiralis. People are infected by eating raw or undercooked larvae containing live Trichinella spiralis. The main clinical manifestations are gastrointestinal symptoms, fever, eyelid edema, and muscle pain.

Basic Information

English name

trichinelliasis

Visiting department

Internal medicine

Common causes

Trichinella parasites

Common symptoms

Gastrointestinal symptoms, fever, eyelid edema and muscle pain

Causes of trichinellosis

Humans become infected by eating raw or immature pig or other animal meat. The cysts in skeletal muscle can survive 57 days at 12 o'clock, and can survive 2 to 3 months in carrion. Insufficient fumigation or grazing is not enough to kill cysts. In addition, the spread of feces among animals has received some attention, and it is not impossible to spread the infection among humans, especially the fecal infection discharged within 4 hours after infection is the strongest.

Clinical manifestations of trichinellosis

The incubation period is 2 to 45 days, most of which are 10 to 15 days. The length of the incubation period is negatively correlated with the severity of the disease. The severity of clinical symptoms was positively correlated with the amount of infection.

Early

Equivalent to the adult in the small intestine stage. Can manifest nausea, vomiting, abdominal pain, diarrhea, etc., usually mild and temporary.

2. Acute phase

The larval migration period. Many ills arise. Main manifestations are fever, edema, rash, myalgia and so on. Fever is often accompanied by chills, and relaxation heat or irregular heat is common, most often between 38 and 40 ° C for 2 weeks, and the longest can be up to 8 weeks. At the same time as fever, about 80% of the patients developed edema, which mainly occurred in the eyelids, face, and eye-combining membranes. In severe cases, there may be edema in the lower limbs or the whole body. Rapid progress characterizes it. It lasts about 1 week. The rash often appears at the same time as fever, and it usually occurs on the back, chest, and extremities. The rash can be maculopapular, scarlet-like rash, or hemorrhoidal rash. Muscle pain is severe throughout the body. It usually occurs at the same time as fever or after fever and edema, accompanied by tenderness and marked fatigue.

The skin was swollen and indurated. Severe patients often feel pain during chewing, swallowing, breathing, and eye movements. In addition, the throat may have difficulty swallowing and hoarseness; the heart muscle may have dull heart sounds, arrhythmia, galloping rhythm, and heart insufficiency; the central nervous system is often manifested as headaches, meningeal irritation, and even convulsions, coma, paralysis Etc .; lung lesions can lead to cough and lung snoring; eye symptoms often blind, blurred vision and diplopia.

3. Recovery period

As cysts form in the muscles, acute inflammation subsides, and systemic symptoms such as fever, edema, and myalgia gradually decrease. The patient was significantly wasted, fatigued, myalgia and sclerosis persisted for months. The symptoms eventually disappeared due to calcification of the cyst wall and larval death. Severe cases are cachectic and die from prolapse, toxemia, or myocarditis.

Trichinellosis test

Blood image

During the active phase of the disease, there is moderate anemia and an increase in the number of white blood cells, the total number of which is (10-20) × 10 ⁹ / L. The eosinophils are significantly increased, the highest being 3 to 4 weeks after onset; it can reach 80% to 90%. It lasts for more than six months; people with severe infection, low immune function, or bacterial infection may not increase.

2. Etiological examination

Specimens should be taken for encapsulation or pepsin digestion and centrifugation. The sediment should be examined by methylene blue staining for microscopy, looking for larvae or feeding residual meat to animals (rats). After 2 to 3 days, check the intestinal larvae. A caterpillar larva is diagnosed. If 10 days have elapsed, a muscle biopsy can be done, often taking a deltoid or gastrocnemius biopsy, the positive rate is higher.

In the early stages of diarrhea, larvae can be found in the stool, and larvae can be found in the centrifuged blood, milk, pericardial fluid and cerebrospinal fluid during the transition period.

3. Immunological examination

(1) Intradermal test : Take 0.1ml of Trichinella spiralis larva extract antigen (1: 2000 1: 10000), and take 15 ~ 20 minutes after intradermal injection. The skin mound is> 1cm and the diameter of red halo is> 2cm. 0.1ml, when the intradermal injection of the other forearm is negative, the skin test is judged to be positive. This method has high sensitivity and specificity, the method is simple, and the results are obtained quickly.

(2) Serological examination of Trichinella spiralis soluble antigen to detect specific antibodies in patients' serum is helpful for diagnosis. The slide agglutination method, latex agglutination test, complement binding test, convection immunoelectrophoresis, indirect immunofluorescent antibody test, and enzyme-linked immunosorbent test can be used to detect the serum antibodies of patients, both of which have better sensitivity and specificity. Such as the increase in serum antibodies in the recovery phase more than 4 times more diagnostic significance.

(3) Trichinella larvae were found on other muscle biopsies. Routine urine tests may include proteinuria and granules or waxy casts and red blood cells. In the course of 3 to 4 weeks, the globulin increased, while the albumin decreased, and even the ratio was inverted, and the immunoglobulin IgE increased significantly.

X-ray, B-ultrasound, electrocardiogram, etc. can be performed accordingly.

Trichinellosis diagnosis

Based on the epidemiological history and typical clinical manifestations of eating immature meat, it is not difficult to suspect the disease, and combined with the results of the etiological examination or immunological examination, the diagnosis is not difficult.

Differential diagnosis of trichinellosis

The disease should be distinguished from food poisoning, enteritis, typhoid fever, leptospirosis, angioedema and dermatomyositis.

Trichinellosis treatment

General treatment

Those who have obvious symptoms should rest in bed and be given adequate nutrition and water. Analgesics can be given for myalgia. Severe patients with significant heterosexual protein response or involvement of the myocardial central nervous system may be given adrenocortical hormones, preferably with an insecticide.

2. Pathogen treatment

Treat symptomatically according to the pathogen. Benzimidazoles can also be used, which have better efficacy and relatively mild side effects.