Trypanosome "chancre"

Introduction African human trypanosomiasis, also known as sleeping sickness, is a vector-borne parasitic disease. Trypanosoma brucei and Trypanosoma brucei are the pathogens of African trypanosomiasis or African trypanosomiasis, and the vector insect is the tsetse fly. The Gambia trypanosomes are distributed along rivers or along forests in West and Central Africa. The Rhodosinia chinensis is distributed in shrubs and shrubs on the savannah and lakeshores of East Africa. African trypanosomiasis (African trypanosomiasis; African sleeping sickness) is divided into three clinical stages. The first is to invade the skin and cause different degrees of lumps and nodules, and evolve into a trypan sag, which occurs in about three minutes. One of the patients and the site often appears to be exposed to the bite of the tsetse fly for about 3 weeks. The second is the hemolymph stage, when there are periodic fever and parasitic symptoms, including burnout, posterior cervical lymphadenopathy, joint pain, headache and trunk rash, common myocarditis, and hemolysis And the cause of liver damage is also common to the appearance of jaundice. Once invaded into the brain, it will enter the third stage of meningoencephalitis. There will be headaches, insomnia, movement disorders and behavioral disorders. Other symptoms include malaise, severe appetite, body weight loss, etc. They may even have a loss of consciousness, coma and even death.

Cause

(1) Causes of the disease:

The pathogen is Trypanosoma brucei, which extensively invades wild animals and livestock. Three subspecies can cause disease to humans, namely Tbgambiense, Tbrhodesiense, Brinell. Tbbrucei, the former causes Gambia trypanosomiasis, the second causes Rhodesia trypanosomiasis, the latter mainly causes wild animals and livestock (bovine-based) nagana disease, rarely caused Clinical cases, so it is not detailed.

The extracellular parasitic worms of the Trypanosoma brucei are closely related in their subspecies. Therefore, there is a nucleus in the center of the worm body, and there is a moving matrix at the back end. The flagella attaches to the moving matrix and reaches the worm along the wavy membrane of the worm body. After the front end of the body is free, the shape of the trypan worm is variable, and the shape is long spindle-shaped. It has a slender shape (length 20 ~ 40 m, free flagella length of 6 m) or a thick short type (length 15 ~ 25m, width 3.5m, free Flagella is shorter than 1 m or flagella is not free. Slim is more common in peripheral blood and is fusiform; thick and short are more common in tissues.

Its life history is divided into the teetee fly, which belongs to the genus Glossinae and the human body. When the tsetse sucks the patient or the sick animal (beast) blood, the trypanosome enters the fly with the blood. The midgut divides and multiplies, penetrates the intestinal wall and swims to the anterior stomach to enter the esophagus, forms the upper flagellate body in the parotid gland, and finally forms an infectious flagellate. This stage takes about 12 to 30 days and makes the flies live for three months. It is contagious. In the human body stage, when the infective tsetse bites the human body, the trypan worm enters with the saliva, enters the bloodstream after local division and reproduction, and is mainly slender during the climax of worm. When the body produces immunity, it is more common in the form of thick and short.

The three subspecies of Trypanosoma are very similar. In the past, they mainly relied on their virulence, biochemical characteristics (isozymes) in certain animals, their breeding in the fly, clinical characteristics and popular areas. In recent years, they have been used. Molecular biology techniques to identify.

(2) Pathogenesis:

Tsetse bites often cause subcutaneous hemorrhage, where trypanosomes develop and multiply, causing inflammatory reactions, sometimes causing hard squats. Later, trypanosomes enter the blood circulation and lymphatic system, continue to divide and multiply, spread the whole body, and form lymphatic blood phase (I Period), trypanosomes can cause the body to produce antibodies, and its reproduction is also limited by antibodies. However, due to the mutated nature of the glycoprotein antigen on the surface of trypanes, the parasites evade the host's immune response, that is, "immune escape", resulting in a large number of hosts. IgM, while trypanosomes can still survive in the human body for a long time, and manifested as fluctuations in parasitemia, antigen-antibody reaction is also a factor causing disease, long-term infection, trypanosome can cause meningoencephalitis in the central nervous system ( Phase II).

Early lymph nodes and spleen enlargement, lymph node biopsy is positive for trypanosomiasis, cell infiltration more than 6 months after the disease and connect with connective tissue, intracardiac, adventitia can be seen spotted and massive bleeding, myocarditis is more common, manifested as heart Hypertrophy, pericarditis and effusion, central nervous system lesions, early meningeal lymphocytes, plasma cells and macrophage infiltration, late encephalitis, brain tissue congestion and scattered bleeding, and can be found in trypanosomes After 1 to 2 years, the basal ganglia, the midbrain, the diencephalon, the white matter, the gray matter and the peripheral nerves are demyelinated, and finally cause subcortical atrophy, hepatic bleeding, congestion and focal necrosis.

an examination

Related inspection

Parasite blood test enzyme-linked immunosorbent assay

Smear test: take the patient's blood smear staining microscopy. Lymph, cerebrospinal fluid, bone marrow puncture, lymph node puncture, etc. can also be taken for smear examination.

Serological diagnostic methods: commonly used enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody test, and indirect hemagglutination test.

Molecular biological methods: PCR, DNA probe technology.

Differential diagnosis

Primary syphilis (hard squat): Primary syphilis is also called primary plum or early sore, and its clinical damage is hard chancre and swollen lymph nodes. Patients with hard squats are extremely cumbersome, whether they are jealous or prognostic. Although the early syphilis patients are the most contagious, they are easier to diagnose and treat. If they can be diagnosed at an early stage and given rational treatment in time, they can complete the cure and avoid the purpose of broadcasting and harming society. Therefore, for the first phase of syphilis must be particularly particular.

Hoarding: It is a common disease in children, especially in children aged 1 to 5. It refers to chronic diseases such as weak body, thin face, yellowness and dryness caused by improper feeding or damage caused by various diseases. The phlegm and measles, convulsions, and smallpox are called the four major pediatrics. However, the "hoarding" in ancient times has been clearly distinguished from the "hoarding" of modern times. In ancient times, due to the limitation of living standards, people often hunger and insufficiency, inadequate feeding of children, and loss of spleen and stomach. The accumulation of hoarding is caused by malnutrition, which is equivalent to the "nutrition" of Western medicine. Now, with the improvement of people's living standards and the recent increase in only children, parents lack knowledge of feeding and blindly strengthen nutrition, which in turn increases the load of spleen, hurts the spleen and stomach, stagnates the coke, and reduces appetite. The lack of nutrition, so the current hoarding is mostly caused by nutritional imbalance. Clinical manifestations The basic processes of two trypanosomes after invading the human body include: the initial reaction phase and the hemolymph phase, as well as the meningitis period that invades the central nervous system. Initial reaction period: About 1 week after the patient was bitten by the tsetse fly, the local skin was swollen and a red dot appeared in the center, that is, the trypan sag.

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