Boa filariasis is called Malay filariasis for short, which causes Malay filariasis, also known as migratory mass or Karaba filariasis mass.Adults parasitize in the subcutaneous tissue of the human body and often crawl under the conjunctiva periodically.Intermediate host: Tabanus maculata.
The pathogenic stage of Rohia silk worm is mainly adult worm.As the migration of the worm and its metabolites cause the inflammatory reaction of the subcutaneous connective tissue, it can lead to a wandering mass or swelling. When the worm leaves, the mass disappears, which most often occurs in the wrist and ankle. The patients haveskin ItchAnd ant walking sensation.Adults can crawl out of the body from under the skin, or invade the stomach, kidney, bladder and other organs. Patients may have proteinuria.Adults also often invade the anterior chamber of the eye and migrate under the conjunctiva or across the bridge of the nose, causing severe conjunctivitis, and also causing bulbar conjunctival granulomaEyelid edemaandExophthalmosPatients often show strange itching of the eyes.
Key points for diagnosis of this disease
Patients have a history of living in epidemic areas, such as people from or to Africa;Typical eye itching, wandering subcutaneous mass with skin itching and other symptoms;The worm can be seen under the bulbar conjunctiva or under the skin;Peripheral blood eosinophils increased.Detection of microfilaria in blood or bone marrow fluid, and detection of adult worms in eye or subcutaneous mass biopsy are the basis for diagnosis of the disease.
Therapeutic drugs
Marine synbioticsAnd furazolidone.IvermectinandMebendazoleIt can clear microfilaria in blood, but has no effect on adults.Apply repellents (such asDimethyl phthalate）It can prevent the transmission vector Tabanus from stinging, so as to avoid the infection of Roa filariasis.
Disease description
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There are two kinds of nocturnal periodic and nocturnal subcyclical forms of Brugia malayi.Adult morphology andFilaria bancroftiSimilar, the main difference is that there are 8-12 pairs of mastoids on both sides of the anal foramen of the males of Bancroft, 1-2 pairs of mastoids can be seen between the anal foramen and the caudal end, while there are only 2 pairs of mastoids on both sides of the anal foramen of the males of Malay, and there is no mastoid between the anal foramen and the caudal end.The life history of Brugia malayi is different from that of B. bancrofti: 1. The intermediate host mosquito is differentCulex quinquefasciatusandCulex pipiens pallensMalayan filariasisAnopheles sinensis, Anopheles nangula and Anopheles mansoni;2. The peak time of microfilariae of Brugia malayi in converted blood was from 8 p.m. to 4 a.m;3 The nocturnal periodic form of Brugia malayi is mainly parasitic on humans, while the nocturnal sub periodic form can be parasitic on a variety of animals except humans, such as leaf monkeys, wild cats, domestic cats, etc., and can spread among animals in the deep.Malayan filariasis is endemic only in Asia. It is distributed in 10 provinces, cities and autonomous regions in China, and exists in many provinces, cities and autonomous regionsFilaria bancroftiMixed infection with Brugia malayi.
Anopheles sinensis
The common characteristics of malayan filariasis endemic areas are: abundant water, large rainfall or springs, and most of them are rice areas suitable for mass breeding of Anopheles.Therefore, Malay filariasis is mainly distributed in: 1 Zhejiang, Fujian, Jiangxi and the eastern mountainous areas in southern Anhui;2 Jianghan limnetic plain area;3 Guizhou Guilin region;4 Emeishan District, Sichuan Province;In addition to people with microfilaria in their blood, some animals infected with Malayan filariasis can also be the source of infection.The media are mainlyAnopheles sinensisThe mosquito density is high in rural areas, so malayan filariasis is widespread in rural areas.
Symptoms and signs
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1、Acute lymphadenitisandLymphangitisIt usually occurs in the lower extremities, with swelling and pain in the groin and abdominal lymph nodes as it grows, followed by lymphangitis in the inner thigh spreading from top to bottom, known as "retrograde lymphangitis". When the inflammation affects the internal capillaries, local redness, swelling and tenderness occur, commonly known as "Liuhuo".lymphadenitisAnd lymphangitis often presents periodic attacks, mostly after fatigue, with high fever in summer and autumn (38 ℃ - 39 ℃).In addition, there are general symptoms such as fatigue, anorexia, muscle joint pain, limb pain and headache.
Filaria bancrofti
2. The filarial fever suddenly chills and high fever periodically, and subsides after 2-3 days.Some have only low heat without chills.Locally NonelymphadenitisOr lymphatic vessel, sometimes with.Filarial fever may be caused by deep lymph nodes orLymphangitisCaused by.Bancroftian filariasisFilarial fever is common in epidemic areas.
3. Seminal vesiculitis, epididymitis and orchitis are characterized by scrotal pain spreading downward from the groin on one side of the fever agent and radiating into the thigh.Local examination showed that the testis and epididymis were swollen with tenderness. One or more nodular masses on the seminal vesicle had obvious tenderness, which could subside after several days. The masses became smaller and harder. Repeated attacks could cause the masses to gradually increase.
4. LungEosinophilsInfiltration syndrome, also known as filarial eosinophilia, is characterized by chills, fever, cough, asthma andLymph node enlargement。The lung has migratory infiltration, the X-ray chest film shows increased bronchial vascular markings and extensive miliary spot shadows, and eosinophils and Xialei crystals can be found in sputum.Peripheral blood eosinophils increased, accounting for 20% - 80% of the total number of white blood cells.Microfilariae can often be found in blood.
（2） The late stage (lymphatic obstructive disease stage) is caused by hyperplasia and obstruction of the lymphatic system. Inflammation still occurs repeatedly, so inflammatory and obstructive diseases overlap in most cases.
1、Lymph node enlargementAnd recurrent lymphangitic varicoselymphadenitisAnd the varicosity of lymph sinus in lymph node are the factors leading to lymph node enlargement.The swollen lymph node and its surrounding centripetal lymphatic varices form a mass, which looks like a spongy cyst on palpation. There is a sense of hard nucleus, and lymph can be obtained by puncture, sometimes microfilaria can be found.Lymph node enlargement is more common in the groin.Lymphatic varices are often found in the groin, spermatic cord, scrotum and inner thigh.Today's varicoceles of the lymphatic vessels often adhere to each other to form cords, which are difficult to distinguish from varicoceles of the spermatic cord, and most of them coexist.
2、Hydrocele of tunica vaginalisIt is common. The mild cases are often asymptomatic. The scrotal volume of the patients with more fluid accumulations increases, wrinkles disappear, and there is a sense of falling without pain. The light transmission test is positive.The effusion can be grass yellow lymph or milky white chyle, and microfilaria can be found in the sediment of effusion.
3. One of the main clinical manifestations of chyluria.Lymphatic obstructionThe lymph in the lymphatic vessels of the intestinal trunk flows back and enters the urinary tract to form chyluria. The mixture with bleeding at the lymphatic fistula is called chyluria.It often occurs suddenly. Before the attack, there may be no symptoms. There may also be chills, fever, pain in the waist, pelvis and groin, followed by chyluria.Generally, the disease lasts for several days or weeks after onset and stops automatically, but it can be induced again after fatigue or eating greasy food.The urine is milky white and pink if mixed with blood. After standing, it is divided into three layers: the upper layer is fat, the middle layer is clear, and the lower layer is pink sediment, containing red cells, specific cells, lymphocytes, and sometimes microfilaria can be found.
4. Elephant skin swelling andLymphedemaThe two are often difficult to distinguish clinically, and often coexist.Lymphedema and reversible edema. The lymph flow can subside automatically after improvement. If the lymph flow can not be recovered, it will develop into elephantiasis over time. At this time, there is or is no concave edema, and the skin is hypertrophic, hard, non sweating, and dry. Later, there is excess fibrosis,Rough skinThere are new folds and warty nodules.Because of the local circulation disorder, the resistance is reduced, and it is easy to lead to streptococcus or other pyogenic bacteria infection, forming chronic ulcers.Elephant skin swelling mostly occurs in the lower limbs, which can develop rapidly and seriously in the whole leg, and can also cause scrotal elephant skin swelling.
Cause of disease
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The life history of Brugia malayi is:
1. The intermediate hosts of Brugia malayi are Anopheles sinensis, Anopheles anopheles narrow and Anopheles mansoni;
2. The peak time of microfilaria malayi in converted blood was from 8 p.m. to 4 a.m;
3. The nocturnal periodic form of Brugia malayi is mainly parasitic on humans, while the nocturnal sub periodic form can be parasitic on a variety of animals, such as langur monkeys, wild cats, domestic cats, etc., and can spread among animals.Malay filariasis is endemic only in Asia. In China, it is distributed in 10 provinces, cities and autonomous regions. There are multiple provinces, cities and autonomous regions with mixed infection of B. bancrofti and B. malayi.The common characteristics of malayan filariasis endemic areas are: abundant water, large rainfall or springs, and most of them are rice areas suitable for mass breeding of Anopheles.Therefore, Malay filariasis is mainly distributed in: 1 Zhejiang, Fujian, Jiangxi and the eastern mountainous areas in southern Anhui;2 Jianghan limnetic plain area;3 Guizhou Guilin region;4 Emeishan District, Sichuan Province;In addition to people with microfilaria in their blood, some animals infected with Malayan filariasis can also be the source of infection.
Pathophysiology
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The incidence and pathological changes of filariasis are mainly caused by adults, and the infected larvae also play a role, which has little relationship with microfilaria in blood.The occurrence and development of the disease depends on the type of filarial worm, the immune response of the body, the frequency of infection, the number of infected larvae entering the human body, the parasitic site of the adult worm, and whether it is combinedSecondary infectionAnd other factors.When the larva enters the body and develops into an adult, the metabolites of the larva and the adult, including the larval molting fluid, the excreta in the uterus of the worm and the lysates of the dead worm, can cause the tissue reaction of the local lymphatic systemSystemic allergic reaction, manifested as periodic attackLymphangitisLymph node spread and filarial fever.The late stage was the result of pathological changes of lymphoid tissue and secondary bacterial infection.It is now believed that the immune mechanism is the main reason for pathological changes.The immune response is related to the damage of the lymphatic system. Acute lymphangitis is considered as type 1 or type 3 allergy, and the group of group C filariasis belongs to type 4 sideband reaction.In the early stage, it is mainly exudative inflammation,Hyperemia of lymph nodes, lymphangitic wall edema, lumen filled with pink protein liquid andEosinophils。Then, there was a granulomatous reaction in the lymph nodes and lymphatic vessels. The center of the granuloma was a deformed adult worm and eosinophils, surrounded by fibrous tissue andEpithelioid cell, you have couragelymphocyteSimilar to plasma cellTuberculous nodule。Endothelial cells of lymphatic vessels proliferate, intima thickens and fibrotic lumens form polyps or fibrous emboli, and finally lymphatic vessels form fibrous cords, which is called obliterative lymphangiitis.Obstruction of the lymphatic system causes the pressure in the distal lymphatic vessels to increase and form lymphatic varices, and even in the tissue, because of its high protein content, it constantly stimulates the proliferation of fibrous tissue to thicken and harden the subcutaneous tissue and form elephantiasis.Due to the local circulation barrier, the reduction of skin resistance is easy to cause secondary bacterial infection, which aggravates and worsens elephantiasis, and even causes local ulcers.
Diagnostic Checks
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Laboratory examination: For patients with anaphylaxis at the early stage of filariasis, the total number of white blood cells is usually 10-20 × 109/L, mainly eosinophils, accompanied by bacterial infectionNeutrophilsSignificantly higher.
（1） Pathogenic examination to detect microfilaria in blood and body fluid is the only reliable method for diagnosis of early filariasis.
1. The detection rate of blood microfilaria was the highest from 10 p.m. to 2 a.m.
Methods:
(1) Thick blood slide method: three drops of earlobe blood are made into thick and thin blood slides on the slide, which are hemolyzed after drying, and stained for microscopic examination;
(2) Blood method: add a large drop of water on the slide behind the earlobe to dissolve blood and dilute it. After the slide is covered, look for microfilaria under the ground power microscope. The microfilaria freely swings, curls back and forth, and is easier to identify.The method is simple, but the positive detection rate is low;
(3) Concentration method: take 2ml of anticoagulant venous blood, add 10ml of rectification for hemolysis, shake up, centrifugate and precipitate, and take sediment for microscopic examination. The positive rate of this method is high;
(4) Inducement in the daytime: After taking 100mg of ethazine orally, peripheral blood was collected for microfilaria 15, 30 and 60 minutes respectively, and the detection rate was low;
(5) Membrane filtration method: 2ml of anticoagulant venous blood was filtered through the nuclear pore membrane with a pore diameter of 3um, and then the membrane was removed. After 5 minutes of staining with hot hematoxylin, the microscopic examination was performed.The detection rate and the number of microfilaria detected by this method were higher than those by thick blood slice method and concentration method.
2. Various body fluid microfilaria examinations can be performed on specimens of hydrocele, lymph, chyluria, chylous ascites, chylous pleural effusion, pericardial effusion and bone marrow.
（2） Immunological examination
1. In the batch test, 0.05ml of canine filariasis antigen was injected into the forearm of the subject, and 15 minutes later, those with papule diameter>0.9cm were positive.This test has high sensitivity and specificity, and the coincidence rate with the detection of microfilaria in blood is 86.2% - 94.1%.
2. In the indirect fluorescent antibody test, adult bovine filariasis is used as antigen in China. The positive rate of antibodies in patients' serum is 85% - 99.2% by indirect fluorescent antibody method.This method is highly specific and sensitive, suitable for epidemiological investigation, and can reflect the effect of prevention and control.
3、ELISAThis method has high sensitivity, strong specificity and simple operation, which is an ideal auxiliary diagnostic method for this disease.
4. Detection of circulating antigen is a specific diagnostic method with high sensitivity to microfilaria positive patients, but it is less sensitive to microfilaria negative patients.Using monoclonal antibodies to detect circulating antigens can be used as a detection method for evaluating the efficacy of anti filariasis drugs.
（3） Molecular biological examination
DNA hybridizationThe test and PCR can be used for the detection of microfilaremia, especially for those with small amount of microfilaria in the blood and who need to be identified.The diagnosis is based on the history of living in the epidemic area, with repeated attackslymphadenitis, lymphangitis, chyluria, spermatitis, elephantiasis and other clinical conditions, that is, filariasis should be considered.The diagnosis can be established when microfilaria is found in the peripheral blood and body fluid.If filariasis is suspected but microfilaria is not detected, a large dose of ethamzine (Hai Qunsheng) can be used for therapeutic diagnosis. If fever, lymphatic system reaction and lymph nodes occur, the diagnosis can be established.AcuteLymphangitisLymphadenitis should be distinguished from bacteria.Attention andinguinal hernia difference.The relationship between spermatitis and epididymitisTuberculosis of epididymisidentify.Enchanted urine is mostly seen in filariasis, but it is also occasionally seen in the obstruction of lymphatic pathway caused by extensive destruction of retroperitoneal lymphatic system caused by tuberculosis, tumor, echinococcosis and other factors.
Treatment plan
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Pathogen treatment
The first choice of drug is ethamin, which has a killing effect on microfilaria and adults. After taking the drug, the reaction is serious, and the treatment of filariasis must be repeated within several years.For adults, ethambuzine can be taken 0.6g/d in three times for 7 days, with a total dose of 4.2g;There are many microfilaria in the blood. The well prepared deep patients can take 1.5g in the afternoon every day for 2 days, or 0.75g twice a day for 2 days, or 1.0g in the afternoon every day for 3 days, with a total dose of 3.0g;The low-dose long course method can also be used, once a week, 0.5g each time, for 7 weeks, with a total dose of 3.6g.
In the epidemic area, the whole people can take medicine to avoid missing treatment of patients with small amount of microfilaria in blood or chronic patients.Adults should take 6 mg/kg of ethazine each time, children should take it at their discretion, once a week or half a month, a total of 12 times. Adults can also take 0.5 g once a day.Released after ethazine kills microfilariaAlloproteinIt can cause allergic reactions, such as fever, joint pain and rash.Subsequently, when the drug acts on the adult, the lymphatic system may react, such asLymphangitis, lymph node swelling and pain, lymphangiectasia and lymphangienodules, etc.Serious heart, liver and kidney diseasesActive pulmonary tuberculosis、Acute infectious diseaseThe treatment of ethaminazine for women within 3 months of pregnancy or more than 8 months of pregnancy and women in Yueqing period should be postponed or contraindicated.
Symptomatic treatment
1. Lymphangiitis andlymphadenitisDelicious antipyretic analgesic or prednisone, and antibacterial drugs are added to those with secondary bacterial infection.
2. When chyluria attacks, you should stay in bed and rest, eat less fat and drink more water. The drug treatment effect is not satisfactory.For those who can not recover after a long time of treatment, 20% sodium iodide or 1% - 2% silver nitrate 6-10ml can be used as intrarenal irrigation, which has certain effect.In patients with intractable chyle material, renal pedicle lymphadenectomy or lymphatic bypass may have satisfactory results.
3. Elephant skin swelling andLymphedemaComprehensive therapy based on rod binding may be effective.Huge scrotum or mammoderma can be surgically reshaped,Hydrocele of tunica vaginalisfeasibleTunica vaginalis testisThe treatment of elephantiasis of lower extremities with the turnover operation of microvascular lymphatic anastomosis of the leg and fiber shell can achieve satisfactory results.
disease prevention
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1. General survey and treatment: In summer, people over 1 year old in the epidemic area will be surveyed, and in winter, those with positive microfilaria or those with negative microfilaria but with a history and signs of filariasis will be generally treated.
2. Eliminate mosquito breeding grounds.Use mosquito nets correctly in mosquito season;When working outdoors, use anti mosquito oil, mosquito repellent or other repellents to coat the skin of exposed parts, and use anti mosquito nets on the head.
3. To protect the susceptible population, Haiqunsheng salt therapy was adopted in the epidemic area. Each kilogram of salt was mixed with 3g Haiqunsheng salt, with an average of 16.7g of salt per person per day, containing 50mg Haiqunsheng. If used continuously for half a year, the positive rate of microfilaria in the population could be reduced.
Medication safety
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The infection rate and incidence rate between 20 and 25 years old are the highest, and those under 1 year old are rare.
