Taenia saginata disease

　　1. Etiology

　　1. Taenia saginata, also known as beef tapeworm, obese tapeworm, and acanthocephalus tapeworm, has adult worms that are milky white in color, measuring 4 to 8 meters in length, with the longest reaching up to 25 meters. The anterior part of the worm is relatively thin and gradually becomes wider and flatter towards the back. The scolex is slightly square-shaped, with a diameter of 1.5 to 2.0 mm, lacking a rostellum and small hooks. The top is slightly concave and often gray due to pigmentation. It has four cup-shaped suckers, each with a diameter of 0.7 to 0.8 mm, located at the four corners of the scolex. The neck is slender and long, several times the length of the scolex. The strobila is composed of over 1000 segments, each segment having a complete set of male and female reproductive organs. The gravid segments account for about 10% of the total number of segments, with 15 to 30 branches in the uterus, distributed in a branching pattern on both sides of the segments, arranged neatly, containing a large number of eggs. The gravid segments can automatically detach from the strobila, often singly or in a few connected segments, excreted with feces. They can also be actively excreted from the anus. Since they can extend and contract, the eggs can be spread in the feces and around the anus, even on clothing. The detached segments often leave residues on the surface of clothing or bedding, which are discovered by the patient.

　　2、每一妊娠节片约含虫卵8万个，一条牛带绦虫每天可排卵约72万个，其中约50％在排出时已成熟，约40％须在宿主体外经过2周后方才发育成熟，粪检发现的虫卵一般卵壳已经脱落，仅为胚膜包被的六钩蚴，圆形或近圆形，直径36～42μm，黄褐色，胚膜3～3.8μm，表面有六角的网状纹理，胚膜内侧为幼胚外膜，薄而透明，紧包六钩蚴，牛带绦虫虫卵对外界环境抵抗力较强，在-4℃可存活168天，在粪便中亦可存活数十天，通常处理污水的方法也不能完全杀死虫卵。

　　3、牛带绦虫以人为其惟一终宿主；中间宿主则有牛科动物，野山羊，野猪，驯鹿，美洲驼，角马，狐，绵羊等，牛带绦虫寄生在人体小肠上部，其虫卵与妊娠节片随粪便排出，牛等动物中间宿主吞食被污染的饲料后，六钩蚴在十二指肠内孵出并借其小钩及穿刺腺溶解黏膜而钻入肠壁，随血流到达身体各部肌肉内，尤其多见于头部咀嚼肌，舌肌，心肌及其他骨骼肌内，经过两三个月发育为有感染性的囊尾蚴，成熟的牛囊尾蚴呈卵圆形，乳白色半透明囊状，约（7～10）mm×（4～6）mm，囊内充满液体，隔囊壁肉眼可见白色小点状头节，当人吞食有感染力的囊尾蚴后，在小肠受胆汁刺激，头节翻出并固着在肠黏膜上，长出节片形成链体，约经3个月发育为成虫，成虫在人体内寿命很长，达30～60年以上，囊尾蚴在牛肉内也可存活3年左右。

　　4、人是牛带绦虫的终宿主，但不能成为其中间宿主，牛带绦虫卵如被人吞食后一般认为不能发育与产生牛囊尾蚴病（牛囊虫病），故与猪带绦虫既以人为终宿主（猪肉绦虫病），也可以成为其中间宿主（猪囊虫病）有所不同。

　　二、发病机制

　　1、牛带绦虫寄生在小肠内，可自空肠下至回肠，吸附在小肠黏膜上，很少产生病理变化，但当寄生虫数较多时，绦虫头节吸盘可压迫并损伤肠黏膜，局部有轻度亚急性炎症反应，当脱落的节片沿着肠壁活动，遇回盲瓣阻挡时，活动增强，引起痉挛而产生腹痛等症状，也可因虫体结团造成部分性肠梗阻。

　　2. Animal experiments have shown that the extract of Taenia saginata can cause the host's intestinal motility and secretory function to be dysregulated, with decreased gastric juice secretion and decreased acidity. Animals may experience diarrhea, bloody stools, spasm, and respiratory and circulatory disorders. Large-scale injection of the extract can cause animal death, therefore, the metabolic products of the worm may have certain toxic effects on the host.

　　3. Taenia saginata has no digestive organs, but its segmental cortex surface is covered with many microvilli, which have the function of absorbing the nutrients of the host. When the worm absorbs a large amount of nutrients from the host's intestinal tract, it can cause hunger, anemia, and vitamin deficiency in patients. Due to the action of the worm's metabolic products, patients may have increased eosinophils, urticaria, itching, and asthma, and other allergic reactions.

　　4. After Taenia saginata infection, specific antibodies can appear in the patient's serum. Animal experiments show that calves immunized with Taenia saginata antigens can produce immunity against attacking infections; the colostrum produced by immunized cows can also give the suckling calves a high degree of resistance to Taenia saginata.

　　Taenia saginata infection can lead to systemic symptoms: fatigue, weight loss, nocturnal bruxism, anemia, malnutrition, and others. Important complications include intestinal obstruction and acute appendicitis, which are often caused by obstruction by the chain or segments.

　　It can occur at any age, with an incubation period from the ingestion of bovine cysticercus to the appearance of worm segments or eggs in feces, which takes about 3 months. The minimum age is 10 months, the maximum age is 86 years, but most cases occur in young and middle-aged people aged 21 to 40, with more males than females. The adult Taenia saginata in humans is usually one, but can also be up to 8, with the most extensive case reaching 31.

　　1. Symptom presentation

　　The severity is related to the number of parasites in the body.

　　1. Mild cases:Patients may have no symptoms at all; the most common symptom is the discovery of white segments in feces or underwear. Most patients seek medical attention due to this. Cysticerci are more often found in feces and excreted along with feces, and they often crawl out from the anus singly or in groups of two or three, making short movements around the anus and slipping to the perineum or thigh, causing anal itching and discomfort. Almost 100% of patients have the symptom of anal itching.

　　2. Severe cases:Symptoms may be so severe that they can even lead to death due to complications.

　　2. Gastrointestinal symptoms

　　Abdominal pain is the most common, seen in about half of the cases. Abdominal pain can occur in the upper abdomen, around the umbilicus, or in an unspecified location, and may be dull, hidden, piercing, biting, or burning. Some patients may have intestinal cramps. In addition, there may be nausea (15.7% to 46%), vomiting (11%), diarrhea (10% to 50%), and other symptoms. Decreased or increased appetite, and indigestion are more common.

　　3. General symptoms

　　Fatigue, weight loss, nocturnal bruxism, anemia, malnutrition, and others.

　　4. A few patients may have

　　1. Nervous symptoms:Dizziness, nervousness, insomnia, epilepsy-like seizures, syncope, and others.

　　2. Skin symptoms:Allergic pruritus, urticaria, nodular pruritus, etc.

　　Vigorously carry out health education, do not eat raw meat, adhere to the separation of raw and cooked utensils, strictly implement meat inspection, ban the sale of beef containing cysticerci, and ensure that chilled beef is kept at -23 to -22°C for 10 days to kill the cysticerci in the meat. Strengthen the management of human feces to prevent fecal pollution of pastures, feed, and water sources. Conduct mass screening and treatment of patients in epidemic areas. With the above comprehensive measures, Taenia saginata disease will be controlled.

　　1. Blood count

　　There are few changes in blood counts, generally no anemia, and eosinophils may slightly increase, often appearing in the early stage of the disease.

　　2. Egg examination

　　Eggs can often be found in the feces of most patients, but since Taenia saginata has no uterine opening, the eggs cannot be directly excreted into the intestines. They are only scattered into the feces when the gravid proglottids contract, move, or rupture. Therefore, not every patient can be found with eggs. Egg examination can be carried out using direct smears or thick smears, sedimentation methods, and floating concentration methods, among which the Hein thick smear method has a detection rate of up to 97% after three tests. An anal smear examination can be performed using a cotton swab, which is simple and has a positive rate roughly equal to that of the sedimentation method, and can be used for mass screening. Tapeworm eggs found in feces or swab smears cannot be distinguished from the species, as the eggs of Taenia saginata and Taenia solium are extremely similar, and it is difficult to distinguish them.

　　3. Gravid proglottid examination

　　The gravid proglottids of Taenia saginata often fall off the strobila and are excreted from the body with vomit or feces. Therefore, it is often a simple and accurate diagnostic method to inquire about vomiting or the presence of proglottids in feces. Observing the number and shape of the uterine branches of the gravid proglottids can be used to identify the species of intestinal tapeworms. The proglottids mixed in the feces can be picked out and washed with clean water, placed between two slides, and the number and shape of the uterine branches can be distinguished under the light with the naked eye. The number of uterine branches in the gravid proglottids of Taenia saginata is 15-30, showing a branching shape, while the number of uterine branches in the gravid proglottids of Taenia solium is 7-13, showing a branched shape.

　　4. Scolex examination

　　After 24 hours of deworming treatment, collecting all feces for examination of the scolex can help assess the efficacy and identify the worm species. The feces can be placed in a large container and washed repeatedly with clean water until the fecal fluid is clear. The sediment is then transferred to a glass container lined with a black background, and the scolex is carefully searched for. If worm bodies are tangled, they should be carefully untangled and followed along the chain to the thin end. The scolex of Taenia saginata is nearly quadrangular, large without a rostellum and small hooks, while the scolex of Taenia solium is round, smaller with a rostellum and two rows of small hooks. The expulsion of the scolex indicates complete treatment. If there is a possibility of multiple infections, attention should be paid to whether the number of chains is consistent with the number of scolexes.

　　5. Immunological examination

　　Intradermal tests, ring precipitation tests, complement fixation tests, or latex agglutination tests can be used to detect antibodies in the body, with a positive coincidence rate of 73.7% to 99.2%. Enzyme-linked immunosorbent assays can also be used to detect specific antigens in the host's feces, with a sensitivity of up to 100% and high specificity, without cross-reactions with Ascaris, small strongyle, hookworm, and whipworm.

　　6. Molecular biological examination

　　DNA-DNA dot blotting method can be used to detect Taenia saginata eggs. In recent years, polymerase chain reaction (PCR) has been used to amplify the微量specific DNA sequences of the exoskeleton surface substances of the eggs or the worm body shed in the feces, to detect the adult Taenia saginata or Taenia solium in the human body, with high specificity and sensitivity.

　　One, steamed meat with quisqualis indica

　　When symptoms such as malnutrition in parasitic diseases, loss of appetite, pale face, gradual weight loss, abdominal pain and distension, thirst, and irritability appear, this dish can be eaten.

　　Ingredients:

　　Quisqualis indica 5-10 grams, lean pork 100 grams, a little salt.

　　Preparation:

　　1. Shell the quince and take out the quince meat for later use.

　　2. Chop the quince meat and lean pork together, mix well, add a little salt, and make meat cakes with both ingredients.

　　3. Place the quince meat cake in a plate, steam it with high heat over water, or place it on top of the rice when cooking congee to steam it until it is ready.

　　Two, Hainan Coconut Chicken Soup

　　Anthrax and health improvement.

　　Ingredients:

　　One coconut, one chicken (about 600 grams in weight), 10 grams of ginger slices, 50 grams of walnuts, 50 grams of dates, about 1500 grams of water, a little salt.

　　Preparation:

　　1. Clean the chicken, peel it, and put it in boiling water for about 5 minutes, then cut into large pieces; soak the walnuts in water to remove the oil taste; wash and remove the seeds from the dates; extract the juice from the coconut and cut the coconut meat into pieces.

　　2. Place chicken, ginger slices, walnuts, dates, coconut milk, and coconut meat in 10 bowls of boiling water, add ginger slices, bring to a boil with high heat, then simmer over low heat for 3 hours, season with salt, and it is ready.

　　One, treatment

　　Currently, there are many drugs for the treatment of Taenia saginata disease, and their efficacy is significant. Most patients can be cured after anthelmintic treatment, with a good prognosis. The following drugs can be chosen.

　　1. Praziquantel has good anthelmintic effects against both Taenia saginata and Taenia solium. It is the first choice of medication at present. Its anthelmintic mechanism is mainly to damage and destroy the surface cells of the worm body, increasing the permeability of the worm body's plasma membrane to calcium ions, causing muscle paralysis and spasm of the worm body, damage to the neck epidermis, and eventually leading to ulceration and death. The usual dose of praziquantel is 10-20mg/kg body weight taken on an empty stomach. Some people believe that a single dose of 2.5-5mg/kg body weight can also achieve satisfactory efficacy. Patients should fast the night before taking anthelmintic medication, take the medication on an empty stomach the next morning, drink plenty of water, or take a laxative to expel the paralyzed or destroyed worm body quickly from the body.

　　2. Albendazole has good anthelmintic effects. The dose for adults is 800mg per day, taken for 3 consecutive days, with mild side effects.

　　3. Albendazole can inhibit the uptake of glucose by Taenia saginata, leading to energy deficiency and paralysis of the worm body. The dose for adults and children is 300mg per dose, twice a day, for 3 consecutive days. Albendazole can completely expel the worm body, and most can find the scolex, with an efficacy of nearly 100%.

　　4. niclosamide can inhibit the oxidative phosphorylation of tapeworm mitochondria, is not easily absorbed after oral administration, and has a high local drug concentration in the intestines. The head segment of the worm is digested and dissolved in the intestines. Dosage: 2g for adults taken on an empty stomach in the morning, 1g for children, chewed and taken with a small amount of hot water. Generally, no laxative is needed, and it is禁忌 for pregnant women in the early stage.

　　5. Combined treatment of pumpkin seeds and areca nuts: The deworming effect of pumpkin seeds or areca nuts alone is poor, but the combined use in the treatment of taeniasis has proven that the two have a synergistic effect, with a cure rate of 92.1% to 100%, averaging 95.2%. In vitro tests have shown that pumpkin seeds and areca nuts have a paralyzing effect on tapeworms, but their action sites are different. Pumpkin seeds mainly act on the middle and posterior segments of the tapeworm, making the mature segments thin and wide. Areca nuts mainly act on the head segment and immature segments, that is, the anterior segment of the worm body. Taking pumpkin seeds first makes the middle and posterior segments of the worm body paralyzed and soft, followed by the areca nut decoction to make the head segment lose its adhesive force, and then taking magnesium sulfate to promote peristalsis of the intestinal wall to accelerate the excretion of the paralyzed adult worms. The specific plan is:

　　(1) Pumpkin seeds: Take 75-120g of peeled pumpkin seeds, roast and shell them, grind the pumpkin seeds into fine powder, and take 80g of pumpkin seed powder by mouth for adults; or it can also be taken after adding a small amount of water and boiling. For children, the dosage should be reduced accordingly.

　　(2) Areca nuts: Use sliced areca nuts, dosage: 30g for children under 10 years old, 50-60g for women and weak adult men, 80g for strong individuals, and boil the areca nuts in about 500ml of water until about 200ml remains.

　　In the morning, take pumpkin seed powder on an empty stomach, then 2 hours later take areca nut decoction, and then 30 minutes later take 60ml of 50% magnesium sulfate. The worm can be excreted as soon as 15 minutes after taking the medicine, and the slowest can be excreted within 8 hours. About 73.9% of those excreted within 1 to 5 hours.

　　The advantages of this therapy are that pumpkin seeds and areca nuts are easy to obtain, inexpensive, simple to use, have few side effects, and are very effective. Hospitalization is not required, especially suitable for the general treatment of deworming in rural China.

　　II. Prognosis

　　The prognosis of this disease is good.