The liver fluke is a parasitic worm belonging to the class of digenetic flukes (trematodes). Infection is possible through consumption of infected freshwater fish, either raw or undercooked. The parasite can also live on aquatic plants, such as some types of watercress, which are also eaten. After entering the gastrointestinal tract, flukes move from the intestines to the bile ducts of the liver, where they begin to grow. The infection can be completely asymptomatic, but often the liver fluke causes disorders of the biliary system, including the bile ducts of the liver and gallbladder. Although infection with this worm (fasciolosis) is rare in developed countries, the fact remains that the disease is periodically diagnosed, and mainly among people traveling to regions where such parasites are most common.
What is fascioliasis?
Initially, the disease was known only to veterinarians, and dangerousa worm called Fasciola hepatica mainly affected cattle in South Africa. Cows, goats and sheep have been carriers of adult flukes that lay their eggs in the water. The eggs hatched into worms at the juvenile stage of development. The young liver fluke infected certain species of slugs living in water bodies and grew, gradually moving to plants (for example, watercress), where it, along with greens, was eaten by domestic animals grazing in the area. The worms gnawed through the walls of the intestine and remained in the liver, where they reached adult forms of development and began to lay eggs. Human fascioliasis is the same cycle, only in the human body.
Infection
The liver fluke (see photo in the article) is dangerous for those who eat raw or poorly fried (undercooked) freshwater fish, as well as raw plants, on the leaves of which parasites live. Among such plants are watercress, wild mint, dandelions, pistia and some other representatives of the flora that grow in water or along the banks of reservoirs and are used to prepare fresh salads. Rarely, a person can get an infection from drinking contaminated water.
Simply rinsing edible leaves with water does not protect against parasite larvae, but they die during cooking and washing plants with 6% acetic acid or potassium permanganate.
Infection by eating the meat of infected animals is impossible.
Symptoms
If a person has caught a parasite such as liver fluke, symptoms of infection may be completely absent. However, in most cases, patients notice signs of pathology that are unusual for them already a month after eating exotic dishes containing aquatic plants or raw fish. At this stage of the disease, the symptoms are associated primarily with the process of penetration of the worm into the liver. Fluke movement can be accompanied by fever, itching, abdominal pain, skin rashes, and even coughing. As soon as the worm reaches the adult stage of development in the liver, the signs of pathology become similar to the symptoms of blockage of the biliary tract. Abdominal pain is more associated with pain caused by gallstones. Jaundice appears, and the bile ducts become more vulnerable to infection - cholangitis. Weakness, lethargy, loss of appetite, weight loss are almost always noted.
Adult liver fluke can live in the human liver for twelve years, but even after the death of the parasite, symptoms are likely to persist due to damage to the bile ducts. The lethal outcome of the disease is extremely rare.
Diagnosis
In the early stages of fascioliasis, the immune system of the human body responds to infection with a change in the number of white blood cells - eosinophilia, which makes it possible to make a presumptive diagnosis. Ultrasound examination, as well as scanning of internal organscomputed tomography (CT), allows you to track the movement of the worm inside the liver. Even if the parasite has already settled in a particular area of the bile ducts, damage to the intestines and liver will still be visible on ultrasound. Also, if liver fluke is suspected, worm eggs are looked for in the feces. There are also specific studies aimed at testing the response of the immune system to the presence of the parasite, but not all clinics can afford such an expensive diagnosis.
Treatment
To get rid of the parasite is quite simple - you need to take a single dose of a drug called "Triclabendazole". Unfortunately, it is not available for purchase in the countries of South Africa, where local residents and tourists most often turn to doctors with complaints about the characteristic symptoms of fascioliasis, but when the diagnosis is confirmed, it is possible to organize an individual supply of the drug. Experts also recommend bed rest and a diet rich in animal and vegetable proteins. You may need to take additional vitamins and iron supplements.
In advanced cases, when severe fascioliasis and active adult liver fluke are diagnosed, treatment may consist of surgical removal of the harmful parasite using endoscopic retrograde cholangiopancreatography.
Prevention
- Soak water plants in 6% acetic acid solution or potassium permanganate for 5-10 minutes.
- Vegetables growing in water should be thoroughly boiled before eating.
- Keep areas where edible plants grow clean; they must not be allowed to be contaminated by sewage.
- Treat sheep and cattle if a veterinarian has diagnosed fascioliasis. A single dose of "Triclabendazole" is also used to treat animals.
Scientists are currently working on a vaccine against fascioliasis.
