More than 21 million people infected with Siberian cat fluke live on Earth. More than half of the total number of infected people live in the post-Soviet space, including in Russia and Ukraine. Mass defeat is characteristic of residents of the Siberian region and Dnieper. What is this parasite and how to avoid infection? And most importantly, how to get rid of “uninvited guests”.
Short description
Medicine conditionally divided the parasites of the human body into three types. These are tapeworms and roundworms, as well as flukes. Siberian fluke is a subspecies of the lanceolate fluke, that is, a flat fluke (trematode). The Latin name for this parasite is Opisthorchis felineus and Opisthorchis viverrini. A small hepatic parasite causes opisthorchiasis in humans and animals, which affects the ducts of the liver, gall bladder and pancreas.
Siberian cat fluke has a lanceolate shape. The length of the parasite does not exceed 18 mm, and the width is 2 mm. Two intermediate hosts are involved in the life cycle. The ultimate host of a trematode can be a person or a carnivore.
Discovery story
The name "Siberian fluke" was first used in April 1891 in the city of Tomsk. Professor Vinogradov performed an autopsy and discovered an unknown type of fluke in the liver. Somewhat later, information appeared, this parasite has already been described, but it was found in the liver of a dead cat. However, the scientist who performed the autopsy failed to determine the type of trematode.
The scientist Blanchard correctly systematized and described the parasite. This happened in 1885. This time the name "cat fluke" was used. And the disease is called opisthorchiasis.
To determine the medical significance of the Siberian fluke, in parallel, many famous scientists worked in different countries. For example, it took almost 10 years only to prove that opisthorchiasis is associated with eating freshwater fish. Various assumptions have also been advanced about the first intermediate host of the parasite. Experimental evidence on gastropod snails was obtained by Hans Vogel. And the Russian scientist Starobogatov established that these are mollusks from the genus Codiella.
Where is opisthorchiasis common?
Siberian fluke, belonging to the subspecies trematode Opisthorchis viverrini, is most common in Southeast Asia. It causes opisthorchiasis among residents and guests of Cambodia, Thailand, Laos, and Vietnam. Sometimes cases are recorded in Europe and America. All of them are associated with the supply of infected fish.
Siberian fluke, belonging to the subspecies of trematodes Opisthorchis felineus, is most common in the territory of post-Soviet countries. It causes foci of opisthorchiasis in Russia, Ukraine, Kazakhstan, along the basins of large rivers. The maximum incidence rate is observed along the Ob and Irtysh rivers. The pools of the Volga, Urals, Kama, Don, Dnieper, Dvina and so on are infected with a parasite.
How the pathogen develops
The hepatic trematode Siberian fluke, the life cycle of which takes place in the body of several hosts, is able to develop only near fresh water bodies. The development cycle begins in the body of the first intermediate host, which is the freshwater gastropod molluscs-bitiniids. These mollusks belong to the genus Codiella. A favorite habitat of such living creatures is the drying up shallow water in the floodplains of the rivers. The gastropod mollusk swallows eggs of the Siberian fluke from contaminated water into which the feces of the final host enter. Within two months, the parasite is converted from eggs to cecaria in the body of the mollusk.
Fluke cecaria is a free-swimming bisexual larva with a swimming tail. Leaving the first host, the larvae invade the tissue of cyprinids. Here is the next stage of development from cecaria to metacecaria. The larva discards the tail that is no longer needed, and creates a protective capsule shell around itself - a cyst. Inside the capsule, the larva remains mobile. It takes about six weeks from the moment a carp fish enters the body to the appearance of the ability to infect humans and carnivores. Only at the stage of metacicaria can the parasite take root in the human body.
The final owner of the fluke is a person or any animal that has eaten an invasive fish. Once in the initial section of the small intestine, metacicaria get rid of cysts and penetrate the bile ducts, gall bladder and liver.
How does infection happen?
Siberian fluke reaches puberty in the body of the final host in 10-14 days. From this moment, the laying of eggs begins, which with feces return to the environment. If the eggs hit the soil, then they will die in 8-10 days. If in water, then they will remain viable for almost a year. In the final host, opisthorchids live up to 20-30 years.
The next round of the cat fluke life cycle begins when the new gastropod mollusk with water and silt swallows the parasite's egg. This vicious circle will not be interrupted while a person eats light-salted, half-baked, or dried fish from fresh water.
Symptoms of opisthorchiasis in humans
Opisthorchiasis develops asymptomatically for a long time. All the symptoms of a disease in humans are associated with the mechanical and allergic effects of the fluke. Allergies are caused by the vital products of the opisthorchus. And the mechanical effect is associated with injuries to the walls of the ducts, to which the oral and abdominal suckers of helminths are attached. In addition, the accumulation of trematodes complicates the flow of bile, causing inflammatory processes.
The incubation period of opisthorchiasis is no more than three weeks. Further, the temperature may rise, pain in the muscles and joints may appear, vomiting and diarrhea will begin. The patient will have an enlarged liver and spleen, and pain in these organs will appear.
Symptoms will vary depending on the stage of opisthorchiasis. In the acute stage, allergic reactions predominate. In the chronic stage - mechanical damage to the duodenum and liver, causing pain.
Symptoms of opisthorchiasis in cats
At the initial stage of helminthiasis, it is almost impossible to understand that a pet is sick. As the disease develops, cats lose weight, hair becomes tousled and untidy, mucous membranes and skin become icteric. Constipation or diarrhea and vomiting also appear. The abdomen of a cat is enlarged, with palpation of the liver pain and anxiety occur.
Siberian fluke: treatment
To confirm opisthorchiasis, feces and duodenal contents of the patient are examined. Additionally prescribed endoscopy, x-ray or ultrasound. For complex treatment using anthelmintic drugs, means to normalize the digestive tract and drugs to increase immunity. In the acute phase, a patient may be prescribed detoxification. Treatment is preferably performed on an outpatient basis.
Prevention of opisthorchiasis
To avoid infection with a cat Siberian fluke, you need to perform simple requirements:
- Do not consume poorly processed freshwater fish.
- Do not feed domestic and wild animals with raw fish.
- Do not contaminate water bodies with feces.
As you can see, everything is simple. You can maintain health if you are careful and attentive.