Mar 27, 2018
Pathogen of opisthorchosis( Opisthorchis felineus) - two species of trematode: catfish trematode and trematode Viverra. . Helminth length 8-13 mm and width 1,2-2,5 mm. Eggs of the parasite are small( 0.011-0.023 mm long and 2-3 μm wide, pale yellow with a delicate two-contour shell).
Characterized by a chronic course with a predominant lesion of the liver, gallbladder and pancreas. On other types of helminthic invasion, see here.
At the puberty stage, opisthores parasitize the bile ducts of the liver, gallbladder and ducts of the pancreas of humans and animals.
At the puberty stage, the parasite lives in the intra- and extrahepatic bile ducts, the gallbladder, the ducts of the human pancreas and a number of carnivorous mammals( cats, dogs, foxes, arctic fox, sable, mink, muskrat, water vole, steppe polecat, pigs).
The helminth eggs that stand out from the faeces of patients with opisthorchiasis of humans and animals are swallowed by the Bithynia leachi mollusk when ingested. In mollusks, the helminth larva develops and multiplies, which then revert to water. The formed larvae penetrate into the body of carp fish( roach, carp, barbel, rudd, yaz, dace, chebach, bream, etc.) and parasitize in their subcutaneous tissue and muscles. After eating the infected fish with the final host, the helminth larvae leave their membranes in the duodenum and from there penetrate the bile ducts, the liver and the pancreas. In the human body and domestic animals helminth can live several dozen( 20-40) years!
Opisthorchis larvae die from cooking fish after 20 minutes, in minced fish - 10 minutes from the beginning of boiling;when salting small fish - after 4 days, large - after 10 days, hot smoking kills larvae, cold - no.
Reservoir and sources of the causative agent: the final hosts of the opisthorchus are cats, dogs, pigs, the person who produces the eggs of the pathogen with feces: the first intermediate hosts are the freshwater mollusks that swallow the eggs. From the mollusks in 2-10 months cercariae exit, which penetrate into the body of the second intermediate host - fish of the Cyprinidae family( ide, roach, carp, tench, crucian carp, etc.), where they become metacercaria.
The latter, getting into the human body or animals, after 10-15 days ripen to the sexually mature stage.
Mechanism of transmission of the pathogen: fecal-oral;the transmission path is food;transfer factor - crude, not sufficiently thermally processed, light-salted, dried fish of the carp family. Metacercaria of opisthorchis live in fish tissues up to 2 years.
Metacercariae are mature opisthorchis larvae, which people eat with insufficiently processed fish. The fish of the Cyprinidae family is mainly infected with metacercariae: ide, bream, European roach, vobla, tench, rudd, sazan, gustera, podost, asp, sticks, oatmeal, zinc, minnow, carp, barbel.
The main epidemiological features: the natural foci of opisthorchiasis caused by the cat's flukes are found in Asian and European countries( in Russia - in the basins of the rivers Ob, Irtysh, Kama, Volga and others);Viverra's opisthorchiasis is common in South-East Asia, mainly in Thailand, in some provinces about 80% of the population is affected.
Currently, in the CIS countries opisthorchosis is prevalent mainly in the areas adjacent to the Ob and Irtysh river basin( West Siberian and Kazakhstan centers), as well as in the basins of Pechora, Kama, Northern Dvina, Dnieper, Southern Bug, Volga, Don, Nemanand other rivers of Russia. In some countries of Asia( Thailand, India, China, Japan) there are other varieties of opisthorchiasis.
In Russia, opisthorchias is the fifth most common among parasitic diseases and accounts for about 2% of detected cases of helminthiosis. The highest incidence rate is observed among the indigenous coastal population. The incidence is observed among children aged 1-3 years, increases by 14-15 years and at this level is kept to 50-60 years. Professionally, fishermen, timber rafters, sailors, agricultural workers are more often affected.
The main foci of opisthorchiasis caused by a feline biotope are found on the territory of Russia. Parasitologists have long been convinced that the opisthorchis is confined to river systems, has a "tape type" area. It is better to analyze the distribution of opisthorchiasis not within the framework of one Russia, but in the territory of the former Union. It turns out more precisely and convincingly. So, let's imagine that we are moving from west to east within the former USSR.
The most western - Dnestrovsky and Neman - the centers of the opisthorchiasis are located on the territory of Moldova, Western Ukraine, Lithuania and Belarus. They are relatively small in area, weak intensity. The severity of the opisthorchiasis of people in them varies from a fraction of a percent to 10%.
Further, in the basins of the Dnieper and its left tributaries: Desna, Vorskla, Psula, Sula, Seimas, on the territory of Ukraine and partly Russia( for example, in the Bryansk region) is the Dnieper hotbed. It is already larger in area and more intense. The severity of people in it also varies greatly, but reaches 20-40% in some territories( for example, in the Vorskla River basin in the Sumy region).Until recently, somewhere before 1970, in the village of Dobryanskoye in the Sumy region, the population's opisthorchiasis was as high as 60-70%.
More east - VOLZHSKY focus, located on the territory of Russia in the basin of the Volga River with its numerous tributaries. It is extensive, but not very intensive, however, in some areas, for example, in some areas of Tatarstan, the population's opisthorchiasis may reach 20-30%.For a long time it was believed that the opisthorchiasis along the Volga channel is more or less evenly distributed, but now it became clear that this is not quite so. The fact is that in addition to the opisthorchiasis in the Volga basin there is a parasitic disease of pseudamphistomosis, the causative agent of which( Pseudamphistomum truncatum) is very similar to the
O. felineus, but we still do not know how much in this huge river basin of both andwhich is more.
In the basin of the Northern Dvina there is a small NORTH-DVINSKY focus, where the population's population varies from 3 to 10-15%.There are foci of opisthorchiasis in the basin of the river. Urals, also of medium intensity.
And, finally, the most powerful in Russia and in the world - the OBSCH focus. It is huge and located in the basin of the Ob and Irtysh in the territory of 12 regions and districts of Western Siberia and Kazakhstan. It is so vast that parasitologists are still arguing about what it really is, whether it is a single "drainage" hearth, a kind of "focal area", a group more or less in contact with inflows of foci with a "drainage zone" alongof the river Ob, or something else.
In this hearth, "all the way to the maximum."As elsewhere, people's involvement in it is not uniform, but in a large area of the Middle Ob, it reaches 50-80% and even higher. There are settlements in which 100% of the people affected were registered. Simply this means that in small towns where at the time of the survey there were no infants, the entire adult and children's population( starting from the age of 3-5 years) is affected by opisthorchiasis.
It is in the Ob Oblast that the manifestation( "soreness") of the opisthorchiasis is expressed to the maximum extent. There are most complications on its background. The population( mostly indigenous) has long been accustomed to eating raw and poorly( in parasitological, of course, sense) cooked fish. In the villages 100% of the affected cats. In rivers, almost 80%( and even higher) of cyprinid infestation, for example, yazey and dace. In the numerous floodplain reservoirs of the Ob River, a huge population of the first intermediate hosts - mollusks. For example, in a floodplain lake near the village of Karga in the North of the Tomsk Region, I had to study the codelle population, in which the number of mollusks exceeded 8 thousand individuals per 1 m2;the total number of mollusks in the population was more than 50 million individuals, and the number of mollusks infected with opisthorchis larvae was approaching one million. This is a huge figure, considering that during the summer period, up to 60-100 thousand cercariae are formed in each infected mollusk, capable of infecting the second intermediate host of the opisthorchis. Approximately the same quantitative characteristics were obtained by me in the territory of the Tyumen region in the old channel of the Irtysh( the so-called Savinovsky Erica) near the city of Tobolsk.
In the north of Western Siberia, in the basins of the rivers Pur, Taz, Nadym there are no opisthorchiasis foci, there is no first intermediate host of the pathogen, however, the number of so-called "imported cases" of the opisthorchiasis among the population is very high.
The most eastern in Russia( known at the present time) is a relatively small IRKUTSKY hotbed in the basin of the river. Biryuys.
Further to the East there is no opisthorchiasis. The whole of Eastern Siberia, apparently, is free of it. The reason is simple - the lack of mollusks capable of playing the role of the first intermediate host. There were, however, brief information on the location of opisthorchiasis in foxes and cats in the Borzya region( cited in Erhardt et al., 1962), but there is no certainty in them.
If a lot of metacercariae of the parasite get into the human body( after all, even one raw raw food, practically in any Priobsky settlement, it is enough that in the human body there are several hundreds, and even thousands of larvae. ..) and, in addition, if a person eats(not in the culinary, of course, but in the parasitological sense. ..) fish for, say, 10-20 years or more( which is a common occurrence, for example, in Western Siberia), parasites are able to inflict on their hosta lot of serious trouble.
Among them may be primary cancer of the liver or pancreas( it is well known that, for example, the areas of the Middle Ob are leading in the world in these severe pathologies).Other very serious liver diseases can develop, complications of pulmonary diseases, bronchial asthma, typhoid fever, complications of pregnancy, etc. may occur. In a word, a "bouquet of pathologies"!
Strictly speaking, it is not so much the opisthorchias themselves that are dangerous, as those that are associated with it or initiated by it. Characterizing the social damage caused by opisthorchiasis, specialists constantly draw attention to the fact that the number of requests for medical care for a variety of diseases among patients with opisthorchiasis is 3-6 times greater than among people who do not have parasites infected in the same areas.
In Russia, up to 50 or more patients with opisthorchiasis are registered annually. Another 10-15 years ago, according to expert estimates, the number of patients with opisthorchiasis in the Soviet Union was about 2 million people. After the collapse of the Union, this figure did not decrease, but rather even increased, and now, apparently, only in Russia( not counting Kazakhstan, Ukraine, Belarus, Moldova, Lithuania. ..) the number of patients with opisthorchiasis is about two million.
Taking into account all this, parasitologists rightly consider opisthorchiasis among the most dangerous for human and widespread in Russia parasitic diseases.
Doctors rightly see a serious medical problem in the opisthorchiasis, however, strictly speaking, opisthorchiasis, first and foremost, an ecological problem associated with intensive biological pollution of the environment. This is also a veterinary problem, since at the stage of metacercaria, opisthorchis are parasitic in cyprinid fishes, and in the adult state - in the body of domestic and wild carnivorous, omnivorous and even some green-owls( for example, water vole) animals. This is also a social problem, connected with the education of parasitologically safe habits of cooking and consumption of fish dishes. Like all social problems, it is the most difficult. This is also a technological problem related to the development and introduction of fish processing technological regimes for decontaminating fish from a dangerous parasite for the human larval stage.
Infection usually occurs in the summer-autumn period, but the frequency of clinical manifestations of pronounced seasonality is not. Epidemic outbreaks are characteristic of the population newly arrived on endemic territory.
During the disease, there are 2 periods: acute( early) and chronic( late).In 2-4 weeks after infection, the allergic reaction to parasites becomes noticeable - this is a direct consequence of poisoning the body with the products of their vital activity. The temperature can rise to 39-40 ° C and more, the duration of the febrile period - from several days to 2 months. There are pains in the muscles and joints, sometimes jaundice, itchy skin rashes, enlarged lymph nodes, liver, less often the spleen;in the lungs in some patients there are infiltrates. In the late phase there is a violation of patency of the biliary tract, sometimes severe bile colic attacks occur;often develop chronic hepatitis and pancreatitis. With intensive invasion and aggravating factors( secondary bacterial and viral infection, alcoholism, etc.), cirrhosis of the liver develops. Helminthiasis can be complicated by biliary peritonitis, which arises from the parasite rupture of the walls of the bile ducts. Possible complications include purulent bacterial cholangitis, primary cancer of the liver and pancreas, which occurs in the population of the opisthorchiasis foci 7-8 times more often than in regions where this helminthiasis does not exist.
Diagnosis at an early stage is made taking into account the symptoms of the disease and the epidemiological anamnesis( eating uncleaned fish caught in the outbreaks of opisthorchiasis).One month after infection, eggs appear in the feces and duodenal contents of the patient, which facilitates the diagnosis.
Treatment: praziquantel( azinox), chloroxyl, bithionol. Specific treatment - the intake of chloroxyl: inside 5 consecutive days in a daily dose at the rate of 60 mg per 1 kg of body weight( adult - about 3.5-4 g per day).The daily dose divided into 3 divided doses and taken after meals, washed down with milk. You can spend a 2-day course of treatment at a daily dose of 0.15 g per 1 kg of weight( for an adult - about 9-10 g).The daily dose divided into 3 divided doses, taken after meals;Drink with 100 ml of milk. Sometimes when treating with chloroxyl, dizziness, light intoxication, increased pain in the liver, which do not require cessation of treatment and quickly pass after its completion. As a result of death and disintegration of helminths occasionally there are allergic skin rashes and eosinophilia of the blood. In these cases, prescribed antihistamines, calcium chloride.
Contraindications to the use of the drug - liver disease with a sharp breakdown of its functions( not related to helminthiases), organic diseases of the cardiovascular system in the stage of decompensation, pregnancy. Treatment with chloroxil is supplemented with symptomatic therapy: duodenal sounding and drainage of the biliary tract without a probe according to Demyanov, administration of cholagogue and antispasmodics;At a secondary bacterial infection of the bile duct and gall bladder, antibiotics are used. How to treat opisthorchias folk remedies look here.
More than a hundred-year history of the study of opisthorchiasis has made it possible to accumulate a huge amount of factual material on various aspects of the problem, which, alas, is not yet radically solved. The unrelenting interest in opisthorchosis at the end of the 20th and in the beginning of the 21st century has several causes.
1. Large-scale economic programs for the development of the natural resources of Siberia led to an intensive inflow of population into the most strained foci of the disease and, in general, increased the migration flows of the population in Russia. This clearly highlighted the economic significance of opisthorchiasis and its negative social impact.
2. In many respects, opisthorchiasis, despite the long history of the study, still remains insufficiently well-studied. For example, this concerns the clarification of the relative role of different definitive hosts in the pathogen of the pathogen, the development of biocenological measures of prevention, the influence of anthropo- pheric factors on the parasitic systems of the pathogen as a whole, and the individual stages of the life cycle of the opisthorchis, etc.
3. It can be clearly stated that opisthorchiasis caused by Opisthorhis felineus, in a number of components: the widest world area of the pathogen, the vastness of numerous foci of the disease, the manifestation, the diversity of host species, etc., is the basis in the so-called "world opisthorchiasistriad "consisting of O. felineus, O. viverrini and Clonorchis sinensis. Studying each of the opisthorchias separately( we are forced to do this, since they are distributed in almost non-contiguous territories of different countries), parasitologists of the world are able to complement and sum up the accumulated information. The contribution of scientists studying the problem of opisthorchiasis, caused by Opisthorhis felineus, is a huge amount of knowledge.
4. And finally, extensive research on the problem of opisthorchosis allows us to understand much more deeply what we can expect from aspirations "to save mankind from parasites," and what we can not expect here is not in the right. ..
Despite the fact that with regard to opisthorchiasisAt present, highly effective anthelmintic preparations have been obtained and widely tested, for example, synthesized by Bayer Prazikvantel, or its domestic analogue - asinox, to the "victory" over the disease is still very far away.
And how to understand the "victory" over natural focal disease? Opisthorchias can not be defeated in a primitive way. You can not, say, catch all the water vole, kill all cats, dogs, foxes, muskrats, etc. They can not even be cured, except for an insignificant number of animals kept in nurseries and fur farms. It is impossible to destroy all mollusks - intermediate hosts, and it is impossible( as, alas, the experience of many countries combating other trematodes dangerous for human beings has shown), it is even possible to essentially reduce the number of their populations. Not to mention the fact that the use of special pesticidal compounds( molluscicides) inevitably causes serious damage to aquatic biocenoses. Passing through years of mistakes, many scientists of the world begin to understand this. The attempts to widely use biological control measures against the pathogen at various stages of its life cycle are not yet successful. For example, attempts to "replace" parthenite O. felineus on other, safe for human trematodes in mollusks - intermediate hosts, almost do not give results.
What should I do? So, are we powerless? In something, yes, there is not. If we want to destroy opisthorchiasis( or any other natural focal parasitic disease) as a natural phenomenon, then we will not be able to do this( and want to say here: - fortunately!), But if we approach the opisthorchiasis as a medical problem, in the sense, that we will continue to search for effective medicines, improve methods of diagnosis, treatment, prevention, then success is likely to be achievable.
It would seem that to protect yourself from opisthorchiasis is quite simple. In those areas where the disease is common, one should not eat raw and poorly cooked( undercooked, undercooked, under-salted, non-smoked) fish of the carp family. Now there is a Russian effective and inexpensive drug - an azinox. How to apply it - the doctor will say. The main way to "fight" with opisthorchiasis, as with a massive focal disease, is its prevention.
Sanitary-epidemiological rules and norms "Prevention of parasitic diseases on the territory of the Russian Federation"( SanPin 3.2.1333-03, M., 2003) were published in 2003, where the section on opisthorchiasis entered. However, six years earlier, in 1997, a similar document was published containing much more detailed information on the regimes of disinfection of fish from opisthorchis larvae( SanPiN 3.2.569-96, M., 1997, Appendix No. 3).The documents gave recommendations on the regimes of disinfection of fish from opisthorchis larvae as a result of salting, freezing, and heat treatment. Considering the high resistance of the metacercariae of the opisthorchis to the effects of environmental factors, these regimes( especially freezing and salting) are rather harsh. Briefly, they are not difficult to bring up here.
1. Disinfection of fish from opisthorchis larvae by salting is ensured by using a mixed strong and medium salting solution( brine density from the first day of salting 1.20, at a temperature of +1. .. 2 ° C) when the mass fraction of salt in the fish tissues reaches 14%.At the same time, the duration of the salting should be: a) gudgeon, glue, golyan, horseracing - 10 days;b) roach, dace, reddish, chubby, zinc, white-eyed, podosta, chehoni, asp, spike, small( up to 25 cm) yazey, bream, line - 21 days;in large( over 25 cm) yazey, bream, line - 40 days.
2. Decontamination of fish from opisthorchis larvae by freezing is achieved under the following regimes: a) at a temperature in the fish body -40 ° C - 7 hours;b) at a temperature in the body of fish -35 ° C - 14 hours;c) at a temperature in the body of fish -28 ° C - 32 hours. Given the high resistance of the metacercariae of opisthorchis to low temperatures, freezing fish at higher temperatures does not guarantee its decontamination.
3. Hot and cold smoking, drying, drying, and making canned food disinfect fish, except for eggs. It can not be used for the production of dried and cold-smoked fish products.while its disinfection does not occur from the larvae of the opisthorchis. The production of such fish products from eggs and roach is allowed only from raw materials previously frozen in the regimes indicated above.
4. Cook the fish in pieces for at least 20 minutes, and fish dumplings - at least 5 minutes from the time of boiling.
5. Fish( fish cutlets) should be fried in portions in fat for 15 minutes. Large pieces of fish weighing up to 100 grams fry in a flattened form for at least 20 minutes. Fry the whole fish for 15-20 minutes.
Personal prevention measures multiplied by the social component, i.e.mass and literacy of their use in the foci of the disease, are already becoming the basis for measures of general prevention.
Health education takes the leading place in the system of opisthorchosis prevention measures.
The forecast is generally satisfactory;with the timely start of treatment, the invasion is completely eliminated and the functions of the organs are restored. With intensive infestation and complications, the prognosis may be pessimistic.