Analysis For Opisthorchiasis: How To Identify And Determine It In Humans

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Analysis For Opisthorchiasis: How To Identify And Determine It In Humans
Analysis For Opisthorchiasis: How To Identify And Determine It In Humans

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  • 1 How to diagnose opisthorchiasis in humans?
  • 2 What tests need to be taken for opisthorchiasis?

    • 2.1 Blood test for opisthorchiasis
    • 2.2 Analysis of feces for opisthorchiasis
  • 3 Decoding analyzes for opisthorchiasis

Opisthorchiasis is a parasitic disease caused by a trematode worm (Opisthorchis felineus). The main danger of this disease lies in significant invasions. Since the symptoms of the disease are largely associated with the affected organ, diagnosis is difficult due to the similarity of the disease with other diseases of this organ. For a correct diagnosis, it is necessary to do an analysis for opisthorchiasis. Since patients come at different stages of the disease, different research methods are used to make a diagnosis. Therefore, only a specialist will be able to determine exactly what tests to take for opisthorchiasis.

How to diagnose opisthorchiasis in humans?

ultrasound procedure
ultrasound procedure

When infected with opisthorchiasis, the feces are examined first. However, it is not always possible to identify the eggs of the parasite in feces. Most often, this is possible only at a late stage of the disease, when the worm has reached the size of a sexually mature individual and began to multiply.

The question arises, how to identify opisthorchiasis in humans at the initial stage of infection, when there are no worm eggs in the feces yet? In this case, it is necessary to donate blood for opisthorchiasis. In this case, the diagnosis of opisthorchiasis can be carried out both on the basis of general clinical blood tests, in which characteristic changes are observed, and by means of special blood tests that allow detecting antibodies to opisthorchis antigens.

If we talk about how to determine opisthorchiasis by other methods, then the doctor can prescribe the following instrumental and laboratory tests and examinations:

  1. Ultrasound examination of all organs that are in the abdominal cavity. If certain pathologies of the gallbladder or an enlarged liver are diagnosed, then this may indirectly indicate the presence of a parasite and is the basis for the study of feces and blood.
  2. Computed tomography or MRI can also help identify abnormalities in the work and structure of the gallbladder, pancreas and liver.
  3. If a person was previously checked for the presence of these parasites, and the tests did not reveal anything, then you can try to do duodenal intubation. During the examination, bile is taken for analysis. It can also detect the eggs of the parasite.
  4. Another endoscopic technique that can be effective in diagnosing opisthorchiasis is retrograde cholangiopancreatography. During this procedure, you can examine the ducts of the gallbladder, where it is easy to find sexually mature individuals of the helminth.

What tests need to be taken for opisthorchiasis?

blood tests
blood tests

If there is a suspicion of opisthorchiasis, blood tests (CBC and biochemical) are the first thing that needs to be passed. The following deviations from the norm in the analyzes can indirectly indicate the presence of a parasite in the body:

  1. In the biochemistry of blood, an excess of the concentration of amylase and bilirubin is found. Also, the results of sublimate test and thymol test are slightly increased. Although this does not allow us to accurately detect worms in the human body, it indirectly indicates damage to internal organs and deviations from the norm in their activity, which is characteristic of opisthorchiasis.
  2. In the general analysis, it is worth paying attention to a decrease in hemoglobin, as well as a decrease in the number of red blood cells. All this is a sign of anemia, which often accompanies this ailment. Often, severe eosinophilia and characteristic leukocytosis indicate the presence of parasites in the body. Such deviations from the norm appear as a result of the immune response to helminth antigens.

If you are suspected of opisthorchiasis, you can take stool tests, CT, X-ray, ultrasound. Even if the eggs of worms are not detected in the feces, but in other studies deviations from the norm characteristic of helminthic invasions will be noticed, it is worth doing an enzyme-linked immunosorbent assay, which is considered the most informative and allows you to identify the disease even at the initial stage. In any case, your doctor will be able to say exactly what tests need to be passed, based on the clinical symptoms and the patient's condition.

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Blood test for opisthorchiasis

blood test for opisthorchiasis
blood test for opisthorchiasis

In the acute stage of the disease, antibodies to opisthorchis are produced in the patient's body, so the ELISA technique (enzyme-linked immunosorbent assay) gives almost 100 percent accuracy. However, the effectiveness of this technique is reduced to 70% in the case of the transition of the disease into a chronic form.

It should be borne in mind that residents of regions where there is an increased risk of opisthorchiasis morbidity, there is a significant underestimation of serological test indicators. This is due to their hereditary reduced sensitivity to these parasites. At the same time, those who have recently arrived in such regions, on the contrary, may experience false-positive results of serological tests due to the lack of innate tolerance.

To carry out an ELISA analysis, you will need the patient's venous blood, taken on an empty stomach on an outpatient basis. In the blood plasma of a sick person, antibodies to opisthorchiasis igg and igm are present. Depending on the presence of certain antibodies and their concentration, conclusions can be drawn about the time when the infection occurred, as well as the stage of the disease. In this case, they are guided by the following data:

  • IgM antibodies are found in the blood several days after infection. The peak in the production of these antibodies occurs in the second week of illness. One and a half to two months after the onset of the disease, the IgM titer rapidly decreases;
  • IgG immunoglobulins appear in the blood on days 14-21 from the onset of the disease. The peak of their production falls on the second or third month of the disease. With the transition of the disease to a chronic form, the concentration of these antibodies remains unchanged for a year or more.

It makes no sense to take an analysis for antibodies to opisthorchis if a person has been sick for a long time. This is due to the fact that in the chronic course of the disease, the antibody titer is significantly reduced. Such a significant decrease in the titer of immunoglobulins to causative agents of the disease is explained by the combination of the parasite antigens with the patient's immunoglobulins and the formation of the CIC.

Analysis of feces for opisthorchiasis

analysis of feces for opisthorchiasis
analysis of feces for opisthorchiasis

The most informative research method is the analysis of feces. If parasite eggs are found in the feces, then this is a reliable confirmation of helminthic invasions. However, the absence of eggs does not guarantee that a person is not sick, since immature individuals cannot reproduce at the initial stage. You can also test bile for the presence of helminths.

Moreover, a one-time analysis will not always be informative, because eggs appear in feces with a certain regularity. Therefore, feces are taken for analysis from three to 6 times with an interval of a couple of days.

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How to take a stool test for opisthorchiasis?

No less informative will be the study of feces by the PCR method. This research technique will be informative regardless of the stage of the disease, since DNA particles of the parasite are found in the test material, and not its eggs. The advantage of the polymerase chain reaction is that the feces need to be tested only a couple of times with an interval of 7-14 days.

It is equally important to know how to take an analysis for opisthorchiasis, since the accuracy of the results depends on it. It is important to follow these guidelines:

  1. It is best to collect faeces in the morning shortly before delivery.
  2. It is better not to use medications and alcohol 24 hours before.
  3. For analysis, you need fresh stool, and not the one that was stored in the refrigerator.
  4. To collect feces, it is better to use a special sterile container (it is sold at the pharmacy).
  5. You should not use a laxative, as this will affect the test results.

Decoding analyzes for opisthorchiasis

analysis decoding
analysis decoding

As for the UAC, such deviations in the results can indicate infection with the parasite:

  • eosinophils normally cannot exceed 5%;
  • leukocytosis (in adults and children, respectively, above 8x10⁹ and 10x10⁹);
  • erythrocytes should normally be above 3.5 million / ml;
  • the norm for hemoglobin is 120 g / l.

A 100% positive result can only be found in the feces of the eggs of the parasite. If the ELISA gave a positive result, but eggs were not found in the test material (bile and feces), then this may indicate the following:

  • a small lesion, therefore, not all areas of feces contain eggs;
  • this happens at the initial stage of the disease, when the parasite has not yet multiplied;
  • the patient healed himself or with the help of medication;
  • laboratory error.

As for the norm for specific immunoglobulins, it is as follows:

  • antibodies of group A - from 0.7 to 4 g / l;
  • antibodies of group G - from 7 g / l, but not more than 16 g / l;
  • immunoglobulins type M - from 0.4 g / l, but not more than 2.3 g / l.

In 1-1.5% of cases, false positive results are obtained using the ELISA method. This is especially common in patients with various allergic diseases, gastrointestinal tract pathologies, diseases of the hepatobiliary system. Quite a large percentage of false positive reactions are attributed to other parasitic diseases (toxocariasis, echinococcosis, trichinosis and fascioliasis).


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