Schistosoma Japonicum: Eggs, Life Cycle, Localization

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Schistosoma Japonicum: Eggs, Life Cycle, Localization
Schistosoma Japonicum: Eggs, Life Cycle, Localization

Video: Schistosoma Japonicum: Eggs, Life Cycle, Localization

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Video: Lifecycle of Schistosomiasis Parasite 2023, February

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  • Japanese schistosoma

    External signs

  • Features of the treatment and diagnosis of schistosomes
  • Treatment of Japanese schistosomiasis
  • Prevention
  • Conclusion
  • You can defeat parasites!

Schistosoma japonicum is yellow or yellow-brown in color. Males of this species are slightly larger than other Schistosomes measuring 1.2 cm by 0.5 mm. Females are 2 cm by 0.4 mm.

The integument of the females is ribbed and pitted and has fewer spines than in the oral sucker, abdominal sucker, and gynecophoric canal of the male. The acetabulum is devoid of thorns. However, in other areas, the spines are evenly distributed in the vicinity of the excretory pore.

What to do in such a situation? To get started, we recommend reading this article. This article details the methods of dealing with parasites. We also recommend contacting a specialist. Read the article >>>

Schistosoma japonicum
Schistosoma japonicum

Japanese schistosoma

This parasite is mainly localized in the portal vein and is the causative agent of helminthiasis that affects the intestinal tract and hepatic ducts. Schistosoma Japonicum is more common in children under 10 years of age. Cities and villages are unfavorable for this type of schistosomiasis:

  • China;
  • Laos;
  • Korea;
  • Thailand;
  • The Philippines;
  • Indonesia;
  • Japan;
  • Korea.

A distinctive feature of the Japonikum schistosome is its ability to lay a large number of eggs. They are carried with the bloodstream not only through the digestive organs, but also through other vital parts. This leads to the development of parasitic foci of inflammation in the lungs, brain and liver. The invasion often causes severe damage to the internal organs and the nervous system, which in turn leads to death.

External signs

The photo of Japonicum schistosome clearly shows its difference from other species. The female of the parasite reaches almost 30 mm in length, and the male has a maximum vertical body size of about 20 mm and is equipped with a smooth cuticle without tubercles. The intestine of the worms has a standard branched shape with subsequent connection in the tail.

The uterus of Japanese schistosoma females is the most capacious and occupies half of the parasite's body. It usually contains at least 50 oval-shaped eggs with a characteristic spine on the lateral surface. When determining the size of the cocoons of the Japanese schistosome under a microscope, it was observed that they are very small. The length of the eggs is no more than 100 microns, and the width is up to 65 microns, which determines their high quantitative content in the female's uterus.

External signs
External signs

Features of the treatment and diagnosis of schistosomes

It is possible to detect schistosomiasis at an early stage only by conducting blood tests using the ELISA method and PCR. These methods help to identify antibodies to parasites and their DNA before the massive spread of parasites throughout the body and internal organs.

In the later stages of invasion, schistosome eggs can be detected by laboratory examination of feces or urine. In severe cases that do not allow the use of other studies, a biopsy of the tissues that make up the lining of the intestine or bladder is performed. Of particular importance in diagnosis is the collection of anamnesis and the establishment of the fact of visiting tropical countries.

Parasites are treated with specific drugs based on praziquantel (Biltricid), while using symptomatic and restorative therapy.

Features of the treatment and diagnosis of schistosomes
Features of the treatment and diagnosis of schistosomes

Treatment of Japanese schistosomiasis

In the past, the main remedies for the treatment of schistosomiasis were trivalent antimony preparations (emetic, fuadin, antiomalin, astiban). All trivalent antimony preparations, although effective, are highly toxic and require a long course of treatment. In this regard, at present, these funds are practically not used for the treatment of schistosomiasis. Praziquantel (Biltricid), which is an isoquinoline-piperazine derivative, is highly effective in all schistosomiasis. It is prescribed orally at a dose of 20-60 mg / kg of body weight in 1-3 doses for 1 day. The drug is effective in 90-100% of patients.

  • Metrifonat (Metrifonat, Bilaroit) - organophosphorus anticholine-esterase compound, is a reserve preparation for S. haematobium invasion. It is administered once enterally at a dose of 7.5-10 mg / kg of body weight. Sometimes it is necessary to re-treat after 2-4 weeks. Side effects (nausea, vomiting, abdominal pain, diarrhea, weakness) are rare. Treatment is effective in 40-80% of patients.
  • Oxamniquine is a 2-aminomethyltetrahydroquinoline derivative, a reserve preparation for S. mansoni invasion. It is effective when administered enterally at the rate of 15 mg / kg 2 times a day for 2 consecutive days. In the next few days after treatment, the content of serum aminotransferases increases (hepatotoxic effect). The drug is effective in 50-90% of patients.
  • Niridazole (Niridazol, Ambilhar)structurally similar to furazolidone and metronidazole, available in tablets of 0.1-0.5 g. It is prescribed for oral administration in case of 5. haemalobium invasion for adults in a daily dose of 25 mg / kg of patient weight for 5-7 days. The daily dose of the drug is divided into 2 doses: in the morning and in the evening after meals. If side effects (hallucinations, convulsions) occur, the drug is canceled. There are changes in the ECG in the form of a flattening of the T wave and a decrease in the ST line, a rash on the skin of an allergic origin, a feeling of fatigue, and heaviness in the muscles. The urine becomes dark brown, which is not a reason to discontinue the drug. After the course of treatment, the urine acquires the usual color. Ambilgar is considered the most effective drug in the treatment of genitourinary and intestinal schistosomiasis. The effectiveness of the drug is noted in 40-80% of patients.
  • Gikanton (Hycanthone, Etrenol) - derivative of miracil. It is administered once intramuscularly at a dose of 2-3 mg / kg. Side effects (nausea, vomiting, abdominal pain, occasionally liver damage) are usually mild. The effectiveness of the drug was noted in 40-80% of patients.
  • Evaluation of the effectiveness of the therapy is carried out on the basis of a long (over several months) and thorough clinical and helminthological examination, since relapses are possible. Serologic tests are used to monitor the effectiveness of specific therapy for schistosomiasis. They become negative 3 months after the disappearance of the helminthic invasion. Specific therapy should be combined with pathogenetic treatment methods. For secondary infection, antibiotics are used, for severe cirrhosis, thrombosis of the splenic veins, polyposis, strictures, along with vitamin therapy and diet therapy, surgical treatment is performed.
  • The prognosis is favorable for all forms of schistosomiasis due to the chronic course of the disease. However, in severe and very severe forms of the course of invasions, cirrhosis of the liver develops, which leads to death. Mild and moderate forms of invasions are treatable with modern methods of therapy.


The fight against schistosomiasis must be based on disrupting the life cycle of the schistosomiasis at any stage. It is advisable to carry out the fight against the disease and its prevention in a comprehensive manner, and it should include:

Prevention of Japanese schistosomiasis
Prevention of Japanese schistosomiasis
  • treatment of patients with schistosomiasis;
  • registration of all patients with schistosomiasis;
  • periodic verification of long-term results of treatment by examining feces for eggs of schistosomes;
  • active detection of latent or initial stages of the disease using laboratory methods for examining urine and feces;
  • dispensary examination of ship personnel.

Extermination of shellfish:

  • the use of molluscicidal agents;
  • correct design and operation of irrigation systems;
  • periodic cleaning, drying and removal of vegetation from ditches and water basins.

Conducting sanitary measures:

  • organization of centralized water supply and provision of personnel with good-quality water;
  • the prohibition to use water for drinking, bathing and household needs from sources that could be contaminated;
  • constant and persistent health education work.


The life cycle of the parasite does not allow it to continue the genus without a special type of freshwater molluscs that live in tropical waters. A person can become infected with schistosomes only through contact with infected water. Therefore, when traveling to hot countries that are unfavorable for schistosomiasis, you should avoid swimming in unauthorized places, and even more so do not drink water of suspicious quality.

If in the first few days after swimming in a pond, the temperature rises or itchy skin appears, you should contact an infectious disease specialist, even if the symptoms were short-lived and quickly passed. Schistosomiasis in the subsequent period can proceed latently until the onset of the stage of severe damage to internal organs.

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