Question

Can you please paraphrase the whole answers with the same thought written in the answer, because that is answered by me and my friend, we have to have different answers.

Trematodes case study

A stool specimen was received in the laboratory, It was collected from a 35-year old man from Xinjiang, China as a part of refugee health screening program. The stool was preserved using 10% formalin and Formalin-Ethyl Acetate concentration was done. A wet mount smear was prepared from the sediment and examined. The Eggs seen measured 26-32 micrometers long. The pictures below were seen in the smear.

Questions to answer:

1. What is your diagnosis? Based on what criteria?

Bases on the criteria above the man is living in china. There is one parasite that is named the Chinese liver fluke. This is also called the Clonorchis sinesis. This parasite is endemic in the areas of the Far East including the China. Also based on the pictures you can see that the eggs of the parasite has an operculum and this is unique only to this parasite. You can also see the presence of distinct shoulders and the presence of the small knob opposite operculum in the eggs based on the pictures above.

Reference:

Zeibig, Elizabeth A. (2013). Clincal Parasitology: A Practical Approach. 2nd Edition

2. How does Human get infected with this parasite?

The human gets infected with this parasite when they ingest an undercooked fish. Now this Fish is contaminated with the encysted metacercaria. The immature flukes will mature in the liver of the human when the human has ingested the contaminated fish. The bile duct is where the adult worm will live and this is the final part of the cycle.

Reference:

Zeibig, Elizabeth A. (2013). Clincal Parasitology: A Practical Approach. 2nd Edition

3. How does adult form of this parasite frequently recover? Can they be seen in stool or duodenal aspirate?

The adult forms of this parasite are only rarely seen. They are seen when there is a surgery or autopsy procedure for the patient. The most morphologic seen in this parasite is the eggs. They are seen in the stool specimens. So my answer if the adults can be seen in stool or duodenal aspirate the answer is no. That is because it can only be seen when there is a surgery that is performed or and autopsy procedure is in progress.

Reference:

        Zeibig, Elizabeth A. (2013). Clincal Parasitology: A Practical Approach. 2nd Edition

Answer 1

(1) according to the the diagram of the egg that is found in the stool ,it is operculated at one pole whereas possess a knob like structure at the other pole. The size of the egg given here is 26-32 micrometers. And the place from where the sample has been isolated i.e. China. All these criteria points towards the trematode Clonorchis sinensis which is commonly found in the areas like china,japan,taiwan and korea. This trematode is also called as Chinese liver fluke.

(2)Human is a definitive host of Chinese liver fluke.

Intermediate host:snail and fish

Mode of infection:infection occurs when raw or inadequately processed fish are eaten by the humans. The infection can also occurs through fingers and utensils contaminated with metacercaria during preparation of fish for cooking. Metacercaria excyst in the duodenum and then adolecercaria that comes out proceed towards the biliary tract where they mature into the adult form. And then adult form gives 10000 of eggs which are excreted in the stool.

optional addition(eggs do not hatch out in the water ,first it is ingested by the snail then miracedium hatches out and development occur and form sporocyst,1st 2nd generation redia and then cercaria which penetrates in the scales of the fish and develop in metacercaria)

(3) No, the adult worms can not be seen in the stool.only the eggs of the adult worms can be seen in the stool sample. Adult worm can obstruct the common bile duct which can cause cholangitis. The size of the adult worm is 25-35mm long and 3-5mm broad which do not appear in the blood sample too, they stay in the biliary tract . They can be seen if the surgery or autopsy procedure is carried out of the biliary system.

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