What causes Clonorchiasis?
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Clonorchiasis is the disease resulting from infection with the trematode Clonorchis sinensis (Chinese liver fluke, or Oriental liver fluke). It is a zoonotic infection in which humans become infected upon ingestion of raw or undercooked fish.
What is metacercariae larva?

Definition of metacercaria : a tailless encysted late larva of a digenetic trematode that is usually the form which is infective for the definitive host.
What are the symptoms of diseases caused by C sinensis F hepatica and P Westermani?
Fasciola hepatica, Clonorchis sinensis, and Opisthorchis viverrini (bile ducts) cause fever, hepatomegaly, abdominal pain, and jaundice. Infections with Paragonimus westermani (lungs, brain) result in cough, hemoptysis, chest pain, and epilepsy.
How is intestinal fluke transmitted?
Humans (and pigs) pass eggs in their feces, which develop in water and infect snails as intermediate hosts. After further development, the parasites leave the snail intermediate host and encyst on water plants. Humans become infected as a result of eating these contaminated water plants raw (or undercooked).

What is a Clonorchis infection?
What is Clonorchis? Clonorchis is a liver fluke parasite (trematode or worm) that can infect the liver, gallbladder, and bile duct. Found across parts of Asia, it is also known as the Chinese or oriental liver fluke.
How is Clonorchis diagnosed?
Diagnosis of Clonorchis infection is based on microscopic identification of the parasite’s eggs in stool specimens. Safe and effective medication is available to treat Clonorchis infections. Adequately freezing or cooking fish will kill the parasite.
What are the symptoms associated with infection of this parasite?
Some of the most common signs of a parasitic infection include:
- Stomach cramps and pain.
- Nausea or vomiting.
- Dehydration.
- Weight loss.
- Swollen lymph nodes.
- Digestive problems including unexplained constipation, diarrhoea or persistent gas.
- Skin issues such as rashes, eczema, hives, and itching.
- Continuous muscle and joint pain.
Is there an acute phase for Clonorchiasis?
Symptoms and Signs of Clonorchiasis In the acute phase, heavier infections can cause fever, chills, epigastric pain, tender hepatomegaly, mild jaundice, and eosinophilia. Later, diarrhea may occur. Symptoms usually last for 2 to 4 weeks.
Where is Ascaris found in the body?
Ascaris is an intestinal parasite of humans. It is the most common human worm infection. The larvae and adult worms live in the small intestine and can cause intestinal disease.
What is the meaning of Digenetic?
Definition of digenetic : of or relating to a subclass (Digenea) of trematode worms in which sexual reproduction as an internal parasite of a vertebrate alternates with asexual reproduction in a mollusk.
What is mean by Encysted?
: to enclose in or as if in a cyst an encysted tumor. intransitive verb. : to form or become enclosed in a cyst protozoans encysting in order to resist desiccation.
Which of the following parasitic metacercariae are found in fish?
Heterophyid metacercariae are usually found encysted in many families of fish, such as: Cobitidae, Cottidae, Cyprinidae, Gobiidae, Mugilidae, Ophicephalidae, Percidae, Plecoglossidae, or Siluridae. Centrocestus formosanus has been encysted experimentally in frogs.
What are the possible complications of metacercariae infection?
Damage to eyes may either be caused by metacercariae with a predilection for the organ (e.g. D. spathaceum) or be a nonspecific side effect (e.g. corneal infection by integument-encysting metacercariae). Impairment of vision is aggravated when metacercarial cysts are accompanied by melanin pigment (black spot).
What are the characteristics of metacercariae?
Metacercariae of the echinostome family is encysted in snails, fishs, and amphibians. The cyst is oval or round; the metacercariae can be folded or not, and they possess collar spines and corpuscles in their excretory tubes, which is characteristic of echinosomes’ cercariae and metacercariae (Fig. 4.6 ).
What is the source of metacercariae infection?
Ingestion of metacercariae in infected raw vegetables (e.g., watercress, lettuce, alfalfa juice, mixed green salads) is a major source of the infection in humans and animals ( Marcos et al, 2004, 2005a ).
What are metacercarial exotic infections?
Metacercarial exotic infections, most notoriously C. formosanus and H. pumilio, have been dispersed through the introduction of the Afro-Asian snail M. tuberculata and have become a health risk for farmed fish in many water bodies in the USA and Mexico ( Mitchell et al., 2000; Scholtz et al., 2001; Brandt southwest.fws.gov/fishery/ trematode.pdf).