Fasciolopsiasis results from an infection

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

 by the trematode Fasciolopsis buski, the largest intestinal fluke

Trematoda

Trematoda is a class within the phylum Platyhelminthes that contains two groups of parasitic flatworms, commonly referred to as "flukes".-Taxonomy and biodiversity:...

 of human

Human

Humans are the only living species in the Homo genus...

s (up to 7.5 cm in length).

Infection cycle

The parasite infects an amphibic snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

 (Segmentina nitidella, Segmentina hemisphaerula, Hippeutis schmackerie, Gyraulus

Gyraulus

Gyraulus is a genus of small, mostly air-breathing, freshwater snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails....

, Lymnaea

Lymnaea

Lymnaea is a genus of small to large-sized air-breathing freshwater snails, aquatic pulmonate gastropod mollusks in the family Lymnaeidae, the pond snails.Lymnaea is the type genus of the family Lymnaeidae.-Species:...

, Pila, Planorbis

Planorbis

Planorbis is a genus of freshwater air-breathing snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails, or planorbids. All species in this genus have sinistral or left-coiling shells.- Description :...

 (Indoplanorbis)) after being released by infected feces; from this intermediate host

Intermediate host

A secondary host or intermediate host is a host that harbors the parasite only for a short transition period, during which some developmental stage is completed. For trypanosomes, the cause of sleeping sickness, humans are the primary host, while the tsetse fly is the secondary host...

, metacercaria infest on aquatic plant

Aquatic plant

Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...

s, which are eaten raw by pigs and humans. Also, the water is possibly infective when drunk unheated ("Encysted cercariae exist not only on aquatic plant

Aquatic plant

Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...

s, but also on the surface of the water.")

Epidemiology

This disease predominantly occurs in Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, especially in areas where humans raise pig

Pig

A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s and consume raw aquatic plants.

"It has been estimated that there may be 10 million people in East Asia infected with this fluke, yet its radiological identification remains unreported."

Clinical features

Most infections are light and asymptomatic. In heavier infections, symptom

Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

s include diarrhea

Diarrhea

Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

, abdominal pain

Abdominal pain

Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...

, fever

Fever

Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

, ascites

Ascites

Ascites is a gastroenterological term for an accumulation of fluid in the peritoneal cavity.The medical condition is also known as peritoneal cavity fluid, peritoneal fluid excess, hydroperitoneum or more archaically as abdominal dropsy. Although most commonly due to cirrhosis and severe liver...

, anasarca

Anasarca

Anasarca, also known as "extreme generalized edema" is a medical condition characterised by widespread swelling of the skin due to effusion of fluid into the extracellular space....

, and intestinal obstruction.

Laboratory diagnosis

Microscopic identification of eggs

Egg (biology)

An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

, or more rarely of the adult flukes, in the stool

Human feces

Human feces , also known as a stool, is the waste product of the human digestive system including bacteria. It varies significantly in appearance, according to the state of the digestive system, diet and general health....

 or vomitus is the basis of specific diagnosis

Medical diagnosis

Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

. The eggs are indistinguishable from those of Fasciola hepatica

Fasciola hepatica

Fasciola hepatica, also known as the common liver fluke or sheep liver fluke, is a parasitic flatworm of the class Trematoda, phylum Platyhelminthes that infects the livers of various mammals, including humans. The disease caused by the fluke is called fascioliasis . F...

.

Treatment

Praziquantel

Praziquantel

Praziquantel is an anthelmintic effective against flatworms. Praziquantel is not licensed for use in humans in the UK; it is, however, available as a veterinary anthelmintic, and is available for use in humans on a named-patient basis....

 is the drug

Medication

A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...

of choice for treatment of fasciolopsiasis.