Schistosoma japonicum
- GEOGRAPHIC DISTRIBUTION: Japan, the Yangtze basin of China, Taiwan, Indonesia, Malaysia, and the Philippines.
- LOCATION IN HOST: In the portal veins.
- PARASITE IDENTIFICATION: The adults of Schistosoma japonicum, like those of other schistosomatids, occur as separate sexes. ...
What is Schistosoma japonicum?
Schistosoma japonicum is the only human blood fluke that occurs in China, Philippines, and Sri Lanka. It is the cause of schistosomiasis japonica, a disease that still remains a significant health problem especially in lake and marshland regions.
Where is Schistosoma found in the world?
Geographic Distribution. Schistosoma mansoni is found primarily across sub-Saharan Africa and some South American countries (Brazil, Venezuela, Suriname) and the Caribbean, with sporadic reports in the Arabian Peninsula. S. haematobium is found in Africa and pockets of the Middle East. S. japonicum is found in China, the Philippines, and Sulawesi.
What is schistosomiasis and what causes it?
Schistosomiasis is an infection caused mainly by three schistosome species; Schistosoma mansoni, Schistosoma japonicum and Schistosoma haematobium. S. japonicum being the most infectious of the three species.
Where is japonicum japonicum found?
S. japonicum is found in China, the Philippines, and Sulawesi. Despite its name, it has long been eliminated from Japan. The other, less common human-infecting species have relatively restricted geographic ranges.
Where does Schistosoma japonicum live?
japonicum is more frequently found in the superior mesenteric veins draining the small intestine (A), and S. mansoni occurs more often in the superior mesenteric veins draining the large intestine (B).
Where is Schistosoma japonicum most prevalent?
japonicum is found in Indonesia and parts of China and Southeast Asia (Map 4-11). Although schistosomiasis had been eliminated in Europe for decades, transmission of S. haematobium was reported in Corsica in 2014, where cases were identified among travelers who had bathed in the Cavu River.
What is the site of infection of Schistosoma japonicum?
Site of infection: Paired adult worms live inside blood vessels in specific sites within the human body. S. mansoni lives principally in the portal veins draining the large intestine, S. japonicum in the mesenteric veins of the small intestines, and S.
Where is schistosomiasis found in the body?
In the body, the larvae develop into adult schistosomes. Adult worms live in the blood vessels where the females release eggs. Some of the eggs are passed out of the body in the faeces or urine to continue the parasite's lifecycle.
How common is Schistosoma japonicum?
japonicum, affects approximately 200 million individuals, mostly in sub-Saharan Africa; 10% have severe liver or urinary disease and 100,000 die per year. Schistosomiasis is endemic in most of sub-Saharan Africa, Asia, and Latin America.
What is the host of Schistosoma japonicum?
Although most Schistosoma species have humans as the only definitive host, S. japonicum may infect a wide range of domestic and wild animals, including cattle, dogs, pigs, water buffaloes and rodents.
Which Schistosoma is found in urine?
Urinary schistosomiasis is a disease caused by infection of people with the parasitic worm Schistosoma haematobium. These worms live in blood vessels around the infected person's bladder and the worm releases eggs which are released in the person's urine.
What class is Schistosoma japonicum?
FlukesSchistosoma japonicum / ClassTrematoda is a class within the phylum Platyhelminthes. It includes two groups of parasitic flatworms, known as flukes. They are internal parasites of molluscs and vertebrates. Most trematodes have a complex life cycle with at least two hosts. The primary host, where the flukes sexually reproduce, is a vertebrate. Wikipedia
Where do blood flukes live in humans?
Paired adults live in copula in the blood vessels of the definitive host. Most human species reside in the mesenteric vessels of the large intestine and rectum except for S. haematobium, which resides in the venous plexus of the urinary bladder. Schistosoma japonicum and S.
How can you prevent Schistosoma japonicum infection?
Prevention & ControlAvoid swimming or wading in freshwater when you are in countries in which schistosomiasis occurs. ... Drink safe water. ... Water used for bathing should be brought to a rolling boil for 1 minute to kill any cercariae, and then cooled before bathing to avoid scalding.More items...
How does Schistosoma enter the body?
Larval schistosomes (cercariae) can penetrate the skin of persons who come in contact with contaminated freshwater, typically when wading, swimming, bathing, or washing. Over several weeks, the parasites migrate through host tissue and develop into adult worms inside the blood vessels of the body.
How do humans become infected with Schistosoma?
Infection occurs when your skin comes in contact with contaminated freshwater in which certain types of snails that carry schistosomes are living. Freshwater becomes contaminated by Schistosoma eggs when infected people urinate or defecate in the water.
Why is japonicum important?
japonicum is a parasite that uses humans as a primary host, and is a major cause of disease in the regions where it lives. Most of the harm it causes is due to the massive number eggs released. These trigger immune responses that in turn cause many health problems.
What is the sucker on a worm's mouth called?
Both sexes have a strong sucker around the mouth, and another called an acetabulum, a little ways further down on the ventral side. The skin of the worms is coated with tiny spines, ridges and sensory organs that are probably involved in helping resist and avoid the host immune system. Other Physical Features.
What is the name of the sporcyst in a snail?
Inside the snail it becomes a sporocyst (larva ). While in the snail the sporocysts reproduce asexually and become daughter sporocysts. The daughter sporcysts then reproduce asexually again, this time producing cercaria. It is in this stage that they enter humans and other vertebrates.
Where do worms get their nutrition?
The source of the worm's nutrition is the host. The sporocyst stage absorbs nutrition through its skin, taking it directly from the tissues of its snail host. Adult worms feed on blood in the intestinal veins where they live (Roberts and Janovy 2000)
What is the benthic biome?
benthic. Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
What is the first stage of a parasitic worm?
These parasitic worms have a complex life cycle with many stages. The first stage, the egg, is round or oval and very small (about 80 by 60 micrometers), with a very small spur on one end. The first stage that hatches from the egg is called a miracidium, and is not much bigger then the egg.
Is Miracidium a protozoan?
It is free-swimming,ovoid, covered with cilia, and could easily be mistaken for protozoan. It has a complex of glands at the front end that are used to penetrate the skin of a snail host. Once inside a snail, the miracidium sheds its skin and cilia, and metamorphoses into a different shape called a sporocyst.
Where is Schistosoma japonicum found?
Epidemiology. Schistosoma japonicum is found principally in China, Indonesia, and the Philippines. In CNS disease, this fluke locates in the brain, whereas Schistosoma mansoni and Schistosoma haematobium are more commonly found in the spinal cord.
Which neurologic system is affected by Schistosoma japonicum?
Schistosoma japonicum (mostly in Asia) involves the superior mesenteric vessels, and Schistosoma haematobium (mostly in Africa) affects the genitourinary system. From: Encyclopedia of the Neurological Sciences (Second Edition), 2014. Download as PDF.
What are the most common schistosomal species in the brain?
Four schistosomal species cause CNS infection (neuroschistosomiasis): Schistosoma japonica, which is the most common species affecting the brain; S. haematobium and S. mansoni, which produce mainly spinal cord lesions (Scrimgeour and Gajdusek, 1985; Pittella, 1997a, 2003; Ferrari and Moreira, 2011 ); and Schistosoma mekongi, a rare cause of brain infection ( Houston et al., 2004). The CNS lesions are produced by a granulomatous reaction around the parasite eggs, comprising three stages: a necrotic-exudative stage, a productive stage, and a healing stage (Pittella, 1997a). In the necrotic-exudative stage, the granuloma is large, with one or more eggs lying in its center. The eggs are surrounded by necrosis, numerous polymorphonuclear cells, mainly eosinophils, and, more externally, lymphocytes, plasma cells, and macrophages (Fig. 5.16). Not unusually, macrophages are identifiable as elongated epithelioid cells lying radially to the center of the granuloma. Productive-stage granulomas are usually smaller than necrotic-exudative ones. The zone of periovular necrosis is no longer present and the inflammatory reaction around the egg consists of epithelioid and multinuclear giant cells surrounded by lymphocytes and plasma cells (Fig. 5.17 ). Granulomas in the healing stage are usually smaller than those in the productive stage. Around the inflammatory cells is a zone of fibrosis ( Fig. 5.18 ). Thus, the granuloma matures, involutes, and finally heals. The species of Schistosoma can be assessed by the shape and size of the egg shell. Schistosoma mansoni and S. haematobium eggs are oval, with a lateral ( S. mansoni) or terminal ( S. haematobium) spine, and vary from 112 to 174 μm in length by 40 to 70 μm in width. When the spine cannot be identified, the eggs can be differentiated using the Ziehl-Neelsen stain: the shell of S. mansoni eggs takes on a bright red color, whereas that of S. haematobium eggs does not stain. Schistosoma japonicum eggs are round-shaped, vary from 70 to 100 μm in length by 50 to 65 μm in width, and have a reduced lateral spine.
What is schistosomiasis caused by?
Schistosomiasis is caused by trematodes of the genus Schistosoma ( Schistosoma japonicum, Schistosoma mansoni, and Schistosoma haematobium ). Humans are definitive hosts for these parasites that enter the body through the skin following aquatic exposure to their larval forms. Larvae migrate and settle, as adult worms, in the mesenteric veins. CNS involvement occurs when larvae migrate to the spinal cord or cerebral vasculature. A diversity of neurological manifestations may occur, mainly related to the Schistosoma species and the location of parasites; S. japonicum almost always affects the brain. In contrast, the other two species usually affect the spinal cord and only eventually the brain.
How big are Schistosoma mansoni eggs?
haematobium eggs are oval, with a lateral ( S. mansoni) or terminal ( S. haematobium) spine, and vary from 112 to 174 μm in length by 40 to 70 μm in width.
What animals carry schistosoma japonicum?
A total of 31 wild mammals and 13 domestic animals have been shown to carry S. japonicum in China, 26 and in the Philippines, cats, dogs, pigs, water buffaloes and rats were found to have a 3–31% prevalence of viable S. japonicum eggs in the stool. 27 In hilly environments of China, where buffalo are less common, dogs appear to be the main zoonotic reservoir, with prevalence of up to 75%. 28 In this setting, inclusion of animal infection prevention as part of schistosomiasis control campaigns has proven a more successful strategy in China. 29
Where do schistosomes migrate?
Schistosomes may reach the CNS at any time from the moment the worms have matured and migrated to the inferior mesenteric vein (S. mansoni and S. japonicum) or to the venous vesical plexus ( S. haematobium ).
What is the cause of schistosomiasis?
Schistosomiasis (Bilharziasis) is caused by some species of blood trematodes (flukes) in the genus Schistosoma. The three main species infecting humans are S chistosoma haematobium, S. japonicum, and S. mansoni.
Where is S. haematobium found?
S. haematobium is found in Africa and pockets of the Middle East. S. japonicum is found in China, the Philippines, and Sulawesi. Despite its name, it has long been eliminated from Japan. The other, less common human-infecting species have relatively restricted geographic ranges.
Where do haematobium eggs come from?
The females (size ranges from 7–28 mm, depending on species) deposit eggs in the small venules of the portal and perivesical systems.
Where do worms live?
Male and female adult worms copulate and reside in the mesenteric venules, the location of which varies by species (with some exceptions) . For instance, S. japonicum is more frequently found in the superior mesenteric veins draining the small intestine , and S. mansoni occurs more often in the inferior mesenteric veins draining ...
What animals are hosts for S. japonicum?
Hosts. Various animals such as cattle, dogs, cats, rodents, pigs, horses, and goats, serve as reservoirs for S. japonicum, and dogs for S. mekongi. S. mansoni is also frequently recovered from wild primates in endemic areas but is considered primarily a human parasite and not a zoonosis.
Can S. intercalatum move between sites?
However, both species can o ccupy either location and are capable of moving between sites. S. intercalatum and S. guineensis also inhabit the inferior mesenteric plexus but lower in the bowel than S. mansoni.
Is Schistosoma spp. dioecous?
Unlike other trematodes, which are hermaphroditic, Schistosoma spp. are dioecous (individuals of separate sexes). In addition, other species of schistosomes, which parasitize birds and mammals, can cause cercarial dermatitis in humans but this is clinically distinct from schistosomiasis.
Where is S. japonicum found?
For instance, S. japonicum is more frequently found in the superior mesenteric veins draining the small intestine , and S. mansoni occurs more often in the inferior mesenteric veins draining the large intestine . However, both species can occupy either location and are capable of moving between sites.
How long are schistosomes?
Male worms are robust, tuberculate and measure 6-12 mm in length. Females are longer (7-17 mm in length) and slender.
How big are Schistosoma mansoni eggs?
Schistosoma mansoni eggs. Schistosoma mansoni eggs are large (114 to 180 µm long by 45-70 µm wide) and have a characteristic shape, with a prominent lateral spine near the posterior end. The anterior end is tapered and slightly curved. When the eggs are excreted in stool, they contain a mature miracidium.
What are intermediate hosts for Schistosoma spp?
Intermediate hosts for Schistosoma spp. The intermediate hosts of Schistosoma spp. are various species of freshwater snails. Eggs are shed from the human host in feces or urine. Under optimal conditions in the environment, the eggs hatch and release miracidia, which swim and penetrate specific snail intermediate hosts.
Where are Schistosoma mekongi eggs found?
Schistosoma mekongi eggs. Schistosoma mekongi is a species similar to S. japonicum that is restricted to the Mekong River area of southeast Asia. The eggs are similar to S. japonicum, but are generally smaller (50-80 µm by 40-65 µm). They also contain a small, inconspicuous spine and are shed in stool.
What animals are hosts for S. japonicum?
Hosts. Various animals such as cattle, dogs, cats, rodents, pigs, horses, and goats, serve as reservoirs for S. japonicum, and dogs for S. mekongi. S. mansoni is also frequently recovered from wild primates in endemic areas but is considered primarily a human parasite and not a zoonosis.
What is the cause of schistosomiasis?
Schistosomiasis (Bilharziasis) is caused by some species of blood trematodes (flukes) in the genus Schistosoma. The three main species infecting humans are S chistosoma haematobium, S. japonicum, and S. mansoni.
Where is Schistosoma japonicum found?
Schistosoma japonicum is found principally in China, Indonesia, and the Philippines. In CNS disease, this fluke locates in the brain, whereas Schistosoma mansoni and Schistosoma haematobium are more commonly found in the spinal cord.
What is schistosomiasis caused by?
Schistosomiasis is caused by trematodes of the genus Schistosoma ( Schistosoma japonicum, Schistosoma mansoni, and Schistosoma haematobium ). Humans are definitive hosts for these parasites that enter the body through the skin following aquatic exposure to their larval forms. Larvae migrate and settle, as adult worms, in the mesenteric veins. CNS involvement occurs when larvae migrate to the spinal cord or cerebral vasculature. A diversity of neurological manifestations may occur, mainly related to the Schistosoma species and the location of parasites; S. japonicum almost always affects the brain. In contrast, the other two species usually affect the spinal cord and only eventually the brain.
What are the most common schistosomal species in the brain?
Four schistosomal species cause CNS infection (neuroschistosomiasis): Schistosoma japonica, which is the most common species affecting the brain; S. haematobium and S. mansoni, which produce mainly spinal cord lesions ( Scrimgeour and Gajdusek, 1985; Pittella, 1997a, 2003; Ferrari and Moreira, 2011 ); and Schistosoma mekongi, a rare cause of brain infection ( Houston et al., 2004 ). The CNS lesions are produced by a granulomatous reaction around the parasite eggs, comprising three stages: a necrotic-exudative stage, a productive stage, and a healing stage ( Pittella, 1997a ). In the necrotic-exudative stage, the granuloma is large, with one or more eggs lying in its center. The eggs are surrounded by necrosis, numerous polymorphonuclear cells, mainly eosinophils, and, more externally, lymphocytes, plasma cells, and macrophages ( Fig. 5.16 ). Not unusually, macrophages are identifiable as elongated epithelioid cells lying radially to the center of the granuloma. Productive-stage granulomas are usually smaller than necrotic-exudative ones. The zone of periovular necrosis is no longer present and the inflammatory reaction around the egg consists of epithelioid and multinuclear giant cells surrounded by lymphocytes and plasma cells ( Fig. 5.17 ). Granulomas in the healing stage are usually smaller than those in the productive stage. Around the inflammatory cells is a zone of fibrosis ( Fig. 5.18 ). Thus, the granuloma matures, involutes, and finally heals. The species of Schistosoma can be assessed by the shape and size of the egg shell. Schistosoma mansoni and S. haematobium eggs are oval, with a lateral ( S. mansoni) or terminal ( S. haematobium) spine, and vary from 112 to 174 μm in length by 40 to 70 μm in width. When the spine cannot be identified, the eggs can be differentiated using the Ziehl-Neelsen stain: the shell of S. mansoni eggs takes on a bright red color, whereas that of S. haematobium eggs does not stain. Schistosoma japonicum eggs are round-shaped, vary from 70 to 100 μm in length by 50 to 65 μm in width, and have a reduced lateral spine.
Where is S. japonicum found?
S. japonicum is found in China, the Philippines, and other parts of South East Asia, but—despite its name—is very rare in Japan. It infects the liver and intestines, but in rare cases also can infect the brain, leading to seizures and neurological effects.
What is schistosomiasis caused by?
Updated on June 01, 2019. Schistosomiasis is a disease caused by the larvae of a small, flat worm found in freshwater lakes. The larvae, which normally mature in snails that also live in those lakes, enter through your skin as you swim or bathe in the lake. NIBSC/Science Photo Library/Getty Images.
Can schistosomiasis cause paralysis?
Others can get trapped in the brain and can cause paralysis, speech problems, and seiz ures. More importantly, the genital lesions from S. haematobium and other schistosomiasis infections may place women at increased risk for acquiring HIV.
Which disease is most common in South America?
S. mansoni, S. haematobium, and S. japonicum cause the most disease. S. intercalatum and S. mekongi are less common. S. mansoni is the most common, infecting over 80 million people worldwide. It is found in multiple areas in South America, the Caribbean, Africa, and the Middle East, and can cause severe damage to the liver.
Does haematobium cause bladder cancer?
S. haematobium leads to bladder scarring, which increases pressure on and damages kidneys. It is also associated with bladder cancer and infertility. The late effects on the liver (and portal blood system) and the bladder and kidneys can be substantial for older members of a community.
Where can I find S. intercalatum?
S. intercalatum is found particularly in the Democratic Republic of the Congo and Cameroon, where its prevalence is dropping. It can cause bloody stool and an enlarged spleen. S. mekongi is similar to S. japonicum, but it is found along the Mekong River, especially in Cambodia and Laos.
Can schistosoma cause genital lesions?
In infections from the schistosoma species that travel into the veins around the liver, the person may experience an increased risk of cirrhosis of the liver and other liver problems, including liver cancer and colorectal cancer.S. haematobium travels to the bladder, but also can cause genital lesions in women.
Overview
Schistosoma japonicum is an important parasite and one of the major infectious agents of schistosomiasis. This parasite has a very wide host range, infecting at least 31 species of wild mammals, including 9 carnivores, 16 rodents, one primate (human), two insectivores and three artiodactyls and therefore it can be considered a true zoonosis. Travelers should be well-aware of where this parasite might be a problem and how to prevent the infection. S. japonicum occurs i…
Discovery
Schistosoma japonicum was discovered in Kofu basin by Fujiro Katsurada, a pathologist in Okayama University in 1904. Later, Katsurada named the parasite Schistosoma japonicum.
Social impacts
Individuals at risk to infection from S. japonicum are farmers who often wade in their irrigation water, fishermen who wade in streams and lakes, children who play in water, and people who wash clothes in streams.
Important factors to influence transmission are age, sex of an individual, as well as the economic and educational level of a population. Males show the highest rates of infection, as well as the …
Individuals at risk to infection from S. japonicum are farmers who often wade in their irrigation water, fishermen who wade in streams and lakes, children who play in water, and people who wash clothes in streams.
Important factors to influence transmission are age, sex of an individual, as well as the economic and educational level of a population. Males show the highest rates of infection, as well as the …
Morphology
The S. japonicum worms are yellow or yellow-brown. The males of this species are slightly larger than the other schistosomes and they measure ~ 1.2 cm by 0.5 mm. The females measure 2 cm by 0.4 mm. The adult worms are longer and narrower than the related S. mansoni worms.
By electron microscopy there are no bosses or spines on the dorsal surface of the male, which is ridged and presents a spongy appearance. Many spines cover the inner surface of the oral suck…
Life cycle
The life cycles of Schistosoma japonicum and Schistosoma mansoni are very similar. In brief, eggs of the parasite are released in the feces and if they come in contact with water they hatch into free-swimming larva, called miracidia. The larva then has to infect a snail of the genus Oncomelania such as species of Oncomelania hupensis within one or two days. Inside the snail, the larva undergo asexual reproduction through a series of stages called sporocysts. After the asexual re…
Hosts
Hosts include cattle.
Pathology
Once the parasite has entered the body and begun to produce eggs, it uses the hosts' immune system (granulomas) for transportation of eggs into the gut. The eggs stimulate formation of granuloma around them. The granulomas, consisting of motile cells, carry the eggs to the intestinal lumen. When in the lumen, granuloma cells disperse leaving the eggs to be excreted within feces. Unfortunately, about two-thirds of eggs are not excreted, instead they build up in the gut. Chroni…
Disease
Schistosoma japonicum is the only human blood fluke that occurs in China, Philippines, and Sri Lanka. It is the cause of schistosomiasis japonica, a disease that still remains a significant health problem especially in lake and marshland regions. Schistosomiasis is an infection caused mainly by three schistosome species; Schistosoma mansoni, Schistosoma japonicum and Schistosoma haematobium. S. japonicum being the most infectious of the three species. Infection by schisto…