Trematode Infection
No Results
No Results
processing….
Trematode infections occur worldwide. Trematodes, also called flukes, cause various clinical infections in humans. The parasites are so named because of their conspicuous suckers, the organs of attachment (trematos means “pierced with holes”). All the flukes that cause infections in humans belong to the group of digenetic trematodes. Important features exhibited by adult digenetic trematodes are summarized below (see Features of digenic trematodes).
Trematode infections such as schistosomiasis have emerged as important tropical infections. An estimated 200 million people in the tropical belts of the world may have schistosomal infection. This makes Schistosoma infection the second most prevalent tropical infectious disease in areas such as sub-Saharan Africa after malaria. [1]
Depending on the habitat in the infected host, flukes can be classified as blood flukes, liver flukes, lung flukes, or intestinal flukes (see Classification of trematodes according to their habitat). The flukes that cause most human infections are Schistosoma species (blood fluke), Paragonimus westermani (lung fluke), and Clonorchis sinensis (liver fluke). Other less-important flukes include the liver flukes Fasciola hepatica and Opisthorchis viverrini and the intestinal flukes Fasciolopsis buski, Heterophyes heterophyes, and Metagonimus yokogawai.
Digenic trematodes are unsegmented, leaf-shaped worms that are flattened dorsoventrally. They bear 2 suckers, one surrounding the mouth (oral sucker) and another on the ventral surface of the body (ventral sucker). These serve as the organs of attachment. The sexes of the parasites are not separate (monoecious). An exception is schistosomes, which are diecious (unisexual).
The alimentary canal is incomplete, and no anus is present. The excretory system is bilaterally symmetrical. It consists of flame cells and collecting tubes. These flame cells provide the basis for the identification of the species.
The reproductive system consists of male and female reproductive organs and is complete in each fluke. The flukes are oviparous. They lay operculated eggs. An exception is schistosome eggs, which are not operculated.
All have complicated life cycles, with alternating asexual and sexual developments in different hosts. [2]
Blood flukes include Schistosoma haematobium, Schistosoma mansoni, Schistosoma japonicum, Schistosoma mekongi, and Schistosoma intercalatum (clade B – mammalian freshwater schistosomes).
Liver flukes include F hepatica, Fasciola gigantica, C sinensis, Opisthorchis felineus, O viverrini, Dicrocoelium dendriticum,Dicrocoelium hospes, and Metorchis conjunctus.
Pancreatic flukes include Eurytrema pancreaticum, Eurytrema coelomaticum, and Eurytrema ovis.
Lung flukes include Pwestermani, Paragonimusheterotremus, Paragonimus kellicoti, Paragonimusmexicana, Paragonimus skrjabin, Paragonimus miyazakii, Paragonimus compactus, and Paragonimushueit’ungensis.
Intestinal flukes include F buski, M yokogawai, Echinostoma ilocanum, Watsonius watsoni, H heterophyes, and Gastrodiscoides hominis.
Eye flukes include Philophthalmus lacrimosus, Philophthalmus palpebrarum, and Philophthalmus gralli (Philophthalmus lucipetus).
Other flukes include Alaria americana and Clinostomum complanatum.
The life cycle of trematodes is completed in 2 different classes of hosts: definitive (ie, humans, domestic animals, wild animals) and intermediate (ie, freshwater snails). See the figures below.
Snails that act as intermediate hosts for trematodes of medical importance are listed in Table 1. The list of these hosts for different trematodes and the source of infections are summarized in Table 2.
Table 1. Vectors and Geographical Areas Associated With Certain Trematode Types (Open Table in a new window)
Vector
Geographical Area
Type of Trematode
Biomphalaria glabrata
Brazil
S mansoni
Bulinus globosa
Nigeria
S haematobium
Bulinus truncate
Iran
S haematobium
Oncomelania hupensis nosophora
Japan
S japonicum
Thiara granifera
China
P westermani; M yokogawai
Semisulcospira libertine
China
P westermani; M yokogawai
Polypylis hemisphaerula
China
F buski
Parafossarulus manchouricus
China
C sinensis
Bithynia leachi
Germany
O felineus
Pirenella conica
Egypt
H heterophyes
Lymnaea truncatula
England
F hepatica
Table 2. List of Definitive and Intermediate Hosts and Sources of Infection of Major Trematodes (Open Table in a new window)
Trematode
Definitive Host
Intermediate Host
1st 2nd
Source of Infection
S haematobium
Humans
Freshwater snails (genus Bulinus)
Absent
Contact with water contaminated by cercariae
S mansoni
Humans, occasionally baboons and rodents
Freshwater snails (genus Biomphalaria)
Absent
Penetration of skin by cercariae
S japonicum
Humans, dogs, pigs, cattle, mice, mustelids, and monkeys
Amphibian snails (Oncomelania species)
Absent
Penetration of skin by cercariae
S mekongi
Humans and dogs
Aquatic snails (Tricula aperta)
Absent
Penetration of skin by cercariae
F hepatica
Sheep, goats, cattle, and other herbivorous animals
Amphibian snails (family Lymnaeidae)
Aquatic vegetations and watercress
Ingestion of aquatic plants and watercress infected with metacercariae
C sinensis
Humans, dogs, pigs, cats, rats, and several species of wild animals
Freshwater snails (family Bulinidae)
Freshwater fish (family Cyprinidae)
Eating raw or partially cooked freshwater fish or dried, salted, or pickled fish infected with encysted metacercariae
O felineus
Humans and other fish-eating mammals
Aquatic snails
Freshwater fish
Eating fish infected with metacercariae
P westermani
Humans, wolves, foxes, tigers, leopards, lions, cats, dogs, and monkeys
Freshwater snails (family Pleuroceridae and Thiaridae)
Freshwater crab or crayfish
Ingestion of freshwater crabs or crayfish infected with metacercariae
F buski
Pigs and humans
Planorbid snails of the genera Segmentina, Hippeutis, and Polypylis
Freshwater plants such as water caltrops, water chestnut, water bamboo, water hyacinth, and lotus
Ingestion of freshwater aquatic plants that harbor metacercariae
Schistosomiasis, or bilharzia, is a tropical parasitic disease caused by blood-dwelling fluke worms of the genus Schistosoma, from the Greek for skhistos (split) and soma (body).Originally thought to be a single organism with a split body, the parasite was eventually recognized as having male and female forms. The main schistosomes that infect human beings include S haematobium (transmitted by Bulinus snails and causing urinary schistosomiasis in Africa and the Arabian peninsula), S mansoni (transmitted by Biomphalaria snails and causing intestinal and hepatic schistosomiasis in Africa, the Arabian peninsula, and South America), and S japonicum (transmitted by the amphibious snail Oncomelania and causing intestinal and hepatosplenic schistosomiasis in China, the Philippines, and Indonesia).
S intercalatum and S mekongi are only of local importance. S japonicum is a zoonotic parasite that infects a wide range of animals, including cattle, dogs, pigs, and rodents. S mansoni also infects rodents and primates, but human beings are the main host. A dozen other schistosome species are animal parasites, some of which occasionally infect humans.
Unlike other trematodes, schistosomes have separate sexes, but males and females are found together. The male is short and stout and holds the relatively long female worm in its gynecophoric canal, a groovelike structure. With S haematobium, both male and female live together in the veins that drain the urinary bladder, pelvis, and ureter, whereas S japonicum and S mansoni live in the inferior and superior mesenteric veins, respectively. Hence, these flukes are known as blood flukes. These species are distinguished from the other schistosomal species based on the morphology of their eggs and their adult and cercarial forms. Shaematobium eggs have a terminal spine, whereas Smansoni and Sjaponicum eggs have lateral spines and central spines, respectively.
Humans are infected by free-swimming, fork-tailed cercaria in fresh water by penetration of the skin. The cercaria loses its tail and outer layer of glycocalyces, transforms into a schistosomula (a larval form), and travels through venous circulation to the heart, lungs, and portal circulation. Larvae mature and develop into adult worms in approximately 3 weeks and reach the vessels that drain the urinary bladder (Shaematobium) or the mesentery (Sjaponicum, Smansoni). At these venous sites, they live and lay eggs for the duration of the host’s life.
The eggs penetrate the vascular endothelium, enter the bladder or gut lumen, and are excreted in urine (Shaematobium) or stool (Sjaponicum, Smansoni). If these excreted eggs gain access to fresh water, the miracidium emerges from the egg and swims freely until it finds an appropriate snail. In the snail host, after 2 generations of asexual multiplication (sporocysts), the forked-tailed cercariae emerge in water to infect other susceptible human hosts. A single miracidium can multiply in the snail to produce nearly 100,000 cercariae.
Table 3. Comparative Features of Major Human Schistosoma Species (Open Table in a new window)
S haematobium
S mansoni
S japonicum
Adult
Body surface of male
Finely tuberculate
Grossly tuberculate
Nontuberculate (smooth)
Testes
4-6, in a cluster
6-9, in a cluster
7, in a linear series
Position of ovary
Posterior to middle of body
Anterior to middle of body
Posterior to middle of body
Number of eggs in uterus
20-30
1-4
50-300
Egg
Size and shape
110-170 μm long
40-70 μm wide
Terminal spine
114-175 μm long
45-68 μm wide
Lateral spine
70-100 μm long
50-65 μm wide
Central spine
Cercaria
Cephalic glands
2 pairs, oxyphilic
2 pairs, basophilic
4 pairs, oxyphilic
The genus Paragonimus contains more than 30 species that have been reported to cause infections in animals and humans. Among these, approximately 10 species have been reported to cause infection in humans, of which Pwestermani is the most important. Pwestermani, also known as the Oriental lung fluke, is the most widespread species in Africa, South America, and parts of Asia. Among other species of Paragonimus that have been reported to cause human disease from around the world is Paragonimus heterotremus, which has been reported from northeastern parts of the Indian subcontinent. [3]
P westermani is a thick, fleshy, reddish brown, egg-shaped worm (7.5-12 mm in length, 4-6 mm in breadth, and 3.5-5 mm in thickness). It inhabits parenchyma of the lung close to bronchioles in humans, foxes, wolves, and various feline hosts (eg, lions, leopards, tigers, cats).
The infection is typically transmitted via ingestion of metacercariae contained in raw freshwater crabs or crayfish. Additionally, consumption of the raw meat of paratenic hosts (eg, omnivorous mammals) may also contribute to human infection. Freshwater snails and crabs are first and second intermediate hosts of Paragonimus species, respectively. In the duodenum, the cyst wall is dissolved, and the metacercariae are released. The metacercariae migrate by penetrating through the intestinal wall, peritoneal cavity, and, finally, through the abdominal wall and diaphragm into the lungs. There, the immature worms finally settle close to the bronchi, grow, and develop to become sexually mature hermaphrodite worms.
Adult worms begin to lay the eggs, which are unembryonated and are passed out in the sputum. However, if they are swallowed, they are excreted in the feces. The eggs develop further in the water. In each egg, a ciliated miracidium develops during a period of 2-3 weeks. The miracidium escapes from the egg and penetrates a suitable species of snail (first intermediate host), in which it goes through a generation of sporocysts and 2 generations of rediae to form the cercariae. The cercariae come out of the snail, invade a freshwater crustacean (crayfish or crab), and encyst to form metacercariae. When ingested, these cause the infection, and the cycle is repeated. Note the image below.
Liver flukes (C sinensis and F hepatica )
C sinensis
C sinensis is a widespread parasite found in Southeast Asia that infects the biliary passage in humans. The fluke is oblong, flat, transparent, and relatively small (10-25 mm long by 3-5 mm wide). It has a pointed anterior and rounded posterior end. Humans are infected by eating raw or partially cooked freshwater fish or dried, salted, or pickled fish infected with the metacercariae. In the duodenum, the cyst is digested and an immature larva released. The larva enters the biliary duct, where it develops and matures into an adult worm. The adult worm feeds on the mucosal secretions and begins to lay fully embryonated operculated eggs, which are excreted in the feces.
Upon reaching fresh water and upon ingestion by a suitable species of operculate snails (first intermediate host), the eggs hatch to produce a miracidium. Inside the snail, the miracidia multiply asexually through a single generation of sporocysts and generations of rediae to fork-tailed cercariae.
See the image below.
The cercariae escape from the snail to the water and penetrate under scales of freshwater cyprinid fish (second intermediate host). In the fish, the cercariae lose their tails and encyst in the scale or muscle of the fish to the metacercariae, which are infectious to humans. When ingested, the infected fish cause infection in humans.
F hepatica
Fascioliasis, a zoonotic disease caused by infection with Fhepatica (a digenetic trematode), is a major disease of livestock that is associated with important economic losses due to mortality; liver condemnation; reduced production of meat, milk, and wool; and expenditures for anthelmintics. The disease has a cosmopolitan distribution, with cases reported from Scandinavia to New Zealand and southern Argentina to Mexico.
Fhepatica, also known as the sheep liver fluke, is a large liver fluke. This fluke primarily causes zoonotic disease in sheep and other domestic animals. Humans are infected by eating watercress and other aquatic plants contaminated by the metacercariae, which enter the duodenum and excyst. They then penetrate the intestinal wall, peritoneal cavity, and liver capsule (Glisson capsule) to reach the bile duct of the liver, where they develop and mature into adult worms.
The adult worms begin to lay the unembryonated eggs, which are excreted in the stool. They develop further in the fresh water. A miracidium hatches out of the egg and invades the appropriate snail host. Inside the snail host, the larva multiplies asexually through a single generation of sporocysts and 2 generations of rediae to finally develop into cercariae. Upon exiting the snail, the cercariae encyst on aquatic plants to form metacercariae. When humans and sheep eat these plants, they become infected, repeating the life cycle.
D dendriticum, D hospes
Dicrocoeliasis is a parasitic disease caused by the small liver flukes D dendriticum and D hospes. The disease represents a worldwide and widespread problem in grazing livestock, and it is sometimes (although rarely) found in humans. However, because of its unusual method of transmission by ingestion of infected ants, human dicrocoeliasis remains a relatively rare occurrence in humans. Cases of human dicrocoeliasis have been reported throughout Eastern Europe, Western Europe, Africa, Australia, India, and Saudi Arabia.
Pancreatic flukes (E pancreaticum , E coelomaticum , E ovis )
These flukes have a thick body and are 8-16 mm long and 6 mm wide. They parasitize the pancreatic ducts and occasionally the bile ducts of sheep, pigs, and cattle in Brazil and Asia. Three species, Epancreaticum, Ecoelomaticum, and E ovis, are recognized.
The first intermediate hosts are terrestrial snails (Bradybaena species), and the cercariae encyst in grasshoppers (Conocephalus species), which are the second intermediate host. After a suitable animal hosts ingests a grasshopper with cercariae, the immature flukes are released and migrate to the pancreatic duct, where they mature and produce eggs within approximately 11-14 weeks.
There are no obvious clinical signs of infection with these parasites. Dicrocoelium -like eggs can be demonstrated in feces. Light infections cause proliferative inflammation of the pancreatic duct, which may become enlarged and occluded. In heavy infections, fibrotic, necrotic, and degenerative lesions develop. Losses are reported due to condemned pancreas, but the pathogenesis suggests an additional loss of production.
Intestinal flukes (F buski, H heterophyes, M yokogawai , G hominis )
F buski is the most common intestinal nematode that causes infections in humans. The trematodes Hheterophyes, Myokogawai, and G hominis are less-common causes of human infection.
F buski, known as the giant intestinal fluke, is found in the duodenum and jejunum of pigs and humans and is the largest intestinal fluke to parasitize humans. Humans are infected by eating freshwater aquatic plants such as water caltrops, water chestnuts, and water bamboo, which can harbor the metacercariae. In the intestine, the metacercariae excyst, attach to the duodenum or jejunum, develop, and grow into adult worms. They lay unembryonated eggs, which are excreted in the feces.
In water, inside the egg, a ciliated miracidium develops, comes out, and penetrates a suitable snail host. Inside the snail, after several stages of asexual multiplication, large numbers of cercariae are produced. The latter emerge from the snail and encyst on the surface of aquatic plants to metacercariae. Ingestion of these plants causes infection in humans, and the cycle is repeated.
United States
Infection with blood flukes, lung flukes, liver flukes, and intestinal flukes in the United States is extremely rare. The condition is observed in travelers and emigrants from endemic areas. The liver fluke M conjunctus is found to be endemic in North America (Canadian population).
International
Trematode infections in general are becoming more prevalent. Schistosomiasis affects about 200 million people worldwide, and more than 650 million people live in endemic areas. Worldwide, more than 250 million people in 74 countries are infected. Currently, 601 million individuals are at risk for Csinensis infection, 293.8 million for infection with Paragonimus species, 91.1 million for infection with Fasciola species, and 79.8 million for infection with Opisthorchis species.
The geographic distribution of schistosomiasis depends on the presence of the freshwater snails that act as the intermediate hosts. Human infection is caused by skin penetration by the schistosomal cercariae upon contact with the contaminated water sources. Persons susceptible to infection include farmers working in irrigated fields, anglers working in culture ponds and rivers, and persons who wash utensils or clothes along banks of canals or rivers.
Residents who live near freshwater bodies have a risk of infection that is 2.15 times that of persons who live farther from water. Exponential growth of aqua culture may be the most important risk factor for the emergence of foodborne trematodiasis.
Foodborne trematodiasis, which is caused by liver flukes (Csinensis,Fasciola species, Opisthorchis species), lung flukes (Paragonimus species), and intestinal flukes (Echinostoma species, Fbuski, heterophyids), is an emerging public health problem in Southeast Asia and the West Pacific region.
The liver fluke M conjunctus has been reported in Russia. The life cycle of this parasite resembles that of Opisthorchis species. Aquatic snails serve as the first intermediate host, white sucker (Catostomus commersoni) serve as the second intermediate host, and humans are incidental hosts. Unlike Clonorchis and Opisthorchis, M conjunctus is not linked to the causation of cholangiocarcinoma. [4] Clonorchiasis is believed to be the third most prevalent worm parasite disease in the world. It is endemic to Japan, China, Taiwan, and South Asia and is currently infecting an estimated 35 million humans, of which 15 million are from China. [5]
The different species of Schistosoma have different geographic distributions. Urinary schistosomiasis caused by Shaematobium is found in 54 countries in Africa and the eastern Mediterranean. Intestinal schistosomiasis is caused by Sjaponicum and is limited to 4 countries in the Far East (ie, China, Thailand, Indonesia, Philippines). Smansoni is found in 52 countries in Africa and Latin America. Smekongi is found along the banks of the Mekong River area in Southeast Asia. It has been estimated that after malaria, schistosomiasis is the most common tropical infectious disease, with 207 million estimated cases. [6, 7] Schistosoma gimvicum and Schistosoma incognitum are rare species of schistosomes reported from India that are known to cause urinary and intestinal schistosomiasis, respectively. [8]
Schistosomal coinfection has been found to affect the malaria transmission in areas in Africa, where both these infections are common. Higher incidence of parasitemia and density of gametocytes has been seen in patients with coinfections. [1]
Cercarial dermatitis is commonly caused by various mammalian schistosomes (belonging to clade B) and rarely by avian schistosomes belonging to clade A (marine avian schistosomes – Austrobilharzia and Ornithobilharzia) and clade D (freshwater avian schistosomes – Trichobilharzia, Gigantobilharzia, Dendritobilharzia, among others). In India and Nepal, clade B mammalian freshwater schistosomes such as like Schistosoma turkestanicum, Schistosoma nasale, Schistosoma indicum, and Schistosoma spindale have been implicated in outbreaks of cercarial dermatitis. The snail Indoplanorbis exustus, seen abundantly in Asia (in contrast to Bulinus and Biomphalaria in Africa), acts as the intermediate host, and domesticated farm cattle act as definitive hosts. [9]
Liver fluke infection is endemic in China, Japan, Korea, Taiwan, and Vietnam (Csinensis); Thailand and Laos (Oviverrini); and the Russian Federation and Eastern Europe (Ofelineus). People who habitually eat raw or partially cooked fish or dried, salted, or pickled fish are more susceptible to infection by Clonorchis species. C sinensis the most common liver fluke in East Asia. Its importance lies in the fact that it has been shown to be responsible for cholangiocarcinoma in humans. In 2009, it was given the status of a group 1 biological carcinogen. [10]
Human fascioliasis occurs worldwide in temperate regions. F hepatica is found on every continent except Antarctica, with the estimated number of infected people over 2 million. The prevalence is highest in areas of extensive sheep and cattle farming and where dietary practices include the consumption of raw aquatic vegetables. In many locations (eg, Portugal, the Nile delta, northern Iran, parts of China, the Andean highlands of Ecuador, Bolivia, and Peru), high infection rates have made fascioliasis a serious public health concern. Outbreaks of Fgigantica infection have been reported from tropical areas of Southeast Asia, Africa, and Hawaii. Human fascioliasis has been reported with increasing frequency from countries such as Turkey in the past few years. [11]
Nearly 100 million people worldwide are infected with F buski. The infection is found most commonly in China, Taiwan, Thailand, Indonesia, Bangladesh, and India. Human infection occurs after ingestion of various parts (eg, fruits, pods, roots, stems) of infected water chestnut, lotus, and other aquatic plants, when they are bitten or peeled off with the teeth. Human infection with H heterophyes has been reported in Egypt’s Nile delta.
Metagonimiasis is common in East Asia (mainly Japan, China, Taiwan, and the Republic of Korea). Echinostoma is endemic in Southeast Asia and the Far East (eg, China, Indonesia, Vietnam, Taiwan, Thailand). The life cycle of all the intestinal flukes is similar. [12]
Human lung fluke infection, most commonly with P westermani, is most common in China, Korea, Thailand, Philippines, and Laos. P skrjabini is more prevalent in China and P miyazakii is common in Japan. Isolated endemic foci have also been reported from the states of Manipur, Nagaland, and Arunachal Pradesh in India, where P heterotremus is the most common agent, followed by P westermani. Infection with a new subspecies of P miyazakii named P miyazakii manipurinus has been recently reported from India. P kellicotti is the agent responsible for pulmonary paragonimiasis in North America. [13]
A low prevalence has been reported from the African countries of Cameroon and Nigeria, where infections with Paragonimus africanus and Paragonimus uterobilateralis are reported. Rare reports of infections with other species of Paragonimus such as P compacta and P hueit’ungensis have been reported from a few countries, including India. [14]
Humans are infected by eating raw or partially cooked crab or crayfish or crabs soaked in wine as a food delicacy or by drinking juice from raw crabs or crayfish as a part of a food habit.
Systemic and intraocular infections in humans have been reported to be caused by A Americana, a 3-host trematode affecting the definitive host, dog. Humans acquire infection by consuming undercooked frogs (intermediate host) that contain the infective mesocercaria stage of the parasite. Humans and snakes act as paratenic hosts. Two intraocular (diffuse subacute neuroretinitis) and one disseminated infection by this parasite has been reported worldwide. [15]
The trematode Philophthalmus affects birds’ eyes (definitive host), and snails act as intermediate host. New definitive hosts (birds and, accidently, humans) acquire infections when encysted metacercaria are ingested or when they come into direct contact with the eye. Cases have been reported from Yugoslavia, Thailand, Sri Lanka, Japan, Mexico, and the United States. [16]
Clinostomum complanatum primarily affects birds (definitive host). Freshwater fish act as a second intermediate host, containing metacercaria, which are infective to birds. Humans acquire infection by ingesting undercooked freshwater fish, releasing the metacercaria into the stomach. The fluke migrates through the esophagus to the upper respiratory tract, causing pharyngitis or laryngitis. Most human Clinostomum infections have been reported in Japan, Korea, and Thailand. [17]
No racial predisposition to trematode infections is apparent.
Most trematode infections have no sexual predisposition.
Most trematode infections affect people of all ages equally. However, with intestinal trematode infections, children are affected more severely, as are children and adolescents with schistosomiasis.
Sangweme DT, Midzi N, Zinyowera-Mutapuri S, Mduluza T, Diener-West M, Kumar N. Impact of schistosome infection on Plasmodium falciparum Malariometric indices and immune correlates in school age children in Burma Valley, Zimbabwe. PLoS Negl Trop Dis. 2010 Nov 9. 4(11):e882. [Medline]. [Full Text].
Parija SC. Textbook of Medical Parasitology. Protozoology and Helminthology. 4 ed. New Delhi: All India: Publishers and Distributers; 2013.
Singh TS, Sugiyama H, Umehara A, Hiese S, Khalo K. Paragonimus heterotremus infection in Nagaland: A new focus of Paragonimiasis in India. Indian J Med Microbiol. 2009 Apr-Jun. 27(2):123-7. [Medline].
MacLean JD, Arthur JR, Ward BJ, Gyorkos TW, Curtis MA, Kokoskin E. Common-source outbreak of acute infection due to the North American liver fluke Metorchis conjunctus. Lancet. 1996 Jan 20. 347 (8995):154-8. [Medline].
Lun ZR, Gasser RB, Lai DH, Li AX, Zhu XQ, Yu XB, et al. Clonorchiasis: a key foodborne zoonosis in China. Lancet Infect Dis. 2005 Jan. 5(1):31-41. [Medline].
Badr HI, Shaker AA, Mansour MA, et al. Schistosomal myeloradiculopathy due to Schistosoma mansoni: Report on 17 cases from an endemic area. Ann Indian Acad Neurol. 2011 Apr. 14(2):107-10. [Medline]. [Full Text].
Mazigo HD, Nuwaha F, Kinung’hi SM, Morona D, Pinot de Moira A, Wilson S. Epidemiology and control of human schistosomiasis in Tanzania. Parasit Vectors. 2012. 5:274. [Medline].
Agrawal MC, Rao VG. Indian schistosomes: a need for further investigations. J Parasitol Res. 2011. 2011:250868. [Medline].
Horák P, Mikeš L, Lichtenbergová L, Skála V, Soldánová M, Brant SV. Avian schistosomes and outbreaks of cercarial dermatitis. Clin Microbiol Rev. 2015 Jan. 28 (1):165-90. [Medline].
Hong ST, Fang Y. Clonorchis sinensis and clonorchiasis, an update. Parasitol Int. 2012 Mar. 61(1):17-24. [Medline].
Sakru N, Korkmaz M, Demirci M, Kuman A, Ok UZ. Fasciola hepatica infection in echinococcosis suspected cases. Turkiye Parazitol Derg. 2011. 35(2):77-80. [Medline].
Chai JY, Song TE, Han ET, Guk SM, Park YK, Choi MH, et al. Two endemic foci of heterophyids and other intestinal fluke infections in southern and western coastal areas in Korea. Korean J Parasitol. 1998 Sep. 36 (3):155-61. [Medline].
Procop GW. North American paragonimiasis (Caused by Paragonimus kellicotti) in the context of global paragonimiasis. Clin Microbiol Rev. 2009 Jul. 22(3):415-46. [Medline].
Singh TS, Sugiyama H, Rangsiruji A. Paragonimus & paragonimiasis in India. Indian J Med Res. 2012. 136:192-204.
McDonald HR, Kazacos KR, Schatz H, Johnson RN. Two cases of intraocular infection with Alaria mesocercaria (Trematoda). Am J Ophthalmol. 1994 Apr 15. 117 (4):447-55. [Medline].
Waikagul J, Dekumyoy P, Yoonuan T, Praevanit R. Conjunctiva philophthalmosis: a case report in Thailand. Am J Trop Med Hyg. 2006 May. 74 (5):848-9. [Medline].
Hara H, Miyauchi Y, Tahara S, Yamashita H. Human laryngitis caused by Clinostomum complanatum. Nagoya J Med Sci. 2014 Feb. 76 (1-2):181-5. [Medline].
Carod-Artal FJ. Neurological complications of Schistosoma infection. Trans R Soc Trop Med Hyg. 2008 Feb. 102(2):107-16. [Medline].
Dainichi T, Nakahara T, Moroi Y, et al. A case of cutaneous paragonimiasis with pleural effusion. Int J Dermatol. 2003 Sep. 42(9):699-702. [Medline].
Kim KU, Lee K, Park HK, Jeong YJ, Yu HS, Lee MK. A pulmonary paragonimiasis case mimicking metastatic pulmonary tumor. Korean J Parasitol. 2011 Mar. 49(1):69-72. [Medline]. [Full Text].
Kim MK, Cho BM, Yoon DY, Nam ES. Imaging features of intradural spinal paragonimiasis: a case report. Br J Radiol. 2011 Apr. 84(1000):e72-4. [Medline]. [Full Text].
Slesak G, Inthalad S, Basy P, et al. Ziehl-Neelsen staining technique can diagnose paragonimiasis. PLoS Negl Trop Dis. 2011 May. 5(5):e1048. [Medline]. [Full Text].
Harries AD, Fryatt R, Walker J, Chiodini PL, Bryceson AD. Schistosomiasis in expatriates returning to Britain from the tropics: a controlled study. Lancet. 1986 Jan 11. 1 (8472):86-8. [Medline].
Garcia LS. Diagnostic Medical Parasitology. 5th ed. Washington, D.C: ASM Press; 2007.
Ubeira FM, Muino L, Valero MA, Periago MV, Perez-Crespo I, Mezo M. MM3-ELISA detection of Fasciola hepatica coproantigens in preserved human stool samples. Am J Trop Med Hyg. 2009 Jul. 81(1):156-62. [Medline].
Allam G, Bauomy IR, Hemyeda ZM, Sakran TF. Evaluation of a 14.5 kDa-Fasciola gigantica fatty acid binding protein as a diagnostic antigen for human fascioliasis. Parasitol Res. 2012. 110:1863-71.
El Dib NA, Sabry MA, Ahmed JA, El-Basiouni SO, El-Badry AA. Evaluation of Capillaria philippinensis coproantigen in the diagnosis of infection. J Egypt Soc Parasitol. 2004 Apr. 34(1):97-106. [Medline].
Grenfell RF, Martins W, Enk M, Almeida A, Siqueira L, Silva-Moraes V, et al. Schistosoma mansoni in a low-prevalence area in Brazil: the importance of additional methods for the diagnosis of hard-to-detect individual carriers by low-cost immunological assays. Mem Inst Oswaldo Cruz. 2013. 108:
Massoud AA, Hussein HM, Reda MA, el-Wakil HS, Maher KM, Mahmoud FS. Schistosoma mansoni egg specific antibodies and circulating antigens: assessment of their validity in immunodiagnosis of schistosomiasis. J Egypt Soc Parasitol. 2000 Dec. 30(3):903-16. [Medline].
Sousa-Figueiredo JC, Betson M, Kabatereine NB, Stothard JR. The urine circulating cathodic antigen (CCA) dipstick: a valid substitute for microscopy for mapping and point-of-care diagnosis of intestinal schistosomiasis. PLoS Negl Trop Dis. 2013. 7(1):e2008. [Medline].
Obeng BB, Aryeetey YA, de Dood CJ, et al. Application of a circulating-cathodic-antigen (CCA) strip test and real-time PCR, in comparison with microscopy, for the detection of Schistosoma haematobium in urine samples from Ghana. Ann Trop Med Parasitol. 2008 Oct. 102(7):625-33. [Medline].
Gonzales Santana B, Dalton JP, Vasquez Camargo F, Parkinson M, Ndao M. The diagnosis of human fascioliasis by enzyme-linked immunosorbent assay (ELISA) using recombinant cathepsin L protease. PLoS Negl Trop Dis. 2013. 7 (9):e2414. [Medline].
Centers for Disease Control and Prevention. DPDx: Fascioliasis. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/dpdx/fascioliasis/index.html .
Wongratanacheewin S, Pumidonming W, Sermswan RW, Maleewong W. Development of a PCR-based method for the detection of Opisthorchis viverrini in experimentally infected hamsters. Parasitology. 2001 Feb. 122:175-80. [Medline].
Le TH, Nguyen KT, Nguyen NT, Doan HT, Le XT, Hoang CT, et al. Development and evaluation of a single-step duplex PCR for simultaneous detection of Fasciola hepatica and Fasciola gigantica (family Fasciolidae, class Trematoda, phylum Platyhelminthes). J Clin Microbiol. 2012. 50:2720-6.
Parvathi A, Sanath Kumar H, Kenchanna Prakasha B, et al. Clonorchis sinensis: development and evaluation of a nested polymerase chain reaction (PCR) assay. Exp Parasitol. 2007 Mar. 115(3):291-5. [Medline].
Kim EM, Verweij JJ, Jalili A, et al. Detection of Clonorchis sinensis in stool samples using real-time PCR. Ann Trop Med Parasitol. 2009 Sep. 103(6):513-8. [Medline].
Guo JJ, Zheng HJ, Xu J, Zhu XQ, Wang SY, Xia CM. Sensitive and specific target sequences selected from retrotransposons of Schistosoma japonicum for the diagnosis of schistosomiasis. PLoS Negl Trop Dis. 2012. 6:e1579.
Ibironke O, Koukounari A, Asaolu S, Moustaki I, Shiff C. Validation of a new test for Schistosoma haematobium based on detection of Dra1 DNA fragments in urine: evaluation through latent class analysis. PLoS Negl Trop Dis. 2012 Jan. 6(1):e1464. [Medline].
Prasad PK, Goswami LM, Tandon V, Chatterjee A. PCR-based molecular characterization and insilico analysis of food-borne trematode parasites Paragonimus westermani, Fasciolopsis buski and Fasciola gigantica from Northeast India using ITS2 rDNA. Bioinformation. 2011 Mar 26. 6(2):64-8. [Medline]. [Full Text].
Ezzat RF, Karboli TA, Kasnazani KA, Hamawandi AM. Endoscopic management of biliary fascioliasis: a case report. J Med Case Rep. 2010 Mar 6. 4:83. [Medline]. [Full Text].
Deng WC, Zhao ZY, Liu JX, Li SM, Guo FY, Wang ZH. [Multi-disciplinary treatment for advanced schistosomiasis]. Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi. 2013 Feb. 25(1):67-9. [Medline].
Echenique-Elizondo M, Amondarain J, Liron de Robles C. Fascioliasis: an exceptional cause of acute pancreatitis. JOP. 2005 Jan 13. 6(1):36-9. [Medline].
Espinoza JR, Maco V, Marcos L, et al. Evaluation of Fas2-ELISA for the serological detection of Fasciola hepatica infection in humans. Am J Trop Med Hyg. 2007 May. 76(5):977-82. [Medline].
Vector
Geographical Area
Type of Trematode
Biomphalaria glabrata
Brazil
S mansoni
Bulinus globosa
Nigeria
S haematobium
Bulinus truncate
Iran
S haematobium
Oncomelania hupensis nosophora
Japan
S japonicum
Thiara granifera
China
P westermani; M yokogawai
Semisulcospira libertine
China
P westermani; M yokogawai
Polypylis hemisphaerula
China
F buski
Parafossarulus manchouricus
China
C sinensis
Bithynia leachi
Germany
O felineus
Pirenella conica
Egypt
H heterophyes
Lymnaea truncatula
England
F hepatica
Trematode
Definitive Host
Intermediate Host
1st 2nd
Source of Infection
S haematobium
Humans
Freshwater snails (genus Bulinus)
Absent
Contact with water contaminated by cercariae
S mansoni
Humans, occasionally baboons and rodents
Freshwater snails (genus Biomphalaria)
Absent
Penetration of skin by cercariae
S japonicum
Humans, dogs, pigs, cattle, mice, mustelids, and monkeys
Amphibian snails (Oncomelania species)
Absent
Penetration of skin by cercariae
S mekongi
Humans and dogs
Aquatic snails (Tricula aperta)
Absent
Penetration of skin by cercariae
F hepatica
Sheep, goats, cattle, and other herbivorous animals
Amphibian snails (family Lymnaeidae)
Aquatic vegetations and watercress
Ingestion of aquatic plants and watercress infected with metacercariae
C sinensis
Humans, dogs, pigs, cats, rats, and several species of wild animals
Freshwater snails (family Bulinidae)
Freshwater fish (family Cyprinidae)
Eating raw or partially cooked freshwater fish or dried, salted, or pickled fish infected with encysted metacercariae
O felineus
Humans and other fish-eating mammals
Aquatic snails
Freshwater fish
Eating fish infected with metacercariae
P westermani
Humans, wolves, foxes, tigers, leopards, lions, cats, dogs, and monkeys
Freshwater snails (family Pleuroceridae and Thiaridae)
Freshwater crab or crayfish
Ingestion of freshwater crabs or crayfish infected with metacercariae
F buski
Pigs and humans
Planorbid snails of the genera Segmentina, Hippeutis, and Polypylis
Freshwater plants such as water caltrops, water chestnut, water bamboo, water hyacinth, and lotus
Ingestion of freshwater aquatic plants that harbor metacercariae
S haematobium
S mansoni
S japonicum
Adult
Body surface of male
Finely tuberculate
Grossly tuberculate
Nontuberculate (smooth)
Testes
4-6, in a cluster
6-9, in a cluster
7, in a linear series
Position of ovary
Posterior to middle of body
Anterior to middle of body
Posterior to middle of body
Number of eggs in uterus
20-30
1-4
50-300
Egg
Size and shape
110-170 μm long
40-70 μm wide
Terminal spine
114-175 μm long
45-68 μm wide
Lateral spine
70-100 μm long
50-65 μm wide
Central spine
Cercaria
Cephalic glands
2 pairs, oxyphilic
2 pairs, basophilic
4 pairs, oxyphilic
Subhash Chandra Parija, MD, MBBS, PhD, DSc, FRCPath Director, Jawaharlal Institute of Postgraduate Medical Education and Research, India
Subhash Chandra Parija, MD, MBBS, PhD, DSc, FRCPath is a member of the following medical societies: Indian Academy of Tropical Parasitology, Indian Association of Biomedical Scientists, Indian Association of Medical Microbiologists, Indian Association of Pathologists and Microbiologists, Indian Medical Association, Indian Society for Parasitology, National Academy of Medical Sciences (India), Royal College of Pathologists
Disclosure: Nothing to disclose.
Thomas J Marrie, MD Dean of Faculty of Medicine, Dalhousie University Faculty of Medicine, Canada
Thomas J Marrie, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Society for Microbiology, Association of Medical Microbiology and Infectious Disease Canada, Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.
Shekhar Koirala, MBBS Vice Chancellor, Department of Medicine, BP Koirala Institute of Health, Nepal
Disclosure: Nothing to disclose.
Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference
Disclosure: Received salary from Medscape for employment. for: Medscape.
Mark R Wallace, MD, FACP, FIDSA Clinical Professor of Medicine, Florida State University College of Medicine; Clinical Professor of Medicine, University of Central Florida College of Medicine
Mark R Wallace, MD, FACP, FIDSA is a member of the following medical societies: American College of Physicians, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, International AIDS Society, Florida Infectious Diseases Society
Disclosure: Nothing to disclose.
Larry I Lutwick, MD, FACP Editor-in-Chief, ID Cases; Moderator, Program for Monitoring Emerging Diseases; Adjunct Professor of Medicine, State University of New York Downstate College of Medicine
Larry I Lutwick, MD, FACP is a member of the following medical societies: American Association for the Advancement of Science, American Association for the Study of Liver Diseases, American College of Physicians, American Federation for Clinical Research, American Society for Microbiology, Infectious Diseases Society of America, Infectious Diseases Society of New York, International Society for Infectious Diseases, New York Academy of Sciences, Veterans Affairs Society of Practitioners in Infectious Diseases
Disclosure: Nothing to disclose.
Trematode Infection
Research & References of Trematode Infection|A&C Accounting And Tax Services
Source
0 Comments