View source for Trematoda: India

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This is an extract from <br/> 
''' ANIMAL RESOURCES OF INDIA: ''' <br/>
''' Protozoa to Mammalia ''' <br/>
''' State of the Art. '''<br/>
Zoological Survey of India, 1991. <br/>
By Professor Mohammad Shamim Jairajpuri <br/>
Director, Zoological Survey of India<br/>
and his team of devoted scientists. <br/>
The said book is an enlarged, updated version of <br/>
''The State of Art Report: Zoology '' <br/>
Edited by Dr. T. N. Ananthakrishnan, <br/>
Director, Zoological Survey of India in 1980.<br/>
</div>
|}
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[[Category:India |T]]
[[Category:Fauna |T]]

=Trematoda= 
==Introduction==
Trematodes constitute an important group among helminths, which occur as parasites of vertebrates in adult condition, inhabiting practically every organ system in the host. In larval condition they complete part of their development in invertebrates, particularly molluscs, and lower vertebrates. There is an alternation of hosts, hence the name Digenea. 

Though John de Brie (1379) was attributed as the pioneer worker on the trematodes, Zeder (1800) was the first to attempt the classification of parasitic worms and to divide them into five classes viz i Round worms, ii Hook worms, iii Sucking worms, iv Tape worms, and v Bladder worms. Trematodes were included by him under Sucking worms. Rudolphi (1808) substituted the name Trematoda to Zeder's sucking worms and adopted it as an order instead of class. Dujardin (1845) made the first taxonomic arrangement of trematode genera and grouped Aspidobothrii of the order Trematoda into two families viz. Distomea, comprising cndoparasitic forms, and Polystomea, consisting of ectoparasitic forms. Burmeister (1856) separated Aspidogaster and proposed three-fold division of trcmatodes into Pectobothrii, Malacobothrii, and Aspidobothrii. 

Till then classification of the trematodes was based mainly on the organ of attachment. Van Beneden (1858) proposed the separation of the trematodes, on the basis of life-cycles, into two orders Monogenesis, including forms with 'direct' development and a single larval stage between sexual generations, and Digenesis, comprising forms with 'indirect' developmcnt and alternation•of sexual and asexual generations. 

This new basis, however, did not greatly affect the overall arrangement of trematodes. Carus (1863) amended van Beneden's tenninology to Monogenea and Digenea. Monticelli (1892) revived Burmeister's scheme of classification proposing three orders. viz., Heterocotylea, Malacocotylea, and Aspidocotylea, which has found favour with many authors. 

Baee and Euzet (1961) removed Monogenea from Trematoda and elevated it to a separate class in the phylum Platyhelminthes. This arrangement was accepted by most of the workers (Mehra, 1970). Baer and Joyeux (1961) recognized three subclasses viz. Aspidogasu:ea, Digenea, and Didymozoidea. Stunkard (1962) restorcd Burmeister's system but revised the status of Aspidogastrea. He divided the Trematoda into two subclasses, viz. Pectobothridea with orders Monopisthocotylea and Palyopisthocotylea; the last one is.now recognised as separate class named Monogrnoidea and Malaobolhridia, with orders Aspidobothrca and Digenea. 

In the latter he (1963) recognised four suborders viz. S trigcatoidcq, Echinostomatoidea, Plagiorchoidea and Apisthorchoidca. 

Odhner (1905) subdivided the order Malacocotylca into two suborders (i) Gasterostomata, and 

(ii) Prosostomata. Poche (1926) rccognised van Bcncdcn's 'orders' and divided Digenea into two suborders, (i) Gasterostomata, with a single fmnily Bucephalidac, and (ii) Prosostomata. He further subdivided Prosostomata into two Tribes (i) Fascioboidca with two substribes, 10 super families and 61 families, and (ii) Aspidogastroidea, with a single f(tmily. Aspidogastridae. Fuhrmann (1928) followed Poche uplO suborder level and accepted 60 families. Faust (1929) agreed with the earlier classification of Burmeister but raised Prosostomata to the rank of an Order, and recognised four suborders under it. 

Daves (1946) accepted three ordcrs in Trcmatoda and two suborders in Digenea. He, however, did not recognise any superfamily grouping. His scheme was accepted by Yamaguti (1958) who recognised "Aspidobothria or Aspidocotylea" as a separate order. Skrjabin (1947-1962) and his collaborators recognised Digenea as a subclass and divided it into two subclasses (i) Gasterostomatoinei and (ii) Prostomatoinei, with two super orders and nine orders. Subsequently Skrjabin et ale 1962 dropped the subclass Gasterostomatoinei, relegating it as order.Poucephalida. 
La Rue (1957) proposed a revision of Digenea, based on life-history data and mode of fonnation of excretory bladder in larval stages designed to show genetic relationships. He divided subclass Dignea into two super orders, five orders, ten suborders and 84 families. Mehra (1957, 1958, 1962) suggested certain modifications to La Rue's classification recognised only eight orders. Subsequently (Mehra, 1970, 1980) proposed a revision of the classification of Trematoda in which he accepted Monogenea as a distinct class. Under class Trematoda he accepted two subclasses viz Aspidobothrca Burmeister, and Digenea van Beneden. He divided the latter into five orders, 14 suborders and 23 super families. 

Most of the modern workers like Stunkard (1946, 1961), Daves (1946), Hyman (1951) and -others are of the opinion that the classification of Digenea is still controversial and the grouping of families ~nto higher taxonomic units is tentative, pending more complete knowledge than available at present, concerning all stages in the life cycle of a large number of species and information furnished by the study of both adult and larval stages reflecting genetic relationships and evolutionary histories of the group. The higher grouping has not met with general acceptance. 
==Historical Resume== 

The rust reference of Indian trematodes in modern times was made by Gilchrist (1841-1846) in his book "A practical treatise on the diseases of elephants, camels and homed cattle" Later on Cobbold (1859,1862,1869-1882) in a series of papers describe<l'parasites of man, elephant, cattle, gangetic dolphin and Orcaella brevirostris etc, thus laying the foundation of a systematic study of tematode fauna of the Indian region. 

Lewis and Cunningham (1872) described Distoma conjunctum (=Opisthorchis naverca) Lewis and Mcconnell (1876) reported Gastrodiscoides holninis from the intestine of man. Banford (1887) recorded spined egg of Schistosoma indicum in the large intestine of bullock in Calcutta. Paramphistomum cervi and Gastrodiscus aegyptiacus were reported by Gibs (1892) from cattle and horse respectively. Same year Fasciola hepatica from Porlax picta, F. jacksoni, Dicrococlium pallaii and Fasci%psis rathouisi were reported by Stossich (1902). Buttle-Reepen (1900) described Distoma ampullaecaeum from a cetacean in the Indian Ocean. Pleurogenes gastroporus (= Pleurogneoides gastroporus) and Mesocoelium sociale from amphibian were recorded by Luhe (1901). 

Fishoeder (1901-1903) reported a number of amphistomes collected from cattle, horses and elephants in India and Sri Lanka. Powerl (1903) reported the presence of Schistosoma haemalobium from a human host in the country. Shipley and and Hornell (1904, 1905) described Problitrema richiardii, Distoma palleniscum, Gymnophallus sumateriae and Aspidogaster margratifera. Stossich (1904) reported Styphlodora hornidun from Boa ,constrictor Luhe. Newmann and Lingard (1905) recorded fla/ipegus longispina, Pneumoneces capyristes Pseudoamphistomum truncatum and Gastrodisus aegypticus. The year 1906 was significant for the discovery of several species of Schistosomes viz. Schistosoma spindalis, S. indicum, S. bovis Ornithobelharzia bomfordi (= Orientobilharzia bomfordi ) from the blood vascular system of domestic animals. The year was also notable for the discovery of Fasciolopsis macrocalpa, Acanthosolus biodorus, Anaporrhuntu largum, Schistorchis carneus, Stephanochasmus ceylonensis and Lyperosolnuln Squalnatum were reported by Luhc (1906) and Linstav (1906). 

Looss (1907) described Gaslrodiscus secondus from a mule in Assaln and (1908) Paradistomum ceralophorae frolll reptile in Ceylon. Evans and Rennie (,908-1910) worked on the parasites of domestic aniInals of Burma. Stiles and Goldberger (1910) described several amphistomes of domestic animals from India and Ceylon. Giager (1910, 1915) published a check list of the parasites of domestic animals in India. Mitter (1912) reported Homalogaster sp. and Nicoll (1912) described Styphlodora majae and Xenopharynx solus from cobra. Southwell (1913) described the trematodes of the Pearl Bank of Sri Lanka and reported I soparochis hypselobargi 
from the air bladder of Wallago attu. Lane (1915) recovered Artyfechinostomum suprartyfex from a girl in Assam. Stephens (1916) recorded Ophsthorchis noverca. Linton and Soparkar (1917) reported the occurrence of Agamodistomes in anophiline mosquitoes. 

Trematodes of fishes of Bengal were reported by Southwell and Prashad (1918). Sewel (1920, 1922) redescribed Mesocoelium sociable and recorded Leucochloridium assamense respectively. Jackson (1921) described Fasciola gigantica from cattle in Burma. Paragonimus campactus was reported from mungoose by Vevers (1923). In the same year Mapplestone (1923) published a monograph on amphistomes in which he discussed the status of several Indian species. The amphistome nos. 2 and 3 of Evans and Rennie (1908) were named Paramphistomum birmiense and P. microon respectively Railliet (1924). 

All these studies were made by foreign workers on material sent to them or collected by them during their stay in India. By now Indians started coming in the field. Bhalerao (1924) gave the description of Eurytrema daji and Testifrondosa cristata from the food mammals of Rangoon. He (1925) identified Isoparorchis hypselobagri from man sent to him by Chandler who was working on the parasites of cats of Calcutta. 

The year 1926 marked the beginning of the study on the trematode fauna of India by several Indian workers. In a series of papers Bhalerao worked out the parasites of house crow, water snakes, bat and the frog in Burma and described several new genera. Chandler discovered eggs of Schistosoma incognitum from human faeces, Mehra and Negi described Tremiorchis ranarum and Paragonimus edwardsi respectively. In 1927 Opisthorchis pedicel/ala, O. dendrilicum. Mesocoelium meggilli, Strigea annandali and Neodiploslomum kashmirensis were described by Verma, Morgan, Bhalerao Faust. 

Northup in Rangoon worked on trematodes of Chiroptera while Mehta and Negi described these from frogs at Allahabad in 1928. Phadke and Gulati (1929) described Pachytrema hewletti and the species of the genus Paradiscomum in Bunnese reptiles and from India by Bhalerao and Narain and Das respectively in the same year. In 1930 Baer, Nagaty, Jordan, Venna, Moghe and Thapar added to our know ledge of trematode parasites of the country. In the year 1931 Mehra, Moghe and Thapar added some new forms of trematodes from reptiles, bat and spine. Choudhary published his remarks on the trematodes of the genus Paradistomum and Bhalerao reported trematodes of pigs in Bengal. 

In the year 1932, Bhalerao dealt with the identity of Schistosomes found in case of nasal granuloma and gave a note on the probability of infection of man and domestic carnivores by Psoparchis hypsclobagri. Datta described the etiology of bovine nasal granuloma. Datta, Mehta, Sinha and Pande reported new species of parasites of the group Typhloplama, Pronocephalidae Cephalogonimus and Cephalogonimidae respectively. Mehra and Bokhari also described a new species of the subfamily Telochinae. Moghe reported two new species of trematodes from an Indian" ruff. Singh and Hickey investigated the way to control Fascioliasis in cattle in India. Rao and Ayyar studied heterophyes species from dogs. Harshey described new forms of the genus Opergaster from dogs. 

Bhalerao (1933) recorded the trematode infection of Indian elephants, gave preliminary note on the life history of common liver fluke and parasitic gastritis and fluke infection of ruminants under field conditions in India. Datta (1933) expressed his opinion on the cause of persistent debility in equines in this country and attributed it to Schistosoma indicum infection. In the same year Mehra erected a new genus Coeurilrema and described the new blood flukes of the family Sperorchiidae Srivastava, Thaparand Dayal, and Dayal reported new parasites of Meniuridae and Lccethodendriidae, Asetotrema respectively. Srivastava also discussed the genera Vitellotrema and Genarchopsis. Rao reported his preliminary findings of adult trematodes from Cercariae indicae bovine nasal Schistosomiasis in the Madras Presidency and included the description of the parasite which caused this disease and succeeded infecting the experimental calves with the larvae of these parasites. 

Mehra, Pande, Srivastava and Thapar and Dayal in the year 1934 added new species of the family Spisorchiidae from turtles and fresh water fishes. Mchra, and Thapar and Dayal also discussed the family of blood flukes and the family Allocreadiidae respectively. Sinha gave an 

account of a new genus of blood flukes of the family Spisorchiidae. Srivastava erected a new genus Mehrarorchis. Bhalerao reported the occurrence of Schis/osomajaponicum in India and Rahimullah and Das recorded the trematode infection in certain fishes of Hyderabad state. A case of Schistosomic dysentry in dog was reported by Swaminatha. Rao studied two species of Schistosomes, S. spindalis andS. nasalis and the latter species was claimed as new by him. 

The year 1935 seems to have induced many workers in the country to take up the study of trematodes. Bhalcrao produced a valuable monogmph of helminth parasites of domesticated animals and described some new monostome trematodes from avaian hosts and reported the parasites collected-from elephants of Andaman and Burma. Dayal, Lal, Mehra, Pande and Srivastava dealt with new trematodes of the genera Haplorchis, Monorchotrema, Notocotylus, family Lecithodendriidae, Pyenoporus, Catatropis respectively. Srivastava also described some new distomes from Indian fishes. He also erected new genus Orientophorus and described a mre parasite of subfamily Dinurinae. Sinha added a new genus to the family Aspidogastridae. Mehra discussed the classification of the family Lecithodendriidae. 

Pande gave his remarks on Anchitrema and LecthOdendruim. Trematodes of birds were reported by Patwardhan, Thapar and Lal. Venna studied the bird parasites mainly dealing with the family Echinostomatidae and Diplostomidae. He rerected the genus Episthoc hasmus apart from describing several new species in the fonn of notes. Rao and Rao and Ayyar reported further observations on bovine nasal Schistosomiasis and included preliminary report on their findings of Schistosome eggs in faeces of dogs. In his preliminary report Pande discussed acute amphistomiasis of cattle in Assam. 

In 1936 Bhalerao published three parts of 'Trematode parasites of India' Lal, Mehra, Srivastava and Venna added new species of the genera Paramonostomum, Harmotrema, Decemtestis and the family Bucephalidae. Mehra revised the family Harmotrematidae. Lal revised the genus Paramonostomum, added a new species under the genus Parorchis and erected a new genus under the subfamily Typhlocoelinae along with a new strigeid parasite of the rare genus Cyathocotyle and another genus Levinseida. Srivastava also added fresh forms of Prosorchinae. Binara while describing Schistosoma japonicum discussed the problem of Schistosomiasis in India. 

Bhalerao in 1937 continue his researches on the Helminth parasites of India and published his fourth part on Indian trematodes. He also studied the trematode parasites collected from Calcutta Zoo and proposed new genus Pneumotrema. Lal published his results on the trematode parasites of birds in two parts, in which he discussed the value of different characters in claissification of avian trematodes and some new blood flukes of the family Schistosomatidae. Pande studied the trematode parasites of fishes and frogs of U.P. and described three new speices fro~ the former and four for from the latter host. Srivastava reported new parasites of the family Hemiurigae and the genus Gyliauchan. He also reported new prasites of the subfamily Discogasterinae and proposed two new genera, Yamagutia and Indolerogenes. 

He also reported the parasites of the families Acanthocolpidae, Gorgoderiddae, Bucephalidae besides erecting family Waretrematidae, subfamily Polyorchitreminae under family Heteropohyidae and a new genus Mehracola. Two new genera were also proposed by him to accomodate the amphistomes of freshwater fishes. He reported the occurrence of Paragonimus westermani in the lungs of cats. 

Thapar discussed about. Helminthological studies in India. Harshey described some more new forms of Opegaster. Vidyartbi described trematodes of the genus Diplostomum. 

In 1938 Bhalerao proposed a new genusTravassosotrema and published a paper on Schistosomes and Schistosomiasis in India. Dayal, Lal, Pande and Srivastava reported new forms of the genera Astiotrema, Psilorchis. subfamily Stomylotre matinae, Crassiphiaia and Gylianchen, Pedunculacetabulum and Prosthogenomus respectively. Dayal also erected four new genera, Neoganatia, Phyllochnus, Nizamia and Gorgotrema from fishes. Pande further repoted two new trematodes from Indian cyprinid fishes, revised the genus Allocreadium and proposed a new genus of Pleurogenetinae apart from reporting Ilarmostomum from toad. Srivastava eluciated the life 
history of Cotylophoro1J cootylophorum and added new forms under family Acanthocolpidae and Gorgoderidae. 

In 1939 Bawa published a premilinary report o~ intestinal amphistomiasis in sheep. Buckley published his observations on Gastrodiscoides hominis and Fasciolopsis buski in Assam. Mehra Mehra, Pande, and Srivastava reported new trematodes of families Spirorchiidae, Pronocephalidae and genera Lyperosormum, Acanthocolpus, Aponeurus, Hysterolecitha. and Stomtlchicola. Pande also described two new' species from India. Bhalerao gave an account of th~ development of the knowledge of trematode fauna of India. In the same year Srivastava studied the parasites of the family Monorchidae, Haplosplanchnidae Monodhelnidae and Hemiuridae besides reporting Fasciola gigantica infection in the lungs of goats. 

In the year 1940 Mehra proposed a new genus Enterohaemtltotrema and described new blood flukes of the genus Hemiorchis and Dendrilobilharzia. He also published his remarks onevolution of blddo flukes. Chauhan described two new species of avian trematodes. 

Bhalerao in 1941 reported the bat fluke Prosthodendrium ovimanosum in a dog and published a paper on trematodes of Indian fishes. Bhalerao and Gideon reported the occurrence of Prosthogoniums putschkowskii in India. Mehra while describing new species of the genus Opisthorchis discussed the synonymity of the genera Gointea and Opisthorchis and proposed a key to species. Srivastava reported new prasites of the genera Haplochadus and Sterrhenurus and Lepocreadoides beside proposing new genus Indoderogenus. 

Bhalerao, Dayal, Srivastava and Sinha in 1942 reported new trem~todes from Mastacembelus and of the genera Diplozoon, Lecithocladium and Acanthostomum. Bhalerao also reported two trematodes from ruminants. He published papers on Strigeids Cephalogonimus and larval clinostomes. Dayal erected two new genera Eucreadium and Plesiodiscomum. Srivastava proposed a new genus Horatrema and reported blood flukes of dog. 

Bhalerao in 1943 reported the occurrence of parasites of the genus Cephalogonimus in India and Bwma, two new trematodes of fishes and some metaceracarial forms of Clinostomidae. Chauhan, and Dayal dealt with some new species Aspidogaster and Mehratrema and the family Bucephalidae respectively. Gupta studied the paramphistomid parasites of Lahore. Mehra discussed the validity of the genera Proalarides and Travassostomum and the species P. tropidonotus and I. natritis. He also dealt with the classification, distribution and evolution of the family Cyathocotylidae and revised the genera Holostephanus and Cyathocotyle. Srivastava revised the genus Plagioporus and Opechona and added new forms. He also proposed a new genus Indocreadium and published a paper on bovine nasal Schistosomiasis. 

In the year 1944 Inamdar and Bhalerao recorded the 9Ccurrence ofPsilochasmus longicirratus in India. Bhalerao also gave some remarks on the identity of immature amphistomes causing diarrhoea domestic animals in this country. Dayal proposed two new genera Eucreadium and Neopodocotyle to accomodate some parasites of freshwater fishes. Kaw dealt with the parasites of freshwater fishes of Kashmir and reported a new spccies of the genus Crepidostomum. Srivastava studied the trematodes of Indian marine fishes and also elucidated the life history of Paramphistomum explanatum, Gastrothylax crumenifer, Dicrocoelium dendriticum and Fasciola hepatica and recorded a new intermediate hosts of F. gigantica. 

In 1945 Bhalerao recorded the common amphistomes of domestic animals of Central Provinces (now M.P.) and their intermediate snail hosts. Chauhan dealt with certain forms of the family Hermiuridae. Moghe published his findings of a survey on the nature and incidence of helminth infection in cattle, sheep and goat in Central Provinces, Berar and Central India. Mudaliar and Ramaniyachary reported a new species, Schistosoma nairi from •elephant. Thapar and Sinha described a new amphistome. 

Bhalerao in the year 1947 dealt with a new species of the genus C linostomum and also elucidated the life history of Dicrocoelium dendriticum. Mehra gave further account on 
classification of the family Cyathocotylidae. Moghe and Chauhan reported blood fluke infection in cattle, goat and sheep of Central Province, Berar and Central India. Mudaliar and Alway published a check-list of parasites. Rao discussed the problem of Schistosomiasis among sheep and• goat in Poona. 

In•the year 1948 Bhalerao dealt with problem of blood fluke in India. Chatterjee, Dayal and Vidyarthi reported some new forms of the genus Platynotrema, family Bucephalidae and Cyathocotylidae respectively. Iyer dealt the immature amphistomes in sheep in Govt. cattle farm, Hosur. Peter and Mudalier elucidated the life cycle of Gastrodiscus secundus. Srivastava studied the parasites of marine food fIShes and tortoises and erected a new family. 

Baugh in 1949 recorded a new avian trematodes of the genus Psilorchis and reported Psilochasmus oxyurus from India. Chauhan dealt with the helminths collections present in the Zoological Survey of India and Dayal reported trematode infection in India fishes. Sinha proposed a new genus of toroise trematode and Tandon described new form of th~ genus Lissemysia. Sinha proposed a new genus of tortoise trematode under the subfamily Encyclometrinae. 

In 1950 Alwar revised the literature on Schistosomes in this country. Baugh, Dayal, Gupta dealt with new trematodes of the genera Paryphostomum and Allocreadium respectively. Gupta redescribed Paramphistomum (Cauliorchis) crassum and Murty reviewed schistosomiasis in cattle. Reddy and Varma reported Paryphostomum suprartyfex infection in man. Sinha elucidated the life history of Cotylophoron cotylophorum. 

Gupta, Rao, Srivastava the year 1951 dealt with some new forms of the genera Cephalogonimus, Phyllodiscomum family Hemiuridae and subfamily Leptophallinae, genera Echinochasmus and Asymphylodora. Gupta and Srivastava proposed new genera Macrotrema and Eumasenia respectively Gupta redescribed Paraphistomum bathycotyle. Srivastava and Dult eluciated the life history of Schistosoma indicum. 

Chatterjee and Dutt and Srivastava, in the year 1952 dealt with two new trematodes of the gencm Platynotrema and Ornithobilharzia respectively. Dayal redescribcd Bucephalopsis karvei and reported a new species of the family Hemiuridae. Dayal and Gupta studied the trematodes of family Cephalogonimidae. Gadgil and Shah discussed the problems of human Schistosomiasis in India. Lal and Baugh and Lal and Gupta studied histopathologial changes in snail tissue due to larval trematodes. Lal and Mathur studied the parasites of the genus Prosthogonimus. Thapar and Tandon worked out the life history of Fasciola gengantica. 

Anantaram and Balsubramanian, Dayal and Gupta and Singh in the year 1953 reported new fonns of the genera Diplostomum, Ganeo, Echinochasmus and Echinostoma. Dayal and Gupta described new species of the family OpisthorchHdae and subfamily Haplorchiinae. They also proposed three new genera Brahamputrotrema, Gauhatiana and Oudhia. The year was also notable for the publication of Trematode fauna of India in four p..arts by Chauhan. New and known species were reported by Gupta, Kant, Lal and Rao and Hiregander. Hawkings, Ray and Mehra reported Dicrocoelium dendrilicum infection in Himalayan lagoons. Varma described a new species Fasciola indica. 

Gupta, Jaiswal and Singh and Saxena reported new forms of the genera Pleurogenes Encyclometra, Ganeo, Gmmatobrephus, Mehrorchis, Cephalogonimus, Asticotrema, Philophthalmus and Neodiplostomoides in 1954. Dhingra studied the spermatologenesis in five species oftrematocles. Gupta and Dhillong reported two new strigeids while Sin~h proposed a new genus P silocollaris . Varma studied the nature, incidence, distribution and central of nasal schistosomiasis and Fascioliasis in Bihar. 

Chatterjee and Chauhan in the year 1955 studied the parasites of subfamily Grassiphialinae ana taxonomic position and distribution of Isoparchis. Dutta and Dutta and Srivastava illucidated the life history of Schistosoma indicum.and Ornithobilharzia dattai respectively. Ganapati and Rao reported metacercaria in freshwater fishes ofWaltair. Jaiswal reported of the genus Philophlhalmus 
La} described a metacercaria from the eye of a trout while Lal and Baugh studied histopathology of snail tissue due to trematode infection. Tandon recorded Paramphistorium goto;. Chatterjee, Srivastava and Srivastava added new forms of Echinochasmus, Brachylaimus, Psilostomum, Diplostomum and Xenopharynx in 1956. Gupta reported two new Allocreadiids. 'Gupta reported trematodes from mrine fiehs of Gulf of Manar. Sinha and Srivastava redescribed Schistosoma inca gnitum. 

Some extensive work on Indian trematodes has been published in the year 1957. Dutt and Srivastava developed a new technique of specific diagnosis of animal schistosomiasis, development of S. spindalis and suceptibility of equines to this pamsite. Gupta, Gupta and Sidgh described new forms of Neodiplostomum, Psilochamus and Diplostomum respectively. Goil studied the carbohydrate metabolism in some treamtodes of domesticated animals. laiswal reported trematode parasites of fishes and birds of Hyderabad state. Krishnaswami and Anantaraman reported Paradistomum infection in Indian reptiles. Srivastava and Trisul reported Schistosoma turkestanicum. Tandon worked out the life cycle 0'( Olveria indica and reported a new species of Paramphistomum. 

Chatterjee, Gupta Siddiqi, and Singh dealt with new forms of Cyciocoeium, Haematotrephus. Ceylonocotyle, Cotylophoron, Astiotrema and Euparadistomum. Chakravarty and Sinha Jain studied the egg. Mirracidium of Paryplzostomum mehrai. Srivastava proposed a new genus Proechinocephaius. Ahluwalia in 1960 discussed two genera Eniyda and Stumkardia. Mukherjee and Srivastava elucidated the life cycle of Gigantocotyle explanatum. Gupta •and Srivastava added new species to genus Fastula. Rai and Agarwal discussed individual variations in Xenopharynx solus and their importance in taxonomy Mehra described trematodes of the group Staphylorchis and discussed the phylogeny and evolution of the family Gorgoderidae. 

In the year 1961 Bhardwaj proposed two new genera, Pseudo~rtYfeehinostomum and Mehra/ormis. Srivastava added two new species to the genus Phyllodistomum. Mehra dicussed the classification of order Echinostomida and erected new superfamilies. 

Mehra in 1962 revised the superfamily Allocreadioidea and family Brachylaemidae and erected several new subfamilies. Gupta continued his work on trematode parasites of Indian birds. SIivastava described two new species from fishes and proposed a new genus Rhynchocreadium. Sinha worked out trematode parasites of reptiles of Hyderabad. Mukherjee studied the miracidium of Stenkardia dilymphora. 

By mid sixties many workers came in the field and studies on trematodes got a boost. Many centres for helminth studies developed. Hafeczullah (1971), Hafeezullah and Siddiqi (1970) worked out the trematode parasites of marine fishes of India. Trematodes have been studied by Rai and Agarwal (1961) Fotedar and his collaborators (1959-1984) Gupta (1965"\1989), Agarwal, (1967, 1989), Pandey, (1962-1990) Srivastava, (1963-1990), Srivastava and Ghosh Mukherjee (1962¬1986), Mukherjee and Ghosh (1967-1900 1967-1969), Gupta, (1956-1986) Madhvi (1971-1989) Karyakarte (1967-1971) Sinha and his collaborators (1962-1989) Hafezullah and Datta (1980, 1981) Mukherjee, and Srivastava (1988, 1989), Ghosh (1979-1989) and many-t)thers. Mehra (1970) gave a detailed classification of Trematoda recognising five orders. No volume on Trematode Fauna of India was available till Mehra submitted his first volume dealing with the order Fasciolatoidea. 

This was published under the Fauna of India series in 1980. Since the volume included species described till about 1963, Srivastava (1982) provided a supplement to this volume updating the volume. Chauhan and Ghosh (1975) reviewed the work done by the ZSI scientists in the last 50 years. Periodic review of the work done in India has been published by Bhalerao (1947, 1948) Thapar (1937, 1947) Srivastava (1960) Chauhan (1962). Studies on Larval Trematodes: The study on larval trematodes in fresh and brackish waters of India apparently have not received as much attention as it deserves. 

Linton and Soparkcr (1918) first started the study of Cercariae in India and began with the life history of Schistosoma spindalia. Kemp and Gravely (1919) investigated into possibility of the• introduction of human Schistosomiasis in In4ia by troops 
returning from overseas after the fust World War. Sewell (1919) studied about the possibility of the occurrence of S.japoricwn in India. Sopakar (1921) published a detailed account of the cercaria of S. spindalis and also few other fork tailed cercariae from Indoplanorbis exustus from Bombay. Sopakar (1924) described Cercaria patialensis which was redescribed by Anantaraman (1948) and belongs to the family Tmnsversotrematidae. 

Sewell (1922) continued the ork on cercariae and published his monumental work "Cercariae Indicae" In this work he modified the scheme of classification given by Luhe (1909) in many respects and attempted to derive the distomes from monostome stem. He laid emphasis on the excretory system and other morphological details of cercariae to show phylogeny and evolution of various groups of Cercariae and their adults. Luhe (1930) gave an ~ccount of C. nicobarcae and a paper on excretory system of Cercariae in general. Rao (1929) described C. anamola which was redescribed by Sewell (1930). Chatterjee reported Cercaria allahabadi from Allahabad, which Singh (1953) confumed as strigeid larva. 

Faruqi (1930) described echinosteme larva, Cercaria mehrai, the life history which was completed by Jain (1958) and adults were identified to belong to the genus Paryphostomum. Rao (1932, 1933) described two new furcocercans cercariae C. hurleyi (Strigeid) and C. saundersi (Schistosome). In 1933-34, he also discovered the life history of a new Schistosome, Schistosoma spindalis, showing that Cercaria indicae XXX Sewell, 1922 was its larva. Bhalderao (1943) made a survey of cercariae fauna of irrigated tracts of Nizam's Dominion and suggested their poss'ible relationship to adults parasitic in man and domestic animsls. Buckley (1939) described cercariae of G. hominis, F. buski and a new amphistome cercariae. 

These studies were followed by a number of workers which in subsequent years has shown promising results. Khaw (1947) reported that I. exustue served as intermediate host of S. indicus. Srivastava and Deltt (1951) studied in detail the life cycle of S. indicum and showed that this cercaria is very similar to that of S. spindalis. Dutt and Srivastava (1952, 1955) described the cercaria'of O. dattai and completed the life cycle. Sinha and Srivastava (1954, 1956) in a series of papers dealt with cercariae belonging to Strigeids, Clinostomes, Spirorchids, Bucephalids and Schistosomes. He also published a detailed account of the life cycle of S. indicum in 1958 and the life cycle of Clinostomum piscidum in 1959. Premavati (1953) described C. cruciata, a Xiphidocercaria and two furcocercons cercariae C. magnacristate and C. quadriglandula. These belong to sanguinicolid and strigcid groups as shown by Singh (1960). 

In 1954 she described C. tuberculatus from Melanoides tuberculatus and two more cercaria C. caudiglandula and C. tuniforka from the same snail host. Premavati (1955, 1956) described C. multiplicata, and C. reniforma, C. flavidusi and C. gomtiensis, all collected from Melanoides tuberculata. Rao, Gadgil and Shah (1953) reported the snail Paludomus obesa may be the likely snail host of S. haematobium. A year later Gadgil and Shah reported F errissia tenuis serving as snail host for this Schistosome. 

Baugh (1954) described C. pendulata and C. lucknowansis from Belamya bengalensis at Lucknow. Peter (1955) dealt with cercariae fauna of Madras and described C. mudaliari. Patki (1956) described C. robertsoni in lophocercans group and discussed their relationship. Agarwal (1956) studied Cercaria stylala, C. humkheri from Bajalpur and life history of a new species of Clinostome, C. giganticum. Tandon (1957) described the life history of G. crumenifer. Srivastava, (1957, 1958) described six cercariae, C. shibi, C. srivastavai, C. luteoli, C. rajai and C mathpurensis. Tandon (1959) reported the cercaria Enterohaematotrema palaearcticum. Srivastava (1958) reported C. sewaili similar to C. bombayensis of Sopakar. Peter (1958) reported two new amphistome cercariae. Tandon (1958) described the cercaria of Fischoederius elongatus. Mukherjee (1960) elucidated the life histories of Ceylonocotyle scoliocoelium and Cotylophoron indicum and reported two new amphistome ~ercariae. In recent years cercariae have been studied by Agrawal (1959), Ganapati and Rao (1962, 1968, 1969) Gupta and Taneja (1969), Hanumantha Rao (1957¬1973), Krishna and Sinha (1979), Madhvi &Rao (1968-1970), Madhvi (1980), Mohandas (1971¬1979) Pandey and his collaborators (1965-1983) and many others. Mukherjee (1986) published a volume on amphistome cercariae under the Fauna of India series. 

In spite of the foregoing work much renlains to be done when we take into account. the 
multiplicity of genera and species available in the country. Ghosh and Srivastava (1990) while discussing the host parasite relationship in reptiles showed that in a total of about 534 species of reptiles only 45 species have been studied for trematode infection. 
==Estimation of Taxa==

A total of 47 families distributed under five orders have been reported from the country. They comprise about 250 hundred genera and 750 species from different hosts. 

There is further scope for. the work. It appears that in the total host species available in the country only a meagre percent had been screened for helminth infection. The applied aspects and life histories are other fields which need attention. 
==Expertise== 
===In ZS=== 
M. Hafeezullah, R. P.. Mukherjee, C. B. Srivastava, R. K. Ghosh, S. 'B. Bhattacharya, I. B. Dutta, D. K. Kundu and S. Chakraborty; all of Zoological Survey of India, 'M' Block, New Alipore, Calcutta -700 053. 
===Elsewhere=== 
S. S. Sinha, Zoology Department Osmania University, Hydembad 

K. C. Pandey, Meerut University, Meerut 

V. Gupta, N. Agrawal, S. P. GuPta, S. Srivastava. S. K. Saxena, all of Zoology Department, Lucknow University, Lucknow 

L. Nars~nha Rao, Kaktiya University, Warangal 

R. Madhvi, and K. Hanumantha Rao, Andhm University, Waltair 

B. S. Chauhan, Narsingpur 

S. M. Agrawal, Raipur 
==Selected References== 
Chauhan, B. S. 1954. Studies on the trematodes fauna of India PL IT, ill, IV. Rec.lndian Mus., 51 : 209-287. 

Mehra, H. R. 1966. Revision of Allocreadioidea Nicoll, 1934. Parts II & III. Dixit Press. Allahabad. 

Mehra, H. R. 1980. The Fauna of India and the adjacent countries Platyhelminthes vol. I. Trematode: Digenea. Zool. S urv. India. Calcutta. 

Skrjabin, K. I. 1947-1974. Trematodes of Animals and man. Vol. I-XXV. Academy NAUK, SSSR, Moscow. ' 

Srivastava, C. B. The Fauna of India and adjacent countries. Platyhelminthes. Vol. 'I (Supplement) 

Additions to Prof. H. R. Mehra's volume on Trematode: Digena. Zoot. Surv. India, 
Calcutta. 
Yamaguti, S. 1971. Synopsis of Digenetic Trematodes of Vertebrates. Vol. I & II. Keigaku Pub. Co. Japan.