Nematoda: India
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Nematoda
Introduction
The Phylum Nematoda consists mostly of cylindrical, sometimes fusiform or rarely saccate multicellular organisms which are usually microscopic in size. It is because of their shape, they are popularly called roundworms or threadoworms. Nematodes have appendageless and nonsegmented body I with a body cavity and complete digestive and reproductive tracts.
They are one of the most economically important, diversified and perhaps the largest groups of invertebrates. According to Platt and Warwick (1983), nematodes occur in a wide range of habitats which is unsurpassed by any other metazoan group. In fact, they are found in all kinds of environment and habitats, sometimes even in uninhabitable habitats like hot spring, ice, desert, etc. Cobb (1914), a legendary nematologist has stated, " .... if all the matters in the universe except the nematodes were swept away, our world would still be dimly recognisable .... we would find its mountains, hills, Valleys, rivers, lakes and oceans represented by a film of nematodes"
According to him every species of vertebrate is infested usually with two species of nematodes. Since there are about 50,000 species of vertebrates, they should harbour some 100,000 species of nematodes. If to this the nematodes associated with invertebrates, plants and those living in soil and waters are added, it would perhaps be fair to estimated 500;000 species are free-living i~ soil and water while others are parasites of arthropods, molluscs, vertebrates, or plants. Out of this huge estimated number, only 9,000 species were known till 1950, whereas the present figure is about 20,000 known species. At present, descriptions of about 300 new species are being published every year.
It is difficult to estimate the exact loss due to nematode parasites of man, animals and plants. Ston (1947) estimated about 2,000 million people infected with nematodes over the world. Only one disease, "river blindness" or "onchocerciasis" has been reported in some 20 million people in Africa. More than 50 species have been reported parasitising the human body, of which about a dozen have been found causing serious disease, e.g., ascariasis, filariasis, U'ichniasis, etc. The average loss due to plant nematodes has been estimated up to 15%, which may, at times, be up to go9& , as in instances like the ufra disease in'rice infestation of cyst nematodes or root-knot nematodes, etc., on agricultural crops. Poinar (1983) has reported the losses amounting to four billion dollars due to nematodes in the United States of America alone.
However, some nematodes have also been found very useful as good model experimental animals or the basic research in nubition, physiology, genetics, aging, etc. Sometimes they take part in maintaining natural balance in the soil, and some are used as indicator of aquatic pollution and biological agent for the oonttol of insects and phytophagous nematodes.
The marine, brackish and freshwater nematodes are usually studied independently as free-living DIIIlotodes. In fact, these nematodes have not been paid much attention in India, though they constitute a substantial part or the known nematodes species. Marine nematodes are most dlvenified in sizes and shapes, and the most abundant in Meiofauna. According to poinar (1985), about 0.1-1.0 million individuals may be found per sq.m. They are considered as free-living because they live in water or soil without any parasitic relationship with animals or plants. Since dley feed on micro-organisms, they are also called Microbotrophic nematodes, meaning, utilisation efmicro-organisms for nourishment.
The classification of nematodes is based on morphological characters. Traditionally, the Mmatodes are divided into two classes, viz., Adnophorea (Aphasmida) and Secrenetia (phasmida.) Class Adenophorea comprises two subclasses (Chromadoria and Enoplio) and the following 9 Qders: aa.r H. Baqri. Zoological Survey of India, Calcutta Araeolaimida (free-living, aqautic and microbotrophic nematodes), Monhyslerida (free-living, aquatic and microbotrophic), Desmodorida (free-living, aquatic and microbotrophic), Chromadorida (free-living, aquatic and microbotrophic), Desmoscolecida (free-living, aquatic and microbotrophic), Enop/ida (free-living,aquatic terrestrial, predators and microbotrophic), Dory/aimada (free-living, microbotrophic, some plant and vertebrate parasites), Monochioda (free-living,microbotrophic and predators) and Mermithida (parasites of invertebrates).
These Orders consist of 35 superfalnilies and 90 families. The Class Secementia includes the following seven Orders: Rhabditida (terrestrial,microbotrophic, and parasites of plants, insects and vertebrates), Tylenchida (parasites of plants and invertebrates), Aphelenchida (predators, microbotrophic and parasites of plants insects and other invertebrates), Strongylida (parasites of vertebrates), Ascaridida (parasites of invertebrates and occasionally of invertebrates), Oxyurida (parasites of invertebrates and vertebrates), and Spirurida (parasites of vertebrates and invertebrates). These Orders are based on 55 superfamilies and 120 families.
In main groups, i.e., (A) the animal nematodes (parasites of vertebrates and invertebrates) which are generally included under Helminthology, and (B) the plant, soil and other nematodes which are dealt under Nematology. The latter group also includes the predaceious nematodes in soil and freeliving nematodes in fresh water, marine, brackish and hypersaline environments. These groups differ so significantly that the scientists involved in helminthology and nematology have different priorities and use different parameters in the identi'fication because of the diversities. In view of these facts, it is preferred to provide the account of nematodes under two headings.
Historical Resume
Our knowledge of nematode parasites of man and animals dates back to 4700 B.C. in the ancient history of China and to 1553 B.C. in Egypt. Hippocrates in 430 B.C. was the fust to record the pinworm, later !lamed as Eruerobius vermicularis. It will be worthwhile to mention here the names of some earlier workers who have contributed significantly to our knowledge -of nematode parasites: Aristotle (384-322 B.C.), Celsus (53 B.C. -7 A.D.), Columella (100 A.D.), Galen (130-200 A.D.), Vegetius (400 A.D.), Albertus Maqnus (1200-1280 A.D.) and Caesalpinus (1600 A.D.). Leidy, Virchow, Herbst and Leukart also made important contributions in the field during the 16th-18th century. Linnaeus (1758) in his Systema Naturea (10th edition) placed all kinds of worms under the Kingdom Vermes.
In 1878, Sir Patrick Manson reported an interesting finding that the nematodes are responsible for causing human filariasis transmitted by a mosquito. Zeder (1800) was the fust to use the tenn roundworm as a class of parasitic wo~s.
In the nineteenth century, a number of helminthologists in Europe were attracted to work on the basic and applied aspects of nematodes of medical and veterinary importance. A few of them are mentioned here : Baird, Carter, Cobb, Cobbold, Diesing, Dubini, Dubini, Dujardin, Giles, Linstow, Looss, Meyer, Molin, Muller, Parona, Railliet, Schineider, etc.
During the twentieth century, a large number of foreign helminthologists have contributed to the taxonomic as well as applied knowledge of animal-nematodes of Asian, European and American countries e.g., Baylis, Buckley, Chubaud, Chitwood, Cobb, Leipper, Magrolis, Petter, Skirjabin, Yamaguit and others.
i) Pre-1900
In India, a few European helminiliologists had contributed some taxonomic information during the send half of the nineteenth century. Carter (1855, 1858) and Cobbold (1876-1884) in England, von Linstow (1899) in Gennany, Parona (1889) in Italy and Raillet (1899) in France were the fll'St to pay attention to the Indian Nematodes. The staff of the Indian Museum Calcutta, collected or received nematodes and sent those to these european helminthologists for identification. Carter (1859), later an Assistant Surgeon in Bombay, made important observations on Dracunculus, nematodes from the brackish water as well as on those from open drains of Bombay.
ii) 1901-1947
During the early twentieth century, significant contributions have been made on the nematOdes from India by the British officers of medical and veterinary sciences. Boulenger (1920-1924), Chandler (1925-1928), Gaiger (1910-1915), Lane (1913-1921), Linstow (1904-1908), Maplsto~e (1903-1932) and Ware (1924) studied the nematodes ofelephant, pigs and other animals dying at the Zoological garden, Calcutta. Their publications included the descriptions of many new species and new host records. Maplestone (1929, 1930) also worked on the seasonal variation of hook worm. Gaiger (1910, 1915) published a list of nematodes recorded from domestic animals in Punjab. The Zoological Survey of India, Calcutta, has made a valuable contribution by collecting animal parasitic nematodes from the Calcutta Zoo and other places.
Dr. Annandale, the fllst Director of Z.S.I., handed over this material to H.A. Baylis of the British Museum (Natural History), London, who, in collaboration with Daubney (1922, 1923) published a number of new species and new host range of these nematodes. Many new species were described by Chandler and Maplestone working at the School of Tropical Medicine, Calcutta. The Indian Museum, Calcutta and the European Helminthologists have played a vital role in increasing the' knowledge of nematodes from this subcontinent up to the fust quarter of this century.
Thaper (1924) was~e fIrst Indian to describe a species of Kilulilma while Mahaskar reported Ancylostomiasis for the first time from Madras in the same year. In 1925, Thapar proposed the new genus Echinopharynx and prepared a monograph on the Oxyuroids of Reptiles. In the meanwhile, Karve (1927-1944) reported a number of amphibian and reptilian nematodes. Mirza (1929, 1933), Mirza and Singh (1934) and Mirza and Basir (1937) published good papers on the taxonomy of animal nematodes from Aligarh. Agarwal (1930) and Kulkarni (1935) reported a species of Procamallanus each. Baylis (1936, 1939) authored the two valuable volumes of "Fauna of British India" which provided the accumulated knowledge of nematodes from the whole• subcontinenL
Among the Indian Helminthologists during the pre-independence period, Mirza (1929-1957) at the Aligarh Muslim University, Thapar (1924-1950) at the Lucknow University and Singh (1938¬1965) at the Osmania University, Hyderabad, established good schools of nematode studies. Bhalerao (1932-1948), another pioneer worker in Indian Helminthology, also contributed significantly on the taxonomy of nematodes of the Indian sub-continent initially from Rangoon and later from Indian Veterinary Research Institute, Izatnagar. A brief but valuable review on the various species of Filaria .)Vas prepared by Basu (1939). In the meantime, a number of taxonomists Anan taram an , Chatterji, Chauhan, Desia, Ghosh, Guha, Iyanger, Lal, Pande, Ray, Saha, Srivastava, Vaidyanatban and others started reporting species from different parts of the country. Some of the Indian helminthologists contributed significantly and also on the applied aspects of nematodes of economic importance, during this period, viz., Acharya (1939) on the control of poultry nematodes, Chopra and Rao (1939) on the treatment of filariasis, Mukherji (1940) on the control measures against hookworm, Rao (1943) on filariasis, Sarwar (1945) on pathological reactions in Setaria, Sen (1945) on Ascariasis, Shastry (1946) on the distribution of elephantiasis. 11lapar (1941) provided a review on the control measures against nematode pests. Moorthy (1941) Investigated the developmental stages of Dracunculus medinensis from southern India.
iii) 1948 -1990
During the post-independence period, Basir, Mirza, Pande, Singh, Srivastava, Mehra, Thapar and a few other continued their valuable contributions in the field of taxonomy, biology, pathogenecity, control, etc., of nematode parasites of vertebrates and invertebrates. Keeping in view the growth in helminthology at different centres in India, the fust volume of the Indian Journal of Helminthology was published in 1948 by the Society of•Indian Helminthoiogists. Thaper and Mirza played the key role as -the founders of the society. S.P. Gupta, Khera, and Sanwal described a number of new species and genera from Lucknow during 1950s. It will be worthwhile to mention here the monograph on the nematode parasites of Arthropoda by Basir (1957). Ali (1956) conducted a survey of nematode parasites of fIShes and birds of Hyderabad while Chakravarty and Majumdar (1959) initiated the work on different aspects of animal nematodes in West Bengal.
Later on, Ali joined the Marathwada University, Aurangabad, Maharashtra, where he encoumged Farooqi and Kalyankar to undertake the work on animal nematode$. They published a series of papers on the nematodes from Marathwada region dwing 1960s. Johnson, a student of Basir, established a good school at the Jodhpur University, during the same period. Ansari (1964) published a comprehensive monograph on the morphology and some applied aspects of Setaria cervi wpereas D.S. Jairajpuri (1963) initiated the research work on the nematodes of birds at Aligarh. Sood (1967-1980) published a series of papers on the nematodes from India. N.K. Gupta and his co-workers (.1973-1980) described a large number of nematode species from the Punjab University, Chandigarh, while Fotedar and Dhar (1970-1980) contributed significantly from Srinagar, Kashmir. In the eastern region, Majumdar at the Burdwan University, Manna at the Calcutta University and Soota, at Z.S.I., Calcutta, made good contributions in different fields of nematode parasites. A few other contributions may also be mentioned here viz., Bhaduri (1948), Chowdhuri (1949), Das and Mukherji (1949), Malhotra (1949), Patel (1948), Premvati (1960), Rai (1958) and others. Bashirullah from Bangladesli and Bilquees, Rashid and Rehana from Pakistan, have also contributed much in the taxonomy of animal nematodes.
Research in ZSI
As mentioned earlier, the Zoological Survey of India, Calcutta, has always been a centre of taxonomic studies of nematodes since the pre-independence days. In the post-independence period, Chauhan (1947) described a new fllarid wonn Squamofilaria choprai from the lung of sea tern of Maldive Islands. Chaturvedi and Kansal (1977) have published a checklist of Indian nematodes. Soota and Chaturvedi (1971), Soota and Dey Sarkar (1975-1984) reported a large number of species of vertebrate nematodes from the northeastern region of India. Soota (1983) has updated our knowledge of nematode parasites of Indian fishes by compiling the descriptions of about 200 species, and providing the keys for their identification. N. Majumdar (1965, 1985) has also described a few new species of nematode parasites from birds. Alvi (1975) at the High Altitude Zoology Field Station of Z.S.I., Solan, has studied the morphology, biology and control measures of fowl caecal nematode of the family Heterakidae. Approximate number of families, genera and species ofanimal parasitic nematodes in India
It is generally felt that our basic knowledge of the vertebrate nematodes has been satisfactorily assembled and organised. Most of the areas of the country have been surveyed for the nematode parasites of vertebrates.
Outside the Zoological Survey of India, most of the institutions studying nematodes, are engaged in taxonomic work. Some scientists at IVRI and a few universities are involved in the applied work also.
Due to the economic importance of nematode parasites of insects (entomophilic nematodes), an independent branch of nematology called 'entomophilic nematology' has been developed in recent years. The nematodes belonging to mennithid' group have been confirmed to act as a very important biological agent in controlling insect pests. Though Basir from the Aligarh Muslim University (AMU), Rao fr~m the Osmania University and a few others have contributed significantly to the taxonomic knowledge of insect nematodes, our knowledge on this group still remains meagre. Recently, D.S. Jairajpuri and her students have initiated the work at AMU and published about 15 papers on the taxonomy of these nematodes. In fact, not only the entomophilic nematodes but also the nematodes of invertebrates as a whole need more attention in the coming years. Present 'stale ofOUT knowledge ofIndian fauna in relation to that ofthe world fauna :
In comparison to the knowledge of nematode fauna of other parts of the world, our knowledge of vertebrate nematode par:asites from India is satisfactorily build up. However, the nematode parasites of Indian invertebrates are poorly known.
Expertise India
In ZSI
T.D. Soota, -Retired Scientist, Zoological Survey of India, 234/4 Acharya J.C. Bose Road, Calcutta 700 020.
S.R. Dey Sarkar, 'M' Block, New Alipore, Calcutta 700 053.
Y Chaturvedi, Gangetic Plains Regional Station, Zoological Survey of India, Handloom Bhavan, Rajendra Nagar, Patna 800 016.
Elsewhere
P.G. Deshmukh, Department of Zoology, Marathwada University, Aurangabad (Maharashtra).
D.N. Fotedar. P.G. Department of Zoology, Jammu &Kashmir University, Srinagar, Kashmir.
Gupta. Department of Zoology, Lucknow University, Lucknow (U.P.).
GuPta, Department of Zoology, Lucknow University, Lucknow (11.P.). Durdana S. Jairajpuri, Department of Zoology, Aligarh Muslim University, Aligarh (U.P .).
Johnson, Department of Zoology, Marathwada University, Jodhpur (Rajashtban).
Kalyankar, Department of Zoology, Mamthwada University, Aurangabad (Maharashtra).
Majumdar. Department of Zoology, BurdwaD University, Burdwan (West Bengal).
Sahay, Department of Zoology, Ranchi University t Ranchi (Bihar).
A.H. Siddiqi, Department of Zoology, Aligarh Muslim University, Aligarh (U.P.).
M.L. Sood, Department of Zoology, Punjab Agricultural University, Ludhiana (Punjab).
Abroad
Anderson, College of Biological Science, University of Guelph, Guelph, Ontario, Canada.
Baros, Czechoslovak Academy of Sciences, 60365 BRNO, Kventa' 8, Czech slovakia.
Campana Rouget, Laboratioire de Pamsitologie, Fac. de M'decine, Dijon, France.
Chabaud, Museum National d'Histoire Naturelle, Laboratoire des Vcrs, 43 Rue Cuvier, 75231 Paris Ceex 05 Franch.
Durette-Dessel, Museum National d'Histoire Naturelle, Laboratoire des Vers, 43, Rue Cuvier, 75231 Paris Cedex 05 France.
Hartwich, Zoologisches Museum, Museum fur Naturkunde der Humboldt-Uni, DDR.I04 Berlin, Invalidenstr, 43.
Inglis, British Museum (Nat. Hist.), Cromwell Road, London, S.W.7.
Margolis, Depl of Environment, Fisheries and Marine Service, Pacific Biological Station, Nanaim, British Colmbia, Canada~
Poinar, Jr., University of California, Berkeley, U.S.A.
Moravec, Czech slovak Academy of Science, Flemingove Mamesti 2, Praha -6, Czech slovakia.
J.C. Quentin, Museum National d'Histoire Naturelle, Laboratoire des Vers, 43 Rue Cuvier, 75231 Paris Cedex 05, France.
0.0. Schmidt, Department of Biology, Univ. of Northem Colamdo, Greeley, colorado, U.S.A.
J.F.A. Sprent, University of Queenslans, Sl Lucia, Brishabe, 4067, Australia..
Selected References
Basir, M.A. 1957. Oxyurid parasites of Arthropoda. A monograph. Zoologica, 220 pp.
Baylis, H.A. 1936. Nematoda, I (Ascroidea and Strongyloidea). Fauna Brit. India including Ceylon and Bwma. Taylor &Francis, London: 408 pp.
Baylis, "H.A. 1939. Nematoda, II (Filaroidea, Dioctophymoidea and Trichinelloidea). Fauna Brit. India including Ceylon &Burma. Taylor and Francis: 273 pp.
Chabaud, A.G. 1974. Keys to the nematode pamsite of vertebrates I. Keys to subclasses, orders and superfamilies. Edit. Anderson, chaband and Willmot. Commonwealth Agricultural Berreaux Farnham Royal, Bucks, England: 17 pp.
Chaturvedi, Y &Kansal, K.C. 1977. Check-list of Indian Nematodes (animal parasites). Res. zool. Surv.lndia, Misc. publ., Occ. Paper No.5: 1-148.
Chitwood, B.O. &Chitwood, M.B. (1974). An Introduction to Nematology (rev. ed.). Baltimore University Park Press: 334 pp.
Poinar, G.O., JR. 1975. Entomogenous Nematodes. A Manual of Host List of Insect Nematode Association. Leiden : EJ. Brill : 317 pp.
Poinar, G.O., JR. 1977. CIH Key to the groups and genera of Nematode Parasites of Invertebrates. Commonwealth Agricultural Bureaux Fornham Royal, Bucks, England: 43 pp.
Platt, H.M. &Warwick, R.M. 1983. Synopsis of the British Fauna No. 28. Free Living Marine Nematodes. Part I : British Enoplids. Piunan Press, Bath, U.K.
Soota, T.D. 1983. Studies on Nematode Parasites of Indian Vertebrates. I. fishes. Rec. Zool. Surv. India, Occ. Paper No. 54 : 1-352.
Yamaguti, S. 1961. Systema Helminthus. Vol. III. The nematodes of vertebrates, pts. 1 &2, Interx. Publishers: 1-2101.
