The First Record of The Monostome Triocellate Cercaria (Ephemera Type) from Bithynia goryi Snail in Egypt

Navigation: Main page » Insect Articles

 Print this page Submit articleComment article

Author: Prof. Dr. Hussein EL-Sheikh( Ass. Prof. Said Nour EL-Din( )

The First Record of The Monostome Triocellate Cercaria (Ephemera Type) from Bithynia goryi Snail in Egypt Prof. Dr. Hussein EL-Sheikh( Ass. Prof. Said Nour EL-Din( ) Dr. Ahmed Abd-Alla Taima( )

Abstract:

In this study 133 Bithynia goryi snail were collected from drains (54) and canals (79) of old planted land from Beheira governorate, Egypt in the period from December 1997 to November 1999, and examined for the larval stages of trematodes. It was found that, three snails from drains (5.55%) were infected with monostome triocellate cercaria (Ephemeratype) for the first time in Egypt. The morphology of the redia and cercaria was described fully in the text. Also the present finding was discussed in the light of the findings of the previous authors. Recommendation are stated.

Introduction

Triocellate monostome cercaria from the ephemera type was described by many authors from different snails in Egypt from these: Looss (1896) from Melania tuberculata snail in Cairo and Alexandria; Omran (1973) from M. tuberculata in Assiut; Nada (1983) from Cleopatra sp. in Sharkia and Wanas et al. (1993) from Pirenella conica in Deversoir. Also Harper (1929) described this type of cercaria from Lymnaea peregra and Physa fontinalis in Britain. The present cercaria belongs to one of Notocotylus spp Parasites which commonly occurs in the caeca and rectum of the fowl , duck , goose and wild aquatic birds and sometimes infect mammals. The intermediate hosts are the snails Planorbis rotundatus , Lymnaea palustris , L. limosa , Bulinus japonicus and Biomphalaria. Cercaria encysts within a short time of emergence from the snail on stones , water plants and the like in the open, but generally on water plants. Notocotylus spp . is not usually considered to be very pathogenic however , it has been associated with erosion of the caecal mucosa and disease in geese and ducklings (Soulsby , 1982 and Frandsen and Christensen , 1984) Infected ducklings were emaciated, had diarrhoea, locomotory ataxia and catarrhal mucoenteritis (Michalski 1977).

Material and Methods

Collection of Snails Bithynia goryi snails were collected from canals and drains of old planted land, from Beheira governorate, Egypt in the period from December 1997 to November 1999. The net used, process of collection and maintenance of snails in the laboratory were carried out as Wanas et al.(1993b).

Identification of the Snails The collected snails were identified on the bases of the morphological characters of the shell and the body according to keys proposed by Nagaty et al. (1961), Abdel-Malek (1974), WHO Snails Identification Center (1973) and (1980) and Nada (1983).

Examination of Snails for Larval Stages of Trematodes a- by exposure of snails to natural or artificial light for one hr. at 25Cْ for cercarial shedding. b- Crushing of snails for detection of the intramolluscan stages using dissecting microscope.

Staining of Fixed Specimens Different stains such as acetocarmine, boraxcarmine and Gowers were tested for permanent whole mount preparations. Acetocarmine gave the best results with rediae and cercariae. The procedure was carried out as the following: After fixation in 70% ethanol a few drops of the stain were added to the fixed specimens for about 2-5 minutes. Dilute solution of acid alcohol (1/2 ml conc. HCl per 100 ml 70% ethanol) was used for differentiation. Specimens were dehydrated in ascending grades of alcohol (80 %, 90 %, 96 % and 100 % ethanol). Clearing was carried out by terpineol or clove oil and mounting in Canada Balsam. Drawing, Measurements and Photomicroscopy Camera Lucida was used for drawing mounted specimens. The measurements (10 specimens) in micrometer of the cercariae were taken from the longest and widest parts of body, tail and other organs. The minimum and maximum values were recorded for each organ with the average in parenthesis. Photomicroscopy was done using automatic camera of Carl Zeiss photomicroscope III with different magnifications.

Identification of the Cercariae

Identification of the cercariae was based on keys proposed by Luhe (1909), Dawes (1946), Yamaguti (1975) and Frandsen and Christensen (1984).

Results

In this work 133 Bithynia goryi snail were collected from drains (54) and canals (79) of old planted land, from Beheira governorate, in the period from December 1997 to November 1999. Three snails from drains (5.55%) were found to be infected with monostome triocellate cercaria from ephemera type. Whereas the collected snails from the canals were found to be free from any infection with larval trematodes.

Redia (Plates 1, 2)

It is yellowish brown in colour cylindrical in shape tapering slightly towards each end, measuring 562-733 (659.33) m in length and 155-213 (185.83) m in breadth. At the anterior end, the redia possesses a circular oral sucker measuring 44-66 (61.33) µ in length and 37-57(50.5) µ in width. Digestive system consists of mouth which leads to oesophagus the latter terminates in a sac like gut. At the tail end of the redia, there is a conical mass of germ cells proliferated as a central rachis from a small area of epithelium at the extreme posterior pole. This mass is connected to the walls by fine strands. In it, the germ cells become enlarged, and by repeatedly dividing produce the cell masses which give rise to the cercariae. The rediae contain 2-5 cercariae. Such cercariae have only 2 eyespots Fig. (1).

Cercaria (Plates 1, 3)

It is monostome triocellate cercaria. The body of immature cercaria is elongated whereas, the body of mature cercaria is oval in shape measuring 266-382 (335.16) m in length and 142-182 (157.66) m in width. The body is only provided with a circular oral sucker, terminal in position and measures 33-40 (3 6.83) m in diameter. The anterior fourth of the body is highly pigmented, especially around the eyespots. There are three black pigmented eyespots arranged in the form of a triangle in the anterior dorsal region of the mature cercaria. By examining several premature cercariae it was noticed that the lateral eyespots are formed firstly then the median one. Occasionally the median eye is not formed at all, they are being then two lateral eyes and between them scattered pigmented granules. The distance between any of the lateral eye spot and the anterior border of the body is 66-80 (72) m, while the distance between the median eye spot and the anterior border of the body is 50-56 (53) m. Each of the lateral eye spots measures 13-20 (16) m in diameter, while the median eye spot being smaller than the lateral ones and measures 11-15 (13) m. The alimentary canal is represented by a short and narrow oesophagus which bifurcates below the level of the eye spots into two intestinal caeca reaching near the upper level of the adhesive pockets. The excretory system consists of a clear vesicle situated above the tail and in between the adhesive pockets, two conspicuous lateral canals united by a transverse duct little below the level of the eyes, they empty into the vesicle and a third excretory canal runs from the bladder passing posteriorly along the entire length of the tail. In stained specimens there are six pairs of button like pigmented bodies on the body. The cystogenous gland cells are numerous and distributed all over the body. The tail attached to the body by a shallow notch. It is thick at the base, then it tapers to a pointed end posteriorly, measuring 391-515 (454) m in length and 48-62 (56.33) m at the base. Discussion According to Lebour (1911) the present cercaria can be classified under the monostome group since it has only one sucker in the anterior end. Moreover the mature cercaria possess three pigmented eye spots, thus it is identified as one of the members of the triocellate group of Faust (1917) which corresponds to the ephemera group of Sewell (1922) and Schell (1985). Looss (1896) described a triocellate monostome cercaria from the ephemera type from Melania tuberculata snail in Cairo and Alexandria. Without an experimental infection he expected that his cercaria may be the larval stage of Notocotylus aegyptiacus. His assumption was based on the presence of the cercariae in the same locality where adults were found in ducks and the similarity between cercaria and adults. Harper (1929) in Britain recorded triocellate monostome cercaria from fresh water snail Lymnaea peregra and Physa fontinalis. On experimental bases the author identified his cercaria as a larva of Notocotylus seineti. Omran (1973) in Assiut described a monostome cercaria, which belongs to the ephemeral type from the fresh water snail M. tuberculata. Since N. aegyptiacus is the only monostome species recovered in Egypt in that time, Omran for this reason postulated her cercaria to be the larva of N. aegyptiacus. In Assiut and on experimental bases Khalifa and El-Naffar(1978) described the cercaria of Paramonostomum aegyptiacus from M. tuberculata. In Sharkia governorate Nada (1983) recovered Notocotylus sp. cercaria from Cleopatra sp. Wanas et al (1993a) recovered a triocellate monostome cercaria belongs to ephemera group from Pirenella conica snail in Deversoir, Ismailia governorate. Table (1) shows no cut differences in measurements between the above mentioned cercariae and the present cercaria. The handled cercaria can differentiated from these cercariae on bases of similarity and differences as follow. - Although the minor measurements recorded by Looss (1896) about his ephemeral cercaria, these measurements coincide with measurements of the present cercaria - The present cercaria is in agreement with the triocellate monostome cercaria of Omran (1973) and Nada (1983) in measurements and description. - The cercaria under discussion differ from the cercaria of Harper (1929) and that of Wanas et al (1993), where the former contains 6 pairs of button like bodies in the body while the latter two were free from such bodies. - The cercaria of Paramonostomum aegyptiacus Khalifa & El- NafFar (1978) is in disagreement with the present cercaria where the oral sucker of the former was surrounded by two long spines while the later is free from these spines. Further work is recommended to confirm and illustrate the nature of this cercaria.

Abbreviations : AP: adhesive pocket. B: body. BLPb: button like pigmented bodies. C: cercaria. E: eye spot. EC: excretory canal. EV: excretory vesicle. G: gut. gb: germ ball. IC: intestinal caeca. O: oesophagus. OS: oral sucker. R: redia. T: tail.

Table (1):

Comparison between rediae and cercariae of ephemera group described by different authors and present specimens. AuthorsOrgans Loss (1896) Harper (1929) Omran (1973) Khalifa and EL-Naffar (1979) Fixed in 4% Formaline Moist heat killed CercariaBody length 300 550-600 350-360 245-360 300-360 Body breadth 150-180 180 150-155 124-168 102-150 Oral sucker 40 in diameter 50 33-34 25.2-30.4 × 20.9-23 29.9-39.1 × 25.3 - 27.6 Lateral eye spots from anterior end - 70 56-80 57.7-62.1 Median eye spots from anterior end - 60 - - Lateral eye spots diameter - 10 - - Tail length 300-600 500-650 377-415 300-360 420-480 Tail width - 56 41.5 66-78 48-72 RediaRedia length - Young 300-1000 mature 3000-4000 - - Redia width - Mature 400-500 - - Oral sucker - - - Locality Cairo, Alex-Andria, Egypt British Assiut, Egypt Assiut, Egypt Snail host M. Tuberculata Lymnaea peregra M. Tuberculata M. Tuberculata

Continued Authors

Organs Nada (1983) Wanas et al (1993a) Present specimens CercariaBody length 300 34 405-427 (416.25) 266-382 (335.16) Body breadth 190 19 149-150 (149.5) 142-182 (157.66) Oral sucker 28.5 9.5 46-50 (48) 33-40 (36.83) Lateral eye spots from anterior end - 61-72.5 (66.75) 66-80 (72) Median eye spots from anterior end - 50-60 (55) 50-56 (53) Lateral eye spots diameter 15.2 3.8 12-15 13-20 (16) Tail length 520.6 144.4 355-356 (355.5) 391-515 (454) Tail width 30.4 7.6 48-50 (49) 48-62 (56.33) RediaRedia length - 800-816 (810.6) 562-733 (659.33) Redia width - 160-208 (176) 155-213 (185.83) Oral sucker - 38-44 (41) 44-66 × 37-57 (61.33 × 50.5) Locality Sharkia, Egypt Deversoir, Ismailia, Egypt EL-BeheiraEgypt Snail host Cleopatra sp. Pirenella conica Bithynia goryi

Plate (1) : Camera lucida drawing of redia and cercaria of Notocotylus sp. Fig. (1): Redia. Fig. (2): Immature cercaria. Fig. (3): Mature cercaria.

Plate (2): Photographs of redia of Notocotylus sp.stained with acetocarmine. Fig (4): Intire rediae, x=125. Fig (5): Enlarged anterior part of the redia, x=500.

Plate (3): Photographs of cercaria of Notocotylus sp. stained with acetocarmine. Fig.(6): Developmental stage of cercaria , x = 125. Figs.(7,8): Entire premature cercariae , x = 125. Fig.(9): Body and anterior part of the tail of premature cercaria, x = 500. Fig.(10): Mature cercaria, x = 125.

References

Abdel-Malek, E. (1974): Medical and economic malacology. A subsidiary Harcout Brace Jovanovich. Academic press New York and London.

Dawes, Ben (1946): The trematoda with special reference to British and other European forms. Cambridge, the Univ. Press.

Faust, E. C. (1917): Notes on the cercariae of the biter root valley, Montana. J. Parasit. 3: 106-123.

Frandsen, F. and Christensen, N. O. (1984): An introductory guide to identification of cercariae from African fresh water snails with special reference to cercariae of trematode species of medical and veterinary importance. Act. Trop. 41: 181-202.

Harper, W. F. (1929): On the structure and life histories of British fresh water larval trematodes. Parasit, 12: 189-219.

Khalifa, R. and El-Naffar, M. K. (1978): The life cycle of paramonost- omum aegyptiacus sp. nov. (Notocotylidae: Trematoda). Act. Parasit. Pol. 25 (38): 223-232.

Lebour M. V. (1911): A review of the British marine cercariae. Parasit. 4:416-456.

Loss, A. (1896): Recherches sur la faune parasitaire de l'Egypte premiere partie. Men. Inst. Egypte. 3:1-252.

Luhe, M. (1909): Parasitche plattwurmer Die susswasser fauna Dentschland. Heft 17, Trematodes: 1-217. Michalski, L. (1977): Studies in the efficacy of zanil in control of Notocotylus infection in ducklings. Wiad. Parasit. 23: 435-439.

Nada, M. S. M. (1983): Biological and ecological studies on some snails in Sharkia governorate. Ph. D. Thesis, Fac. Vet. Med. Zagazig University.

Nagaty, H. F.; El-Gindy, M. S. and Rifaat, M. A. (1961): Medical parasitology and entomology. Anglo, Egypt. Books shop, UAR.

Omran, L. A. M. (1973): Studies on the relation of snails to parasitic infection in Assuit governorate. Ph. D. Thesis, Fac. Vet Med. Assuit Univ, Egypt.

Schell, S. C. (1985): Hand Book of trematodes of North America, North of Mexico. University press of Idaho.

Sewell, R. B. S. (1922): Cercariae Indicae. Ind. J. Med. Res. 10: 1-372. Souslby, E. J. L. (1982): Helminths, arthropods and protozoa of domesticated animals (seven edition).The English Language Book Society and Baillier, Tinall, London. Wanas, M. Q. A.; Abu-Senna, F. M. and Al-Shareef, A. M. (1993a): Larval stages of digentic trematodes of Pirenella conia from Deversoir (Ismailia, Egypt). J. Egypt. Soc parasit. 23(2): 515-526.

Wanas, W. Q. A.; Abou-Senna, F. M. and Al-Shareef, A. M. F. (1993b): Studies on larval digenetic trematodes of xiphidiocercariae from some Egyptian fresh water snails. J. Egypt. Soc. Parasit. 23(3): 829-850.

W. H. O. (1973): Snail Identification Centre. A field guide to African freshwater snails 3-North East African species. Danish Bilharziasis labortory.

W. H. O. (1980): A practical guide to the identification of African freshwater snails Danish Bilharziasis Laboratory.

Yamaquti, S. (1975): A synoptical review of life histories of digenetic trematodes of vertebrates with special references to the morphology of their larval forms. Keigoku publishing Co., Tokyo, 590 PP.

اكتشاف السركاريا وحيدة الممص ثلاثية العيون (من نوع افيميرا)من قوقع بيثينيا جوري للمرة الأولى في مصر

ملخص البحث: في هذه الدراسة تم تجميع 133 قوقع بيثينيا جوري Bithynia goryi من مصارف (54) وقنوات (79) الأراضي القديمة بمحافظة البحيرة، مصر. في الفترة من ديسمبر1997 الى نوفمبر 1999، وفحصت للكشف عن يرقات التريماتودا .ووجد أن ثلاثة قواقع من المصارف( 5.55%) كانت مصابة بالسركاريا وحيدة الممص ثلاثية العيون من نوع افيميرا monostome triocellate cercaria (ephemera type) لأول مرة في مصر. وتم وصف الشكل الخارجي لهذه السركاريا والريديا redia الحضانة لها تفصيلياً في متن هذا البحث كما تم مناقشة ما وجد على ضوء ما وجده الآخرون. وذكرت توصيات ذات الصلة بالموضوع.