Studies On Certain Helminth Parasites Of Some Fishes From Three Egyptian Lakes:

Gehan Hassan Ahmed Lashen . 

It is well established that helminth parasites are amongst the mostimportant etiological agents of fish diseases.In Egypt, the study of helminth parasites of fresh-water fishes wasreceived a good deal of attention by parasitologists working on this subjects.Also, the study of helminth parasites of marine fish have received a particularattention, but the studying of helminth parasite of fishes in lakes received lessattention; Wannas, 1977 on Lake Nasser and Lamloom, 1987, on Lake Qarunand Wadi AI Rayyan.The present investigation is concerned with a helminthological study ofsome of the common species of fish in three Egyptian Lakes, Manzallah, Edkuand Timsah.The thesis includes a general introduction and three chapters.Chapter I deals with the general methods used in the present workincluding collection of fishes and their subsequent examination for helminthparasites. It also includes an account on the techniques followed in the fixationof helminth parasites and their subsequent preparation for the detailedmorphological and taxonomical studies.Chapter II includes the results of a general survey made on 1612 fishbelong to 15 families, 18 genera and 18 species. The total incidence ofhelminth infections 714 (44.30%) belonging to twelve families, fifteen generaand fifteen species of these fishes, 656 (40.60%) were infected withtrematodes, 23 (1.40%) were infected with cestodes, 59 (3.60%) were infectedwith nematodes and 46 (2.8%) were positive for acanthocephala. The highestincidence of the helminth infections was recorded in Serranus sp. (93.5%) andSaurus tumbil (80.4%) while moderate incidence was recorded in Oreochromisniloticus (64.60%) and (47.3%) in Chirocemrus dorab. The lowest incidence(19.5%) in Mugil cephalus and (18.8%) in Trachurus indicus. The chapter alsoincludes incidence of digenetic trematode genera in infected fishes collectedfrom three lakes, incidence of trematode infections arranged according to thefish families as well as the host’s sex and host specificity in species of fish.Chapter III, includes a critical historical and systematic review of thetrematode genera involved, together with a detailed assessment of the variousviews suggested by different investigators on the important-diagnostic featuresused in the specific identification of members of the genus. This is consideredan important fundamental step in order to formulate a clear and sound policyfor the identification of the various species involved. The chapter includesdescription of twenty five species of trematodes belonging to twenty genera andtwelve families. Out of these, fifteen species are new to science while tenothers are redescribed in detail, some of them being recorded for the first timefrom Egypt. The new species are: Astiotrema oreochromae, cypseluritrembuckleyi, Genolinea gohari, Genolina roshdi, Hemiurus shalabyi,Lecithocladium chirocentri, Lecithostaphylus ismailensis, Myosacciumsardinellae, Plagioporus (Plagioporus) labraxae, Prosorhynchus aegyptiacus,Prosorhynchus nagatyi, Rhipidocotyloides labraxae, Uterovesiculurus serrani,Uterovesiculurus manteri and Bucephalopsis aqualae.The rcdescribed trematode genera belonging to Plagiorchiidae,Cryptogonimidae, Haplosplanchnidae, Masenidae, Acanthocolpidae,Acantostomatidae, Opecolidae and Allocreadiidae. These are Astiotremasudanensis Khalil, 1959 from Lakes Edku and Timsah, Haplorchoides cahirinus(Looss, 1896) Chen, 1949 from Lake Manzallah; Haplosplanchnus pachysoma,Looss, 1902 and H. Indica, Gupta and Ahmed, 1979 from Lakes Timsah andEdku, Eumasenia aegyptiacus, Mohamed, 1978 from Lake Edku; Deropristisit!flata (Molin, 1859) Odhner, 1902 from Lakes Edku and Manzallah;Acanthostomum (Atrophocaecum) aswanensis Wannas, 1977 from Lakes Edku,Manzallah and Timsah; Pseudoplagioporus, Yamaguti, 1942 from LakeTimsah; Podocotyle temensis Fischthal and Thomas, 1970 from Lake Timsah,and Orientocreadium batrachoids Tubangui, 1931 from Lakes, Edku,Manzallah and Timsah.