Yasser Karar

Dr. Yasser Karar

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Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 November 2017
Verified
Journal Article
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CBCharles K. Blend
Charles K. Blend
Yasser KararYasser Karar
Yasser Karar
NDNorman O. Dronen
Norman O. Dronen
Modified and/or new keys to the four subfamilies now recognized within the Megaperidae Manter, 1934 n. comb. (Syn. Apocreadiidae Skrjabin, 1942) as well as the genera within each subfamily are presented. Two new genera, Paraschistorchis n. gen. and Plesioschistorchis n. gen., both within the Schistorchiinae Yamaguti, 1942, are erected and keys are provided to the species considered in both new genera—distinguished by possessing caeca that end either in separate ani or blindly. Plesioschistorchis callyodontis (Yamaguti, 1942) n. comb. and Plesioschistorchis haridis (Nagaty, 1957) n. comb. are re-described from new material collected from the common parrotfish, Scarus psittacus Forsskål (Perciformes: Scaridae), inhabiting the Red Sea off Egypt; S. psittacus represents a new host record for both species. The taxonomic status of Schistorchis sensu stricto Lühe, 1906 is examined and revised, a key to the four species we consider in this genus offered, and the monotypic genus Megacreadium Nagaty, 1956 declared a junior synonym of Schistorchis. Members of Schistorchis sensu stricto possess a unique “complex” (i.e. highly cellular/glandular) instead of “simple” (i.e. entirely muscular) type of oral sucker that is quite large in relation to body size; an elongate, somewhat sub-rectangular-shaped body; 5+ testes arranged in at least two rows; caeca that open via separate ani; a long post-testicular region; a median genital pore either at the anterior margin of or just anterior to the ventral sucker; and species of Schistorchis sensu stricto parasitize the intestine of marine fish within the Order Tetraodontiformes Berg. With the revision of this genus, we re-describe Schistorchis carneus Lühe, 1906 from the lower and mid-intestine of the white-spotted puffer, Arothron hispidus (Linnaeus) (Tetraodontiformes: Tetraodontidae), collected in the Red Sea off Egypt. Finally, a plea is made for further study of the Megaperidae n. comb. focusing, in particular, on the following: (1) obtaining new type/voucher materials of Plesioschistorchis manteri (Gupta & Tandon, 1984) n. comb. and Schistorchis paruchini Kurochkin, 1974; (2) elucidating the life histories (i.e. intermediate hosts) of members of the Postporinae Yamaguti, 1958 and Schistorchiinae; and (3) generating DNA sequence data for more species of megaperids to help future workers produce increasingly accurate taxonomic classifications that better reflect phylogenetic relationships within this ecologically diverse group of digeneans.

16 January 2025 in Frontiers in Veterinary Science
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SASara Abdel-Hakeem
Sara Abdel-Hakeem
GMGaber Megahed
Gaber Megahed
AAAhmed M. Al-Hakami
Ahmed M. Al-Hakami
MTMohammed E. M. Tolba
Mohammed E. M. Tolba
Yasser KararYasser Karar
Yasser Karar
Introduction: Blood parasitism is a significant clinical disease that silently undermines the livestock industry, particularly affecting camels. This study aimed to assess the prevalence of Trypanosoma evansi in Arabian camels (Camelus dromedarius) and its impact on infertility by examining serum protein fractions, lipids, reproductive indices, and the expression of heat shock protein (HSP70) during breeding season.Methods: A total of 107 male post-pubertal camels, aged between 5 and 10 years, were collected randomly from slaughtering house in Assiut Governorate, Egypt.Results: Microscopic and serological examinations revealed that 23.4% (25/107) of the camels were infected with T. evansi. Infected camels exhibited a highly significant increase in total serum protein. The assessment of dyslipidemia, measure as binary variables for lipid profiles (cholesterol, triglycerides, HDL, and LDL), indicated a nonsignificant increase in risk of dyslipidemia in infected camels compared to healthy camels. Proteomic analysis identified four major protein fractions in the infected camels compared to healthy camels with molecular weights of 181.72, 87.59, 30.5, and 19.5 kDa using SDS electrophoresis. Testicular tissue of the infected camels showed degeneration and necrotic changes in seminiferous tubules and interstitial tissue, along with edema and congestion. There was a significant reduction in the diameter of seminiferous tubules and germinal epithelium height. A marked reduction in testosterone levels and a high expression of HSP70 in spermatogonia, spermatocytes, Sertoli cells, and Leydig cells were observed.Discussion: Consequently, a combination of physiological and hormonal analyses may serve as a reliable indicator of Trypanosoma infection.

23 June 2021 in Zootaxa
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Journal Article
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Yasser KararYasser Karar
Yasser Karar
CBCharles K. Blend
Charles K. Blend
NDNorman O. Dronen
Norman O. Dronen
AAAsmaa Adel
Asmaa Adel
Species of Astiotrema Looss, 1900 (sensu lato) infect a wide range of fishes, amphibians and reptilians. They also possess a considerably wide spectrum of morphological features. Several species were recognized for variable, confusing, overlapping and unspecialized morphological characters rather than for unique distinguishing features, causing continuing dispute around the validity of several species. Following comprehensive review, a revised restricted concept of Astiotrema is proposed including a morphologically strict definition. Both Tremiorchis Mehra & Negi, 1926 and Astioglossimetra Bilqees, Khatoon & Khan, 2002 are synonymized with Astiotrema (sensu stricto). Several nominal species are synonymized, others are excluded and characters for each recognized species are presented and explained. Only eight species are recognized: Astiotrema cyclemysi Siddiqi, 1965, Astiotrema emydis Ejsmont, 1930, Astiotrema fotedari Dhar, 1977, Astiotrema impletum (Looss, 1899) Looss, 1900, Astiotrema karachiensis (Bilqees, Khatoon & Khan, 2002) n. comb., Astiotrema odhneri Bhalerao, 1936, Astiotrema ranarum (Mehra & Negi, 1926) Fotedar, 1971 and Astiotrema reniferum (Looss, 1898) Looss, 1900. A key to the species of Astiotrema (sensu stricto) is presented, a comprehensive list of all host-locality records is included and host-parasite specificity is elucidated.

2 August 2019 in Systematic Parasitology
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Journal Article
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Yasser KararYasser Karar
Yasser Karar
CBCharles K. Blend
Charles K. Blend
RKRefaat M. A. Khalifa
Refaat M. A. Khalifa
HHHemely Abdel-Shafy Hassan
Hemely Abdel-Shafy Hassan
HMHoda S. Mohamadain
Hoda S. Mohamadain
NDNorman O. Dronen
Norman O. Dronen

1 April 2019 in The Bulletin of zoological nomenclature
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Journal Article
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CBCharles K. Blend
Charles K. Blend
Yasser KararYasser Karar
Yasser Karar
NDNorman O. Dronen
Norman O. Dronen
The purpose of this application, under Articles 78.1 and 81.1 of the Code, is to suspend the application of Art. 35.5 so as to re-establish the precedence of MegaperidaeManter, 1934 over ApocreadiinaeSkrjabin, 1942 for certain digenean trematodes of fish. Both names have been used as valid in recent literature, with some authors treating the former as a subfamily (MegaperinaeManter, 1934) of the latter, which is now treated also as a family (Apocreadiidae Skrjabin, 1942). While Apocreadiidae may possibly be regarded as enjoying prevailing usage, Megaperidae is the older name, and its supposed lack of precedence under Art. 35.5 is an aberrancy resulting from historical contingencies.

24 June 2016 in Zootaxa
Verified
Journal Article
Closed access
PDF file
NDNorman O. Dronen
Norman O. Dronen
CBCharles K. Blend
Charles K. Blend
RKRefaat M. A. Khalifa
Refaat M. A. Khalifa
HMHoda S. Mohamadain
Hoda S. Mohamadain
Yasser KararYasser Karar
Yasser Karar
Bianium spongiosum Bray & Cribb, 1998 (Lepocreadiidae), described from the yellow boxfish, Ostracion cubicus Linnaeus (Ostraciidae), off Lizard Island, Queensland, Australia, possesses a combination of the following three morphological features which distinguishes it from all the other species currently assigned to the genus: (1) large internal patches of large cells forming sponge-like pads we have termed “pelops”(“pelop” sing.) laterally in the forebody extending from near the anterior extremity to about the level of the intestinal bifurcation rather than possessing a scoop; (2) ceca that reach to near the posterior extremity where they end blindly without ani; and (3) a vitellarium which is present laterally but not dorsal to the ceca. Based on this we propose the erection of Pelopscreadium n. gen. (Lepocreadiidae) with the assignment of B. spongiosum to this new genus as the type-species, Pelopscreadium spongiosum (Bray & Cribb, 1998) n. comb. Pelopscreadium aegyptense n. sp., also from the yellow boxfish but from the Red Sea off Sharm El-Naga, Egypt, is described as the second member of the new genus because it shares these three characteristics with P. spongiosum.