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2024
Ibrahim, M. M., M. M. Attia, H. B. Baghdadi, and M. Abdelsalam, "First report of Kudoa species (Myxozoa, Multivalvulida) infection in purple-spotted Bigeye (Priacanthus tayenus) from the Saudi Arabian Gulf", PLOS ONE, vol. 19, issue 1: Public Library of Science, pp. e0295668 - , 2024/01/10. AbstractWebsite

The purple-spotted bigeye, Priacanthus tayenus, is a marine benthic fish native to the Indian and Pacific Oceans, including the Arabian Gulf in Saudi Arabia. This study identified a myxozoan parasite infecting wild P. tayenus from the Saudi Arabian Gulf. These parasites produced spherical to ovoid-shaped, white plasmodia enclosed within pseudocysts in the fish musculature. The annual infection rate was 5.1%, with the highest prevalence in summer (7.6%), followed by spring (6%), and autumn (2.5%), while no infections were observed in winter. The number of plasmodia per fish ranged from 100 to 150 (135.1 ± 16.2). Their dimensions were 4–4.7 mm (4.3 ± 0.3 mm) in length and 4.5–7 mm (6 ± 1.1 mm) in width. Milky-colored exudates within the plasmodia contained mature spores measuring 8–9 μm (8.6 ± 0.4 μm) x 6–7.5 μm (6.9 ± 0.5 μm). The polar capsules of the spores exhibited dimensions of 2–5 μm (3.5 ± 0.5 μm) x 2.5–4.5 μm (3 ± 0.45 μm). Both morphological and genetic analyses confirmed these plasmodia as a novel Kudoa species. Histopathological examination revealed atrophy in the surrounding muscles without an inflammatory response. This study documents the first occurrence of a novel Kudoa sp. in P. tayenus at the Jubail landing site in Saudi Arabia, emphasizing the need for further surveillance and investigations to elucidate its pathogenesis and implications for wild fish stocks.

2022
Elgendy, M. Y., M. Shaalan, M. Abdelsalam, A. E. Eissa, M. M. El-Adawy, and A. A. Seida, "Antibacterial activity of silver nanoparticles against antibiotic-resistant Aeromonas veronii infections in Nile tilapia, Oreochromis niloticus (L.), in vitro and in vivo assay", Aquaculture ResearchAquaculture Research, vol. 53, issue 3: John Wiley & Sons, Ltd, pp. 901 - 920, 2022. AbstractWebsite

Abstract Antibiotic-resistant Aeromonas veronii isolates (4) were identified from moribund Oreochromis niloticus by phenotypic and genotypic characterization using 16S rDNA gene sequence analysis. Antibacterial efficacy of silver nanoparticles (AgNPs) was assessed in vitro and in vivo against A. veronii isolates. A minimum inhibitory concentration (MIC) and 48 h lethal concentration 50% (LC50) for AgNPs were estimated to be 3.125 ?g/ml and 8.77 mg/L respectively. Four hundred fifty fish were divided into 10 groups in triplicate (15/replica). Two control groups were untreated with AgNPs: The first (G1) was not infected, whereas the second (G2) was experimentally infected with A. veronii. AgNPs were added to aquarium water with fish either noninfected (G3?G6) or infected (G7?G10) with A. veronii. AgNPs concentrations were 100, 250, 500 and 750 ?g/L, respectively, for both sets of fish groups. Fish infected with A. veronii but untreated with AgNPs showed septicaemic symptoms, a high mortality rate (71%) and poorer haematological parameters (red blood cells [RBCs], haemoglobin concentration [Hb], hematocrit [HCT%], mean cell volume [MCV] and mean cell haemoglobin [MCH]); impaired nonspecific immune responses (total protein, albumin, globulin and lysozymes); reduced antioxidant capacity (catalase [CAT], peroxidase and superoxide dismutase [SOD]); a significant increase in creatinine, uric acid, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP); and genotoxic effects in gills. Treatment with AgNPs increased fish survival; improved haematological, immunological and antioxidant activities; and optimized liver and kidney function. The most favourable outcome was seen using an AgNPs concentration of 750 ?g/L. Various histopathological changes were found among experimental fish.

Attia, M. M., M. Abdelsalam, M. Y. Elgendy, and A. H. Sherif, Dactylogyrus extensus and Pseudomonas fluorescens dual infection in farmed common carp (Cyprinus carpio), , vol. 173, pp. 105867, 2022. AbstractWebsite

Dactylogyrus extensus and Pseudomonas fluorescens are serious pathogens in Cyprinus carpio aquaculture causing severe impacts and substantial economic losses. During the early spring of 2021, abnormal mortalities were reported among farmed C. carpio. Moribund fish showed anorexia, respiratory distress, dermal ulcers, and septicemia. The water analysis revealed low dissolved oxygen (3.4 mg/L), and high un-ionized ammonia levels (0.65 mg/L). Seventy moribund C. carpio specimens were collected and subjected to parasitological and bacteriological examinations. The monogenetic trematode D. extensus was discovered in wet mounts from the gills of all the examined fish samples (100%). The identity of recovered parasites was confirmed by sequencing and alignment of the 28S rDNA gene. P. fluorescens was concurrently identified in the infested fish samples (58.5%) based on phenotypic characteristics using the API20 E. The identity of bacterial isolates was confirmed further by sequencing and alignment of 16S rRNA gene. The IL-1β and MHCII were upregulated in infested fish in tandem with the severity of infections. P. fluorescens isolates displayed high resistance to most of the tested antibiotics. The study is one of the earlier reports on D. extensus and P. fluorescens co-infections in farmed C. carpio and highlights the need of effective control programs to protect fish health and minimize losses.

Mahdy, O. A., M. Abdelsalam, S. Z. Abdel-Maogood, M. Shaalan, and M. A. I. A. SALEM, "First genetic confirmation of Clinostomidae metacercariae infection in Oreochromis niloticus in Egypt", Aquaculture ResearchAquaculture Research, vol. 53, issue 1: John Wiley & Sons, Ltd, pp. 199 - 207, 2022. AbstractWebsite

Abstract Clinostomiasis is a zoonotic disease of freshwater fish caused by digenetic trematodes in the genus Clinostomum. This parasite causes ?Laryngopharyngitis? disease in people and may result in human fatalities from asphyxiation when consumed improperly cooked Clinostomum complanatum?encysted metacercariae (EMC) infected fish. This study provides genetic confirmation, phylogenetic analysis and histopathological evaluation of Clinostomidae EMC recovered from infected wild-caught and farmed Nile tilapia (Oreochromis niloticus) in Egypt. Recovered parasites were identified as Clinostomum complanatum, C. phalacrocoracis and Euclinostomum heterostomum using macroscopic and microscopic examination. PCR amplification and sequencing of rDNA-ITS2 gene regions of C. complanatum; C. phalacrocoracis and mtDNA CO1 gene regions of E. heterostomum were carried out. Nucleotide sequences of C. complanatum, C. phalacrocoracis and E. heterostomum were registered in GenBank with accession numbers MT133890.1, MT158303.1 and MW193532.1, respectively. Histopathological findings in buccal cavities and kidney tissues of infected O. niloticus were described.

Khalefa, H. S., M. M. Attia, M. Abdelsalam, M. A. Mahmoud, and M. A. Z. Ewiss, Immunological status of some edible fishes exposed to parasitic infections in relation to heavy metals pollution, , vol. 46, issue 3, pp. 653 - 663, 2022. AbstractWebsite

In this study, six heavy metals (Pb, Fe, Cu, Ni, Cd, and Mn) have been measured in water, and muscles from mullet (Mugil cephalus), tilapia (Oreochromis niloticus), and African catfish (Clarias gariepinus) collected from Lake Manzal, Egypt. In addition, the existence of different encysted metacercariae in fish muscle with an evaluation of cell-mediated immune response in infected muscles was also investigated. Water samples generally contained less than the permissible level of heavy metals. The metal accumulation levels in muscle were: Pb > Ni > Cd > Cu > Fe > Mn. The levels of Pb and Ni in the muscles exceed the permissible limits, while the concentration of Mn varied significantly (p < 0.05) depending on fish species. Based on the estimated weekly intake in this study, the EWI values of these heavy metals are below the established Provisional Permissible Tolerable Weekly Intake. On the other hand, Prohemistomum vivax encysted metacercaria were found in the muscle of O. niloticus and C. gariepinus with the intensity of 1–10 cyst per 1 cm of muscle. While M. cephalus was found to be infected with Heterophyes heterophyes EMC. TNF- α1 was 10 folds upregulated in O. niloticus than in control fish. IL-1β expression in O. niloticus was upregulated by 15 folds compared with the control one. By examining C. gariepinus, the MHC II gene expression was increased by 15-fold in comparison to the control group.

Elgendy, M. Y., M. Abdelsalam, S. A. Mohamed, and S. E. Ali, Molecular characterization, virulence profiling, antibiotic susceptibility, and scanning electron microscopy of Flavobacterium columnare isolates retrieved from Nile tilapia (Oreochromis niloticus), , vol. 30, issue 2, pp. 845 - 862, 2022. AbstractWebsite

Columnaris is a common flavobacterial disease affecting tilapia aquaculture. Flavobacterium columnare has been identified as being responsible for the heavy mortalities of earthen-pond-cultured Nile tilapia (Oreochromis niloticus) at the Fayoum Governorate, Egypt. Mortalities have been closely associated with bad husbandry in the overstocked ponds. Diseased fish showed fin and tail rot with a thick yellowish turbid mucus covering the affected skin and gills. Scanning electron microscopy revealed the presence of numerous bacterial cells dispersed in the affected gill tissues. Most of the investigated specimens (60%) were infected with F. columnare. Forty-seven bacterial isolates were phenotypically identified based on cultural and biochemical characteristics. Molecular identification, virulence property assessment, and antibiotic-sensitivity testing were performed on 10 randomly selected isolates. The identities of the isolates were confirmed by gene sequence and phylogenetic analyses. These isolates yielded variable results regarding virulence genes (gtf, norB, and trx) and ability to adhere to fish gills. All isolates exhibited proteolytic and chondroitin lyase activities but had different antibiotic-sensitivity profiles. The pathogenicity of one highly pathogenic isolate was tested via intramuscular injection into juvenile O. niloticus. The challenged fish showed fin rot and skin ulceration with 80% cumulative mortalities. The study discussed critical points in the pathogenesis of columnaris disease affecting Nile tilapia that may help to find out effective control measures and refers to the need for prudent use of antimicrobials in aquaculture to protect aquatic animals and human health.

Elgendy, M. Y., A. H. Sherif, A. M. Kenawy, and M. Abdelsalam, Phenotypic and molecular characterization of the causative agents of edwardsiellosis causing Nile tilapia (Oreochromis niloticus) summer mortalities, , vol. 169, pp. 105620, 2022. AbstractWebsite

Edwardsiellosis is a serious bacterial disease affecting Nile tilapia (Oreochromis niloticus), causing septicemia and mortalities. Edwardsiella tarda and Edwardsiella anguillarum were isolated from Nile tilapia summer mortality events in Egypt. Diseased fish showed hemorrhagic septicemia, skin erosions, and eye opacity. A total of 24 Edwardsiella spp. isolates were retrieved from the investigated fish specimens. Phenotypic and biochemical characteristics grouped isolates into typical Ed. tarda (n = 14 strains) and atypical Ed. tarda (n = 10 strains). The BLAST analysis of sodB gene sequencing confirmed the conventional identification of typical Ed. tarda strains (n = 14) and reidentified all the atypical strains (n = 10) as Ed. anguillarum. Isolates showed a combination of virulence factors, including biofilm formation (66.6%), hemolysis (100%), chondroitinase (50%), and proteolytic activity (20.8%). The major part of isolates showed high resistance to ampicillin, amoxicillin, gentamycin antibiotics and harbored tetA, blaCTX-M, and aadA1 resistance genes. Pathogenicity testing of isolates in O. niloticus confirmed their virulence. Challenged fish exhibited septicemic signs similar to naturally diseased fish. Infections in naturally infected tilapia triggered acute and chronic histopathological alterations. Degenerative and necrotic changes were noticed in hematopoietic organs. Granulomas were noticed in between the hepatic parenchyma. The data extracted from the study confirm that accurate identification of the causative agents of edwardsiellosis should be reliant on genetic-based approaches. Analysis of the bacterium virulence properties offers insights into establishing novel therapeutics for edwardsiellosis control. The findings refer to the need for antimicrobial sensitivity testing to minimize antimicrobial resistance and increase therapy efficacy.

Elgendy, M. Y., M. Abdelsalam, A. M. Kenawy, and S. E. Ali, Vibriosis outbreaks in farmed Nile tilapia (Oreochromis niloticus) caused by Vibrio mimicus and V. cholerae, , vol. 30, issue 5, pp. 2661 - 2677, 2022. AbstractWebsite

Vibriosis is a common disease in aquaculture. Nile tilapia (Oreochromis niloticus) farmed within some commercial fish farms in Kafr El-Sheikh governorate Egypt showed signs of disease and exhibited heavy mortality. In order to get to the root of the problem, ninety moribund tilapia were sampled from the affected fish farms and subjected to bacteriological and molecular examinations. Biochemical characterization of bacterial isolates was performed via the API 20E analytical system. All examined fish samples were infected with Vibrio species. Eighteen Vibrio isolates, V. mimicus (n = 12), and V. cholerae (n = 6) were taken randomly for molecular characterization and further analysis. Isolates were genotyped via sequencing and alignment of the recA gene. Isolates possessed numerous virulence traits, including the production of hemolysins, proteases, lipases, and nucleases. The prevalence of ompU, vmh, vpsR, and flrA virulence genes in Vibrio strains was 61.1%, 66.6%, 27.7%, and 33.3 %, respectively. The blaTEM (55.5%), apHAI (50%), and qnrVC (27.7%) antibiotic resistance genes were recorded in Vibrio strains. All Vibrio isolates (100%) were resistant to ampicillin 10 μg and amoxicillin 30 μg, while they showed high sensitivity against florfenicol 30 µg (83.3%) and ciprofloxacin 5 µg (77.7%). Challenge experiments in Nile tilapia confirmed pathogenicity of the isolates. Fish showed symptoms of septicemia and high mortality was observed. Infections induced numerous histopathological alterations in diseased fish. This is the first report of V. mimicus outbreaks associated with mass mortality in Egyptian farmed Nile tilapia. The findings form the basis for future development of effective control and preventive measures against one of the most infectious pathogens that affect fish and humans.

2021
Eissa, A. E., M. Abou-Okada, A. R. M. Alkurdi, R. A. El Zlitne, A. Prince, M. Abdelsalam, and H. I. M. Derwa, "Catastrophic mass mortalities caused by Photobacterium damselae affecting farmed marine fish from Deeba Triangle, Egypt", Aquaculture ResearchAquaculture Research, vol. 52, issue 9: John Wiley & Sons, Ltd, pp. 4455 - 4466, 2021. AbstractWebsite

Abstract Farmed marine fish constitute 20% of the total farmed fish production in Egypt, and the Deeba Triangle produces a relatively large portion of this percentage. Last year, several private fish farms in the Deeba Triangle have suffered severe economic losses due to acute fish mass kills. This study aimed to investigate the hidden aetiologies behind these colossal mass fish kills and to propose an emergency control strategy. Several tons of dead farmed fish were remarkably scattered throughout affected ponds and at the vicinity of impacted fish farms. Moribund farmed European seabass (Dicentrarchus labrax), thin-lipped grey mullet (Liza ramada) and gilthead seabream (Sparus aurata) have exhibited skin darkness, emaciation, congested gills and fins, ascites, skin erosions and ulcerations. Internally, moribund fish emitted unpleasant odour upon opening the abdomen together with severe congestion and haemorrhages in kidneys and brain. Mottled atrophied spleens were the most prominent findings, while the gastrointestinal tracts were filled with whitish caseous material. The liver was pale with multiple whitish nodules. Photobacterium damselae was the most retrievable bacterial pathogen from most infected fish and trash fish. Photobacterium damselae subspecies piscicida and Photobacterium damselae subspecies damselae were definitively identified from examined moribund fish using both conventional morpho-chemical and molecular assays. Data analysis has revealed that the poor water quality was profoundly incriminated in triggering the bacterial infections with a fate of mass mortalities. Conclusively, adopting various strict biosecurity strategies will be the key factors in prevention of future episodes of mass kills.

Attia, M. M., M. Abdelsalam, R. M. S. Korany, and O. A. Mahdy, Characterization of digenetic trematodes infecting African catfish (Clarias gariepinus) based on integrated morphological, molecular, histopathological, and immunological examination, , vol. 120, issue 9, pp. 3149 - 3162, 2021. AbstractWebsite

Parasitic infection may cause massive losses in Clarias gariepinus fries and fingerlings. Therefore, this study aimed to characterize the digenetic trematodes species (two adults’ flukes and one metacercariae) infecting African catfish Clarias gariepinus, as well as their histopathological impacts on infected fish. The intestinal flukes were identified as Orientocreadium batrachoides and Masenia bangweulensis based on their morphological and molecular characteristics. Sequencing of their 28S (LSU rRNA) and 18S rRNA (SSU rRNA) genes confirmed that these trematodes belong to the families Orientocreadiidae and Cephalogonimidae, respectively. The metacercariae trematode infecting skin and muscles were only morphologically identified as Cyanodiplostomum sp. The gene expression levels of MHC II increased in naturally infected fish either with O. batrachoides or Cyanodiplostomum sp. alone, compared with uninfected catfish. In addition, lysozyme levels in individual fish serum increased in catfish infected either with O. batrachoides or Cyanodiplostomum sp. alone. Histopathological examination of the skin revealed embedded parasitic cysts that displaced tissue in the dermis. Surrounding tissues were infiltrated with melanomacrophages and displayed dermal edema. Histopathological analysis showed O. batrachoides or M. bangweulensis between the gastric folds of the stomach of infected catfish, causing infiltration of mononuclear inflammatory cells in the lamina propria.

Abdelsalam, M., M. A. Z. Ewiss, H. S. Khalefa, M. A. Mahmoud, M. Y. Elgendy, and D. A. Abdel-moneam, Coinfections of Aeromonas spp., Enterococcus faecalis, and Vibrio alginolyticus isolated from farmed Nile tilapia and African catfish in Egypt, with an emphasis on poor water quality, , vol. 160, pp. 105213, 2021. AbstractWebsite

The high mortality rate among Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) polycultured in earthen ponds in Manzala, Egypt, was investigated. Mortality has been linked to poor water quality parameters accompanied with bacterial infections. Moribund farmed fishes exhibited general septicemic signs. Fish from both species (45 each) were sampled and analyzed bacteriologically. Vibrio alginolyticus (32.3%), Enterococcus faecalis (29.4%), Aeromonas caviae (23.5%), and A. veronii (14.7%) were isolated from moribund fishes using selective media and further identified by biochemical tests. 16S rRNA gene sequencing and phylogenetic analysis confirmed the identity of these isolates. Experimental infection of O. niloticus with different bacterial isolates resulted in clinical signs of hemorrhagic septicemia and mortality rates of 80%, 60%, 40%, and 30%, respectively, for E. faecalis, A. veronii, V. alginolyticus, and A. caviae. Water parameter analysis revealed marked divergence from typical values. In addition, different bacterial isolates (including Staphylococcus sciuri, S. aureus, E. faecalis, A. veronii, A. caviae, and V. alginolyticus) were identified and isolated from water samples. BLAST analysis of water bacterial isolates displayed a 100% similarity score with relevant fish isolates, indicating that the water was the likely source of infections. Histopathological examination revealed signs of bacterial infection in both fish species. In addition, common circulatory and degenerative changes with melanophore aggregation, and lymphocytic depletion in hematopoietic organs were recorded.

Abdel Ghaffar, L., and et al, Comparative analysis of 16S rRNA based phylogeny, antibiotic susceptibility, and virulence traits of Arcobacter species recovered from domestic fowl and the Nile tilapia, , vol. 25, issue 3, pp. 263 - 279, 2021. AbstractWebsite

Untreated poultry manure/droppings were used in integrated fish ponds as organic fertilizers. This process could put an additional complexity on the bacterial load within fish's ponds ecosystem. Arcobacter species is one of the most important food-borne zoonotic pathogens that infect humans, animals, fish, and fowl. This study aimed to examine if raw poultry manure could possibly enhance Arcobacter propagation among the cohabitant Nile tilapia. In addition, the comparative phenotypic and molecular characterizations among various Arcobacter spp. retrieved from two diverse animal hosts (the Nile tilapia and fowl) with special reference to antibiotic-resistant and virulence genes traits were also studied. Clinically, the examined Nile tilapias exhibited darkness, fin rot, and skin hemorrhages. Internally, the Nile tilapias displayed severe congestion in internal organs, catarrhal enteritis, and swollen gall bladder. The moribund chickens exhibited mild diarrhea, anorexia, and ruffled feathers. Internally, chickens displayed enlarged spleen and liver, enteritis, and kidney congestion. The bacterial colonies on Arcobacter selective agar appeared small and non-pigmented with an intact edge. The recovered bacterial isolates were identified as Arcobacter spp. depending on the phenotypic characters and PCR. Sequencing of 16S rRNA gene confirmed the identity of Arcobacter butzleri (A. butzleri), A. skirrowii, and A. cryaerophilus in both fish and fowl, while A. cloacae was confirmed in fish. PCR confirmed the occurrence of two virulence genes (pldA and tlyA) in most fish and chicken Arcobacter isolates. All chicken Arcobacter isolates showed resistance against ampicillin, ampicillin-sulbactam, and cefotaxime, and variable susceptibility to ciprofloxacin, aztreonam, imipenem, and amikacin. Fish Aeromonads were sensitive to ciprofloxacin, sulpha-trimethoprim, and amikacin.

A. Salem, M., S. Z. Abdel- Maogood, M. Abdelsalam, and O. A.Mahdy, Comparative morpho-molecular identification of Clinostomum phalacrocoracis and Clinostomum complanatum metacercaria coinfecting Nile tilapia in Egypt, , vol. 25, issue 1, pp. 461 - 476, 2021. AbstractWebsite

Clinostomiasis is one of the parasitic diseases infecting freshwater fish caused by digenetic trematodes that belong to family Clinostomatidae. During the course of the present study, it was found that 392 out of 520 examined Nile tilapia Oreochromis niloticus were infected with EMC belonging to family: Clinostomatidae with an overall prevalence in (mean ± SD) was 74.12 ± 5.19. The investigated O. niloticus were found to be simultaneously infected with two morphologically different encysted metacercariae (EMC); small cysts (Type 1) ranged from 1.0-3.0 mm in diameter and large cysts (Type 2) were measured 4.0-8.0 mm. Furthermore, an identification of the main morphological features (size of suckers, body length) in both excysted metacercariae was assessed to assist the morphological differentiation of these EMC; namely, Clinostomum complanatum and C. phalacrocoracis. The prevalence rates of C. complanatum and C. phalacrocoracis infections were 35.94± 2.24 and 60.93± 6.70, respectively. In the present study, the molecular identification was carried out by sequencing their COI mtDNA; BLAST analysis of C. complanatum (MT140101.1) showed 100% and 99.74% nucleotide similarity (MK501949.1; MF741769.1) in China, respectively. On the other hand, C. phalacrocoracis (MT140102.1) revealed 100%  nucleotide identity (KY906238.1) in South Africa and 99.66% (KJ786967.1) in Israel.

Eissa, A. E., A. M. Abu-Seida, M. M. Ismail, N. M. Abu-Elala, and M. Abdelsalam, "A comprehensive overview of the most common skeletal deformities in fish", Aquaculture ResearchAquaculture Research, vol. 52, issue 6: John Wiley & Sons, Ltd, pp. 2391 - 2402, 2021. AbstractWebsite

Abstract Skeletal deformities in fish are abnormal transformations of normal bony and/or cartilaginous structures into abnormal skeletal structures that are histologically and anatomically different from their normal prototype. Such deformities are diverse in their location, morphology and impact. The three main topographic regions of a fish (head, trunk and tail) could be affected by several types of deformities with various degrees of severity depending on the cause, age and histology of the affected tissue, regardless of whether it is bony or cartilaginous. The degree of skeletal deformity could impact physiological processes, including swimming, reproduction, growth, resistance to diseases and susceptibility to predation, as well as being the direct or indirect cause of low body weight gain or even death in young fish. Skeletal deformities are commonly recorded from wild and cultured fish, with high incidence in fish hatcheries. Skeletal deformities are responsible for considerable economic damage to the sector of aquaculture by making fish unsightly and affected fish consequently remain unsold. Such deformities are also proposed as biological indicators of aquatic environmental pollution and defaults in aquaculture management. Several diagnostic techniques, such as radiography, ultrasonography and magnetic resonance imaging, have been used for detecting and defining skeletal deformities in fish. Here, the present review summarizes the incidence, classification, aetiological factors, diagnostic procedures and prevention of the most common skeletal deformities in fish.

Sherif, A. H., M. E. - S. El-Sharawy, S. I. El-Samannoudy, A. A. Seida, N. M. Sabry, M. Eldawoudy, M. Abdelsalam, and N. A. Younis, "The deleterious impacts of dietary titanium dioxide nanoparticles on the intestinal microbiota, antioxidant enzymes, diseases resistances and immune response of Nile tilapia", Aquaculture ResearchAquaculture Research, vol. 52, issue 12: John Wiley & Sons, Ltd, pp. 6699 - 6707, 2021. AbstractWebsite

Abstract Titanium dioxide nanoparticles (TiO2 NPs) are used in numerous products, such as paints, pharmaceuticals, environmental sanitizing agents and even as a whitening food additive (E171). Residual TiO2 NPs are considered among the emerging contaminants of aquatic environments. However, the effect of such exposure on intestinal microbiota population, microbial disease resistance and the immune-related gene expression of Nile tilapia (Oreochromis niloticus) is largely obscure. Three groups of fish were nurtured on diets containing 1 mg/ml TiO2 NPs with three different sizes (53, 31 and 13 nm), beside the control group for four weeks before sampling fish tissues. Fish groups fed on TiO2NPs diets showed significantly increased higher levels of tumour necrosis factor (TNF-α), interleukin (IL-6) and IL-1?, along with insignificant changes in IL-8 and IL-10 compared with the control group. These changes indicate a strong inflammatory response. Treated fish groups showed a marked decrease in the count of some intestinal microbiota, aeromonas, pseudomonas and lactobacillus. Fish were challenged against A. hydrophila, and a higher mortality rate was observed in the group fed on smaller TiO2 NPs (13 nm). The levels of antioxidant enzymes such as catalase, glutathione peroxidase and superoxide dismutase were significantly increased in groups fed on TiO2 NPs, while metallothionein levels were only slightly changed. In conclusion, feeding fish with diets containing TiO2 NPs (13 and 31 nm) for 4 weeks alters the intestinal microbiota population and provides additional information on the toxic impacts of TiO2 NPs on the health and immune status of O. niloticus.

Abou-Okada, M., H. O. AbuBakr, A. Hassan, S. H. I. M. A. A. ABDEL-RADI, S. H. Aljuaydi, M. Abdelsalam, E. Taha, N. A. Younis, and D. A. Abdel-moneam, Efficacy of Acriflavine for controlling parasitic diseases in farmed Nile tilapia with emphasis on fish health, gene expression analysis, oxidative stress, and histopathological alterations, , vol. 541, pp. 736791, 2021. AbstractWebsite

Parasites often cause serious outbreaks of disease in farmed fish. The present study is the first to describe the antiparasitic efficacy of Acriflavine on Oreochromis niloticus parasitized with Centrocestus formosanus metacercariae and Trichodina centrostrigeata protozoa. A total of 550 O. niloticus suffering from respiratory distress were collected from a fish farm. Clinical and parasitological examinations of 150 fish revealed a mixed infestation with Centrocestus formosanus and Trichodina centrostrigeata. The median lethal dose (LC50) of Acriflavine (5, 10, 25, 50, & 100 mg/L) was calculated against 160 healthy O. niloticus. Results revealed that the 12 h and 96 h LC50 of Acriflavine was 114.61 and 35.196 mg/L. Further, an experimental design consisting of three fish groups was used to assess the efficacy of Acriflavine (10 mg/L, long-term bath) against Centrocestus formosanus- and Trichodina centrostrigeata-infested fish; the first group was treated with Acriflavine (treated fish), the second group was not treated (nontreated fish) and the third group was healthy fish (negative control). Acriflavine was effective against Centrocestus formosanus and Trichodina centrostrigeata, reducing the mean intensity of parasites by 91.1% and 95.6%, respectively, compared with infested fish (nontreated). Moreover, treated fish exhibited restoration of normal gill histoarchitecture and normal central cartilaginous support after treatment. Treated O. niloticus also showed significant downregulation of inflammatory-related enzyme (Cox-2) and pro-inflammatory cytokine (IL-1ß) genes compared with infested fish, as well as a significant reduction in lipid peroxidation (LPO) levels. Acriflavine provides a safe and efficient treatment for controlling Centrocestus formosanus metacercariae and Trichodina centrostrigeata protozoans, improving the health, productivity and welfare of Oreochromis niloticus.

Mahdy, O. A., S. Z. Abdel-Maogood, M. Abdelsalam, M. Shaalan, H. A. Abdelrahman, and M. A. I. A. SALEM, "Epidemiological study of fish-borne zoonotic trematodes infecting Nile tilapia with first molecular characterization of two heterophyid flukes", Aquaculture ResearchAquaculture Research, vol. 52, issue 9: John Wiley & Sons, Ltd, pp. 4475 - 4488, 2021. AbstractWebsite

Abstract Fish-borne zoonotic trematodes (FBZT) are extremely important zoonotically and can infect humans via the consumption of poorly cooked fish containing active metacercariae. In this context, the present study aimed to update the epidemiological information of FBZT among Nile tilapia (Oreochromis niloticus) collected from Giza and Fayoum Governorates. Concerning the molecular characterization and phylogenetic analysis of adult flukes from experimentally infected pigeons and histopathological alterations of both larval and adult trematode flukes. Oreochromis niloticus were found to be infected with different encysted metacercaria (EMC); Prohemistomum, Haplorchis and Pygidiopsis species from wild caught in Giza and farmed fish in Fayoum with the total mean of prevalence that 81.89 ± 6.48, 18.03 ± 2.9 and 34.64 ± 3.42 respectively. Three recovered flukes from experimentally infected domestic pigeons (Columba livia domestica); Prohemistomum vivax, Haplorchis pumilio and Pygidiopsis genata in their small intestine. First molecular characterization and phylogenetic analysis of heterophyid flukes; P. genata and H. pumilio. The sequences obtained in this study were registered in the GenBank with accession numbers (MT672308.1 and MT707975.1) respectively. Moreover, constructing a phylogeny and phylogenetic relationships between two heterophyid species was performed through analytic study of the second internal transcribed spacer nuclear ribosomal genes (rDNA-ITS2). Phylogenetic analysis of P. genata and H. pumilio showed 99.42% nucleotide similarity with that sequence from Israel (AY245710) and 99.71% from Vietnam (EU826636.1). In addition, histopathological alterations of EMC and adult flukes induced necrosis of fish muscle bundles and a severe inflammatory response with muscular necrosis in intestinal tract of infected pigeons.

Mahmoud, M. A., M. M. Attia, M. Abdelsalam, D. A. Abdel-moneam, and M. A. Z. Ewiss, "Ergasilus extensus and bacterial co-infection in flathead grey mullet, Mugil cephalus (Linnaeus, 1758), are associated with pathological changes and immunological gene expression alterations", Aquaculture ResearchAquaculture Research, vol. 52, issue 12: John Wiley & Sons, Ltd, pp. 6143 - 6151, 2021. AbstractWebsite

Abstract We studied the ectoparasite, Ergasilus extensus or gill lice in gills from farmed grey mullet, Mugil cephalus. Streptococcus agalactiae and Enterococcus faecalis were also studied and isolated from infected fish. We identified these pathogens using 16S rRNA gene sequencing. Our analyses revealed high homology percentages with identical sequences in GenBank. Moreover, phylogenetic tree analysis confirmed S. agalactiae and E. faecalis from other close related pathogens. We also used quantitative real-time polymerase chain reaction (qRT-PCR) to investigate cell-mediated immunity in infected fish with this co-infection. Enhanced cell-mediated immunity was observed as a function of increased interleukin 1 ? (IL-1?) and tumour necrosis factor-α (TNFα) levels. Histopathological examinations revealed the presence of haemorrhaging and many parts of the parasite near infected gill lamellae. Also, bacteria aggregated as multiple cocci close to areas of parasite attachment, together with eosinophilic granular cell infiltration. Hepatic tissue showed haemorrhaging and melanophore aggregation with vacuolar degeneration observed in hepatocytes.

A. Abdelbaky, A., and et al, Genotypic characterization of some dermotropic and systemic bacterial pathogens affecting two commercial Red Sea fishes, , vol. 25, issue 6, pp. 297 - 312, 2021. AbstractWebsite

The genotypic characterization of some bacterial pathogens that were incriminated in disease outbreaks among Haffara seabream “Rhabdosargus haffara” and marbled spine foot “Siganus rivulatus” was investigated in full through the current study. A total of 250 fish samples (125 of each species) were collected along the Red Sea coasts of Hurghada City, Egypt. Fish samples were inspected for clinical signs, post-mortem changes, and bacteriological examination. The investigated fishes displayed septicemic signs and external skin lesions characteristic of streptococcosis and tenacibaculosis. Enterococcus spp., Streptococcus spp., and Flavobacterium spp. were isolated from moribund fishes using selective media. These isolates were phenotypically and genetically identified and characterized. The identities of bacterial isolates were confirmed as Enterococcus fecalis, Streptococcus iniae, Enterobacter cloacae, and Tenacibaculum maritimum based on sequencing the 16S rRNA gene. Enterococcus fecalis was the most common pathogen isolated from S. rivulatus and R. haffara and accounted for 46.8% and 47.8% of the total isolates, respectively. Accordingly, the present study proved that Enterocoocus spp., Streptococcus spp., and T. maritimum are important pathogenic bacteria incriminated in wild fish outbreaks in the Red Sea in Egypt. These findings proved the importance of regular and permanent bacteriological examination of wild fish to overcome fish mortalities, which lead to economic losses. Finally, sequencing and phylogenetic relationship techniques proved their usefulness as an ideal assay to develop a reliable, accurate, and rapid detection method for bacterial pathogens in the aquatic environment.

El-Adawy, M. M., A. E. Eissa, M. Shaalan, A. A. Ahmed, N. A. Younis, M. M. Ismail, and M. Abdelsalam, "Green synthesis and physical properties of Gum Arabic-silver nanoparticles and its antibacterial efficacy against fish bacterial pathogens", Aquaculture ResearchAquaculture Research, vol. 52, issue 3: John Wiley & Sons, Ltd, pp. 1247 - 1254, 2021. AbstractWebsite

Abstract This study aimed to assess the antibacterial efficacy of Gum Arabic-based silver nanoparticles against certain fish bacterial pathogens. Silver nanoparticles were green-synthesized using Gum Arabic (AgNPs-GA), which served as a stabilizing and reducing agent. The AgNPs-GA were analysed using a UV spectrophotometer set at a wavelength of 450 nm. Transmission electron micrograph analysis showed that nearly all AgNPs-GA were sphere-shaped and 10.0 nm in diameter. Dynamic light scattering (DLS) analysis showed a narrow size distribution curve, whose highest peak was at 26.2 nm. The particles were negatively charged (?17.1 ± 4.9 mV). Silver concentration measured by inductively coupled plasma optical emission spectrometry (ICP-OES) and found to be 104 µg/ml. The in vitro antibacterial activity of AgNPs-GA was tested against Aeromonas hydrophila and Pseudomonas aeruginosa. Gum Arabic-silver nanoparticles exhibited clear inhibition zones of 22 and 20 mm against A. hydrophila and P. aeruginosa, with a minimum inhibitory concentration of 1.625 µg/ml and 3.25 µg/ml for AgNPs-GA respectively. The antibiofilm activity indicated that AgNPs-GA significantly inhibit A. hydrophila and P. aeruginosa biofilm formation at AgNPs-GA concentrations of 1.625 µg/ml. There was no significant difference at a AgNPs-GA concentration of 0.8215 µg/ml between the control-positive groups and the AgNPs-GA treatment groups in both bacterial strains. In summary, green-synthesized sliver nanoparticles display efficient antibacterial properties, which suggests that they would be suitable for use in a commercialized antibacterial product for the aquaculture industry.

W. Soliman, A., and et al, Molecular detection of the most common bacterial pathogens affecting economically important Egyptian Red Sea fishes, , vol. 25, issue 4, pp. 669 - 688, 2021. AbstractWebsite

The current study aimed to investigate the most common pathogenic bacteria that are naturally infecting wild marine fishes collected at different localities along the coastline zone of Hurghada City, Egypt. A total of 300 samples of marbled spine foot Siganus rivulatus and the Haffara Seabream Rhabdosargus haffara were subjected to clinical and bacteriological examinations. The examined fishes showed the characteristic clinical signs and postmortem lesions of vibriosis and photobacteriosis. Based on the morpho-chemical characterization, bacterial isolates retrieved from the naturally infected fishes were identified as Vibrio spp. and Photobacterium spp. Through sequencing 16S rRNA genes, the identities of bacterial isolates were confirmed as V. alginolyticus, V. vulnificus, P. damselae subsp. damselae and P. damselae subsp < em> piscicida. Vibrio alginolyticus was the most frequent isolated bacterial pathogen and represented 54.4% and 46.7% of the total isolates recovered from S. rivulatus and R. haffara, respectively. Thus, the current study confirmed that Vibrio and Photobacterium species remain the most prevalent bacterial pathogens infecting Egyptian Red Sea fishes.  From food safety perspective, these types of infections could pose potential public health hazards.

Attia, M. M., M. Y. Elgendy, M. Abdelsalam, A. Hassan, A. Prince, N. M. K. Salaeh, and N. A. Younis, Morpho-molecular identification of Heterophyes heterophyes encysted metacercariae and its immunological and histopathological effects on farmed Mugil cephalus in Egypt, , vol. 29, issue 3, pp. 1393 - 1407, 2021. AbstractWebsite

Molecular and immunological aspects of heterophyid infections in mullets are scanty. This study was initiated to identify heterophyid encysted metacercariae infecting gray mullet Mugil cephalus by morphological and molecular assays and to evaluate its immunological effects on infected mullets. Both farmed fish, from a private farm nearby Lake Manzala in Damietta, Egypt, and wild-caught fish, from the Mediterranean Sea in Alexandria, were investigated. The presence of heterophyid encysted metacercariae was significantly higher (80%) in wild than in farmed fish (30%). Morphological identification of metacercariae showed characteristic features of H. heterophyes. The result of sequences of 28S and ITS2 rDNA regions of Heterophyes EMC was consistent with the morphological data. The gene expression analysis of tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) in tissues of infected fish qRT-PCR showed a significant increase (p < 0.05). Encysted metacercariae were detected microscopically in sections of infected fish with variable histopathological lesions.

Eissa, A. E., and et al, Morphological, molecular and clinical assessment of different Anisakis species infecting horse Mackerel Trachurus trachurus from South Mediterranean, , vol. 25, issue 4, pp. 1085 - 1098, 2021. AbstractWebsite

This study aimed to identify and characterize the most common Anisakis larvae infecting Atlantic horse Mackerel (Trachurus trachurus) in the South Mediterranean basin; based on morphological and advanced molecular characterization. Also, the linkage between the prevalence of Anisakis spp. larvae and some biological variables including Mackerel age and sex were also investigated. Moreover, the clinical intensity of larvae infection in different organs of infected Mackerel was assessed. Atlantic horse mackerel collected from the southern Mediterranean shores were found to be infected with third stages larvae (L3) of Anisakis species. The Anisakis larvae were found encapsulated as coiled tightly in different fish organs and uncoiled freely in the abdominal cavity of infected T. trachurus. These larvae were categorized into 3 types of Anisakis spp. as A. simplex type1; A. pegreffii; Anisakis simplex / pegreffii hybrid based on their morphological and molecular characterizations. Subsequently, the phylogenetic analysis of ITS region of different investigated larvae confirmed the identification of collected Anisakis spp. The remarkably high intensity of Anisakis spp. larvae in Mackerel gonads warns of possible future deleterious impacts on the growth, development and sustainability of Mackerel fisheries at the south Mediterranean coasts.

Attia, M. M., M. Y. Elgendy, A. Prince, M. M. El-Adawy, and M. Abdelsalam, "Morphomolecular identification of two trichodinid coinfections (Ciliophora: Trichodinidae) and their immunological impacts on farmed Nile Tilapia", Aquaculture ResearchAquaculture Research, vol. 52, issue 9: John Wiley & Sons, Ltd, pp. 4425 - 4433, 2021. AbstractWebsite

Abstract Trichodiniasis is one of the most serious ectoparasitic diseases disturbing tilapia aquaculture worldwide, causing deleterious effects and significant economic losses. This study aimed to characterize two Trichodina species concomitantly infecting farmed Nile tilapia Oreochromis niloticus based on integrated morphological, molecular, and immunological approaches. One hundred and eighty of 250 examined Nile tilapia were found to be infected with trichodinids belonging to the family Trichodinidae, with an overall prevalence rate of 72%. The morphological characterization of trichodinids fixed on Giemsa-stained smears revealed that fish were concomitantly infected with Trichodina heterodentata and T. centrostrigeata. Subsequently, the phylogenetic analysis of the 18S rRNA gene of the two investigated trichodinids confirmed the detected species? identities. The gene expression levels of MHCII? and CD4 gens were increased during the trichodinid infection. Furthermore, potassium permanganate and hydrogen peroxide chemicals, which have well-known records for treating ectoparasites infections in farmed fish, were successfully verified to control trichodiniasis in a small-scale trial.

Eissa, A. E., M. M. Attia, M. Y. Elgendy, G. A. Ismail, N. M. Sabry, A. Prince, M. A. Mahmoud, G. O. El-Demerdash, M. Abdelsalam, and H. I. M. Derwa, Streptococcus, Centrocestus formosanus and Myxobolus tilapiae concurrent infections in farmed Nile tilapia (Oreochromis niloticus), , vol. 158, pp. 105084, 2021. AbstractWebsite

Stress triggered concurrent microbial/parasitic infections are prevalent in earthen pond based farmed Nile tilapia Oreochromis niloticus. In the current study, a total of thirty five O. niloticus were collected from a commercial fish farm with a history of severe mortalities at Port Said, Egypt. Nile tilapia samples were subjected to bacteriological, parasitological and pathological examinations. Twenty one Enterococcus fecalis and 15 Streptococcus agalactiae isolates were presumptively identified utilizing the semi-automated API 20 Strept test kit. The identities of the retrieved bacteria were confirmed by the sequencing of 16 S rRNA gene. Moribund O. niloticus were found to be heavily infected by one or both of Centrocestus formosanus encysted metacercariae (EMC) and/or Myxobolus tilapiae spores presenting a unique form of synergistic and/or symbiotic relationship. The identities of both parasites were confirmed through morphological and molecular characterization. Variable circulatory, degenerative, necrotic and proliferative changes were also noticed in hematopoietic organs. Interestingly, multiple myxobolus spores and EMC were noticed in some histological sections. It was obvious that the current concurrent bacterial and parasitic infections are triggered by the deleterious effects of some stressing environmental conditions. The unfavorable climatic conditions (high temperature and high relative humidity) recorded at the surge of mortalities are probable predisposing stress factors.

2020
Eissa, A. E., M. Abdelsalam, M. A. Mahmoud, N. A. Younis, A. A. Abu Mhara, and R. A. El Zlitne, Cutaneous fibropapilloma in Egyptian-farmed gilthead seabream (Sparus aurata; Linnaeus, 1758), , vol. 28, issue 5, pp. 2081 - 2091, 2020. AbstractWebsite

In this study, three farmed Gilthead seabream exhibited tumor-like mass above the left pectoral fin. The mass measured 9 mm in length, 8 mm in width. Morphometrically, the mass was fleshy, raised, circumscribed, and rosy colored with grayish-white center. The affected fish showed poor growth with 280 g average body weight after 30 months rearing period. Internally, moribund fish exhibited pale kidney/liver, mottled spleen with remarkable visceral adhesions. The presumptive bacteriological and conventional biochemical assays revealed that fish were clinically infected with Photobacterium damselae subspecies piscicida. The histopathological picture of the tumor-like mass concurred with the standard cellular criteria of fibropapilloma. In brief, the epidermal papilloma was denoted by the remarkable hyperplasia of epidermis together with eosinophilic intracytoplasmic inclusion bodies and prominent mitosis in the hyperplastic cells. Ultimately, the proliferated dermal fibroblasts appeared whirling and elongated with spindle nuclei. Such pathological alterations have confirmed a typical form of dermal fibroma upon positively reacted with Masson’s trichrome stain. In the spleen, characteristic granulomatous reactions were observed especially in the area of melanomacrophage centers where the granuloma showed different developmental stages. The occurrence of skin tumors in farmed marine fish is an alarm for the critical impacts of the erratic usage of pesticides on marine aquaculture presenting a staggering prototype for the growing aquatic environmental pollution.

EI-Jakee, J., S. Elshamy, A. - W. Hassan, M. Abdelsalam, N. Younis, M. A. El-Hady, and A. E. Eissa, Isolation and characterization of Mycoplasmas from some moribund Egyptian fishes, , vol. 28, issue 3, pp. 901 - 912, 2020. AbstractWebsite

Mycoplasma is associated with fatal diseases in human, animals, and fish. Mycoplasma of aquatic origin has not been thoroughly studied. The current study has shed the light on isolation and characterization of unique piscine Mycoplasma isolates retrieved from diverse geographical locations across the Egyptian state. Mycoplasma spp. was isolated using specific culture media. Mycoplasma was identified using the morphochemical tests and then confirmed molecularly by PCR of the 16S rRNA gene. The results indicated that the incidence of Mycoplasma from Cyprinus carpio, Oreochromis niloticus, Aulopiformes synodontida, and Clarias gariepinus were 33.33%, 16.36%, 8.108%, and 6.45%, respectively, while Mugil cephalus were negative for Mycoplasma isolation. Mycoplasma was detected only from gills and swim bladder of affected fish. Biochemically, the isolated Mycoplasmas were grouped into two clusters. Mycoplasma cluster 1 (35 isolates) and Mycolplasma cluster 2 (7 isolates). Mycoplasma cluster 1 was positive for tetrazolium reduction while Mycoplasma cluster 2 was negative. The phylogenetic tree of partial sequences of 16S rRNA showed that both clusters were grouped in one branch and separated from other Mycoplasma spp., suggesting that both clusters are belonging to one species. Interestingly, all fish Mycoplasma isolates were PCR negative for both Mycoplasma mobile and Mycoplasma monodon using specific species primers. This result confirmed that these two clusters belonged to unspecified Mycoplasma species, for which the temporary names Mycoplasma cluster 1 and Mycoplasma cluster 2 were designated. Pathogenicity trials of both Mycoplasmas clusters revealed that all inoculated Nile tilapias were susceptible to the unspecified Mycoplasmas.

Mahdy, O. A., M. A. Mahmoud, and M. Abdelsalam, Morphological characterization and histopathological alterations of homologs Heterophyid metacercarial coinfection in farmed mullets and experimental infected pigeons, , vol. 28, issue 6, pp. 2491 - 2504, 2020. AbstractWebsite

In this study, samples of farmed thin-lipped mullets, Mugil capito from Lake Manzala and wild-caught grey mullet Mugil cephalus from Alexandria were found to be infected with heterophyid encysted metacercariae (EMC), and the overall prevalence rates were 80 and 100%, respectively. The number of metacercarial infection in tail tissue was significantly higher than that recovered from trunk and head among M. capito and M. cephalus. M. capito were simultaneously infected with two morphologically different EMC that ascribed to Heterophyes and Pygidiopsis species, while M. cephalus were infected with EMC of Heterophyes species. The experimental infection of domestic pigeons (Columba livia domestica) with the recovered encysted metacercariae confirmed the successful development of two types of Heterophyid flukes: identified as Heterophyes heterophyes and Pygidiopsis genata in the small intestine of pigeons. The histopathological examination revealed that Heterophyes cyst was small, elliptical with thick wall and predominating between cardiac muscle fibres and in the lumen of atrioventricular region of the heart. Pygidiopsis species cyst appeared larger in size, rounded with thin cyst wall and prominent internal structure. Pygidiopsis species were few in the abdominal fat and prominently encysted in the internal visceral organs including wall of the stomach, kidneys and muscular tissue away. They were also deeply encysted in testes and ovaries. Interestingly, the adult flukes were demonstrated in the intestinal lumen of the experimentally infected pigeons but with minor histopathological alterations. Our findings suggest that the heterophyids EMCs in mullets have genera-specific morphological characters and may induce histopathological changes in surrounding host-associated tissues.

Eissa, A. E., S. K. Abolghait, N. A. Younis, A. A. Dessouki, M. M. El-Lamie, A. A. Abu Mhara, and M. Abdelsalam, Myxobolus episquamalis infection in farmed flathead grey mullet Mugil cephalus L. and thin-lipped mullet Liza ramada, , vol. 28, issue 1, pp. 363 - 376, 2020. AbstractWebsite

Egypt is the largest producer of farmed mullets worldwide. The mullet seeds are collected from natural waters at the north and northern east of Egypt. Thus, the occurrence of parasitic diseases is relatively high even after being stocked in aquaculture facilities. The current study was conducted on a fish farm located at the coastal area of the Suez Canal region, Egypt. Farmed flathead grey mullet (Mugil cephalus L.) and thin-lipped grey mullet (Liza ramada) showed pinkish-white granular cysts on their body surfaces that measured approximately 5 mm (4–6 mm) in width and 7 mm (5–9 mm) in length and contained a milky coloured exudate. The proximal portion of the fins and apical part of the scales were the only sites of infection. These cysts are randomly scattered throughout the fish body surface. No mortalities were detected among moribund mullets, but these cysts make the fish unsightly, causing commercial rejection. The overall prevalence of infection was 40%. Giemsa-stained wet smears initially indicated that the spores were of Myxobolus species. Subsequently, the phylogenetic analysis of the 18S rRNA gene confirmed the identification of spores as being those of Myxobolus episquamalis. Furthermore, amprolium-salinomycin mixture, which has an established track record for treating myxozoan infections in multiple fish species, was successfully tested in a large-scale field trial. Moribund mullets displayed significant reduction in myxosporean infection following treatment with amprolium-salinomycin mixture. To the best of our knowledge, this is the first report describing the detection of M. episquamalis in farmed flathead grey mullet (Mugil cephalus L.) and thin-lipped grey mullet (Liza ramada) collected from fish farms in the Suez Canal, Egypt.

Abdelsalam, M., M. M. Attia, and M. A. Mahmoud, "Comparative morphomolecular identification and pathological changes associated with Anisakis simplex larvae (Nematoda: Anisakidae) infecting native and imported chub mackerel (Scomber japonicus) in Egypt", Regional Studies in Marine Science, vol. 39, pp. 101469, 2020. Abstractanisakis.pdfWebsite

Native and imported Scomber Japonicus were collected from Egypt and found to be infected with the third stage larvae (L3) of Anisakidae. The Anisakidae larvae were found encapsulated tightly coiled in the mesenteries associated with pyloric ceca and the serosal surface of visceral organs and/or uncoiled larvae free in the abdominal cavity of infected S. japonicus. The prevalence, mean intensity, and mean abundance of L3 were 80%, 24.4, and 19.5 in imported fish, and they were 36%, 7.36, and 2.65 in native fish, respectively. These larvae were identified as Anisakis simplex type 1 based on their morphological and molecular characteristics. The larvae were cylindrical in shape, and the oral openings had a prominent boring tooth. The esophago-intestinal junction (ventriculus) was oblique. The bodies of the larvae were covered with a transversely striated cuticle. The posterior end of the larvae had a short mucron or spine. Subsequently, phylogenetic analysis of the internal transcribed spacer region and COI gene of investigated larvae confirmed the identification of A. simplex when compared with relevant species sequences in GenBank. Histopathological examination revealed multiple A. simplex larvae in the abdominal cavity near the pyloric appendages, stomach, and under the visceral peritoneum, which appeared as a very thin and glistening capsule covering the larvae with a prominent adhesive fibrinous peritonitis together with mononuclear and eosinophilic granular cell infiltration. The importance of A. simplex infection in both native and imported S japonicus in Egypt is emphasized.

2019
Mahmoud, M. A., H. A. Mansour, M. Abdelsalam, H. O. AbuBakr, S. H. Aljuaydi, and M. Afify, Evaluation of electrofishing adopted by Egyptian fish farmers, , vol. 498, pp. 380 - 387, 2019. AbstractWebsite

Upon the demand of a private fish farmer, this study was applied to assess the influence of electro-fishing adopted by some Egyptian fish farmers on the fish welfare and quality. Therefore, a total of 60 Nile tilapia (Oreochromis niloticus) were sampled; from which 30 were stunned by electrofishing and the remainders by conventional fishing. Biochemical analysis (oxidative stress and energy status), meat quality based on total bacterial count (TBC) and pathological alterations were assessed. Biochemical analysis in both liver and muscle tissue showed that electro-stunned fish exhibited low oxidative stress and high energy status. Meat of electro-stunned fish showed an acceptable limit of TBC (Max. limit 107) while the histopathological examination revealed various tissue reactions. These were in the form of congestion in branchial, hepatoportal, brain and splenic blood vessels with edema in brain and pericardium. In addition, there was mild inflammatory reaction together with the presence of eosinophilic granular cells and perivascular melanophores aggregation in both branchial and muscular tissue. As a consequence of this work, we recommend the use of electrofishing method in Egypt after modifying the current tool by reducing applied voltage. Further studies and more optimization are needed to cover both fish farmers and animal welfare issues, and take in consideration the human safety precautions.

Mahmoud, M. A., A. H. Abd El-Rahim, K. F. Mahrous, M. Abdelsalam, N. A. Abu-Aita, and M. Afify, "The impact of several hydraulic fracking chemicals on Nile tilapia and evaluation of the protective effects of Spirulina platensis.", Environmental science and pollution research international, 2019. Abstract

Hydraulic fracturing (fracking) chemicals are used to maximize the extraction of hard-to-reach underground energy resources. Large amounts of fracking fluid could escape to the surrounding environments, including underground and surface water resources, during the chemical mixing stage of the hydraulic fracturing water cycle due to equipment failure or human error. However, the impact of pollution resulting from operational discharges is difficult to assess in aquatic ecosystems. In this study, pathological investigations, chromosomal aberrations, DNA damage, and biochemical and hematological parameters were used to evaluate the effects of such chemicals on Nile tilapia. Chromosomal aberrations are considered very sensitive genetic markers of exposure to genotoxic chemicals and are used as indicators of DNA damage. The appearance of different types of chromosomal aberrations (gaps and breaks) due to chemical exposure was significantly reduced by treatment with spirulina. Various deleterious findings in Nile tilapia, in the current study, could attributed to the presence of fracking chemicals in the aquatic environment. However, the presence of spirulina in the diet reduced the hazards of such chemicals. In addition, cytogenetic studies in the current work revealed the importance of spirulina in ameliorating the genotoxic effects of a mixture of some chemicals used in fracking.

2017
Abdelsalam, M., M. Shaalan, and M. Moustafa, "Rapid identification of pathogenic streptococci isolated from moribund red tilapia (Oreochromis spp.).", ActaVeterinaria Hungarica, vol. 65, issue 1, pp. 50-59, 2017.
, "Potential Role of Anaerobic Bacteria as Fish Pathogens", Journal of Aquaculture Research & Development, vol. 8, no. 7: OMICS International.,, pp. -, 2017. AbstractWebsite
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2016
Abdelsalam, M., M. M. A., O. A.Mahdy, M. Warda, and R. A. E. - H. A. El-Gaber, "Morphological, molecular and pathological appraisal of Callitetrarhynchus gracilis plerocerci (Lacistorhynchidae) infecting Atlantic little tunny (Euthynnus alletteratus) in Southeastern Mediterranean", Journal of Advanced Research, vol. 7, issue 2, pp. 317-326, 2016.
Mahmoud, M. A., M. Abdelsalam, O. A. Mahdy, H. M. F. E. Miniawy, Z. A. M. Ahmed, A. H. Osman, H. M. H. Mohamed, A. M. Khattab, and M. A. Z. Ewiss, "Infectious bacterial pathogens, parasites and pathological correlations of sewage pollution as an important threat to farmed fishes in Egypt.", Environmental pollution (Barking, Essex : 1987), vol. 219, pp. 939-948, 2016. Abstract

This paper is a part of a multi-disciplinary research "Application of Decentralized On-Site Water Treatment System in Egypt for Use in Agriculture and Producing Safe Fish and Animal Proteins". The project aimed to investigate the environmental impact of implementing sewage water before and after treatment using the effluent of the on-site decentralized Japanese' Johkasou system, in agriculture and producing fish protein. The aim is to establish such system in Egypt to strengthen the sanitary conditions of water resources. In the present study, the impact of the sewage pollution in some fish farms at El-Fayyum, Port Said and El-Dakahlia governorates in Egypt was carried out. Water and fish (Oreochromis niloticus and Mugil cephalus) samples were collected from private fish farms of such localities. Bacteriological and chemical examination of water samples revealed the existence of coliforms and many other bacterial species of significant human health hazards. The chemical parameters of water showed a marked deviation from normal levels while examination of fish flesh specimens indicated contamination with Streptococcus Sp., Staphylococcus Sp., and Salmonella in all examined localities. Other bacterial isolates of human health importance (Morganella morganii, Pseudomonas cepacia and Enterococcos durans) were identified. The parasitological examination revealed the presence of encysted metacercariae (EMC); Diplostomatidae, Prohemistomatidae and Heterphyidae. Moreover, two protozoan parasites (Mxyoboulus tilapiae and Ichthyophthirius multifilis) were also recorded. The histopathological examination revealed mild tissue reaction in case of bacterial infection and severe pathological lesions in different organs in case of EMC infection. Lamellar hyperplasia and mononuclear cell infiltration in branchial tissue was common findings. In skeletal muscles, atrophy of muscle fibres, myolysis and myophagia were detected.

2015
Abdelsalam, M., M. Fujino, A. E. Eissa, S. C. Chen, and M. Warda, "Expression, genetic localization and phylogenic analysis of NAPlr in piscine Streptococcus dysgalactiae subspecies dysgalactiae isolates and their patterns of adherence", Journal of Advanced Research, vol. 6, issue 5, pp. 747-755, 2015.
Abdelsalam, M., A. E. Eissa, and S. - C. Chen, "Genetic diversity of geographically distinct Streptococcus dysgalactiae isolates from fish.", Journal of Advanced Research, vol. 6, issue 2, pp. 233-238, 2015. 1-s2.0-s2090123213001471-main.pdf
Abdelsalam, M., Streptococcus dysgalactiae, a new fish pathogen, , Saarbrücken, LAP Lambert Academic Publishing ( 2015-05-26 ) , 2015.
Abu-Elala, N., M. Abdelsalam, S. H. Marouf, and A. Setta, "Comparative analysis of virulence genes, antibiotic resistance and gyrB-based phylogeny of motile Aeromonas species isolates from Nile tilapia and domestic fowl.", Letters in applied microbiology, vol. 61, issue 5, pp. 429-36, 2015. Abstractabu-elala_et_al-2015-letters_in_applied_microbiology1.pdf

UNLABELLED: The nucleotide sequence analysis of the gyrB gene indicated that the fish Aeromonas spp. isolates could be identified as Aeromonas hydrophila and Aeromonas veronii biovar sobria, whereas chicken Aeromonas spp. isolates identified as Aeromonas caviae. PCR data revealed the presence of Lip, Ser, Aer, ACT and CAI genes in fish Aer. hydrophila isolates, ACT, CAI and Aer genes in fish Aer. veronii bv sobria isolates and Ser and CAI genes in chicken Aer. caviae isolates. All chicken isolates showed variable resistance against all 12 tested antibiotic discs except for cefotaxime, nitrofurantoin, chloramphenicol and ciprofloxacin, only one isolate showed resistance to chloramphenicol and ciprofloxacin. Fish Aeromonads were sensitive to all tested antibiotic discs except amoxicillin, ampicillin-sulbactam and streptomycin.

SIGNIFICANCE AND IMPACT OF THE STUDY: Many integrated fish farms depend on the application of poultry droppings/litter which served as a direct feed for the fish and also acted as pond fertilizers. The application of untreated poultry manure exerts an additional pressure on the microbial world of the fish's environment. Aeromonas species are one of the common bacteria that infect both fish and chicken. The aim of this study was to compare the phenotypic traits and genetic relatedness of aeromonads isolated from two diverse hosts (terrestrial and aquatic), and to investigate if untreated manure possibly enhances Aeromonas dissemination among cohabitant fish with special reference to virulence genes and antibiotic resistant traits.