Cholera is a negative public health event caused by Vibrio cholerae. Although V. cholerae is abundant in natural environments, its pattern and transmission between different niches remain puzzling and interrelated. Our study aimed to investigate the occurrence of nonpathogenic V. cholerae in the natural environment during endemicity periods. It also aimed to highlight the role of molecular ecoepidemiology in mapping the routes of spread, transmission, and prevention of possible future cholera outbreaks. V. cholerae was detected in different aquatic environments, waterfowl, and poultry farms located along the length of the Nile River in Giza, Cairo, and Delta provinces, Egypt. After polymerase chain reaction amplification of the specific target outer membrane gene (Omp W) of suspected isolates, we performed sequence analysis, eventually using phylogenetic tree analysis to illustrate the possible epidemiological relationships between different sequences. Data revealed a significant variation in the physicochemical conditions of the examined Nile districts related to temporal, spatial, and anthropogenic activities. Moreover, data showed an evident association between V. cholerae and the clinically diseased Synodontis schall fish. We found that the environmental distress triggered by the salinity shift and elevated temperature in the Middle Delta of the Nile River affects the pathogenesis of V. cholerae, in addition to the characteristics of fish host inhabiting the Rosetta Branch at Kafr El-Zayat, El-Gharbia province, Egypt. In addition, we noted a significant relationship between V. cholerae and poultry sources that feed on the Nile dikes close to the examined districts. Sequence analysis revealed clustering of the waterfowl and broiler chicken isolates with human and aquatic isolated sequences retrieved from the GenBank databases. From the obtained data, we hypothesized that waterfowl act as a potential vector for the intermediate transmission of cholera. Therefore, continuous monitoring of Nile water quality and mitigation of Nile River pollution, in addition to following good managemental practices (GMPs), general hygienic guidelines, and biosecurity in the field of animal production and industry, might be the way to break this cyclic transmission between human, aquatic, and animal sectors.

Parasitic isopods have received considerable attention as they cause series impacts on their hosts either alone or with other environmental stresses such as water pollution. The present study investigated the infestation status with isopods among the fry collected from the natural sources .Also to demonstrate the effects of different salinity and temperature combination on the survival rates of the identified isopods under the laboratory conditions. In March 2017,a total of 16 thousand mugiliid fry were sampled from The Fry Collection center at Al Behera Governorate ,Egypt and examined for the presence of isopods .Samples were found infested with a rate of 10.6% , the result which practically documented that isopods were introduced into lake Qarun through dumping millions of infected fry from this source without biosecurity procedures. The isolated juvenile isopods were morphologically and molecularly identified as Livoneca redmanii species by using 16S rRNA gene and recorded in the GenBank with accession number: MK584629. The effects of variables of salinity/ temperature combination on the survival% of the identified juveniles showed that the best survival rate(100%) was recorded in salinity 15 -20% at temperature 25⁰C while the lethal combination was in salinity 10, 20,50 and 60% at temperature 35⁰C . Statistical analysis using A-two way ANOVA indicated a significant interaction between the effect of different degree of temperature and variance of salinity% on the survival of L. redmanii juveniles. Analysis of one way ANOVA indicated that the most effective temperature of overall mean temperature affected on survival of juvenile stage was 35 C⁰ while the most effective salinity percentage on survival of Juvenile from overall mean of salinity % was 10% .Results of this study provided applicable procedures which can be recommended as a precaution measures and for eliminating the isopod juvenile stages among the mugiliid fry.

Background and Aim: Salmonella causes most foodborne bacterial illnesses worldwide. It is found in various hosts, including pets, farm animals, and wild animals, as well as the environment. This study aimed to examine the epidemiological relationship between Salmonella isolates from aquatic environments and those from other avian hosts. Materials and Methods: The study examined 12 water samples, 210 aquatic animals, and 45 migratory aquatic bird samples collected from the protected area of Lake Qarun in El-Fayoum Governorate, Egypt, during migration seasons from different waterfowl migration areas (from October 2018 to January 2019). In addition, 45 fecal samples from domestic chickens were collected from the same geographic location from poultry farms. Bacteriological examination and polymerase chain reaction assay of two virulence genes (i.e., invA and stn) were performed to isolate and identify Salmonella. Results: Salmonella was isolated from 58.3% (7/12) of Lake Qarun water samples, 13.3% (6/45) of migratory waterfowl, 6.6% of (3/45) of chickens (Gallus gallus domesticus), and 4.3% (3/70) of fish and pooled brine shrimp. In migratory aquatic bird species that were sampled, Salmonella were isolated from 23.1% (3/13) of Eurasian coot (Fulica atra), 12.5%, (1/8) of green-winged teal (Anas cardolinesis), 10% (2/20) of northern shoveler (Spatula clypeata), and 0% (0/4) of mallard duck (Anas platyrhynchos). In 35 Tilapia, Salmonella was isolated by (8.6%) 5.7% of external surfaces, 2.85% from the intestine, and 0% from the muscle. No Salmonella was isolated from the 175 brine shrimp samples. Phylogenetic analysis using the stn genes of Salmonella isolated from the aquatic environment, migratory aquatic birds, and chicken showed a strong association between these isolates. In addition, a higher nucleotide identity percentage was observed between the sequences recovered from migratory aquatic birds and Lake Qarun water samples. Conclusion: Salmonella distribution was confirmed through migratory aquatic birds, based on our phylogeny tree analysis, Salmonella considered a likely carrier of zoonotic bacterial pathogens. Furthermore, the close relationship between chicken and fish sequences highlights the scenarios of using chicken manure in fish farms and its public health implications. The presence of Salmonella in different environmental sources spotlights the urgent need to control and break down its epidemiological cycle.

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A total number of samples, 270 Common pandora (Pagellus erythrinus), were clinically examined for possible streptococcal infection. The fishes were collected from the area extending from Tripoli to Tajoura (east to Tripoli). S. iniae, S. dysgalactiae, S. phocae, Enterococcus fecalis, and other non-streptococcal spp. Such as Aeromonas hydrophila, Pseudomonas, and Photobacterium damselae were biochemically identified. 90 fish per season were thoroughly screened for streptococcal infection for three successive seasons. Regardless of the season, S. iniae and E. fecalis were the most isolated streptococcal spp (13% and 8.88%, respectively). In contrast, the most retrieved non-streptococcal spp were A. hydrophila, followed by Pseudomonas spp, with isolation percentages of 10% and 14.44%, respectively. The highest infections have occurred during winter, followed by summer, then spring seasons with isolation percentages of 53.34%, 50%, and 43.4%, respectively. The majority of the isolated bacterial spp were sensitive to Erythromycin, Florfenicol, and sulfamethoxazole-Trimethoprim. Molecular screening utilizing the sequences of 16S rRNA genes has confirmed the phylogenetic relationship to S. dysgalactiae, E. faecalis, S. iniae, and S. phocae isolates with similarity percentages exceeding 99.6%. The sequences were deposited in the GenBank with accession numbers (OK033868, OK033869, OK033870, and OK033871).