Sahar Zaied

Yellow grub disease, caused by Clinostomum metacercaria, is an endemic zoonotic infection in freshwater fish, responsible for Halzoun syndrome transmitted through the consumption of raw infected fish. This study aimed to conduct a multidisciplinary investigation integrating detailed morphology, oxidative stress, immunology, and histopathology alteration to advance our understanding of Clinostomum infection. In this annual study, 400 Nile tilapia (Oreochromis niloticus) were collected from the Nile River at Al Bahr Al Aazam, Giza Governorate to assess Clinostomum infection prevalence. Of the examined fish, 160 individuals (40.0%) harboured larval Clinostomum infections. Clinostomum metacercariae were observed in various anatomical locations, with 135 fish (33.8%) in buccal cavities, 21 fish (5.25%) in gill chambers, and 4 fish (1.0%) on the skin. Infection intensity ranged from 2 to 12 cysts per fish, averaging 5 cysts, notably with skin infections characterized by a single cyst in each fish. Macroscopic encysted metacercariae were collected from buccal cavities, gills, and skin. Micro-morphology revealed distinct features in C. complanatum, including an elliptical oral sucker with collar-like rings and large sensory papilla-like structures, contrasting with the absence of these features in C. phalacrocoracis. Oxidative stress, assessed through malondialdehyde (MDA) and nitric oxide levels, revealed an elevation in MDA to 35.13 ± 6 nmol/g and nitric oxide to 25.80 ± 3.12 µmol/g in infected fish. In infected fish, MHC-I gene expression increased approximately 13-fold, MHC-II peaked at 19-fold, and IL-1β significantly upregulated by 17-fold, compared to control levels. Histopathology detailed associated lesions, such as cyst encapsulation and eosinophilic infiltration. Clinstomiasis and its impacts on fish hosts offer crucial insights to control this emerging fish-borne zoonotic disease, threatening wildlife, aquaculture, and human health.

Trichomonas gallinae is a protozoan parasite that causes canker in pigeons. Squabs (young pigeons) are frequently infected with T. gallinae and can die because of the infection, while adult pigeons can act as carriers showing no clinical signs. In the present study, 50 squabs, up to 1-month-old, were purchased from pigeon markets in different regions of the Giza governorate, Egypt. Direct wet mount preparations of the oral excretions of the squabs (mouth wash) and Giemsa staining revealed that 64% (32/50) were positive for T. gallinae. Experimental infection of ten squabs with 10 T. gallinae trophozoites/ml resulted in oral lesions on the mouth, tongue, and soft palate, with the presence of yellowish-white nodules (cheese-like) in the oral cavity on the sixth day post-infection in all squabs. A subset of five samples were cultured in modified Diamond's media, their DNA was extracted, and a portion of the ribosomal internal transcribed spacer region (ITS1/5.8S/ITS2) was amplified by polymerase chain reaction (PCR) followed by sequencing. Phylogenetic analysis of the five isolates revealed 64-91% homology with some reference isolates circulating in Egypt and related countries.