A multidisciplinary study on Clinostomum infections in Nile tilapia: micro-morphology, oxidative stress, immunology, and histopathology

Vector-borne pathogens in dogs in Egypt: Molecular and immunological insights

Canine vector-borne diseases (CVBD) constitute a significant global health challenge, impacting dogs and posing zoonotic risks to humans. These diseases are transmitted through blood-feeding vectors such as ticks, fleas, and mosquitoes. This study, conducted in Cairo and Giza, Egypt, aimed to assess the prevalence, diversity, and clinical impact of CVBD in both domestic and stray dogs. Using microscopic and molecular diagnostic techniques, several pathogens were identified, including two primary zoonotic blood pathogens, Anaplasma platys and Leishmania spp., as well as other blood pathogens with varying degrees of zoonotic potential, such as Ehrlichia canis (E. canis), Anaplasma phagocytophilum, Anaplasma marginale, Babesia canis vogeli (B. canis vogeli), Hepatozoon canis, and Trypanosoma evansi. Stray dogs exhibited a higher prevalence of infection than domestic dogs, frequently presenting with co-infections. Clinically, infected dogs displayed clinical signs including weight loss, pale mucous membranes, lethargy, and anorexia, with more severe manifestations observed in cases with co-infections, particularly involving B. canis vogeli and E. canis. The immune response in these dogs was marked by elevated levels of inflammatory cytokines, such as tumor necrosis factor-α, interferon-γ, and interleukin-1β, which were significantly higher in symptomatic dogs, indicating a robust immune defense against the pathogens. Furthermore, markers of oxidative stress, including glutathione, malondialdehyde, and nitric oxide, were elevated in infected dogs, suggesting increased cellular damage due to prolonged infection and inflammation. The findings underline the key significance of stray dogs in the transmission and maintenance of CVBD and emphasize the necessity for comprehensive diagnostic, preventive, and control strategies to mitigate the prevalence of these diseases in dog populations and their potential zoonotic impact on human health.

Glucose reduced nano-Se mitigates Cu-induced ROS by upregulating antioxidant genes in zebrafish larvae

This study compares the therapeutic efficiency of bovine serum albumin-stabilized selenium nanoparticles in reducing oxidative stress and improving cellular health. The nanoparticles were synthesized using mussel-extracted selenium with two reducing agents: d-glucose and orange. Inductively coupled plasma-optical emission spectroscopy and X-ray diffraction analyses confirmed the presence of selenium. The reducing agent and duration influenced the nanoparticle size. Reduction with d-glucose for 1 hour revealed that the particles exhibited an average size of 10 nm. Copper sulfate-induced malformations such as yolk sac and pericardial edema were observed with 25 μg ml-1 of orange-reduced nanoparticles, while d-glucose-reduced nanoparticles mitigated these malformations at 25 μg ml-1. Treatment with stabilized Se-NPs reduced with d-glucose for 30 minutes showed 33% dose-dependent radical scavenging activities, upregulated approximately 2-fold of superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase encoding genes and restored homeostasis by decreasing lipid peroxidation (27.32 nmol mg-1 ml-1) and nitric oxide levels (6.71 μM). They also had the potential to restore cognitive properties such as larval movement (93.40 m) without altering larval behaviour. Live cell imaging indicated a significant decrease in cellular reactive oxygen species and lipid peroxidation levels in the gut and liver. These findings suggest that Se-NPs reduced for 30 minutes with d-glucose are promising candidates for oxidative stress-induced neurodegeneration.

Yellow grub diseases on two seasonal killifish (Cyprinodontiformes, Rivulidae): a histopathological study

Yellow grub disease is a parasite infection, caused by Clinostomum spp. Metacercariae and affecting axial muscles and internal organs of freshwater fish. Killifishes live in seasonal ponds and are short-lived; in the Neotropical region they are among the most vulnerable vertebrates. The current study analyzes the possible injury and inflammatory reaction caused by parasitic infection with Clinostomum spp. metacercariae in testes, ovaries, liver, intestine and mesentery in the seasonal killifishes Trigonectes aplocheiloides and Titanolebias monstrosus. Apparently, this parasite could migrate through the circulatory system to different organs, since a cercaria was found in the lumen of a hepatic sinusoid. In all organs the inflammatory response showed dilated, congested vascular areas and infiltration of numerous inflammatory cells, mainly composed of lymphocytes, eosinophilic granular cells and macrophages. However, the most affected organs were the pancreas, ovaries and testes. In these organs, severe pancreatitis with degranulation of the pancreatic acini, scarce ovarian follicles and spermatocysts dilated with few or no seminiferous cells were observed. In seasonal killifish, yellow grub disease could cause low fertility rates or even sterility by reducing or impairing their reproductive capacity. Therefore, this type of parasitism has a considerable impact on the perpetuation of this species due to the short periods they have to breed before their habitats dry out.

An innovative approach to control fish-borne zoonotic metacercarial infections in aquaculture by utilizing nanoparticles

Fish-borne zoonotic trematodes (FBZTs) pose significant health risks and economic challenges worldwide. This study investigated the prevalence of encysted metacercariae (EMCs) in Nile tilapia (Oreochromis niloticus) from two Egyptian governorates and evaluated the antiparasitic efficacy of chitosan, silver, and selenium nanoparticles against these parasites. A cross-sectional analysis of 453 O. niloticus specimens revealed an overall EMC prevalence of 40.8%, with infection rates of 34.11% in Giza and 49.5% in Dakahlia. Clinostomid and Prohemistomid metacercariae were the most common, with mixed infections observed. Transmission electron microscopy characterized the synthesized nanoparticles, showing average diameters of 9.6-18.7 nm for chitosan, 13.2-19.8 nm for selenium, and 11.7-15.1 nm for silver nanoparticles. In vitro antiparasitic assays demonstrated varying efficacies among the nanoparticles. Against Clinostomum spp. metacercariae, chitosan nanoparticles showed the highest potency, achieving LC50 at 66 μg/ml after 30 min and LC90 at 100 μg/ml after 120 min. For Prohemistomum vivax EMCs, chitosan nanoparticles exhibited superior efficacy, achieving LC50 at 8 μg/ml after 1 h and LC90 at 16 μg/ml after 2 h. Silver and selenium nanoparticles showed lower efficacy for both parasite species. Scanning electron microscopy revealed significant ultrastructural damage to the parasite tegument following nanoparticle exposure, including disappearance of transverse ridges, integument shrinkage, and formation of blebs. This study provided valuable insights into the prevalence of FBZTs in Egyptian Nile tilapia and demonstrated the potential of nanoparticles, particularly chitosan, as effective antiparasitic agents. These findings pave the way for developing novel, targeted strategies to control fish-borne zoonotic trematodes, potentially reducing their impact on public health and aquaculture economies.

Innovative molecular and immunological approaches of heterophyiasis infecting some Egyptian marketed fishes

Heterophyiasis is a highly endemic disease in the Nile Delta, Egypt, where people consume raw or undercooked Oreochromis niloticus and Mugil cephalus. Birds and rats play a crucial role in fish-borne zoonotic trematode transmission since they serve as natural and experimental hosts. This study aimed to update the epidemiological information, morphological description, molecular identification and gene expression of two distinct heterophyid metacercariae in Giza, Wadi Al-Rayan, and Lake Manzala, Egypt, whereas various heterophyid infections could be expected. The present Centrocestus formosanus, Heterophyes heterophyes, and Heterophyes nocens with accession numbers OR947651.1, OR947700.1, and OR947719.1, respectively, matched with those recorded in the GenBank. Findings of the current investigation indicated that various cytokines like IL-1β, MHC-II, and TNF-α rapidly elevated in the infected pigeon's intestines. Additionally, the infection expanded due to the parasite's ejection from the host and the host's clinical affliction, which induced humoral immune responses. Interestingly, investigation of other trematode species is in extreme demand in terms of zoonoses. We suggest controlling snails, managing migratory birds, and examining and frying fishes to the point when the encysted metacercariae is destroyed.

Novel insights into immune stress markers associated with myxosporeans gill infection in Nile tilapia (molecular and immunohistochemical studies)

Nile tilapia (Oreochromis niloticus) is valued in aquaculture because of its quick development and ability to thrive in various environments. Myxosporeans are among the fish parasites that affect fish productivity, as they impact fish growth and reproduction, resulting in large fish deaths in farms and hatcheries. This study has been focused on morpho-molecular identification for the myxosporean parasites infecting Nile tilapia from three governorates in Egypt and assessment of gene expression of different cytokines (Interleukin-1βeta (IL-1β), major histocompatibility complex class II (MHC-II), and clusters of differentiation 4 (CD-4) and 8 (CD-8)) in tissues. Additionally, this work aimed to correlate the developed histopathological alterations and inflammatory reactions in gills with immunohistochemical expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α). Finally, the infected fish's cortisol levels and blood glucose were assessed. Results of BLAST sequence analysis of the 18S rRNA for the collected protozoans confirmed Myxobolus agolus, M. brachysporus, M. tilapiae, and Henneguya species. The molecular characterization of the immunological status of gills revealed marked upregulation of different inflammatory cytokines in the gills of infected fish. There was a significantly increased serum cortisol and glucose level in infected fish compared with control, non-infected ones. Severe histopathological alterations were observed in the infected fish gills, associated with increased expression of iNOS and TNF-α and related to myxosporean infection. The present study provides new insights into oxidative stress biomarkers in Nile tilapia infected with Myxosporeans and elucidates the gill's immune status changes as a portal of entry for protozoa that contribute to tissue damage.

Immunological and molecular evaluation of zoonotic metacercarial infection in freshwater fish: A cross-sectional analysis

Improperly cooked fish, carrying active metacercariae (MCs), can pose a significant risk for transmitting fish-borne zoonotic trematodes (FBZTs) to human consumers. This study aimed to enhance our understanding of FBZTs by conducting a comprehensive cross-sectional analysis involving various fish species, such as Nile tilapia (Oreochromis niloticus), African catfish (Clarias gariepinus), and red-belly tilapia (Tilapia zillii). These fish specimens were collected from distinct Egyptian governorates, specifically Giza, Kafr al-Shaykh, and Fayoum. The recovered flukes from experimentally infected domestic pigeons were identified as Prohemistomum vivax, Haplorchis pumilio, and Pygidiopsis genata based on morphological features. Furthermore, the identity of the retrieved adult flukes was confirmed using three species-specific primers for PCR amplification and sequencing analysis of the ITS rDNA region and have been deposited in GenBank with the following accession numbers: P. vivax (OR291421.1 and OR291422.1), P. genata (OP099561.1), and H. pumilio (OM439581.1-OP090510.1). Quantitative real-time PCR targeting the immunological genes Tumor Necrosis Factor-alpha (TNF-alpha) and Interleukin-1 (IL-1Β) was employed to compare the cellular immune response between infected with EMCs and uninfected O. niloticus. The results indicated a significant increase in TNF- and IL-1Β levels in FBZTs-infected vs un-infected fishes. Importantly, the presence of adult flukes and EMCs led to substantial histological alterations in both experimentally infected pigeons and naturally infected fish tissues. These changes included the necrosis of fish muscle bundles and a pronounced inflammatory reaction with muscular necrosis in the digestive tracts of experimentally infected pigeons.