Background

Synanthropic filth flies thrive in human and animal habitats, posing health risks through the transmission of infectious agents. They breed on organic waste, including animal feces, making them carriers of various pathogens. In Egypt, where livestock farming is common and poor sanitation, these flies may contribute to zoonotic disease transmission. The current study investigates parasitic infections in filth flies from three livestock farms in Assiut Governorate, Upper Egypt, highlighting their role as vectors for zoonotic infections, particularly Cryptosporidium, via morphological and molecular tools.

Methods

A total of 12,749 flies were collected from the study sites via sweep nets. After taxonomic identification, the flies were examined microscopically for parasites using various concentration and staining techniques. Positive samples were further confirmed for infections, particularly for Cryptosporidium parasites, via nested PCR and sequence analysis targeting the COWP and SSU rRNA genes.

Results

This study revealed the presence of several fly species from seven dipteran families, particularly the family Muscidae, primarily Musca domestica, which presented a high parasite infestation rate of 96.6%. This study revealed a high prevalence of various protozoans and helminths in the collected flies. Cryptosporidium was the most prevalent parasite (64.4–100%), infecting all fly species. Entamoeba and Balantidium were also significant, especially in M. domestica (22.6–90.1%, 8.9–100%), Fannia canicularis (10.5–74.4%, 44.2–88.2%), and Borborillus vitripennis (11.1–50%, 37.2–91.4%). Giardia, Trichuris, and Trichostrongylidae had low to moderate prevalence in multiple fly species. Mites are commonly detected on fly exoskeletons, with high infestation rates observed in Musca domestica (77–100%) and Physiphora alceae (66.7–100%). The present study also reported sporadic infections with Trichomonas, Toxocara vitulorum, and pseudoscorpions, along with notable midge larval infestations (52.1%), mainly at site B. Parasitic infections were highest in autumn and spring, with the lowest rates in winter. Molecular identification confirmed the presence of the zoonotic species Cryptosporidium parvum and Cladotanytarsus gedanicus.

Conclusion

This study revealed that zoonotic parasites exist in flies and pose potential risks when they are found near humans. Cryptosporidium parvum is the prevalent parasite causing diarrhea outbreaks in animals. This is the first genetic evidence of Cladotanytarsus gedanicus midge from Upper Egypt.

Spermatogenesis in teleosts is essential for reproductive function; however, it varies considerably among species. The testis of the viviparous molly fish (Poecilia sphenops) was
examined using both ultrastructural and immunohistochemical methods. The testis displays a restricted lobular type, where germ cells develop synchronously within Sertoli
cell-forming cysts. Transmission electron microscopy (TEM) revealed all stages of spermatogenesis. Mature sperm are at the apex of the cysts and migrate toward the sperm
ducts. Sperm duct epithelium is lined by cuboidal cells joined by tight junctions, with
apical cilia and desmosomal complexes contributing to transport and structural integrity.
The sperm ducts showed strong Periodic Acid–Schiff (PAS)-positive expression among
negative stained spermatocysts. Centrally, a cavity serves as a storage area for spermatozoa
that are organized into unencapsulated bundles known as spermatozeugmata. Sertoli cells
exhibited extended cytoplasmic processes that supported developing germ cells, whereas
Leydig cells occupied the interstitial tissue, contributing to hormonal regulation. Immunohistochemical labeling demonstrated strong vimentin expression in Sertoli cells and
telocytes, indicating their mesenchymal origin and structural role. Calretinin expression
was confined to Leydig cells and certain ductal epithelial cells, supporting its use as a
marker for steroidogenic and secretory functions. These findings provide new insights into
the testicular specialization of P. sphenops, highlighting key somatic–germ cell interactions,
ductal adaptations, and marker expression patterns that underlie male reproductive success
in viviparous fish 
 

The spleen plays a critical role in the immune and hematopoietic systems of
teleost fish, functioning as a major secondary lymphoid organ. This study provides a
detailed morphological and ultrastructural assessment of the spleen in goldfish (Carassius
auratus), focusing on its immunological organization and cellular diversity. Through light
and transmission electron microscopy, we examined red and white pulps, identifying key
features such as melanomacrophage centers (MMCs), ellipsoids, and various immune cell
types. The red pulp was rich in sinusoidal capillaries and splenic cords, whereas the white
pulp housed lymphocytes, dendritic cells, macrophages, and telocytes, all contributing to
immune regulation. Notably, ellipsoids were surrounded by reticular and macrophage
sheaths, forming a filtration barrier against pathogens. Ultrastructural analysis revealed
diverse immune cells with active morphological traits, including macrophages with pseudopodia and pigment granules, dendritic cells with dendrite-like extensions, and epithelial
reticular cells involved in forming the blood–spleen barrier. These findings highlight
the complex immunological microarchitecture of the goldfish spleen and its functional
relevance in teleost immune responses 
 

The kidneys of molly fish (Poecilia sphenops) exhibit complex immune and cellular activities, which
are crucial for maintaining renal function and responding to environmental stressors. This study
aimed to investigate the histological and immunohistochemical characteristics of immune cells,
autophagy, and stem cell activity within the renal tissues of molly fish. Histological analysis revealed
the presence of immune cells, including macrophages and granular leukocytes, concentrated around
the renal corpuscles (RC) and renal tubules (RT). Additionally, numerous lymphocytes were observed
surrounding the RC, and a notable presence of rodlet cells with a thick capsule and rodlet-like
inclusions was detected around the RT. Immunohistochemical staining confirmed macrophage activity
through CD68 and Iba1 expression, while APG5, an autophagy marker, was observed in macrophages,
rodlet cells, and podocytes, indicating active autophagic processes. Polymorphic granulocytes
expressed iNOS-2. Inflammatory markers IL-1β and NF-κB were highly expressed in rodlet cells and
macrophages, respectively, suggesting their role in immune modulation. The expression of S100
protein in rodlet cells and acetylcholine in macrophages further highlights their specialized functions
in immune regulation. Additionally, renal stem cells were identified by expressing Nrf2 and Sox9,
indicating a potential role in tissue repair and regeneration. These findings provide critical insights into
the kidney’s dual function in immunity and regeneration, contributing to a better understanding of
fish renal physiology and potential applications in environmental monitoring and aquaculture health
management. 
 

This study provides a detailed histological and immunohistochemical analysis of the kidney and adrenal gland in Varanus niloticus (Nile monitor lizard), highlighting their structural features and adaptive mechanisms. Ten adult female Nile monitors were
collected from Qena Province, Egypt, and their kidneys and adrenal glands were examined. Kidney tissues were processed for
histological analysis, and immunohistochemistry was performed to evaluate the expression of key markers, including vimentin, E-cadherin, CK7, and NSE. In contrast to other reptiles, the kidney was divided into the cortex and medulla and contained
a loop of Henle. The cortex contains renal corpuscles and nephron tubules, while the medulla primarily comprises collecting
ducts. The proximal tubules were lined with acidophilic cuboidal cells, whereas the distal tubules exhibited pale cuboidal cells
with fewer microvilli. Immunohistochemistry revealed vimentin expression in podocytes and a few renal tubule epithelial cells,
while E-cadherin was expressed in the distal tubules, loop of Henle, and collecting ducts. NSE was strongly expressed in the renal
corpuscles and macula densa of the juxtaglomerular apparatus, as well as in the peripolar cells, but was absent in the proximal
tubules. CK7 was predominantly expressed in the distal tubules and collecting ducts. The adrenal glands comprise steroidogenic
and chromaffin cells associated with the posterior cardinal veins of the kidney. NSE was strongly expressed in chromaffin cells,
while vimentin was detected in steroidogenic cells. E-cadherin and CK7 are not expressed in the adrenal tissues. These findings
provide insights into the structural and functional adaptations of the kidney and adrenal glands in Nile monitors, offering a foundation for future research into the comparative anatomy and functional ecology of reptilian excretory and endocrine systems 
 

Cartilage is a crucial component of the vertebrate skeletal system, providing
structural integrity, flexibility, and adaptive functions across species. In teleost fish, cartilage
exhibits significant morphological and functional diversity, providing specialized biomechanical properties essential for aquatic life. This study presents a detailed histological,
immunohistochemical, and ultrastructural investigation of cartilage in molly fish (Poecilia
sphenops), identifying five distinct types of cartilage: hyaline-cell, scleral, cell-rich hyaline,
elastic cell-rich, and matrix-rich hyaline cartilage. Histological staining techniques revealed
notable differences in cellular architecture and composition of the extracellular matrix
among the cartilage types. Immunohistochemical analysis demonstrated the expression
of S100 protein and acetylcholinesterase (Ach), suggesting their involvement in cartilage
regulation and maintenance. Endochondral ossification was observed in the head and
gill arches. Electron microscopy provided detailed insights into chondrocyte morphology,
interactions between cartilage and the perichondrium, and interactions between telocytes
and fibroblasts. The findings enhance our understanding of skeletal adaptations in teleost
fish, emphasizing the functional diversity of cartilage in aquatic environments. This study
contributes to evolutionary biology and may have implications for regenerative medicine
and biomaterials research 
 

Goldfish (Carassius auratus) gills function as both respiratory and immuneregulatory organs, integrating neuroendocrine and immune responses to environmental
stimuli. This study explores the spatial organization and interaction of neuroendocrine
cells (NECs) and immune cells within goldfish gills using confocal immunohistochemistry
and transmission electron microscopy. NECs, identified near blood capillaries and nerve
fibers, highlight their role in environmental sensing and physiological regulation. These
cells express serotonin (5-HT), a neurotransmitter critical for neuroimmune communication.
Two distinct macrophage subsets were observed: iNOS-positive macrophages, concentrated in the basal epithelium, suggest a pro-inflammatory role, whereas 5-HT-positive
macrophages, dispersed in the subepithelium, likely contribute to immune modulation. The
co-localization of MHC-II and CD68 in macrophages further supports an active antigenprocessing system in the gills. Ultrastructural analysis revealed diverse immune cells,
including rodlet cells, telocytes, and lymphocytes, within the gill epithelium. Telocytes
formed intricate networks with immune cells, highlighting their role in immune coordination and tissue homeostasis. These findings provide new insights into the neuroimmune
interactions in fish gills, contributing to a broader understanding of aquatic immune
systems and environmental adaptability. 
 

Bovine theileriosis, caused by T. annulata, results in high morbidity and mortality rates, as well as severe financial losses for the livestock industry in Egypt. In this study, fifty cattle were utilized. Whole blood samples were collected for laboratory analysis. Giemsa-stained blood films were employed to detect Theileria infection. PCR was used to evaluate various target genes, like 30-kDa and Cyto B of T. annulata. Nine (18%) samples tested positive for piroplasm of Theileria by microscopic examination of blood film. Twenty-one (42%) of the analyzed samples tested molecularly positive based on the 30-kDa gene (N516/N517), while 10 (20%) samples were positive based on the Cyto B gene. In our study, we carried out DNA sequencing and phylogenetic analysis of T. annulata using the Cyto B gene. Phylogenetic analysis of the Cyto B gene of the Egyptian strain of T. annulata (Assiut) revealed a nucleotide identity ranging from 96.16% to 98.92% with T. annulata strains from various Egyptian governorates (Sharkia and Qalyubia), as well as from Sudan, Tunisia, Turkey, Iran, and India. The obtained isolates were closely clustered with an isolate from Sudan (accession number LC431533). We identified thirty-point changes at the amino acid sequences. There was substantial variance (P<0.05 and P<0.01) between age and sex of tested cattle, respectively, and percentages of T. annulata infection. The data obtained from our study on the characterization of the Cyto B gene of T. annulata in Assiut Governorate suggest that the Cyto B gene may be used as a genetic marker to identify resistant isolates of T. annulata.

A dangerous zoonotic bacterial infection that has a significant financial impact on the sheep industry is Chlamydophila spp. This investigation's aims were to determine the prevalence of Chlamydophila spp infection, study particular risk indicators, and assess the antioxidant status and biochemical changes of infected sheep. One hundred sheep were used in this study. Whole blood and serum samples were collected for laboratory analysis. ELISA and PCR had been employed for Chlamydophila spp diagnosis. The observed clinical findings of Chlamydophila spp infection in sheep were abortion, infertility, respiratory signs, conjunctivitis, diarrhea, and nervous manifestations. The seroprevalence of Chlamydophila spp infection was 2.20% (2/91) using ELISA. Of the studied sheep, 89 (89%) and 76 (76%) of 100 whole blood samples showed molecularly positive results for Chlamydophila spp, 16S rRNA and OMP2 genes, respectively. The infection rate of Chlamydophila spp had no significant variation by age and sex of infected sheep, but prevalence of Chlamydophila spp infection was significantly higher in autumn and winter, on farms, and in clinically diseased sheep. The concentration of TAC in the serum of Chlamydophila spp-infected sheep was significantly higher compared to healthy animals. The mean concentration of total protein, albumin, and GGT in Chlamydophila spp-infected sheep did not differ significantly from clinically healthy ones. It is essential to highlight the importance of efficient preventative and control measures throughout Egypt to reduce the prevalence of Chlamydophila spp infection in sheep.