Nano-PCR is a recent tool that is used in viral diseases diagnosis. The technique depends on the fundamental effects of gold nanoparticles (AuNPs) and is considered a very effective and sensitive tool in the diagnosis of different diseases including viral diseases. Although several techniques are currently available to diagnose foot and mouth disease virus (FMDV), a highly sensitive, highly specific technique is needed for specific diagnosis of the disease. In the present work, a novel AuNPs biosensor has been designed using thiol-linked oligonucleotides that recognize the conserved 3D gene of FMDV. The AuNPs-FMDV biosensor specifically recognizes RNA standards of FMDV, but not that of swine vesicular disease virus (SVDV) isolates. The analytical sensitivity of the AuNPs-FMDV biosensor was 10 copy number RNA standards in RT-PCR and 1 copy number RNA standard in real-time rRT-PCR with a 94.5% efficiency, 0.989 R2, a − 3.544 slope and 100% specificity (no cross-reactivity with SVDV). These findings were confirmed by the specific and sensitive recognition of 31 Egyptian FMDV clinical isolates that represents the three FMDV serotypes (O, A, and SAT2). The AuNPs-FMDV biosensor presents in this study demonstrates a superior analytical and clinical performance for FMDV diagnosis. In addition, this biosensor has a simple workflow and accelerates epidemiological surveillance, hence, it is qualified as an efficient FMDV diagnosis tool for quarantine stations and farms particularly in FMDV endemic areas.

Background: Gold nanoparticles (AuNPs) have been considered as an ideal candidate in various biomedical applications due to their ease of tailoring into different size, shape, and decorations with different functionalities. The current study was conducted to investigate the epigenetic alteration in the lung in response to AuNPs administration regarding microRNA-155 (miR-155) gene which can be involved in AuNP-induced lung pathogenesis. Methods: Thirty-two Wister rats were divided into two equal groups, control group and AuNPs treated group which received a single intravenous (IV) injection of plain spherical AuNPs (0.015 mg/kg body wt) with an average diameter size of 25±3 nm. Lung samples were collected from both the control and injected groups at one day, one week, one month and two months post-injection. The alteration of relative expression of miR-155 gene and two of its putative target genes; tumor protein 53 inducible nuclear protein 1 (TP53INP1) and protein S (PROS1) was investigated by real time PCR and protein S (PS) expression was analyzed by Western blotting technique. Results: The obtained results revealed that AuNPs administration significantly increases the expression level of miR-155 and reduce relative mRNA expression of TP53INP1 and PROS1 genes at one day post-injection. In contrast, a significant down-regulation of miR-155 level of expression concurrent with up-regulation of expression level of TP53INP1 and PROS1 genes were shown at one week, one month and two months post-injection. PS levels were mirrored to their PROS1 mRNA levels except for two month post-injection time point. Conclusions: These findings indicate epigenetic modulation in the lung in response to AuNPs administration regarding the miR-155 gene which can be involved in AuNP-induced lung pathogenesis.

Background: Avian metapneumovirus (aMPV) is an economically significant respiratory pathogen of poultry that affects performance, egg production, and fertility of breeder flocks. Despite its impact, aMPV continues to be ill-defined in Egypt with no integrated surveillance studies conducted in breeder flocks. Therefore, the current study was designed to provide the first integrated molecular and serological evaluation of aMPV circulation in broiler breeders in Egypt. Methods: Between 2024 and 2025, a total of 6,000 serum samples and 800 tracheal swabs were collected from 60 unvaccinated broiler breeder flocks across twelve Egyptian governorates. Sera were obtained at 16 weeks (rearing phase) and 35 weeks (production phase) of age and screened for aMPV subtypes A and B by ELISA. Tracheal swabs collected during the production phase were pooled into 80 composite samples and tested for the viral RNA by reverse transcription quantitative real time PCR (RT-qPCR). Results: Serological analysis revealed widespread aMPV exposure, with governorate-level seroprevalence ranging between 64.4% (Luxor) and 89% (Giza). Antibody titers increased between 16 and 35 weeks of age, reflecting cumulative viral exposure. Molecular testing detected aMPV RNA in 67 (83.75%) of pooled swab samples. Subtype B was the predominant genotype detected solely in 65 (81.25%) sample pools and in co-detection with subtype A in 2 pools (2.5%). Serological and molecular findings were generally aligned, with flocks positive for aMPV RNA often exhibiting higher antibody titers. Conclusion: These findings indicate that aMPV, particularly subtype B, is likely endemic across the Egyptian broiler breeder flocks. The study highlights critical knowledge gaps and emphasizes the need for viral isolation, sequencing, and controlled evaluation of biosecurity and vaccination strategies.

Background and Aim: Highly pathogenic avian influenza H5N8 virus of clade 2.3.4.4 was newly emerged to Egypt and firstly detected in carcasses of wild birds in November 2016. This study assessed the protection efficacy and virus shedding reduction of three different inactivated avian influenza (AI) H5 (H5N1, H5N2, and H5N3) commercial vaccines against challenge with two newly emerging highly pathogenic AI virus H5N8 Egyptian isolates in specific-pathogen-free (SPF) chicks. Materials and Methods: 10-day-old SPF chicks (n=260) were divided into 20 groups (n=13). Groups 1-5 were vaccinated through the subcutaneous route (S/C) with 0.5 mL of H5N1 vaccine, Groups 6-10 were vaccinated (S/C) with 0.5 mL of H5N2 vaccine, and Groups 11-15 were vaccinated (S/C) with 0.5 mL of H5N3 vaccine. Positive control groups (16-19) were challenged at 25 and 31 days old (2 and 3 weeks post-vaccination [PV]) using H5N8 clade 2.3.4.4 A/duck/Egypt/ F13666A/2017(H5N8) and H5N8 clade 2.3.4.4 A/chicken/Egypt/18FL6/2018(H5N8). Group 20 was left non-vaccinated as a control. All vaccinated groups were divided and challenged with both viruses at 25 and 31 days of age. The viral challenge dose was 0.1 mL of 106 EID50/0.1 mL titer/chick, and it was administered oronasally. All chicks were kept in isolators for 14 days after each challenge. Sera samples were collected weekly and at 2 weeks post-challenge (PC) to detect a humoral immune response. PC mortalities were recorded daily for 10 days to calculate the protection percentages. Tracheal swabs were collected from the challenged chicks in different groups at 3, 5, 7, and 10 days PC. Kidneys and spleens were collected at 3, 5, 7, and 10 days PC and kept in formalin for histopathological examination to assess lesions and severity scores. Tracheal swabs were inoculated in 10-day-old SPF embryonated chicken eggs for virus titration and to calculate shedding levels. Results: All studied vaccines displayed 70-100% protection within 10 days PC. Hemagglutination inhibition results from sera samples revealed antibody titers ranging from 0.6 to 5.4 log2 starting at 1-week PV with the highest titers at 4 weeks PV. Challenged SPF chickens exhibited a notable reduction in virus shedding, with an average of 1.5-2 log10, compared to control birds. Various histopathological lesions with different scores were detected. Conclusion: Our findings suggest that the inadequate virus shedding reduction and protection efficacy of studied vaccines were variable and that the type of vaccine to be used under field conditions should be reconsidered. Study of the variability between the Egyptian old emerged AI (AIV) 2017 H5N8 strains and the new emerging AIV 2018 H5N8 is required to achieve optimal protection and limit the current economic losses.

Avian influenza viruses (AIVs) pose a global threat, with wild waterfowl serving as key reservoirs for transmission to poultry. The present study investigated the pathogenicity, viral shedding patterns, tissue distribution, and pathological effects of a highly pathogenic avian influenza virus (HPAIV) in two duck breeds, including Muscovy and Sudani ducks. An Egyptian H5N1 strain (A/ibis/Egypt/RLQP-229S/2022), originally isolated from a wild ibis, was used. Forty ducks (20 Muscovy and 20 Sudani) were divided into infected and control groups (10 per group per breed). At four weeks of age (Average weight of 1.2 ± 0.1 kg), each infected duck received a single intranasal dose of 10⁶ EID₅₀. Cloacal and oropharyngeal swabs were collected at 3, 5, 7, and 10 days post-infection (DPI) to monitor viral shedding, while clinical signs were recorded daily. Mortality was higher in Muscovy ducks, which exhibited higher mortality (70%) than Sudani ducks (50%), with both breeds showing neurological signs and lethargy. Viral load analysis of cloacal swabs via RT-PCR (Targeting the AIV M gene), exceeded oropharyngeal shedding, peaking by five DPI and persisting longer in Muscovy ducks (Seven DPI compared to five DPI in Sudani ducks), suggesting that fecal-oral transmission is the primary route of spread and that viral replication is more active in the intestinal tract. Tissue distribution analysis revealed broader viral dissemination in Muscovy ducks, particularly in the brain, lung, kidney, and spleen. These findings demonstrated differential susceptibility between breeds, with Muscovy ducks posing a higher transmission risk due to prolonged viral shedding and tissue tropism. The virus used in the present study carried pathogenicity markers across several proteins, including hemagglutinin (HA), neuraminidase (NA), polymerase basic 1 (PB1), polymerase basic 2 (PB2), nucleoprotein (NP), non-structural protein 1 (NS1), and polymerase acidic (PA) protein. Overall, while both duck breeds are vulnerable to the circulating H5N1 HPAI strain, their susceptibility and clinical outcomes differ. These findings demonstrated that both Muscovy and Sudani ducks are susceptible to H5N1 HPAIV infection, Muscovy ducks showing higher mortality and more extensive viral shedding and histopathological alterations. However, both duck breeds are variable in their susceptibility to H5N1 infection.

Avian metapneumovirus (aMPV) is a major respiratory pathogen of poultry with a significant economic impact; however, its epidemiology at the wildlife–poultry interface remains poorly understood, particularly within Afro–Eurasian migratory systems. This cross-sectional study (December 2024–April 2026) investigated aMPV occurrence in wild birds across eleven Egyptian governorates representing key ecological zones along major migratory flyways. A total of 1280 samples were collected from 800 wild birds representing migratory waterfowl and synanthropic species, including 800 oropharyngeal swabs tested by real-time RT-qPCR for aMPV subtypes A and B and 480 serum samples analyzed using indirect ELISA. aMPV RNA was detected in 28/800 samples (3.5%), with all positives identified as subtype B and confined to the Nile Delta, Middle Egypt, and Canal Region. In contrast, serological analysis revealed a high seroprevalence of 58.3% (280/480), indicating widespread prior exposure with significant spatial and species-level variation (p < 0.05). The marked disparity between low molecular detection and high seroprevalence supports transient infection with cumulative exposure. The exclusive detection of subtype B may reflect epidemiological connectivity between poultry and wild bird populations within shared ecological interfaces; however, the directionality of transmission and the possibility of independent wildlife maintenance could not be determined within the scope of the present cross-sectional study. Future studies incorporating whole-genome sequencing, longitudinal surveillance, and broader flyway-scale sampling are needed to resolve transmission pathways and distinguish field strains from potential vaccine-derived viruses within wildlife–poultry interfaces.