Avian orthoavulavirus1, formerly known as avian paramyxovirus type-1 (APMV-1), infects more than 250 different species of birds. It causes a broad range of clinical diseases and results in devastating economic impact due to high morbidity and mortality in addition to trade restrictions. The ease of spread has allowed the virus to disseminate worldwide with subjective virulence, which depends on the virus strain and host species. The emergence of new virulent genotypes among global epizootics, including those from Egypt, illustrates the time-to-time genomic alterations that lead to simultaneous evolution of distinct APMV-1 genotypes at different geographic locations across the world. In Egypt, the Newcastle disease was firstly reported in 1947 and continued to occur, despite rigorous prophylactic vaccination, and remained a potential threat to commercial and backyard poultry production. Since 2005, many researchers have investigated the nature of APMV-1 in different outbreaks, as they found several APMV-1 genotypes circulating among various species. The unique intermingling of migratory, free-living, and domesticated birds besides the availability of frequently mobile wild birds in Egypt may facilitate the evolution power of APMV-1 in Egypt. Pigeons and waterfowls are of interest due to their inclusion in Egyptian poultry industry and their ability to spread the infection to other birds either by presence of different genotypes (as in pigeons) or by harboring a clinically silent disease (as in waterfowl). This review details (i) the genetic and pathobiologic features of APMV-1 infections in Egypt, (ii) the epidemiologic and evolutionary events in different avian species, and (iii) the vaccine applications and challenges in Egypt.

Background: Infectious bronchitis virus (IBV) causes a significant illness in birds, making it a leading source of financial loss in the poultry business. The objective of this study was to assess the effectiveness of proliposomes (PLs) containing ivermectin (IVM) against IBV using embryonated chicken eggs (ECEs). Methods: A three-factor, two-level (2³) full factorial design was employed; carrier/lipid phase ratio (A), stearyl glycyrrhetinate amount (B), and phospholipid type (C) were studied as independent variables, while product yield (PY), entrapment efficiency (EE), particle size (PS), polydispersity index (PDI), zeta potential (ZP), and cumulative percentage of drug released after 6 h (Q6h) were characterized. The selected formulations (PL2 and PL6) were subjected to further characterizations, including IVM toxicity and anti-viral activity. Results: The PY% ranged from 88.6 ± 2.19% to 98.8 ± 0.45%, EE% was from 71.8 ± 2.01% to 96.1 ± 0.51%, PS was from 330.1 ± 55.65 nm to 1801.6 ± 45.61 nm, PDI was from 0.205 ± 0.06 to 0.603 ± 0.03, ZP was from −18.2 ± 0.60 mV to −50.1 ± 1.80 mV, and Q6h was from 80.95 ± 1.36% to 88.79 ± 2.03%. IVM-loaded PLs had lower toxicity in ECEs than pure IVM; the mortality rate was substantially reduced in IBV-infected ECEs injected with PL2 rather than pure IVM. As further evidence of IVM’s anti-viral action against IBV, quantitative real-time polymerase chain reaction (qRT-PCR) revealed that the PL2-treated group exhibited further reduction in IBV’s copies in comparison with the pure IVM-treated group. Conclusions: PLs loaded with IVM are an innovative and potentially effective way to inhibit IBV.

Avian orthoavulaviruses1, formerly known as Newcastle disease virus (NDV) is able to infect a wide variety of bird species resulting in various clinical signs and consequences. The easiness of transmission has endorsed the virus to spread globally showing variable levels of virulence based on host species and virus strain. The pathogenicity and transmissibility of field Egyptian chicken-origin NDV genotype VII 1.1 to induce the disease in 35-day-old Japanese quails were investigated. Twenty-five percent of quails inoculated oculonasally with 106EID50 showed conjunctivitis and depression, whereas 11% of cases exhibited greenish diarrhea. Neurologic signs consisting of incoordination and tremors were recorded in 37.5% of infected quails at day 8 post-infection (dpi). Congested meningeal blood vessels and hemorrhagic cecal tonsils were seen in both NDV-infected and contact quails. Microscopically, the NDV-infected quails showed brain edema, lymphocytic encephalitis and pulmonary congestion. Using hemagglutination inhibition (HI) assay, the anti-NDV antibodies for NDV-infected and LaSota-vaccinated at 7 dpi were relatively similar. The antibody titers reached 6±0.8 log2 in the NDV-infected birds and 5.25±0.5 and 4±0.8 log2 in LaSota-vaccinated and contact quails, respectively at 21 dpi. Additionally, the infected quails shed virus via the oropharynx and cloaca. Virus titers of approximately 102.8 and 105.2 EID50/mL were determined in the oropharyngeal and cloacal swabs on day 5 post-infection, respectively. These results demonstrate that Japanese quails can indeed be susceptible to NDV genotype VII 1.1 and might be a source of infection to additional birds.

Newcastle disease virus (NDV) inflicts considerable financial damage to the poultry industry globally. Japanese quails act as natural reservoirs for NDV and play significant role in virus epidemiology. Previous studies have documented variable susceptibility levels to the NDV among Japanese quails; however, the underlying mechanisms are still not well understood. In this study, the innate immune responses of quails to velogenic and lentogenic NDV strains were characterized. Pronounced transcriptional responses were seen in lung and spleen shortly after viral infection, inducing genes related to innate antiviral and pro-inflammatory cytokines. In the NDV genotype VII 1.1 infected group, a notable increase in the expression levels of interleukin-6 (IL-6), interleukin-8 (IL-8), and interferon-gamma (IFN-γ) was observed at 3 days post-infection (dpi), prior to their peak expression in the spleen at 5 dpi. In contrast, the LaSota inoculated group exhibited different transcriptional responses, with a notable increase in lung on day 1 post-infection. The NDV genotype VII 1.1 exhibited an increased viral load in the spleen at 5 dpi. Meanwhile, the viral load of LaSota strain was considerably higher at 3 dpi. These findings imply that infections with NDV strains of varying virulence are linked to variable viral loads and unique cytokine expression patterns in different tissues, proposing that the host response could possess a role in the pathobiology of NDV in quails. As well, the results emphasize significant variations in the quail's innate immune responses, infection dynamics and disease progression following NDV infection with different virulence. Additional research is warranted to further elucidate the molecular mechanism involved in NDV infection in a wide range of avian species.