Explore the vast range of titles available.

Infectious bursal disease virus (IBDV) induces severe immunosuppression in chickens, leading to significant economic losses in the global poultry industry. This study investigated 52 chicken flocks, including commercial broilers, layers, and baladi, from various Egyptian governorates in 2023. These flocks exhibited symptoms of depression, along with kidney and bursa lesions, indicative of IBDV infection. Pooled Bursal homogenates were tested using RT-PCR with VP2-specific primers, revealing that 20 flocks tested positive for IBDV. Six representative samples were selected from 20 positive flocks for isolation in embryonated chicken eggs. The embryonic lesions observed included haemorrhage, skull swelling, and liver necrosis with a pale-yellow appearance, in addition to congestion and thickening in the chorioallantoic membrane (CAM). Partial amplification of the VP2 gene from the harvested embryo suspensions of the six IBDV isolates was performed for sequencing. Phylogenetic analysis of the sequences revealed that five IBDV isolates (VV4, VV5, VV6, VV10, and VV16) belonged to the very virulent strain group A3 cluster, whereas one isolate (VV2) clustered with Chinese Variant strains in the A2d group. Sequence analysis of the hypervariable region (HVR) of VP2 compared to that of Egypt-USC-IBD-1-2019 and vvIBDV/Beh21/Egypt/18 highly virulent IBDV strains revealed several amino acid mutations. The VP2 HVR of all isolates maintained the serine-rich heptapeptide sequence SWSASGS, which is adjacent to the major hydrophilic peak B and serves as a virulence marker. Histopathological examination revealed that bursae from chickens infected with vvIBDV exhibited marked interlobular oedema and lymphoid depletion. In contrast, bursae from chickens infected with Variant IBDV showed massive lymphoid depletion, with hyperplasia of the bursal capsule. These findings highlight the circulation of both virulent and Variant IBDV strains in Egyptian chicken flocks, complicating disease control. Consequently, there is a need to update vaccination programs and vaccine strains for IBDV in Egypt.

The current study was conducted to isolate and characterize Newcastle disease virus (NDV) from recent outbreaks affecting poultry farms in Egypt between 2011 and 2012. Trachea, spleen, liver, proventriculus and caecal tonsils were collected from clinically infected NDV ten different vaccinated broiler farms in Fayoum, Behira and Giza Provinces. Inoculation of all the collected samples in 10-day-old embryonated chicken specific-pathogen-free eggs resulted in isolation of haemagglutinating agents in three samples. These haemagglutinating agents were confirmed as NDV by real-time reverse transcription polymerase chain reaction (rt RT-PCR) using matrix (M) gene-specific primers. The deduced amino acid sequences of the fusion protein revealed that one isolate possessed the motif ¹¹²RRQKRF¹¹⁷ at the cleavage site, indicating that this isolate is velogenic genotype, whereas the other two isolates carries the motif ¹¹²GRQGRL¹¹⁷ indicating they are lentogenic genotype. The phylogenetic analysis revealed that the velogenic genotype isolate clustered with published class II genotype VII sub genotype d NDVs and closely related to Middle East isolates, whereas the other two isolates clustered with published class II genotype II NDVs. The spread of velogenic genotype strain to Egypt via Middle Eastern countries is likely to be the source of infection.

The present study was aimed to establish a protocol for the evaluation of the potency of commercial inactivated Newcastle disease virus (NDV) oil-adjuvanted vaccines using hemagglutination test (HA) and blocking ELISA (B-ELISA) based on polyclonal antibodies. Aqueous phases from a total of 47 batches of inactivated NDV vaccines manufactured by 20 different companies were extracted with isopropyl myristate. The viral antigen in each sample was detected and quantified by a standard HA test and a B-ELISA assay. To verify the efficiency of the antigen extraction method used in the batches which showed HA and to test the validity of using antigen quantification by HA and B-ELISA tests, a subset of 13 batches (selected from the total 47 batches) was inoculated in groups of 3-4-week-old specific pathogen-free chickens using the recommended vaccine dose. The immunogenicity of the selected vaccine batches was assessed by the NDV-hemagglutination inhibition antibody titers in individual serum samples collected 4 weeks after vaccination. Further, the efficacy of the vaccines and their protection rates were determined by a challenge test carried out for the vaccinated chickens with the Egyptian 2012 isolate of the virulent NDV genotype VII. A strong correlation was observed between HA titers and B-ELISA mean titers in the tested 47 batches (R =0.817). This indicated the possibility of using the latter assays for vaccine potency assessment. The recommended protective NDV antigen titer measured by B-ELISA was determined to be 28 ELISA units per dose. The comparison between the HA titers of the aqueous extracts of test vaccines and the corresponding results of potency assays (i.e., immunogenicity and efficacy), including antibody titers in the serum of vaccinated birds, indicated that the efficiency of the antigen extraction used may interfere with obtaining a strong correlation between the and results. HA or B-ELISA tests can be used as rapid and cost-effective alternatives to traditional potency tests for vaccine potency assessment by quantifying the NDV antigen present in aqueous phase extracts of the tested vaccines. The latter protocol, however, requires efficient extraction of the antigen to be able to obtain good correlation with the traditional potency tests.

Following the introduction of highly pathogenic avian influenza (HPAI) virus subtype H5N1, the Egyptian government implemented a massive poultry vaccination campaign as the cornerstone of its policies to control the virus. The efficacy of vaccination has been evaluated primarily by measuring titers of antibodies inhibiting the hemagglutinating activity of the viral hemagglutinin (HA). However, other aspects of the host response remain poorly understood. In the present study, in addition to hemagglutination inhibition (HI) titers, cytokine profiles were examined and IFNγ concentrations were measured in vivo after immunization with a whole inactivated virus (WIV) prepared from a classical strain of clade 2.2.1.2 (C121) and an antigenic drift variant of clade 2.2.1.1 (V1063). The results revealed an earlier response and higher HI titers and IFNγ levels in sera from chickens immunized with C121, accompanied by significantly higher expression of IL8, IL10, and IL18 in the spleen and IL6 and IL10 in the bursa, compared to those immunized with V1063. Furthermore, stimulation of the HD11 cell line with C121 induced gradual upregulation of pro-inflammatory cytokines, which was observed at 24 hours post-inoculation (hpi), and became more pronounced at 48 and 72 hpi, accompanied by upregulation of IFNα. Conversely, V1063 induced very early transient higher expression of pro-inflammatory cytokines at 3 and 6 hpi accompanied by upregulation of IL10, which then decreased at 24, 48 and 72 hpi. In summary, our results provide evidence of a correlation between adaptive immune responses induced by WIVs and higher expression of IL10 and IL18 in addition to early induction of IFNα. These findings could be used to improve immune responses induced by WIVs.

Large-scale sequence analysis of Matrix (M) gene and its coding proteins M1 and M2 was performed for 274 highly pathogenic avian influenza viruses H5N1 circulated in Egypt from 2006 to 2016. The aim is to study the amantadine-resistant markers distribution and to estimate the evolutionary rate. 246 viruses were obtained from the Global Initiative on Sharing All Influenza Data base, and 28 additional viruses were sequenced. Maximum clade credibility (MCC) phylogenetic tree revealed that the M gene has evolved into two different lineages. Estimated Evolutionary analysis showed that the M2 protein possessed higher evolutionary rates (3.45 × 10 −3 ) than the M1 protein (2.73 × 10 −3 ). M gene encoding proteins revealed significant markers described to be associated with host tropism and increase in virulence: V15I, N30D, and T121A in M1 and L55F in M2 protein. Site analysis focusing attention on the temporal and host distribution of the amantadine-resistant markers was carried out and showed that vast majority of the M2 amantadine-resistant variants of clade 2.2.1.1 ( n  = 90) is N31 marker, in addition to G27 ( n  = 7), A27 ( n  = 5), I27 ( n  = 1), and S30 ( n  = 1). In 2010–2011, amantadine resistant frequency increased considerably resembling more than half of the resistant variants. Notably, all viruses of clade 2.2.1.1 possessed amantadine-resistant marker. However, almost all current circulating viruses in Egypt of clade 2.2.1.2 from 2014 to 2016 did not carry any amantadine-resistant markers.

Neonatal diabetes mellitus is a rare condition, the causes of which are mostly unknown. One well defined though very rare entity is the autosomal recessive Wolcott-Rallison syndrome, in which permanent neonatal diabetes, osteopenia, and epiphyseal dysplasia occur. Only five previous families have been reported, and here we describe the second in which parental consanguinity was present. The proband was born to first cousin parents and died at 2 years from the sequelae of poorly controlled diabetes. To test the hypothesis that mutation of PAX4, required in the mouse for pancreatic islet beta cell development, might cause WRS, the structure of the human PAX4 gene was deduced and DNA from two unrelated WRS patients sequenced. No PAX4 mutation was present, though the entire coding region was sequenced in both patients. It therefore appears unlikely that PAX4 is involved in the aetiology of Wolcott-Rallison syndrome, though it remains a good candidate for other forms of neonatal diabetes mellitus.

The H9N2 subtype of avian influenza A virus (aIAV) is circulating among birds worldwide, leading to severe economic losses. H9N2 cocirculation with other highly pathogenic aIAVs has the potential to contribute to the rise of new strains with pandemic potential. Therefore, rapid detection of H9 aIAVs infection is crucial to control virus spread. A qualitative reverse transcription recombinase polymerase amplification (RT-RPA) assay for the detection of aIAV subtype H9N2 was developed. All results were compared to the gold standard (real-time reverse transcription polymerase chain reaction (RT-PCR)). The RT-RPA assay was designed to detect the hemagglutinin (HA) gene of H9N2 by testing three pairs of primers and a probe. A serial concentration between 106 and 100 EID50 (50% embryo infective dose)/mL was applied to calculate the analytical sensitivity. The H9 RT-RPA assay was highly sensitive as the lowest concentration point of a standard range at one EID50/mL was detected after 5 to 8 min. The H9N2 RT-RPA assay was highly specific as nucleic acid extracted from H9 negative samples and from other avian pathogens were not cross detected. The diagnostic sensitivity when testing clinical samples was 100% for RT-RPA and RT-PCR. In conclusion, H9N2 RT-RPA is a rapid sensitive and specific assay that easily operable in a portable device for field diagnosis of aIAV H9N2.

Background Paratuberculosis (PTB), caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a contagious and chronic enteric disease of ruminants and many non-ruminants leading to emaciation and death of the animal. PTB is poorly investigated in sheep and goats in Sudan, where these animals contribute significantly to food security and poverty alleviation as sources of income. They also play an important role in the national economy through animal exports. The objectives of this study were to investigate the prevalence of PTB and associated risk factors in small ruminants. Blood and faecal samples were collected from 818 sheep and goats aged > 1 year in 111 flocks distributed over five states (Blue Nile, West Kordofan, Khartoum, the Gezira and White Nile) of the country from November 2020 to October 2022. Serum samples were tested by an enzyme-linked immunosorbent assay (ELISA) for detection of MAP antibodies and the faecal samples were tested for MAP DNA using a recombinase aided amplification (RAA) assay. Results The overall true animal-level prevalence of PTB was 10.7% by RAA (4.2% in sheep, 6.5% in goats) and 1.7% by ELISA (0.7% in sheep, 1.0% in goats). At the flock level, prevalence was 41.8% by RAA and 8.5% by ELISA. While no significant associations were found between animal-level factors and PTB, several flock-level factors including breed homogeneity, source of new animals, management system, animal movement, separation of sick animals, and flock history of PTB were significantly associated with MAP detection ( P  < 0.05). Conclusions The high flock-level prevalence of MAP DNA indicates a potential risk for environmental dissemination, especially under open grazing systems. Despite the relatively low seroprevalence, molecular detection suggests subclinical infection may be underdiagnosed. These findings highlight the importance of using combined diagnostic methods for effective PTB surveillance and control. Improved flock management practices are recommended to reduce MAP transmission and environmental contamination.

The objective of the present study was to prepare a trivalent inactivated vaccine of Newcastle disease virus (NDV), H5N1, and H9N2 viruses. Three monovalent and a trivalent vaccines were prepared by emulsifying inactivated NDV (LaSota strain), reassortant H5N1, and H9N2 viruses with Montanide ISA 71 oil adjuvant. Parameters used for evaluation of the efficacy of the prepared vaccines in specific pathogen-free chickens were cellular immunity assays (blastogenesis, interferon gamma, interleukin 1 [IL1], and IL6), humoral immunity by hemagglutination inhibition, protection percentage, and shedding. A single immunization with trivalent vaccine-enhanced cell-mediated immunity as well as humoral immune response with 90% protection against challenges with highly pathogenic avian influenza (HPAI) H5N1 and low pathogenic (LP) avian influenza H9N2 viruses with 100% protection after challenge with NDV. Development and evaluation of the trivalent vaccine in the study reported the success in preparation of a potent and efficacious trivalent vaccine which is a promising approach for controlling HPAI H5N1, LP H9N2, and ND viral infections.