Genetic Sequence and Pathogenicity of Infectious Bursal Disease Virus in Chickens in Egypt During 2017-2021.

The continued circulation of infectious bursal disease virus (IBDV) in Egypt, despite the use of various vaccines, is a serious problem that requires continuous detection of IBDV. In the current study, real-time reverse transcriptase polymerase chain reaction testing of 100 diseased chicken flocks during 2017-2021 revealed the presence of very virulent IBDV (vvIBDV) in 67% of the flocks, non-vvIBDV in 11%, and a mixture of both vvIBDV and non-vvIBDV in 4%. Twenty-nine IBDV isolates were submitted for partial sequencing of the viral protein 2 hypervariable region (VP2-HVR), and 27 isolates were confirmed to be genogroup A3 (vvIBDV) with 96.3%-98.5% similarity to the global A3 (vvIBDV) and 88.9%-97% similarity to genogroup A1 vaccine strains. The remaining two isolates were non-vvIBDV and showed 91.1% and 100% identity with classical genogroup A1 strains, respectively. Furthermore, the sequence and phylogenetic analysis of VP1 (amino acids 33-254) of two selected isolates of A3, 5/2017 and 98/2021, clustered them as B2, vvIBDV-like, strains with high similarity (99.5%) to four Egyptian, 99% to Chinese and European, and 97.7% to Chinese and Polish vvIBDV isolates. Experimental infection of commercial broiler chickens with two vvIBDV-A3B2 isolates (5/2017 and 98/2021) showed no mortality despite typical tissue lesions, clear histopathological changes, and strong ELISA antibody response. Isolate 98/2021 was more pathogenic, as confirmed by histopathology, whereas isolate 5/2017 induced a stronger serological response. In conclusion, vvIBDV (A3B2) strains with two amino acid (aa) substitutions in VP1 as V141I and V234I as well as VP2 as Y220F and G254S are still circulating in Egypt.

Análisis de las secuencias genéticas y de la patogenicidad del virus de la enfermedad infecciosa de la bolsa de pollos en Egipto durante los años 2017­2021. La circulación continua del virus de la enfermedad infecciosa de la bolsa (IBDV) en Egipto, a pesar del uso de varias vacunas, continua siendo un problema serio que requiere la detección continua de este virus. En el presente estudio, se realizó una prueba de transcripción reversa y reacción en cadena de la polimerasa en tiempo real de 100 parvadas enfermas de pollos durante los años 2017­2021 y reveló la presencia de virus muy virulentos (vvIBDV) en el 67% de las parvadas, otros tipos diferentes a los muy virulentos en el 11%, y una mezcla de virus muy virulentos y otros tiposen un 4% de las parvadas. Se enviaron veintinueve aislados del virus de la enfermedad infecciosa de la bolsa para la secuenciación parcial de la región hipervariable de la proteína viral 2 (VP2-HVR), y se confirmó que 27 aislados pertenecían al genogrupo A3 (vvIBDV) con una similitud del 96.3% al 98.5% con el genogrupo A3 global (vvIBDV) y de 88.9% a 97% de similitud con las cepas vacunales del genogrupo A1. Los dos aislamientos restantes no resultaron ser muy virulentos y mostraron un 91.1% y un 100% de identidad con las cepas clásicas del genogrupo A1, respectivamente. Además, la secuencia y el análisis filogenético de la proteina VP1 (aminoácidos 33-254) de dos aislados seleccionados de genogrupo A3, 5/2017 y 98/2021, los agruparon como cepas B2, similares a virus muy virulentos, con alta similitud (99.5%) con cuatro aislamientos de Egipto, con similitud de 99% con aislados chinos y europeos, y de 97.7% con aislados muy virulentos chinos y polacos. La infección experimental de pollos de engorde comerciales con dos aislados muy virulentos tipo A3B2 (5/2017 y 98/2021) no mostró mortalidad a pesar de las lesiones tisulares típicas, los cambios histopatológicos claros y la fuerte respuesta de anticuerpos por ELISA. El aislado 98/2021 fue más patógeno, según lo confirmado por histopatología, mientras que el aislado 5/2017 indujo una respuesta serológica más fuerte. En conclusión, las cepas muy virulentas (A3B2) con dos sustituciones de aminoácidos (aa) en la proteina VP1 como V141I y V234I, así como en VP2 tales como Y220F y G254S, todavía circulan en Egipto.

Dietary lysozyme and avilamycin modulate gut health, immunity, and growth rate in broilers.

BACKGROUND: Attempts to use dietary lysozyme (LYZ) as an alternative to antibiotics in broilers have been successful, but further research is needed for effective use. Here, we compared the differences between LYZ and avilamycin (AVI) feed additives for growth performance, gut health and immunity of broilers. One-day old, one hundred and twenty broiler chicks (Ross 308) were randomly allocated into three groups consisting forty birds in each group. Standard diet without supplementation was applied as the control group (I), while the chicks of the other groups were supplemented with 100 mg of AVI per kg diet (AVI, group II), and 90 mg LYZ per kg diet (LYZ, group III) for five consecutive weeks. RESULTS: Body weight, feed conversion ratio, body weight gain, and European production efficiency factor were markedly (p < 0.05) increased in both AVI and LYZ groups in relation to CON group, but the feed intake and protein efficiency ratio were not affected. Both AVI and LYZ significantly (p < 0.001) upregulated the mRNA expression of ileal interleukin-18 (IL-18), interferon-gamma (IFN-γ), and interleukin-10 (IL-10), interleukin-2 (IL-2), and glutathione peroxidase (GSH-PX) genes compared to CON group. However, IL-2, IL-10, IL-18, and GSH-PX genes were markedly (p < 0.01) upregulated in LYZ compared to the AVI group. LYZ treated group had a significant increase (p < 0.05) in the serological haemagglutination inhibition titers of H5N1 vaccination and a significant decrease (p < 0.0001) in coliform counts compared to control and AVI groups, but all growth parameters were nearly similar between AVI and LYZ groups. The VH and VH/CD were markedly higher in LYZ than AVI and control groups. CONCLUSION: Exogenous dietary lysozyme supplementation by a dose of 90 mg/kg broilers' diet induced better effects on intestinal integrity, fecal bacterial counts, immune response, and growth performance which were comparable to avilamycin. Therefore, dietary lysozyme could safely replace avilamycin in the broiler chickens' diet. However, further experimental studies regarding the use of lysozyme in commercial broilers, both in vitro and in vivo, targeting more communities of intestinal microbiome and explaining more details about its beneficial effects need to be conducted.

Corrigendum: Epidemiology, pathology, prevention, and control strategies of inclusion body hepatitis and hepatitis-hydropericardium syndrome in poultry: A comprehensive review.

[This corrects the article DOI: 10.3389/fvets.2022.963199.].

Epidemiology, pathology, prevention, and control strategies of inclusion body hepatitis and hepatitis-hydropericardium syndrome in poultry: A comprehensive review.

Infection with fowl adenoviruses (FAdVs) can result in a number of syndromes in the production of chicken, including inclusion body hepatitis (IBH), hepatitis-hydropericardium syndrome (HHS), and others, causing enormous economic losses around the globe. FAdVs are divided into 12 serotypes and five species (A-E; 1-8a and 8b-11). Most avian species are prone to infection due to the widespread distribution of FAdV strains. The genus aviadenovirus, which is a member of the adenoviridae family, is responsible for both IBH and HHS. The most popular types of transmission are mechanical, vertical, and horizontal. Hepatitis with basophilic intranuclear inclusion bodies distinguishes IBH, but the buildup of translucent or straw-colored fluid in the pericardial sac distinguishes HHS. IBH and HHS require a confirmatory diagnosis because their clinical symptoms and postmortem abnormalities are not unique to those conditions. Under a microscope, the presence of particular lesions and inclusion bodies may provide clues. Traditional virus isolation in avian tissue culture is more delicate than in avian embryonated eggs. Additionally, aviadenovirus may now be quickly and precisely detected using molecular diagnostic tools. Preventive techniques should rely on efficient biosecurity controls and immunize breeders prior to production in order to protect progeny. This current review gives a general overview of the current local and global scenario of IBH, and HHS brought on by FAdVs and covers both their issues and preventative vaccination methods.

Muscovy ducks infected with velogenic Newcastle disease virus (genotype VIId) act as carriers to infect in-contact chickens.

This work was designed to study the dynamics of transmission of Newcastle disease virus (NDV), genotype VIId, from Muscovy ducks (Cariana moscata) infected either by intramuscular (IM) or intranasal (IN) inoculation, to in-contact broiler chickens (Gallus gallus). IM-infected Muscovy ducks (G1d) exhibited only 5% mortality, and the concentration of virus shed from the cloaca was greater and for longer period than virus shed from the trachea. In contrast, IN-infected ducks (G2d) exhibited no mortality, and virus shedding from the trachea was higher than that from the cloaca starting from 4 days post infection (dpi) and continued up to 16 dpi, while in IM-infected ducks (G1d), tracheal shedding stopped at 11 dpi. Chickens in contact with IM-infected and IN-infected ducks, G1c and G2c, respectively, not only developed severe clinical symptoms and death (80% and 20% mortality, respectively), but also shed the virus at higher concentrations than infected ducks. G1c chickens had higher viral shedding titers in both the trachea and cloaca than G2c chickens until 11 dpi. All broiler chickens infected by IM route (G3c) died, while the IN route of infection resulted in lower mortality (70%) in G4c. Generally, all IM-infected birds produced an earlier and higher level of NDV hemagglutination inhibition (HI) antibody titer, along with higher rates and shorter periods of viral shedding than those infected by the intranasal route. Our conclusion is that Muscovy ducks are efficient carriers of NDV-genotype VIId and transmit the virus to contact chickens.

Evidence for differing evolutionary dynamics of A/H5N1 viruses among countries applying or not applying avian influenza vaccination in poultry.

Highly pathogenic avian influenza (HPAI) H5N1 (clade 2.2) was introduced into Egypt in early 2006. Despite the control measures taken, including mass vaccination of poultry, the virus rapidly spread among commercial and backyard flocks. Since the initial outbreaks, the virus in Egypt has evolved into a third order clade (clade 2.2.1) and diverged into antigenically and genetically distinct subclades. To better understand the dynamics of HPAI H5N1 evolution in countries that differ in vaccination policy, we undertook an in-depth analysis of those virus strains circulating in Egypt between 2006 and 2010, and compared countries where vaccination was adopted (Egypt and Indonesia) to those where it was not (Nigeria, Turkey and Thailand). This study incorporated 751 sequences (Egypt n=309, Indonesia n=149, Nigeria n=106, Turkey n=87, Thailand n=100) of the complete haemagglutinin (HA) open reading frame, the major antigenic determinant of influenza A virus. Our analysis revealed that two main Egyptian subclades (termed A and B) have co-circulated in domestic poultry since late 2007 and exhibit different profiles of positively selected codons and rates of nucleotide substitution. The mean evolutionary rate of subclade A H5N1 viruses was 4.07×10(-3) nucleotide substitutions per site, per year (HPD 95%, 3.23-4.91), whereas subclade B possessed a markedly higher substitution rate (8.87×10(-3); 95% HPD 7.0-10.72×10(-3)) and a stronger signature of positive selection. Although the direct association between H5N1 vaccination and virus evolution is difficult to establish, we found evidence for a difference in the evolutionary dynamics of H5N1 viruses among countries where vaccination was or was not adopted. In particular, both evolutionary rates and the number of positively selected sites were higher in virus populations circulating in countries applying avian influenza vaccination for H5N1, compared to viruses circulating in countries which had never used vaccination. We therefore urge a greater consideration of the potential consequences of inadequate vaccination on viral evolution.