Antigenic variations of infectious bronchitis virus from broiler flocks in Al-Beheira governorate

Seventeen avian infectious bronchitis virus [IBV] isolates were isolated from broiler chickens showing respiratory and renal lesions. The isolated strains were characterized by real time reverse transcriptase polymerase chain reaction used for N gene, and then RT-PCR and sequence analysis of the hypervariable region 3 of the S1 spike glycoprotein gene of six isolates. Six isolates showed 87.15% to 89.71% and 87.27% to 90.82% amino acid sequence identity and 87.61% to 89.19% and 87.91% to 89.72% nucleotide sequence identity to the Egyptian variant 1 and the IS/885 strains, respectively. The six isolates formed a distinct phylogenetic group with the Ck/Eg/BSU-2/2011 and Ck/Eg/ BSU-3/2011 [Var 2]. Amino acid and nucleotide identities between the six Egyptian isolates and variant 2 [Ck/Eg/BSU-2/2011 and Ck/Eg/BSU-3/2011] ranged from 97.27% to 100% and 97.88% to 99.38%, respectively. The results indicate that the six isolates IBV/CK/Beh/101/013/S1, IBV/CK/Beh/204/013/S1, IBV/CK/Beh/105/013/S1, IBV /CK/Beh/1011/013/S1, IBV/CK/Beh/1017/013/S1, IBV/CK/Beh/2020/013/S1 can be considered a variant 2 as Ck/Eg/BSU-2/2011 and Ck/Eg/BSU-3/2011. This study demonstrates a constant evolution of IBV in Egypt that necessitates continuous monitoring to control the spread of infections, and the development and use of vaccines based on indigenous viruses

Protection of chickens against infectious bronchitis virus with a multivalent DNA vaccine and boosting with an inactivated vaccine

The protective efficacy of DNA plasmids encoding avian infectious bronchitis virus (IBV) S1, N, or M protein was investigated in chickens. Chickens were inoculated monovalently (with plasmid pVAX1-16S1, pVAX1-16M, or pVAX1-16N alone) or multivalently (combination of the three different plasmids, pVAX1-16S1/M/N). A prime-boost immunization protocol against IBV was developed. Chickens were immunized with the multivalent DNA vaccine twice and then boosted with an inactivated vaccine once. Antibody titers of the chickens immunized with pVAX1-16S1/M/N were much higher than those of the monovalent groups (p < 0.01). A protective rate up to 90% was observed in the pVAX1-16S1/M/N group. The serum antibody titers in the prime-boost birds were significantly higher than those of the multivalent DNA vaccine group (p < 0.01) but not significantly different compared to the inactivated vaccine group at 49 days of age. Additionally, the prime-boost group also showed the highest level of IBV-specific cellular proliferation compared to the monovalent groups (p < 0.01) but no significant difference was found compared to the multivalent DNA vaccine group, and the prime-boost group completely protected from followed viral challenge.

A liquid phase blocking ELISA for the detection of antibodies against infectious bronchitis virus

A liquid phase blocking ELISA (LPB-ELISA) was developed for the detection and measurement of antibodies against infectious bronchitis virus (IBV). The purified and nonpurified virus used as antigen, the capture and detector antibodies, and the chicken hyperimmune sera were prepared and standardized for this purpose. A total of 156 sera from vaccinated and 100 from specific pathogen-free chickens with no recorded contact with the virus were tested. The respective serum titers obtained in the serum neutralization test (SNT) were compared with those obtained in the LPB-ELISA. There was a high correlation (r2 = 0.8926) between the two tests. The LPB-ELISA represents a single test suitable for the rapid detection of antibodies against bronchitis virus in chicken sera, with good sensitivity (88 per cent), specificity (100 per cent) and agreement (95.31 per cent).

Caracterización antigénica de un virus de la bronquitis infecciosa, aislado en pollos de traspatio en Yucatán, México / Antigenic characterization of an infectious bronchitis virus isolated in backyard chicken in the state of Yucatan, Mexico

La producción animal de traspatio es una actividad tradicional en México, cuya finalidad es solucionar algunos problemas de la difícil situación económica de los campesinos. Los pollo son la especie más común en dicho sistema en Yucatán y son alimentados con subproductos, En estudios previos se encontró que las enfermedades respiratorias constituyen las más importantes en estos animales. En el presente estudio se obtuvo un aislamiento del virus de la bronquitis infecciosa en pollos de engorda introducidos al traspatio del poblado Sinanché, Yucatán, México; aquél se denominó SIN6. La caracterización antigénica de este aislamiento se realizó mediante la prueba de inhibición de la hemaglutinación, utilizando antígeno hemaglutinante producido a partir de 11 serotipos de referencia del virus de la bronquitis infecciosa (Massachusetts 41, Arkansas, Connecticut, Holte, CVL/9, 793/B, Holandés 274, Holandés 1466, Australiano "T", italiano 624, y Chileno 368), y antisueros contra estos serotipos y el Iowa 97; de este último no se logró obtener antígeno a pesar de repetidos intentos. El aislamiento SIN6 tuvo una relación antigénica baja con todos los serotipos de referencia, lo que indica que probablemente es un serotipo nuevo, aunque estudios de secuencia genética son necesarios para confirmarlo. El serotipo CVL/9 presentó una fuerte relación antigénica con todos los demás, esta circunstancia lo hace un candidato para la producción de una vacuna universal contra la bronquitis infecciosa

Isolation of egg yolk immunoglobulins [IgY] by chloroform polyethylene glycol technique and assaying of antibodies against avian infectious bronchitis

The present research study was conducted to isolate the chicken egg yolk immunoglobulins [IgY] by chloroform polyethylene glycol [CPEG] technique and to measure antibody titers against avian infection bronchitis [AIB]. For this purpose 300 eggs of broiler breeder were procured from 10 different flocks [30 eggs from each], at least 3 to 4 weeks post-vaccination against avian infectious bronchitis [AIB]. The yolk of three eggs was pooled and subjected to the isolation of IgY by SPEG technique. The concentration of purified IgY was quantified by spectrophotometer and antibody titers against AIB were measured through hemagglutination inhibition [HI] test. Mean concentration of IgY in different flocks ranged from 2.65 to 3.7 g/dl with overall mean of 3.24 g/dl. The geomean antibody titers [GMT] against AIB ranged from 147 to 388 with cumulative GMT of 256. Correlation between concentration of IgY and AIB antibody titers was computed to be 0.88