المستخلص
Contagious ecthyma is additionally referred to as (Orf) and it is known in many names; scabby mouth, sore mouth, and contagious pustular dermitis. It is a disease that spreads easily and is brought on by the epitheliotropic, is endemic around the world and has a serious economic impact. Present study aimed to understand the immune response mechanisms of the lambs to defense against Contagious ecthyma virus and molecular detection of the virus with the determining the sequence of the gene and mutant in the gene sequence of the virus in 91 lambs (41 lambs have clinical signs of Orfv and 50 lambs control do not have clinical sign of Orfv ) for the period extended from September 2022 to April 2023 by using two methods in diagnosis Enzyme.-linked immune sorbent assay(ELISA) and molecular identification Polymerase chain reaction (PCR).
Blood samples were collected from all the mentioned groups to apply for detection the level of IgM, IgG, IL-10, IFN- gamma (IFN- γ) of Orfv using the ELISA test. Subsequently a diagnosis of the positive and negative Orfv IgM and IgG in serum blood samples.
The distribution Orfv IgM in infected lambs showed positive result in 75.6% (31out of 41of the infected lamb), while in the non-infected group, it was 72% (36 out of 50) of the lambs. Regarding the distribution of Orfv IgG in Lambs was found that among the infected lambs at 90.2% (37 out of 41) tested positive for Orfv IgG. Similarly among the non-infected lambs showed positive Orfv IgG results 88% (44 out of 50).
Furthermore this study aimed to investigate the effect of Orfv infection on the immune response by examine the level of IL-10 and IFN-γ in the infected lambs and their correlation with IgM and IgG level . The results showed a significant increasing in IL-10 levels in all Lambs with positive Orfv IgM at (54.58 ± 38.47) pg /ml compared with negative Orfv IgM Lambs (8.56 ± 6.43) pg/ml. However the level of IFN-γ did not show significance difference between lambs with positive Orfv IgM at (111.13 ± 71.13) pg /ml and lambs with negative Orfv at (101 ± 06) pg/ml . Regarding for to related Orfv IgG, the level of IL-10 showed a significant increasing in all Lambs positive Orfv IgG at (45.18 ± 39.84 ) pg/ml compared with level of IL-10 in a negative Orfv IgG Lambs at (20.34 ± 19.95 ) pg /ml. and the level of IFN- γ showed a non-significant differences in all Lambs positive Orfv IgG at (110.09 ± 67.88) pg/ml and the level of IFN – γ in a negative Orfv IgG Lambs at (95.33 ± 69.41) pg/ml.
Molecular detection of Contagious ecthyma virus was perform by DNA extraction and applied in PCR method for the detection of the viral DNA. The molecular detection Orf virus result in this study was confirmed the positivity of all samples and gave positive Orfv IgM. And the sequencing of the Orf virus DNA showed a mutant in the some allele compared with references strain registered at NCBI. Based on the findings of this study, it can be concluded that there is a high prevalence of Contagious ecthyma Virus among lambs. Furthermore, the presence of mutants in the viral genome contributes to increased virulence of the virus which subsequently impacts the immune response
