Comparison of the immune response between local manufactured and commercial inactivated Newcastle Disease Virus vaccine in a challenge trail with field isolated Newcastle Disease Virus

A I Ahmed

doi:10.30539/iraqijvm.v42i1.30

Abstract

Velogenic Newcastle Disease Virus was isolated from broiler chickens in Northern Iraq. An inactivated vaccine was manufactured locally using as seed virus ELD50/ml109 and then compared with commercial inactivated vaccine in an experimental study which included 120 broiler chicks divided into three groups (G1 unvaccinated control, G2 for commercial vaccine and G3 for local vaccine). The chicks were injected subcutaneously at 3 days old followed by booster Lasota live vaccine eye drop. Indirect ELISA technique was used to estimate the antibody titer from the collected sera of chicks at age 7, 17 and 27 days (pre-challenge) and challenged at 31 days old with the same virus. The results indicated that there were significant differences (P<0.05) between vaccinated group G2 and G3 at 27th day old and showed a high antibody level with high protection percentage compared with the control. G1 which shown no survival, 100% mortality and severe histopathological lesions, while in G2 and G3 was 43% and 87% respectively. Post-challenge antibody titers of survival chicks showed in G3 significantly over the G2 with less severe histopathological lesions. This study concluded that vaccine failure could occur due to factors of the immune status of the host, improper storage of vaccine, improper vaccination and variant pathogenic virus strain. More epidemiological surveillances are required to decide the actual impact of the disease in poultry farms and matching the vaccines.

Highlights

China belong to the VIId sub-genotype of Newcastle disease (ND) is one of the most important diseases that affect birds, in particular chickens
All groups except control were vaccinated with ND Clone 30 (Intervet®) at 1 day old, at 3 days old the chicks in the second group were vaccinated with 0.5 ml of commercial inactivated ND, the third groups vaccinated with 0.5 ml of field isolate inactivated vaccine subcutaneously followed with Lasota vaccine at 10 days old via ocular route and control left without vaccines
The evaluation of immune response was determined (Table, 1) at 7, 17 and 27 days-old chicks pre-challenge the result showed significantly differences in mean±SE titer at 27days-old in vaccinated group (G2 and G3) were 1008±193 and 2816±614 respectively similar finding with [12], titer produced after immunization with inactivated vaccine produce higher titer after 27 days old, while decline mean±SE antibody titer in non-vaccinated control group (G1) was 296±16.69

Summary

Introduction

China belong to the VIId sub-genotype of Newcastle disease (ND) is one of the most important diseases that affect birds, in particular chickens. The Newcastle disease virus (NDV) strains pathogenicity can be classified into three pathotypes (velogenic, mesogenic and lentogenic) on the basis of the severity of disease in chickens. The spread of NDV in chickens routinely vaccinated with NDV genotype VII in poultry in spite of excessive vaccination programs (3 and 4). They suggested that these VIId isolates are antigenically distinct from the currently available NDV vaccine strains. Some researchers concluded that vaccine produced from virus isolated from previous local NDV outbreak revealed high level of protection (5 and 6). The research was designed to prepare an inactivated vaccine from recently local isolates of NDV and study the efficacy of the vaccine and their protections capacity against the infection with significant level of antibodies to reduce mortality rate

Methods

Results

Conclusion