Evaluate the Effects of Air Quality on the Onset (Infection), Transmission and Severity of Respiratory Disease Caused by IBV as a Model
PI: Mark W. Jackwood and Brian J. Jordan
Investigate the multifactorial etiology involving poultry respiratory diseases and specifically examines environmental factors in the pathogenesis and control of respiratory disease.
Our objective is to evaluate the effects of reduced air quality on the onset (infection), transmission and severity of respiratory disease caused by IBV as a model system. In the first set of experiments we will vaccinate broiler chickens for IBV in normal and reduced air quality environments at 1 and 14 days of age and examine the development of immunity by following replication of the vaccine using quantitative real time RT-PCR and examining the level of IgA in the upper respiratory tract. We will then determine if the birds are protected by challenging them with a homologous strain of IBV. Protection will be based on recovery of the challenge virus, ciliostasis scoring, clinical signs and lesions, and histopathology. In a second set of experiments we will vaccinate and challenge the birds with IBV similarly to the first experiments but this time we will add contact control birds to determine if the challenge virus can be transmitted horizontally in normal and reduced air quality environments. In both sets of experiments we will maintain the appropriate positive and negative control groups, which will allow us to measure the onset, severity and duration of respiratory disease in both normal and reduced air quality environments. Our approach will be to vaccinate birds before and after exposing them to poor air quality to study the effect on development of immunity and protection from challenge. We will also challenge immunized and susceptible birds in the presence of normal and poor air quality to examine its effect on severity and longevity of disease. This study will provide data on the interaction between air quality and control of respiratory pathogens through vaccination.
Years 1 & 2:
Evaluate the effects of air quality on ciliostasis and the onset if immunity to IBV.
Years 3 & 4:
Examine the effects of air quality on protection from challenge and transmission of challenge viruses to susceptible hosts.
Examine the effect of air quality on the severity and longevity of disease.
Potential Impact and Expected Outcomes:
The data obtained from this study will provide important information on the effect of poultry house air quality on vaccine efficacy for upper-respiratory disease pathogens. The information obtained will be used to maintain air quality that optimizes respiratory disease control measures.