Recipient Organization
IOWA STATE UNIVERSITY
S. AND 16TH ELWOOD
AMES,IA 50011
Performing Department
VETERINARY MEDICINE
Non Technical Summary
M. hyopneumoniae is one of the pathogens found most frequently in the porcine respiratory disease complex (PRDC), an economically significant respiratory disorder characterized by slow growth, decreased feed efficiency, lethargy, anorexia, fever, cough and dyspnea. Many swine practitioners time M. hyopneumoniae vaccinations in pigs based upon the assumption that maternal antibody interference is a real phenomena. SwiVax-MH will be evaluated for its ability to reduce macroscopic lesions and induce an effective immune response in our M. hyopneumoniae infection model.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
The objective of this study is to evaluate the ability of SwiVax-MH to reduce clinical disease in young pigs vaccinated at 1 and 3 weeks of age with maternal antibodies and subsequently infected with M. hyopneumoniae.
Project Methods
Ninety M. hyopneumoniae-free barrows will be obtained at 10-14 days of age. All pigs selected for inclusion in the study will be bled and weighed upon arrival and their weights recorded. All pigs will be treated with ceftiofur hydrochloride the day following arrival. A second dose of ceftiofur hydrochloride may be administered the next day, same dose and route as initial administration. Upon arrival, pigs will receive a concentrated medicated diet daily, free of any known contaminants or pesticides and have free access to water. Approximately two weeks prior to the scheduled challenge, pigs will receive a non-medicated diet daily. Each group will be housed in separate rooms. The first vaccination at 1 week of age will occur at the source farm. Challenge will occur at 2 weeks post-vaccination. The pigs will be necropsied at 28 days post-challenge with M. hyopneumoniae. Challenge Procedure: A tissue homogenate containing a derivative of M. hyopneumoniae, strain 11 (105
color changing units (CCU)/ml) will be administered intratracheally in the morning at a dilution of 1:100 in 10 ml of mycoplasmal Friis medium to pigs in the appropriate groups two weeks after vaccination. Clinical Evaluation: Tag number for each animal, date(s) of illness, presumptive diagnosis, treatment regimen and disposition of the animal will be recorded. No treatment will be provided following challenge. Serology: Blood will be collected from study piglets via the anterior vena cava 5 days prior to delivery, upon arrival, prior to vaccination, prior to challenge and at each necropsy. M. hyopneumoniae antibody levels will be determined using a Tween-20 ELISA. Production Parameters: Pigs will be weighed five days prior to delivery, upon arrival, prior to vaccination, prior to challenge and at necropsy to evaluate weight gain. Necropsy: Pigs will be necropsied at approximately 28 days post inoculation. The right rib cage will be reflected and a portion of the lung removed
aseptically for culture. Tracheal swabs will be collected aseptically for bacterial isolation and titration of M. hyopneumoniae. The lungs will be evaluated for macroscopic lesions. The lungs will be removed and bronchoalveolar lavage (BAL) fluid will be obtained by lavaging the bronchi with 50 ml of PBS containing antibiotics. The lavage will be aliquoted and stored at -80 for future assays which may include cytokine and Real Time PCR assays. Lesions consistent with M. hyopneumoniae will be sketched on a standard diagram and assessed for the proportion of lung surface exhibiting lesions using a Zeiss SEM-IPS image analyzing system. M. hyopneumoniae Isolation and Culture: M. hyopneumoniae will be isolated from lung tissue and bronchial swabs.