Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2011
Publication Date: 10/15/2011
Citation: Wang, L., Qin, Z., Pantin Jackwood, M.J., Faulkner, O.B., Suarez, D.L., Garacia, M., Lupiani, B., Reddy, S., Saif, Y., Lee, C. 2011. Development of DIVA (differentiation of infected from vaccinated animals) vaccines utilizing heterologous NA and NS1 protein strategies for the control of triple reassortant H3N2 influenza in turkeys. Vaccine. 29:7966-7974. Interpretive Summary: Turkeys are commonly infected with both avian and swine influenza viruses. When turkeys are infected with swine influenza, the most common disease symptom observed is drops in egg production, which are costly to the turkey industry. Swine influenza viruses can infect, but rarely cause disease in young turkeys. Vaccination is often used to protect turkey breeders, but current vaccines provide poor protection. This study looked at several new vaccines that were developed to provide better protection, but that could also be used as a differentiation of infected from vaccinated animals (DIVA) vaccine. A DIVA vaccine provides the ability to differentiate birds that are vaccinated from those that are naturally infected. This type of test is helpful when trying to control a disease because it allows you to easily identify when flocks of birds are being naturally infected in the field. This study looked at the immune response of tf both the neuraminidase protein and the non-structural protein 1 of influenza as possible DIVA test markers. Both markers could be used as a DIVA test, but because not all the birds could be differentiated by the tests used, it could only be used as a flock test and not an individual bird test.
Technical Abstract: Since 2003, triple reassortant (TR) swine H3N2 influenza viruses containing gene segments from human, avian and swine origins have been detected in the U.S. turkey populations. The initial outbreak that occurred even involved birds that were vaccinated with the currently available H3 swine- and avian- origin influenza vaccines. Antigenically, all turkey swine-lineage TR H3N2 isolates are closely related to each other but show little or no antigenic cross-reactivity with the avian origin or swine origin influenza vaccine strains that are currently being used in turkey operations. These results call for re-evaluation of currently available influenza vaccines being used in turkey flocks and development of more effective DIVA (differentiation of infected from vaccinated animals) vaccines. In this study, we selected one TR H3N2 strain, A/turkey/OH/313053/04 (H3N2), that showed broad cross reactivity with other recent TR turkey H3N2 isolates, and created NA- and NS-based DIVA vaccines using traditional reassortment as well as reverse genetics methods. Protective efficacy of those vaccines was determined in two-week-old and eighty-week-old breeder turkeys. The reassortant DIVA vaccines significantly reduced the presence of challenge virus in the oviduct of breeder turkeys as well as trachea and cloaca shedding of both young and old breeder turkeys, suggesting that proper vaccination could effectively prevent egg production drop and potential viral contamination of eggs in infected turkeys. Our results demonstrate that the heterologous NA and NS1 DIVA vaccines together with their corresponding serological tests could be useful for the control of TR H3N2 influenza in turkeys.