vaccines-world-2017-posters-accepted-abstracts

4 / 20

alliedacademies
Virology Research Journal
Volume 1 Issue 4 Vaccines World 2017
Notes:
Page 36
November 09-10, 2017 Vienna, Austria
21st World Congress and Exhibition on
VACCINES, VACCINATION & IMMUNIZATION
Protection of horses from West Nile virus lineage
2 challenge following immunization with a whole,
formalin-inactivated WNV lineage 1 vaccine
Richard A Bowen1, Angela Bosco-Lauth1, Kevin Syvrud2, Anne Thomas3, Todd
R Meinert4, Deborah R Ludlow4, Corey Cook4, Jeremy Salt3 and Ellen Ons3
1Colorado State University, USA
2Summit Research, USA
3Zoetis, Zaventem, Belgium
4Zoetis, Kalamazoo, USA
Over the last years West Nile Virus (WNV) lineage 2 has
spread from the African to the European continent. This
study was conducted to demonstrate efficacy of an inactivated,
lineage 1-based, WNV vaccine (Equip WNV) against intrathecal
challenge of horses with a recent isolate of lineage 2WNV. Twenty
horses, seronegative for WNV, were enrolled and were randomly
allocated to one of two treatment groups: an unvaccinated control
group (T01, n=10) and a group administered with Equip WNV
(T02, n=10). Horses were vaccinated at day 0 and 21 and were
challenged at day 42withWNV lineage 2, Nea Santa/Greece/2010.
Personnel performing clinical observations were blinded to
treatment allocation. Sixty percent of the controls had to be
euthanized after challenge compared to none of the vaccinates. A
significantly lower percentage of the vaccinated animals showed
clinical disease (two different clinical observations present on
the same day) on six different days of study and the percentage
of days with clinical disease was significantly lower in the
vaccinated group. A total of 80% of the non-vaccinated horses
showed viremia while only one vaccinated animal was positive by
virus isolation on a single occasion. Vaccinated animals started
to develop antibodies against WNV lineage 2 from day 14 (two
weeks after the first vaccination) and at day 42 (the time of onset
of immunity) they had all developed a strong antibody response.
Histopathology scores for all unvaccinated animals ranged from
mild to very severe in each of the tissues examined (cervical
spinal cord, medulla and pons), whereas in vaccinated horses
8 of 10 animals had no lesions and two had minimal lesions in
one tissue. In conclusion, Equip WNV significantly reduced the
number of viremic horses, the duration and severity of clinical
signs of disease and mortality following challenge with lineage
2 WNV.
Biography
Anne Thomas is DVM and PHD from University of Liège (Belgium). She has
also a PostDoc from the same university. She joined Pfizer Animal Health in
2006 and works in Zoetis-VMRD from 2011.
Anne Thomas, Virol Res J 2017, 1:4