Infection studies with West Nile virus lineage 1
and 2 in large falcons
J. Angenvoort1*, U. Ziegler1, D. Fischer2, C. Fast1, M. Eiden1, S. RevillaFernández3, N. Nowotny4, J. Garcia de la Fuente5, M. Lierz2 and M. H.
Groschup1
1
Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health,
Institute of Novel and Emerging Infectious Diseases, Südufer 10, 17493
Greifswald-Insel Riems, Germany;
2
Clinic for Birds, Reptiles, Amphibians and Fish, Justus Liebig University
Giessen, Frankfurter Str. 91-93, 35392 Giessen, Germany;
3
Institute for Veterinary Disease Control Mödling, Austrian Agency for Health
and Food Safety (AGES), Robert Koch-Gasse 17, 2340 Mödling, Austria;
4
Zoonoses and Emerging Infections Group, Clinical Virology, Department of
Pathobiology, University of Veterinary Medicine, Vienna, Veterinärplatz 1,
1210 Vienna, Austria;
5
Roc Falcon S.L., Finca Caballera Alta, Odèn (Lleida), Spain
*presenting author
Keywords: West Nile virus, experimental infection, falcons, lineage 1
and 2
Abstract: West Nile virus (WNV) is an important zoonotic flavivirus
that is transmitted by blood-suckling mosquitoes and uses birds as
primary vertebrate reservoir hosts (enzootic cycle). Some bird species
like ravens, falcons and jays are highly susceptible and develop
deadly encephalitis while others are only going through a subclinical
infection.
Findings in the past indicated a high susceptibility of raptors for both
WNV lineages (WNV lineage 1 and the Austrian/Hungarian WNV
lineage 2 isolate). The aim of this experimental study was to evaluate
the effect of WNV lineage 1 (NY99) and 2 (strain Austria) using three
different virus doses in falcons to clarify the role of these species in
WNV enzootic cycle.
For the infectious trial we used for each virus lineage six captive-bred
hybrid falcons (Falco rusticolus x Falco cherrug). Always two falcons
were subcutaneously inoculated with low, intermediate or high dose
of WNV-NY99 or WNV-strain Austria. Blood samples, cloacal and
oropharyngeal swabs were collected at 2, 4, 6, 10 days post
infectionem (dpi) and at the end of the experiment after 2
respectively 3 weeks. Clinical signs were observed over time and
birds were necropsied between 14 and 16 dpi (lineage 1) or 20 and
21 dpi (lineage 2). All experiments were carried out under biosafety
level 3 conditions.
Following the challenge with virus from both lineages falcons
developed clinical signs and typical gross pathological findings were
observed. Detailed results of virus re-isolation, qRT-PCR and serology
will be presented for a range of tissues and bodily fluids.