2.1 Experimental
design
Two independent animal trials were included in this study. Domestic pigs
(Sus scrofa domesticus ) were obtained from a commercial pig farm
and wild boar (Sus scrofa scrofa ) were provided by wildlife parks
in Mecklenburg-Western Pomerania. For the infection experiments,
domestic pigs and wild boar were transferred into the high containment
facilities of the Friedrich-Loeffler-Institut (L3+) and were left for
acclimatization for a week.
In both studies, domestic pigs and wild boar were oro-nasally inoculated
with 2 ml cell culture supernatant containing
105.25 haemadsorbing units (HAU)/ml of ASFV
“Estonia2014”. A clinical score was assessed daily, based on a
previously described scoring system . Rectal temperatures were measured
each day in domestic pigs and at autopsy in wild boar. 6 domestic pigs
and 7 wild boar were left untreated and served as controls. In trial 1,
12 German landrace pigs, 3 months of age, and 12 wild boar, 1-2 years of
age, were used. 4 animals of each group were randomly chosen for autopsy
5 and 7 dpi. For trial 2, 11 German landrace pigs, 3 months of age, and
12 wild boar, 1-2 years of age, were used. Autopsies were done 4, 7, and
10 dpi with 3 animals of each group (see table 1). Results from control
animals and animals investigated 7 dpi, respectively, were grouped for
all applicable analyses. For scheduled autopsies or when animals reached
the humane endpoint, animals were narcotized with tiletamine/zolazepam
(Zoletil ®, Virbac) and xylazine (Rompun® 2%, Bayer HealthCare) and
then euthanized by intracardial injection of pentobarbital (Release,
Wirtschaftsgenossenschaft deutscher Tierärzte) or exanguination. For
analysis of the immune response, blood, lung, spleen, gastro-hepatic
lymph node (ghLN, Lymphonodi hepatici or gastrici ), as
well as liver were collected.