EXPERIMENTAL-INFECTION OF WEANER PIGS WITH A FIELD ISOLATE OF HOG-CHOLERA CLASSICAL-SWINE-FEVER VIRUS DERIVED FROM A RECENT OUTBREAK IN LOWER SAXONY .1. CLINICAL, VIROLOGICAL AND SEROLOGICAL FINDINGS

Ten weaner pigs were inoculated intranasally with 250 TCID50/pig of a classical swine fever (CSF) virus isolated during a recent outbreak in Lower Saxony. After an incubation period of 7 days all animals became febrile and 9 died or were euthanized between the 17(th) and 25(th) d ay of infection showing a strong clinical reaction typical for CSF. On e animal developed the chronic form of disease without manifesting the classical symptoms. CSF virus could be reisolated first from leucocyt es of 5 animals 4 days after inoculation. From nasal secretions and fa eces CSF virus could be reisolated during the prodromal and manifestat ion phase of illness from 9 and 8 pigs, respectively. All pigs develop ed neutralizing antibodies against the homologous isolate of CSF virus . However, using two different ELISA-Kits, 3 and 5 weaners, respective ly, were found antibody positive. According to the experimental data t he field isolate, designated ''Diepholz 1/Han94'', was characterized t o be of high virulence.