[Typing of 17 porcine enterovirus isolates from polio encephalomyelitis cases during the years 1983-1991]. / Typisierung von 17 porzinen Enterovirusisolaten aus Polioenzephalomyelitisfällen der Jahre 1983-1991.

Seventeen strains of porcine enteroviruses (PEV) were isolated from organs of 119 pigs with symptoms of polioencephalomyelitis submitted to the State Veterinary Institute Arnsberg/Westphalia between 1983 and 1991. 15 isolates originated from the central nervous system and 2 from organ suspensions made up of a brain-spleen-pool and a lung-spleen-lymph node-pool, respectively. Isolates were assigned to 7 PEV types which were present at the following frequencies: PEV1: 2x; PEV2: 6x; PEV4: 3x; PEV5: 1x; PEV6: 2x; PEV 12: 1x; PEV 13: 2x. Mortality rates of affected groups exhibited an age-dependent curvilinear relationship suggesting that the PEV involved possessed a rather similar low to medium grade neurovirulence, irrespective of type. Exceptions were 1 herd with 100% mortality at the age of 10-18 weeks from which PEV2 strain 6793/83 was isolated (described earlier) and a second herd with 18% mortality at the age of 14-18 weeks from which PEV types 1, 2 and 4 were recovered. Sensitivity of 5 cell lines for the isolation of PEV was compared. Rates of isolation from organ suspensions which had proved positive in any of the cell lines tested were as follows: PS-EK: 77%; IB-RS-2: 63%; ST: 56%; PK-15: 47%; BHK21 (CT): 10%.

Grouping of porcine enteroviruses by indirect immunofluorescence and description of two new serotypes.

Porcine enteroviruses (PEV) types 1-11 were assigned to three serologic groups by indirect immunofluorescence (IIF). Serotype group I consists of PEV types 1-7 and 11 and is correlated with CPE-type I. Serotype group II is represented by PEV type 8, producing CPE-type II, while PEV types 9 and 10 are classified as serotype group III and cause CPE-type III. Three PEV isolates from the central nervous system of pigs with polioencephalomyelitis were assigned to serotype group I by IIF but to none of the established 11 serotypes by cross-neutralization. It is concluded that these isolates are representatives of two new PEV types for which the designation PEV12 and 13 is suggested.

[Induction of humoral antibodies by a BHV-1 intradermal test]. / Induktion humoraler Antikörper durch einen BHV 1-Intrakutantest.

An intradermal test for the diagnosis of BHV 1 (Intrakutantest Behringwerke AG) was applied to 53 nonvaccinated BHV 1-seronegative cattle aged 7 months to 8 years. Serologic blood testing performed subsequently using ELISA (Enzygnost-IBR/IPV, Behringwerke AG) and SNT revealed seroconversion in 24 of 45 animals without previous maternal antibodies. A second application of the intradermal test after these BHV 1-antibodies had declined, lead to a 'booster-effect' while a control group remained negative. Six of nine animals not affected by the first intradermal application of BHV 1-antigen, developed BHV 1-antibodies following the second intradermal test. Eight animals possessing maternal antibodies showed no serological response to the intradermal test at all. Present results strongly suggest an induction of humoral BHV 1-antibodies by the intradermal application of inactivated BHV 1. Consequently, the indirect control of BHV 1 infections, especially in cattle breeding farms, should be done exclusively by serological examination.

Technical improvements of a commercial ELISA to detect antibodies against bovine herpesvirus 1.

Prevention and control of the spread of IBR/IPV virus in cattle presumes exact diagnosis even with large sample collections. The requirements are fulfilled firstly by the application of the most sensitive testing methods for virus specific antibodies, such as the enzyme-linked immunosorbent assay (ELISA), and secondly by the introduction of bovine milk as a specimen for sampling. Data are presented demonstrating the application of a commercial ELISA system for evaluation of large sample collections and its optimization for this purpose.