Comparative studies on susceptibility of the mouse (Mus musculus) and the vole (Microtus arvalis) to Listeria monocytogenes and Erysipelothrix rhusiopathiae.

The susceptibility of mice and voles to intraperitoneal and subcutan injection of virulent strains has been tested comparatively on 261 mice and 120 voles. Using various germ-doses, 50 per cent lethality has been established. Listeria monocytogenes serovar 1/2a killed mice in doses of 120,000 and 1.

Leptospiral abortions of sows: new data.

In an immunization experiment, 460 sows at 7-60 days of gestation were inoculated with a rodent-adapted live strain of Leptospira interrogans serovar tarassovi at a large swine farm previously affected by this serovar. The inoculum consisted of a haemoculture prepared from the 52nd guinea-pig passage and the dose was 2 X 10(7) leptospires per sow. Over the period from the 48th to the 73rd day after inoculation 54 out of 283 sows having been inoculated at 32-60 days of gestation, aborted or delivered weak piglets.

A simple method for the isolation of phages from Listeria monocytogenes.

By application of a combined mitomycin-/heat treatment after freezing, 7 out of 29 Listeria monocytogenes strains which were found to be non-phage carriers by UV irradiation could release phages. Propagation of the obtained phages was promoted by storage at 4 degrees C. Apart from TNSA plates the application of chocolate plates appears to be necessary in order to study these phages.

Experimental syphilis and serological examination for treponematosis in hares.

Of 202 captive hares studied, many of which had lesions on their external genital organs or testicular atrophy or both, 27% had positive serological tests for syphilis although dark-field examination of extracts of atrophic testes was negative. A total of 12 hares that were nonreactive for the serological test for syphilis was inoculated with Treponema pallidum, 9 intratesticularly and 3 intradermally. Six of the animals inoculated intratesticularly exhibited orchitis after 7 days with an associated accumulation of treponemes.

Isolation of pathogenic treponemes from hare.

A presumably new species of pathogenic treponemes was isolated from a lesion on the male organs of hare (Lepus sp.) and the scrotum of a rabbit (Oryctolagus sp.) was infected with this treponeme.