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Biomedical subjects

F Steck

Publications and source records attributed to F Steck.

At least 19 recordsLinked to original sources

Antibodies to Berne virus in horses and other animals.

After inoculation into 2 foals, Berne virus induced neutralizing antibody, but did not cause clinical symptoms. In a horizontal study of seropositive mares and their offspring, a decline of maternal antibodies and a sudden synchronous seroconversion in all foals were observed, again without clinical symptoms. The virus is widespread in the Swiss horse population and has been so during the last decade; rises in antibody titers were noted in 9% of paired sera sampled at random. Positive reactions were also obtained in serum neutralization tests and ELISA using small numbers of horse sera from Germany, France and the U.S.A. The results of neutralization tests and ELISA were correlated in 83% of random samples tested; 13% were neutralization-positive and ELISA-negative and in 4% the inverse was observed. Neutralizing activity was found in the sera of other ungulates (cattle, goat, sheep and pig), laboratory rabbits and 2 species of wild mice (Clethrionomys glareolus and Apodemus sylvaticus). Inconclusive results were obtained with feline and human sera; those from dogs and foxes (Vulpes vulpes) were consistently negative. The probable occurrence of antigenic variants in Berne-type viruses is discussed.

Animals↗

Purification and partial characterization of a new enveloped RNA virus (Berne virus).

In Berne (Switzerland), a virus was isolated from a horse which was found to be serologically unrelated to known equine viruses. Its growth was unaffected by iododeoxyuridine and it was inactivated by organic solvents. A purification procedure involving ammonium sulphate precipitation and sucrose gradient equilibrium centrifugation was developed and viral activities were monitored using infectivity and enzyme-linked immunosorbent assays. Purified virions of density 1.16 g/ml were shown by negative staining electron microscopy to be roughly spherical and to measure 120 to 140 nm in diameter; projections (peplomers, about 20 nm long) were identified on the virion surface. In thin sections, an envelope and an elongated core structure could be distinguished. The core, measuring about 23 nm across and 104 nm in length, appears to assume a rod-, crescent- or open ring-shape within the envelope. It has a tubular structure and shows a transverse striation (periodicity 4.5 nm). Binding at the plasma membrane was observed. Berne virus is considered as a representative of a hitherto undefined family of widespread animal viruses serologically related to recent bovine isolates in Ames, Iowa (U.S.A.) and Lyon (France).

Animals↗

Small mammal studies in a SAD baiting area.

Studies in the laboratory or in the field on the effect of SAD virus on small rodents are reported. Laboratory experiments by oral inoculation of SAD strain in a wide variety of small mammals led to the conclusion that spontaneous SAD transmission from rodent to rodent is a rare event. Field experiments were conducted by live-trapping, sacrifice and analysis of 192 Apodemus sylvaticus, 28 Clethrionomys glareolus and 48 Crocidura russula. They gave no indication that SAD virus became established in this small animal community on an island after a single exposure to a high density (300 sites on 10 hectares) of vaccine baits.

Administration, Oral↗

Assessment of fox control in areas of wildlife rabies.

This paper describes a technique for the analysis of the interaction between rabies control measures and the annual turnover of a fox population. The basic conditions are deduced from data on the turnover of a steady fox population, which have been found to be representative for large parts of central Europe. These conditions, together with field data on the critical density for rabies transmission and the recovery of reduced fox populations, provide a model for the prediction and evaluation of various measures of rabies control. The method is simplified by the introduction of a semigraphical procedure using the relative density of a reduced fox population, defined as the ratio of the actual population density to that of a non-reduced population.Simulation of epidemics and control measures over consecutive population cycles shows the limited effect of population control in a rabies-free area and demonstrates the questionable impact of measures that reduce a regular fox population by less than 40%, even when such reduction is effected annually.The method is easy to apply in the field and helps in assessing a number of disease and service indicators, as well as ecological factors in the planning and evaluation of comprehensive rabies control programmes.

Animals↗

Everglades virus infection in man, 1975.

Within 72 hours of visiting the Everglades National Park in south Florida, a 43-year-old man became ill with fever, malaise, myalgia, severe headache, pharyngitis, and enlarged, tender lymph nodes. Everglades (Venezuelan equine encephalomyelitis, subtype II) virus was isolated from a blood sample drawn from the patient five days after onset of symptoms.

Adult↗