Physical characterization of a stomatitis papulosa virus genome: a cleavage map for the restriction endonucleases HindIII and EcoRI

The genome of stomatitis papulosa virus (a parapoxvirus) was cleaved with the restriction endonucleases HindIII and EcoRI, each giving rise to 6 fragments respectively. Double digestion with both enzymes resulted in 8 bands, two of which contained DNA fragments in double molar concentrations as revealed by reciprocal digests of isolated DNA fragments. The genome size, estimated by summation of the molecular weights of the fragments, is approximately 86 X 10(6) daltons, some 30 X 10(6) daltons smaller than vaccinia virus (an orthopoxvirus) DNA. The cleavage sites of HindIII and EcoRI endonucleases were mapped on the genome by analysis of reciprocal digests of isolated DNA fragments and by cross-hybridization experiments. This yielded two mapped segments which were then oriented relative to one another by cleavage of isolated partial digestion products. The terminal restriction fragments show rapid renaturation after alkali denaturation and subsequent neutralization, indicating that stomatitis papulosa virus DNA contains terminal cross-links analogous to those found in vaccinia virus DNA.

[Facts and speculations on viruses in food (author's transl)]

The danger to which man is exposed as a result of viruses contained in food differs basically from the risk to man caused by bacteria, fungi or their toxins. With respect to viral injuries it is not the specific diseases (e.g. hepatitis and polio) that are in the foreground but the much more dangerous noxious groups whose cause/effect relationships are rather complex. 1. the oncogenic risk, 2. synergistic interactions with opportunistic problem viruses, 3. slowly developing chronic diseases and persistent infections with their indirect injuries, 4. new infectious pathogens (viroids). Viral contamination of food can be exogenous or endogenous. Exogenous contamination is possible by: 1. specific human-pathogenic viruses, 2. polyphagous, human-pathogenic and animal-pathogenic viruses (zoonosis), 3. animal-pathogenic viruses only, 4. fish viruses, 6. bacteriophages, 7. fungal viruses. The viruses of group 1 and 2 are of practical importance, those of group 6 and 7 are it occasionally. Endogenous contamination is caused when an animal suffered from a viral infection at the time of slaughter or product extraction (e.g. milk, egg, fish) or when the animal has picked up a virus shortly beforhand. As far as endogenous contamination is concerned, a distinction must be made between 1. primarily biological and 2. primarily mechanical contamination. For the first, mainly the clinically inapparent especially persistent infections and viraemic stages at the end of incubation are dangerous. In both cases the animal is clinically healthy. In primarily biological contamination the zoonosis viruses predominate. In addition the bacteriophages must be taken into account. Primarily mechanical contamination is restricted to fish, molluscs, milk and eggs. The possibilities and consequences of exogenous and endogenous contamination are discussed. The risk of viral transmission by foodstuffs depends chiefly on the tenacity of the virus in the affected food, but also on its virulence and concentration. Basic considerations are discussed. Practically from any useful, healthy animal the most varied viruses can be isolated. In order to avoid destroying the confidence of the consumer, it is necessary to take stock of the following: 1. viral contamination in foodstuffs demonstrated so far 2. verified human diseases caused by the intake of virus-contaminated foodstuff and 3. speculations on imaginable consequential damage caused by the consumption of food containing virus. This is also dealt with in the paper. In a final, critical review the importance of virus contained in food is discussed comprehensively from a scientific, legal and practical point of view.

[Nature and significance of persistent infections (author's transl)]

The "persistent" viral infections, besides "subclinical" infections, pertain to the vast group of "clinically inapparent" infections. They differ from subclinical infections by a temporally unlimited "co-existence" with the pathogen. Pathogenetically, three forms of development are possible: 1. latent infections, 2. tolerated infections, 3. occult infections. Persistent viral infections are the inexhaustible reservoir for many viruses. To the organism affected they may be of benefit (infection immunity, interference, paraimmunity) or of disadvantage (activation of the infection with conversion into a disease, cause of many chronic, slowly developing disease processes, immunopathogenic consequences), the disadvantages prevailing. To the environment, persistent infections are invisible sources of danger as they produce carriers and chronic carriers.

Control of acute virus diseases of calves in the Federal Republic of Germany

The most important acute viral diseases of calves in the Federal Republic of Germany (FRG) are:Enzootic bronchopneumoniaBovine viral diarrhoea - mucosal disease (BVD-MD)Infectious bovine rhinotracheitis - infectious pustular vulvovaginitis (IBR-IPV)Rota- and Coronavirus infections The incidence, diagnosis and control of these infections in the FRG are discussed. Stomatitis papulosa and malignant catarrhal fever are also briefly mentioned.

[The smallpox vaccination strain MVA: marker, genetic structure, experience gained with the parenteral vaccination and behavior in organisms with a debilitated defence mechanism (author's transl)]

The MVA virus is a lab virus ideally suited for vaccination of both man and animal which can be differentiated from the known Vaccinia strains by the use of numerous biological markers. Its reduced virulence for the chick embryo, for experimental animals and for man is a particularly characteristic feature. With the exception of chick embryo fibroblasts, the MVA virus grows in cell cultures only abortively. This applies particularly to cells of human origin in which the cytopathic effect and plaque formation are completely missing. The restriction analysis of the DNS of the MVA virus demonstrates that its genetic structure differs from that of the CVA basic virus and other orthopox viruses. In contrast to the WHO reference strain Elstree, the MVA virus has a genome shortened by about 9 per cent. The use of the MVA virus for human vaccination is particularly indicated in persons to be vaccinated for the first time and likely to entail a risk (on account of allergies etc.) because it brings about a state of revaccination without complications. The MVA virus can be administered in intracutaneous, subcutaneous or intramuscular injections. Innocuoursness and successful vaccination have been demonstrated in more than 120000 persons. While other Vaccinia strains, such as the Elstree virus, experience a drastic increase of virulence in the immunosuppressed organism (subjected to whole-body irradiation), the MVA virus cannot be activated not even in this situation.

In vitro studies on Borna virus. I. The use of cell cultures for the demonstration, titration and production of Borna virus

Borna virus produces non-lytic infections in a wide spectrum of primary cell cultures and cell lines. The sensitivity and virus yields vary with the different cell systems. Accurate virus titrations can be performed in the RK 13 cell line by counting immunoflourescent microfoci between the 5th and 10th day after infection. Since the virus is not released from the cells and does not spread via the culture medium, the use of a semisolid overlay in unnecessary in virus titrations. The cell line most productive for Borna virus is the CV 1 line. The conditions for optimum virus production include a prolonged cultivation period of at least two weeks with regular changes of medium, and an incubation temperature of 35 degrees C. Harvest of the virus requires thorough disruption of the infected cells, preferably by ultrasonication, since Borna virus seems to be closely associated with cellular structures.

[Premunity, premunization and paraspecific effect of immunizations (author's transl)]

A considerable part of the paraspecific effect of immunization falls under the common term of a general increase in resistance. Bacterial competition, antibiosis, interference, interferon formation and lymphocyte stimulation, on the other hand, are more than an increase in resistance. It is proposed that the sum of the stimulation of all these activities including increased resistance shall be called premunization and the short-lasting nonspecific protection against a number of quite different infectious diseases produced by this in the body shall be called premunity. Experience with the paraspecific effect of immunizations, with increasing drug resistance, interferonization and lymphocyte stimulation form the basis for the development of a "premunity inducer". The efficacy of a biological inducer is described with reference to our own experiments.

[Experimental investigations on the immunity development in irradiated mice after local and parenteral immunization with tetanus-toxoid (author's transl)]

Using the "tetanus-mouse" model the differences in immunity development between animals exposed to irradiation (300 R and 400 R) and animals not exposed to irradiation after nasal and subcutaneous vaccination was investigated. Immunization was carried out 1, 3, 6 and 10 days before and after exposure to irradiation. Efficacy of immunization was tested by challenge with 10 X LD50 tetanus-toxin and by antitoxin determination with L+-method. The degree of the immune response was dependent on 1. the irradiation dose, 2. the interval between active immunization and the ensuing or preceding irradiation, 3. the mode of vaccination (local or parenteral) and 4. the vaccination dose.

[Vaccinations of animals and human health (author's transl)]

Vaccination of animals may have both positive and negative effects on human health. The negative consequences largely occur with live vaccines. The protection provided by vaccination to animals is taken advantage of for human health in the most diverse ways, both directly and indirectly. Typical examples are vaccination of dogs and cats against against rabies and inoculation against diseases of cattle, horses and dogs in which reoviruses of serotypes 1, 2 and 3 are involved. An important contribution to the protection of human health is also provided by vaccination with inactivated pathogens against leptospirosis and salmonellosis, against stomatitis vesicularis and American equine encephalitis and in developing countries against brucellosis.

[A new possibility of "non-parenteral" (local) vaccination: immunization per wound (author's transl)]

Hitherto the term "non-parenteral" (local) vaccination meant all those modes of vaccination where the vaccine is applied on the skin or the mucous membranes. The most common types of local immunization are oral and nasal vaccination. Using model studies with the mouse immunization per wound was investigated as an alternative mode of vaccination. Immunization was done with tetanus-toxoid, efficiency was tested by challenge with 10 LD50 tetanus toxin. For immunization per wound only slightly higher antigen doses are necessary compared with subcutaneous immunization. A single subcutaneous vaccination with 2 Lf tetanus-toxoid and a single application per wound of 10 Lf resulted in the same efficiency index of 100. Immunization per wound has to be carried out immediately after injury. It seems to be optimal within the first 3 to 5 hours. At a later time the same efficiency index can only be achieved by use of a higher antigen doses. Immunization per wound is possible with all kinds of wound, even with burns. Size of wound and wound-supply do not influence the efficacy of wound-immunization. Immunization per wound does not disturb wound healing. The experiments reported here showed, for the first time, that immunization per wound is as effective as parenteral immunization. The most important advantage of wound-immunization is the speed and ease with which it can be administered, a fact which predestines it for vaccination in emergency cases. In practice it will be useful to combine wound-vaccination with wound-sprays.

[Experimental investigations on oral immunization with tetanus-toxoid (author's transl)]

Model-experiments in mice were used for the investigation of oral immunization with tetanus-toxoid. The efficacy of oral toxoid application was tested by challenge and anti-toxin determination. The oral immunization with tetanus-toxoid induced only a sufficient protection, when toxoid was in intensive contact with the mucous membranes of the oral cavity. Local immunization via gastro-intestinal-tract failed. After a single vaccination with 200 Lf tetanus-toxoid onto mucous membranes of the oral cavity the efficiency index was 75. In comparison, a single subcutaneous application of 2 Lf tetanus-toxoid resulted in an efficiency index of 100 and a single intranasal immunization of 100 Lf in an efficiency index of 93. So the application of toxoid subcutaneously or onto nasal mucous membranes induced higher protection than oral application. Temporary development of immunity after immunization via the mucous membranes of the oral cavity was much better than parenteral immunization. 20 per cent of orally immunized animals were immune 5 days p. vacc. At the same time subcutaneously immunized animals failed to develop any protection. The efficiency rates obtained in challenge correlate with antitoxin content in the serum.

Sporadic bovine meningo-encephalitis-isolation of a paramyxovirus

Isolation of a viral agent (107) directly from brain explants of a 15-month-old heifer with symptoms of a sporadic encephalomyelitis is described. The virus shares properties with the paramyxovirus family. It grows in a variety of cell cultures from different species, and induces nuclear and cytoplasmic inclusion bodies in infected cells. Nucleocapsids measuring 17 nm in diameter were found in the nucleus and cytoplasm of these cells when studied electron microscopically, thus indicating a close relationship of the agent to the measles-distemper-rinderpest group. No infectious virus was released from infected cells, although alignment of nucleocapsids was observed beneath the cell membrane, and no hemagglutinating activity could be detected with the methods employed. The 107 agent was compared serologically with parainfluenza viruses type 1, 2 and 3, simian virus 5, mumps and Newcastle disease virus (NDV), two bovine respiratory syncytial viruses and measles/subacute sclerosing panencephalitis, distemper and rinderpest viruses, always using 107 virus infected CV1 cells and antiserum of the different viruses in indirect FA tests. Positive FA reactions were observed only with two sera obtained from SSPE patients with high antibody titer to SSPE virus, and with one rabbit-anti-rinderpest serum. The titers of these sera to 107 virus, however, were significantly lower than those against homologous viruses. Five out of 9 sera from randomly selected healthy cattle showed antibody titers between 1:10 and 1:80 to 107 virus in FA tests. The significance of these results is discussed with respect to the epidemiology of SSPE in children and its possible implication with rinderpest in Europe.