Virus infections are the medical challenge of our time.
Virus infections are the most frequent infections of man. They have a great socio-economic significance.
Almost 95% of all infections of the respiratory tract and 40-60%. of the infections of the gastrointestinal tract are caused by viruses. Most embryopathias with permanent cerebral damage go back to an infection with either the cytomegalovirus or with the virus of German measles.
As far as the cytomegalo-virus is concerned it has been proved by serological tests that in countries with high hygienic standards more than half, in developing countries on the other hand almost 100% of the adult population.has come in contact with this virus. In Germany 3% of pregnant women excrete the cytomegalo-virus with the urine. One percent of all newborn children are infected either prenataly or internatal by this virus and of these 5% show signs of a generalized cytomegalie or permant damage of the brain.
Pregnancy, birth, accommodation in hostels, blood transfusion, suppression of the immune response all bring about the increased risk of an infection by the cytomegalo-virus. The degree of contamination with the surface antigen of the hepatitis-B-virus amounts in Central Europe to 1-2%, in some African countries, however, to 15%.
Virus-infections, the so called "slow-virus infections", are causing some rare diseases of the central nervous system. So diseases such as sclerosing panencephalitis, morbus Guillain-Barre, lateral sclerosis and postencephalitic Parkinson syndrome are probably due to a virus-infection. For multiple sclerosis a controlled study, using measles vaccine, started more than, 10 years ago in the USA. Since measles virus is supposed to be connected causally with multiple sclerosis. This connection, explored by epidemiological means, meets with geographical relationships, that ist, the relative scarcity of multiple sclerosis in southern and its frequency in northern regions. A result of the forementioned vaccination study can be expected in about 4 years.
Virus infections play a part in oncogenesis. Manifoldly substantiated in animals the virogenesis of human tumors has still to be conclusively proven. For the time being wartsare the only tumors of man which are with certainty of viral origin.
Nevertheless, evidence grows that human leukemia is equally caused by viruses as are the leukemias of fish, mice, cats, calves and apes.
Condylomata lata and papilloma of the larynx, both known precanceroses, are likewise suspected to be of virus origin as are some malignant lymphomas and sarcomas.
The Epstein-Barr virus is the cause of mononucleosis infectiosa, which is accompanied by heterophilic antibodies. The virus participates casually in the origin of both the Burkitt-lymphoma which is widespread in Africa and the anaplastic naso-pharynx carcinoma which is
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