Studies on Tick-borne Encephalitis and Other Arthropod-borne Virus Diseases

Threa new foci" of TBE virus were found in Lower Austria. In studies eiraed at interrupting the virus cycle in nature Gardens^ was very effective against ticks. Effect of the snail maromal control program in Carinthia ia not yet clear. Attachment of TBE virus to its ruceptor (TPI) is a twostep reaction consisting first of a loose electrostatic and later a stronger binding. TPI inhibits the infectivity for mice of group B but not of group A arbovirusos. Antibodies against TPI were obtained in rabbits. In animal experiments no conclusive evidence was obtained that formation of HNAse is one of the defense mechanisms against arbovirusee. Interferon does not account for the resistance of house mice to fatal TBE. Tilorone (R'HCl protects white mice against TBE. Combined application of this compound with Poly I:C did not improve the results. 320 cases of TBE were diagnosed in Austria. The disease can rapidly be diagnosed by demonstration of IgM-antibodies in the patient's serum with 2-l*lercaptoethanol. Interferon can be demonstrated in the CMS of patients who succumb to TBE provided death occurs soon after onset of disease. Tahyna and Celovo viruses are regularly active on the Eastern side of Neusiedlersee but not on the Western side of the lake. No evidence was found for the hibernation of Tahyna virus in Culex modestus. For the first time antibodies against Tahyna virus wore found in birds (Sturnus vuloaris). hares (Lepus europaeus) are not susceptible to Calowo virus. t M0&*®2&2>t^mi;ix&K ?s-*z «.■r ■