Reaction of the host to the tick-bite. II. Distribution of tick borne encephalitis virus in sucking ticks.

No reactive histological changes of the dermis and no cement cone formation were observed at the insertion site of tick mouthparts by feeding of H. inermis larvae. Conversely, cement formation was observed by feeding of H. inermis female. Fully fed D. marginatus larvae on viraemic mice showed bright fluorescence in oesophagus, suboesophageal ganglion, salivary glands, a few gut cells and in lumen of Malpighian tubuli. We consider the penetration of virus from oesophagus to suboesophageal ganglion as the possible route of primary virus infection. Sections through the D. reticulatus nymphs during virus transmission (38 hours after attachment) showed specific fluorescence in epidermis and gut cells. This finding is in agreement with the secretory activity of epidermial and gut cells during feeding.