[The larval development of Dipetalonema rugosicauda (syn. Wehrdikmansia rugosicauda) in the tick Ixodes ricinus. II. The development of Dipetalonema rugosicauda in Ixodes ricinus and investigations about the occurrence of the microfilariae in the roe deer (C. capreolus) (author's transl)].

Microfilariae of D. rugosicauda, which were taken up by nymphs of I. ricinus during their attachment on roe deers, developed in those ticks to infective larvae after two moults. The larval development lasted 56-67 days at 20-22 degrees C and occurred similar to other species of Dipetalonema inclusive a sausage stage. During this time the nymphs moulted to adult ticks. Adult females and males of I. ricinus collected in the area of Biberach/Riss, Southern-Germany, contained up to 12 infective larvae of D. rugosicauda per tick. The occurrence of those infective larvae and of microfilariae in roe deers depended on the season. The highest rate of infected ticks was 4.3% in spring, whereas the maximum rate of infected roe deers was 46.8% in autumn. Based on investigations of fawns of roe deers the prepatent period of D. rugosicauda can be estimated as approximately 6 months. Compared with microfilariae of Onchocerca tarsicola from red deers the microfilariae of D. rugosicauda prefered deeper layers of the ear skin of their hosts. Besides D. rugosicauda microfilariae of a further hitherto unknown species were detected in the ear skin of roe deers additionally. They resembled microfilariae of O. tarsicola.