Dipetalonema viteae (Filarioidea): development of the infective larvae in vitro.

The development of Dipetalonema viteae third stage larvae was attempted in vitro. A monophasic culture system consisting of BHK-21 medium supplemented with 10% tryptose-phosphate broth and 15% fresh jird serum allowed the growth of previously in vivo triggered larvae, but not of those isolated from ticks. The larvae could complete their third moult and grew on a fourth stage larvae up to 5 mm. This development was comparable to that observed in vivo. The presence of an irradiated hamster kidney cell feeder layer could replace an in vivo trigger. The development of the infective larvae took place up to the third moult. Some larvae completed the moult to the fourth stage and reached a maximum length of 3 mm after 14 days. These culture systems offer the possibility to study in vitro the complete development of the infective larvae to fourth stage larvae.