The migratory Pathway of a Filarial Parasite

A detailed observation on the site of development and the path of migration of the larvae of Breinlia sergenti (a filaria of slow loris) in Aedes togoi is presented. The larvae develop in the fat-body of mosquitoes. They are distributed abundantly in the fat-body of the abdomen and there is a scarcity of the larvae in the fat-body of the thorax and the head region. The majority of the larvae migrate into the head alongside the oesophagus and the thoracic ganglia. After entering the head, the mature larvae congregate in the large subcibarial haemocoelic space situated at the root of the proboscis. They then continue to migrate through the root of the proboscis into the lumen of the labium, where the infective larvae lie parallel to each other among the fascicles of the mouthparts in a unidirectional manner. The head of the larva is always directed towards the labella. In some heavily infected mosquitoes, the infective larvae are found to be coiled in the lumen of the labella