Development of Brugia pahangi in the flight muscles of Aedes togoi. Ultrastructural changes in the infected muscle fibers and the infecting filarial larvae.

Abstract

The ultrastructural changes seen in the indirect flight muscles of Aedes togoi infected with Brugia pahangi included the disarray or disruption of the parasitized muscle fiber, the reduction and disorganization of the interfibrillar mitochondria, the reduction of muscle glycogen and, finally, the complete dissolution of the muscle fiber. These changes are restricted to individual parasitized muscle fibers while adjacent non-parasitized fibers retain their usual arrangement. The damage inflicted to these parasitized fibers may be due to the presence and movement of the larvae within the fibrils and the active ingestion of muscle mitochondria by these developing larvae. The damaged muscle may be capable of partial repair as the extent of injury was usually less severe in infected mosquitoes from the 9th day after the infecting feed, when most of the infective larvae had migrated from the thorax to the head and proboscis.