EFFECTS OF TSETSE DNA VIRUS-INFECTION ON THE SURVIVAL OF A HOST FLY, GLOSSINA-MORSITANS CENTRALIS (DIPTERA GLOSSINIDAE)

Freshly deposited third instar Glossina morsitans centralis larvae wer e infected with the tsetse DNA virus by microinjection, At emergence c omparative observations were made on longevity and feeding behavior of infected and control flies, Gut tissues from the control and virus-in fected flies were fixed and processed for light and electron microscop y. The longevity of infected flies was significantly reduced compared to that of the controls (P < 0.05). The main mortality factors in the virus-infected flies with severe lesions in the salivary glands were s tarvation due to failure to feed and clotting of blood in and/or ruptu re of the crop, Rupture of the midgut also caused some mortalities, In fected flies probed significantly more times during feeding to repleti on (P < 0.05) and took significantly longer to feed compared to the co ntrol flies (P < 0.05), Infected flies which fed took significantly le ss blood compared to the controls (P < 0.05). Histological studies rev ealed pathological changes in the epithelial cells of the anterior mid gut secretory midgut and the posterior midgut, There was severe disint egration of the membranous organelles, especially the mitochondria and rough endoplasmic reticulum, leading to extensive vacuolation in such epithelial cells, No viral particles were observed in the secretory a nd posterior midgut. Virions were observed in the anterior midgut lume n and occasional particles were seen invading the epithelial cells in this area of the midgut, especially in heavily infected flies. (C) 199 7 Academic Press.