LE3 .A278 2018

2018

Smith, Todd

Acadia University

Bachelor of Science

Honours

Biology

Biology

Hepatozoon species infect the erythrocytes of green frogs and are vectored by the mosquito, Culex territans. Previous research has shown that mosquitoes that take a blood meal from frogs heavily infected with Hepatozoon species die within 48 hr of feeding. Gamonts of Hepatozoon species exit through the midgut epithelium and enter the haemocoel en route to the Malpighian tubules, and heavy infections of Hepatozoon species may cause irreparable morphological and physiological damage and subsequent death to mosquitoes. The objectives of this study were to examine the basis of the pathological effects of heavy infections of Hepatozoon species on C. territans using microbiological and microscopic methods, and to determine the immune response, if any, of the mosquito against well-tolerated lighter infections of this parasite. Mosquitoes were treated with antibiotics to eliminate any deleterious septicaemic effects of midgut bacteria following physical damage from parasites as they exit the midgut. Surprisingly, control mosquitoes that were not treated with antibiotics survived significantly longer than those that were treated, suggesting a protective role of the gut microbiota on survival of infected mosquitoes. Dissected midguts of mosquitoes at various intensities of infection were viewed using scanning electron microscopy to investigate evidence of damage to the midgut epithelium. Although obvious physical damage was not observed, midguts of heavily infected mosquitoes were difficult to dissect, and often disintegrated upon preparation, suggesting that the integrity of the midgut was significantly compromised by parasite exit. Lastly, peroxide assays of haemolymph performed on blood-fed mosquitoes revealed that there was a significant immune response in mosquitoes that took a blood meal with a light infection of parasites compared to uninfected mosquitoes.

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https://scholar.acadiau.ca/islandora/object/theses:2674