Date Published: December 6, 2012
Publisher: Public Library of Science
Author(s): Elizabeth S. Andrews, Philip R. Crain, Yuqing Fu, Daniel K. Howe, Stephen L. Dobson, David S. Schneider.
Heterologous transinfection with the endosymbiotic bacterium Wolbachia has been shown previously to induce pathogen interference phenotypes in mosquito hosts. Here we examine an artificially infected strain of Aedes polynesiensis, the primary vector of Wuchereria bancrofti, which is the causative agent of Lymphatic filariasis (LF) throughout much of the South Pacific. Embryonic microinjection was used to transfer the wAlbB infection from Aedes albopictus into an aposymbiotic strain of Ae. polynesiensis. The resulting strain (designated “MTB”) experiences a stable artificial infection with high maternal inheritance. Reciprocal crosses of MTB with naturally infected wild-type Ae. polynesiensis demonstrate strong bidirectional incompatibility. Levels of reactive oxygen species (ROS) in the MTB strain differ significantly relative to that of the wild-type, indicating an impaired ability to regulate oxidative stress. Following a challenge with Brugia pahangi, the number of filarial worms achieving the infective stage is significantly reduced in MTB as compared to the naturally infected and aposymbiotic strains. Survivorship of MTB differed significantly from that of the wild-type, with an interactive effect between survivorship and blood feeding. The results demonstrate a direct correlation between decreased ROS levels and decreased survival of adult female Aedes polynesiensis. The results are discussed in relation to the interaction of Wolbachia with ROS production and antioxidant expression, iron homeostasis and the insect immune system. We discuss the potential applied use of the MTB strain for impacting Ae. polynesiensis populations and strategies for reducing LF incidence in the South Pacific.
Lymphatic filariasis (LF) affects 120 million people globally and has been a leading cause of morbidity in South Pacific regions . An ongoing global campaign to eliminate LF relies upon mass drug administration (MDA) strategies. However, because of inherent issues associated with MDA, such as efficacy of antifilarial drugs and public compliance with drug regimens, an integrated approach that targets the vector has been suggested for the successful control of LF in some regions, such as the South Pacific.