Novel <i>Wolbachia</i>-transinfected <i>Aedes aegypti</i> mosquitoes possess diverse fitness and vector competence phenotypes

<div><p><i>Wolbachia pipientis</i> from <i>Drosophila melanogaster</i> (<i>w</i>Mel) is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector <i>Aedes aegypti</i>. To date, <i>w</i>Mel-infected <i>Ae</i>. <i>aegypti</i> have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing <i>w</i>Mel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of <i>w</i>Mel, transinfecting different or additional <i>Wolbachia</i> strains into <i>Ae</i>. <i>aegypti</i> may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of <i>Ae</i>. <i>aegypti</i> with the <i>Wolbachia</i> strains <i>w</i>MelCS (<i>D</i>. <i>melanogaster</i>), <i>w</i>Ri (<i>D</i>. <i>simulans</i>) and <i>w</i>Pip (<i>Culex quinquefasciatus)</i> and assess the effects on <i>Ae</i>. <i>aegypti</i> fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that <i>w</i>MelCS provides a similar degree of protection against dengue virus as <i>w</i>Mel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of <i>w</i>Mel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by <i>w</i>Ri is markedly weaker than that of <i>w</i>MelCS, consistent with previous characterisations of these lines in <i>Drosophila</i>, while <i>w</i>Pip was found to substantially reduce the fitness of <i>Ae</i>. <i>aegypti</i>. Thus, we determine <i>w</i>MelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative <i>Wolbachia</i> strain with more desirable attributes than <i>w</i>Mel for future field testing.</p></div>