WolbachiastrainwMel induces cytoplasmic incompatibility and blocks dengue transmission inAedes albopictus

Abstract

Wolbachia inherited bacteria are able to invade insect populations using cytoplasmic incompatibility and provide new strategies for controlling mosquito-borne tropical diseases, such as dengue. The overreplicating wMelPop strain was recently shown to strongly inhibit the replication of dengue virus when introduced into Aedes aegypti mosquitoes, as well as to stimulate chronic immune upregulation. Here we show that stable introduction of the wMel strain of Drosophila melanogaster into Aedes albopictus, a vector of dengue and other arboviruses, abolished the transmission capacity of dengue virus-challenged mosquitoes. Immune up-regulation was observed in the transinfected line, but at a much lower level than that previously found for transinfected Ae. aegypti. Transient infection experiments suggest that this difference is related to Ae. albopictus immunotolerance of Wolbachia, rather than to the Wolbachia strain used. This study provides an example of strong pathogen inhibition in a naturally Wolbachia-infected mosquito species, demonstrating that this inhibition is not limited to naturally naïve species, and suggests that the Wolbachia strain is more important than host background for viral inhibition. Complete bidirectional cytoplasmic incompatibility was observed with WT strains infected with the naturally occurring Ae. albopictus Wolbachia, and this provides a mechanism for introducing wMel into natural populations of this species.

Wolbachia uses a host microRNA to regulate transcripts of a methyltransferase, contributing to dengue virus inhibition in Aedes aegypti

“…Studies have shown that in Ae. aegypti, the symbionts up-regulate the expression of a large number of host immune genes such as defensins, cecropins, JAK-STAT, and Toll pathway genes (10,33,35,43,44). These suggest that similar to Drosophila, Wolbachia-infected Ae.…”

“…Recently, some strains of Wolbachia were successfully introduced into various mosquito species such as Ae. aegypti, Aedes albopictus, and Anopheles gambiae (somatic infection) in an effort to limit replication and spread of various vector-borne pathogens such as DENV and malaria (6,7,43). Wolbachia effectively suppress DENV, Chikungunya virus, yellow fever virus, and Plasmodium in their new hosts (9-12, 43, 44).…”

Global stabilizing feedback law for a problem of biological control of mosquito-borne diseases

“…There is evidence that the spread of certain strains of Wolbachia in populations of Aedes aegypti drastically reduces the vector competence of the mosquito for dengue and other diseases [8], [9], [10]. Some strains of Wolbachia reduce the lifespan of the mosquito, consequently limiting the proportion of surviving mosquitoes at the completion of the incubation period.…”

“…As a conclusion, the decomposition (9), that seemed a natural framework to analyze the behavior of the controlled system (6) immediately fails to produce a global vision of the asymptotic behavior.…”

“…3) Monotonicity revisited and proof of the global stability: A crucial step in the proof of Theorem 7 is the introduction of a decomposition of system (6) different from (9). Let |z| ± := z if ±z ≥ 0, 0 otherwise.…”