Related Experiment Video
Updated: Sep 3, 2025
Detecting Wolbachia Strain wAlbB in Aedes albopictus Cell Lines
Published on: June 1, 2022
Wolbachia wPip Blocks Zika Virus Transovarial Transmission in Aedes albopictus
Yan Guo1, Jiatian Guo2, Yifeng Li1
1Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Science, Guangzhou, Guangdong, China.
Abstract:
Wolbachia is being developed as a biological tool to suppress mosquito populations and/or interfere with their transmitted viruses. Adult males with an artificial Wolbachia infection have been released, successfully yielding population suppression in multiple field trials. The main characteristic of the artificial Wolbachia-infected mosquitoes used in the suppression program is the lower vector competence than that in native infected/uninfected mosquitoes in horizontal and vertical transmission. Our previous studies have demonstrated that the Aedes albopictus HC line infected with a trio of Wolbachia strains exhibited almost complete blockade of dengue virus (DENV) and Zika virus (ZIKV) in horizontal and vertical transmission. However, the extent to which Wolbachia inhibits virus transovarial transmission is unknown since no studies have been performed to determine whether Wolbachia protects ovarian cells against viral infection. Here, we employed ovarian cells of the Ae. albopictus GUA (a wild-type mosquito line superinfected with two native Wolbachia strains, wAlbA and wAlbB), HC, and GT lines (tetracycline-cured, Wolbachia-uninfected mosquitoes), which exhibit key traits, and compared them to better understand how Wolbachia inhibits ZIKV transovarial transmission. Our results showed that the infection rate of adult GT progeny was significantly higher than that of GUA progeny during the first and second gonotrophic cycles. In contrast, the infection rates of adult GT and GUA progeny were not significantly different during the third gonotrophic cycle. All examined adult HC progeny from three gonotrophic cycles were negative for ZIKV infection. A strong negative linear correlation existed between Wolbachia density and ZIKV load in the ovaries of mosquitoes. Although there is no obvious coexistence area in the ovaries for Wolbachia and ZIKV, host immune responses may play a role in Wolbachia blocking ZIKV expansion and maintenance in the ovaries of Ae. albopictus. These results will aid in understanding Wolbachia-ZIKV interactions in mosquitoes. IMPORTANCE Area-wide application of Wolbachia to suppress mosquito populations and their transmitted viruses has achieved success in multiple countries. However, the mass release of Wolbachia-infected male mosquitoes involves a potential risk of accidentally releasing fertile females. In this study, we employed ovarian cells of the Ae. albopictus GUA, HC, and GT lines, which exhibit key traits, and compared them to better understand how Wolbachia inhibits ZIKV transovarial transmission. Our results showed an almost complete blockade of ZIKV transmission in HC female mosquitoes. Wolbachia in natively infected GUA mosquitoes negative affected ZIKV, and this interference was shown by slightly lower loads than those in HC mosquitoes. Overall, our work helps show how Wolbachia blocks ZIKV expansion and maintenance in the ovaries of Ae. albopictus and aids in understanding Wolbachia-ZIKV interactions in mosquitoes.
Insights
Wolbachia bacteria effectively block Zika virus (ZIKV) transovarial transmission in Aedes albopictus mosquitoes, particularly in the HC line. This research clarifies how Wolbachia protects ovarian cells, aiding in mosquito-borne virus control strategies.
Area of Science:
- Vector-borne disease control
- Microbial symbiosis in insects
- Arbovirus transmission dynamics
Background:
- Wolbachia is a promising biological control agent for suppressing mosquito populations and reducing arbovirus transmission.
- Previous studies show Wolbachia reduces Dengue virus (DENV) and Zika virus (ZIKV) in Aedes albopictus, but transovarial transmission inhibition is not fully understood.
- Understanding Wolbachia's effect on ovarian cells is crucial for assessing its efficacy in blocking virus transmission.
Purpose of the Study:
- To investigate the role of Wolbachia in inhibiting ZIKV transovarial transmission in Aedes albopictus ovarian cells.
- To compare ZIKV infection rates and viral loads in ovarian cells of Wolbachia-infected (GUA, HC) and uninfected (GT) mosquito lines.
- To elucidate the mechanisms by which Wolbachia interferes with ZIKV replication and transmission within mosquito ovaries.
Main Methods:
- Comparison of ZIKV infection rates in progeny from GUA (native Wolbachia), HC (triple Wolbachia), and GT (Wolbachia-uninfected) Aedes albopictus lines across three gonotrophic cycles.
- Quantification of ZIKV load in mosquito ovaries.
- Analysis of the correlation between Wolbachia density and ZIKV load.
- Assessment of host immune responses in Wolbachia-mediated viral inhibition.
Main Results:
- HC mosquito progeny showed a complete absence of ZIKV infection across all gonotrophic cycles.
- GUA mosquito progeny exhibited significantly lower ZIKV infection rates than GT (uninfected) mosquitoes in early cycles, with similar rates in the third cycle.
- A strong negative correlation was observed between Wolbachia density and ZIKV load in mosquito ovaries.
- No direct spatial overlap between Wolbachia and ZIKV was found in ovaries, suggesting host immune responses may be involved.
Conclusions:
- Wolbachia confers significant protection against ZIKV transovarial transmission in Aedes albopictus, with the HC line showing near-complete blockade.
- Natively infected Wolbachia in GUA mosquitoes also negatively impacts ZIKV, though to a lesser extent than in HC mosquitoes.
- The findings highlight Wolbachia's potential as a key tool for controlling ZIKV and other mosquito-borne viral diseases by disrupting their transmission cycles.
