Molecular Evidence of Wolbachia Species in Wild-Caught Aedes albopictus and Aedes aegypti Mosquitoes in Four States of Northeast India

Abstract

Wolbachia, a Gram-negative intracellular bacterium, naturally infects many arthropods, including mosquito vectors responsible for the spread of arboviral diseases such as Zika, chikungunya, and dengue fever. Certain Wolbachia strains are involved in inhibiting arbovirus replication in mosquitoes, and this phenomenon is currently being studied to combat disease vectors. A study was conducted in four states in north-eastern India to investigate the presence of natural Wolbachia infection in wild-caught Aedes albopictus and Aedes aegypti mosquitoes, the established vectors of dengue. The detection of a Wolbachia infection was confirmed by nested PCR and sequencing in the two mosquito species Ae. aegypti and Ae. albopictus. Positivity rates observed in Ae. aegypti and Ae. albopictus pools were 38% (44 of 115) and 85% (41 of 48), respectively, and the difference was significant (chi-square = 28.3174, p = 0.00000010). Sequencing revealed that all detected Wolbachia strains belonged to supergroup B. Although Wolbachia infection in Ae. aegypti has been previously reported from India, no such reports are available from north-eastern India. Data on naturally occurring Wolbachia strains are essential for selecting the optimal strain for the development of Wolbachia-based control measures. This information will be helpful for the future application of Wolbachia-based vector control measures in this part of the country.

A tangled threesome: understanding arbovirus infection in Aedes spp. and the effect of the mosquito microbiota

“…albopictus could have a Wolbachia pipientis prevalence of up to 90% in some regions, and wAlbA and wAlbB are the two prominent strains. Although A. aegypti it has been artificially infected with Drosophila melanogaster (wMel and wMelpop) and A. albopictus Wolbachia strains (Moreira et al, 2009;Walker et al, 2011), with reports of some populations with natural infections (Supplementary Figure 1) (Thongsripong et al, 2018;Balaji et al, 2019;Carvajal et al, 2019;Kulkarni et al, 2019;Zhang et al, 2022;Chao and Shih, 2023;Somia et al, 2023;Vinayagam et al, 2023).…”

Revisiting Wolbachia detections: Old and new issues in Aedes aegypti mosquitoes and other insects

“…The incidence of Wolbachia detected is often very low (e.g. 3.3% in Taiwan, (Chao & Shih, 2023 ); 5% Yunnan, China, (Zhang et al., 2022 ), 7% in Gabon (Zouache et al., 2022 )) or cannot be estimated due to the use of pooled data (Vinayagam et al., 2023 ). Low frequencies are not expected to occur in populations with stable, maternally transmitted Wolbachia , and may reflect environmental contamination unless there is a clear geographic pattern.…”

“…albopictus and Ae . aegypti (Vinayagam et al., 2023 ), whereas the former species is typically double infected with w AlbB and w AlbA (Yang et al., 2022 ).…”