Could Wolbachia be an alternative to dengue-fighting GMOsquitos? | Public HealthPosted: January 3, 2013
The use of a Wolbachia infection-based strategy in controlling the spread of dengue in the US, however, does come with its own set of questions and concerns. It is not clear exactly how Wolbachia guards mosquitoes from dengue infection, but studies indicate that Wolbachia infection seemingly boosts or manipulates the mosquito’s immune system to interfere with replication of the dengue virus (7 & 8). Furthermore, protection against dengue virus appears to be dependent on the extent of Wolbachia infection in the mosquito (9). For instance, the wAlbB strain of Wolbachia, which naturally infects A. albopictus, does not provide A. albopictus any protection against dengue. However, scientists have found that when wAlbB infects A. aegypti it can prevent dengue infection in its newly-infected host species. The key appears to be that wAlbB is capable of surviving in higher numbers in its non-native host, A. aegypti, than it can in its normal host, A. albopictus. This suggests that Wobachia infection must reach a critical, minimum level in order to guard against dengue infection.
One potential explanation for the low level of wAlbB infection in A. albopictus is that A. albopictus, as wAlbB’s natural host, has had sufficient time to adapt to wAlbB and keep the level of infection low. Therefore, it’s possible that over time, as a mosquito species becomes adapted to Wolbachia infection, the corresponding protection against dengue may wear off. There is also the question of how to replace wAlbB infections in A. albopictus with an infection by a dengue-protective Wolbachia strain. In the lab, Wolbachia infection can be cleared by antibiotics, but that may not be practical in the field. Lastly, since the research cited here have tested Wolbachia protection against only the serotype 2 dengue virus, the ability of Wolbachia infection to protect against the other 3 dengue serotypes still needs to be studied. This is where the OX513A strategy has the upper hand since it eradicates the mosquito while paying no mind to the serotype of the virus being carried.