Just a short update
on our Wolbachia miniseries from last
summer. Remember that question I posed a few months ago -- how effective will Wolbachia-infected mosquitoes be at
limiting the spread of human disease? Three months later and we are already closer to getting some answers. Science's Kelly Servick recently reported that two different types of mosquitoes will be released in Brazil to try and
prevent the spread of infectious diseases transmitted by the mosquito species Aedes
aegypti. The data collected from these releases (in addition to others) will provide
the data necessary to continue evaluating the effectiveness of various methods.
The first release will focus on Wolbachia-infected mosquitoes (previously
described here)
and is being implemented by the nonprofit organization Eliminate Dengue.
These mosquitoes are infected with a strain of Wolbachia that will spread through existing mosquito populations
and prevent mosquitoes from transmitting diseases (such as Dengue and Zika). While
these releases consist of females (that can bite), the effects of the release
are longer lasting because Wolbachia should
persist in the resident population of mosquitoes.
The second release is a genetically
modified mosquito developed by the for-profit company Oxitec. These are
different from the Wolbachia-infected
mosquitoes because their genome has been altered and now contains a modified gene
(tTAV: tetracycline-repressible
transcriptional activator variant) that kills developing mosquitoes. Males with this gene are released, they
mate with females of the resident population, and then the males die. All
offspring from these matings contain the modified gene and die before they
reach reproductive maturity as adults. Thus, this method is different than the Wolbachia-infected mosquitoes because
its goal is to control mosquito populations rather than eliminate their ability
to transmit disease. This method may appeal to residents because it reduces
mosquito populations and only introduces new males into the population (that
cannot bite); however, once the males mate and die a new batch of males must be
released. And this can get expensive.
Again, the risks (and expense) associated with these
methods needs to be considered in conjunction with the benefits. Preferably
from objective third parties. I’ll keep you updated as the story continues to
progress.
