Genetic engineering could turn the mosquito from an infector to a
26 March 2010
Japanese researchers have shown that a transgenic mosquito can
induce an immune response from a bite.
Mosquitoes transmit infectious diseases to millions of people
every year, including malaria, for which there is no effective
vaccine. The new research led by Associate Professor Shigeto Yoshida
from the Jichi Medical University in Japan, reveals that mosquito
genetic engineering may turn the disease transmitter into a natural
‘flying vaccinator’, providing a new strategy for biological control
over the disease.
“Blood-sucking arthropods including mosquitoes, sand flies and ticks
transmit numerous infectious agents during blood feeding,” said
Yoshida. “This includes malaria, which kills between 1-2 million
people, mostly African children, a year. The lack of an effective
vaccine means control of the carrier has become a crucial objective
to combating the disease.”
For the past decade it has been theorized that genetic
engineering of the mosquito could create a ‘flying vaccinator,’
raising hopes for their use as a new strategy for malaria control.
However, so far research has been limited to a study of the insect’s
gut and the ‘flying vaccinator’ theory was not developed.
“Following bites, protective immune responses are induced, just
like a conventional vaccination but with no pain and no cost,” said
Yoshida. “What’s more, continuous exposure to bites will maintain
high levels of protective immunity, through natural boosting, for a
life time. So the insect shifts from being a pest to being
In this study Dr Yoshida’s team successfully generated a
transgenic mosquito expressing the Leishmania vaccine
within its saliva. Bites from the insect succeeded in raising
antibodies, indicating successful immunization with the
Leishmania vaccine through blood feeding.
While the ‘flying vaccinator’ theory may now be scientifically
possible, the question of ethics hangs over the application of the
research. A natural and uncontrolled method of delivering vaccines,
without dealing with dosage and consent, alongside public acceptance
to the release of ‘vaccinating’ mosquitoes, provide barriers to this
method of disease control.
“For the past decade it has been postulated that the salivary
gland could be the way to gain biological control over this
important infectious disease,” concluded Yoshida. “In this study we
have shown, for the first time, the achievement of the original
concept of the ‘flying vaccinator.”
Yamamoto.D, Nagumo.H, Yoshida.S. Flying vaccinator; a transgenic
mosquito delivers a Leishmania vaccine via blood feeding. Insect
Molecular Biology, March 2010, Wiley-Blackwell, DOI