Biology Reference
In-Depth Information
viruses can be grown in mammalian cells and the viruses produced can infect either
mosquitoes or mosquito cell cultures. Infection is sustained and Sindbis infection
was used to express an antisense form of a dengue protein in
Ae. aegypti
adults,
making the mosquitoes unable to transmit the viral disease (
Olson et al. 1996,
Olson 2000
). The Sindbis virus can be fed to mosquitoes, allowing expression of
transgenes in the midgut (
Olson et al. 2000
). No arthropods that have been geneti-
cally modified using these viruses have been released into the environment.
14.5.4 Transfer of
Wolbachia
from Another Arthropod
Transfer of
Wolbachia
into a novel arthropod host can result in unstable or
stable infections (
Werren and Bartos 2001
). For example,
Kawai et al. (2009)
introduced
Wolbachia
into planthoppers by injecting cultured
Wolbachia
into
nymphs. One line of
Laodelphax striatellus
lost its infection within several gen-
erations. In the second line, the infection was present for
>
7 years, but the
frequency of infection declined from
≈
80% to
<
10% after 40-60 generations.
Heath et al. (1999) found that
Wolbachia
can be transmitted to a parasitic wasp
(
Leptopilina boulardi
) from its host,
Drosophila simulans
, although the infection
was lost after three generations.
Some strains of
Wolbachia
reduce the rate of transmission of diseases by
mosquitoes, either by reducing lifespan or by inhibiting the replication of mos-
quito-borne pathogens such as filarial worms, dengue, or chikungunya viruses
in
Aedes aegypti
and of
Plasmodium
parasites in
Ae. aegypti
and
An. gambiae
(
Min and Benzer 1997
,
Cook et al. 2008
,
Kambris et al. 2009, McMeniman et al.
2009, Moreira et al. 2009a,b, Bian et al. 2010, Hussain et al. 2011
). One of the
most-advanced efforts to use
Wolbachia
to control disease transmission by the
mosquito
Aedes aegypti
has been studied by Scott O'Neill's group in Australia,
as described in
Box 14.3
in Section 14.13.
Hancock et al. (2011)
discuss methods for introducing
Wolbachia
into wild
mosquito populations for control of mosquito-borne diseases. They modeled
different introduction scenarios involving the releases of infected mosquitoes,
included seasonal fluctuations in the size of populations, and concluded that
releases of mostly males allow the infection to spread after the introduction of a
few females. This strategy was expected to cause substantial reductions in trans-
mission without increasing risk of disease.
14.5.5 Site-Specific Modifications
The ability to introduce cloned genes into the germ line at a predictable chromo-
somal site is especially desirable, because it should reduce the likelihood of position
