- Hello Jeff - Many people, like myself, have been very
worried since the release of genetically modified mosquitoes in Malaysia
and Africa.
-
- Could the release of modified mosquitoes enable new types
of mosquitoes to develop? No one can say for sure, however, we are now
- faced with a new type of Anopheles mosquito and question
need to be addressed and answered.
-
- Patty
-
-
- MALARIA, NEW ANOPHELES MOSQUITO - WEST AFRICA
- **********************************************
-
-
- Date: Tue 3 Feb 2011
- Source: BBC News [edited]
- http://www.bbc.co.uk/news/science-environment-12352565
-
-
- New mosquito type raises concern
- --------------------------------
- Scientists have identified a new type of mosquito. It
is a subgroup of _Anopheles gambiae_, the insect species responsible for
most of the malaria transmission in Africa. Researchers tell Science magazine
that this new mosquito appears to be very susceptible to the parasite that
causes the disease -- which raises concern. The type may have evaded classification
until now because it rests away from human dwellings where most scientific
collections tend to be made.
-
- Dr Michelle Riehle, from the Pasteur Institute in Paris,
France, and colleagues made their discovery in Burkina Faso, where they
gathered mosquitoes from ponds and puddles near villages over a period
of 4 years. When they examined these insects in the lab, they found many
to be genetically distinct from any _A. gambiae_ insects previously recorded.
-
- The team grew generations of the unique subtype in the
lab to assess their susceptibility to the malaria parasite and this revealed
them to be especially vulnerable, more so than indoor-resting insect types.
-
- But Pasteur team-member Dr Ken Vernick cautioned that
these mosquitoes' significance for malaria transmission had yet to be established.
"We are in a zone where we need to do some footwork in the field to
identify a means to capture the wild adults of the outdoor-resting sub-group,"
he told BBC News. "Then we can test them and measure their level of
infection with malaria, and then we can put a number on how much -- if
any -- of the actual malaria transmission this outdoor-resting subgroup
is responsible for."
-
- The researchers report that the new subgroup could be
quite a recent development in mosquito evolution and urge further investigation
to understand better the consequences for malaria control.
-
- They also emphasise the need for more diverse collection
strategies. The subtype is likely to have been missed, they say, because
of the widespread practice of collecting mosquitoes for study inside houses.
In one sense this has made sense -- after biting, mosquitoes need to rest
up and if they do this inside dwellings, the confined area will make them
an easier target for trapping. However, the method is also likely to introduce
a bias into the populations under study.
-
- Commenting on the study, Dr Gareth Lycett, a malaria
researcher from the Liverpool School of Tropical Medicine in the UK, said
it was an interesting advance that might have important implications for
tackling malaria. Larvae are collected from pools of water for study.
-
-
- "To control malaria in an area you need to know
what mosquitoes are passing on the disease in that district, and to do
that you need sampling methods that record all significant disease vectors,"
Lycett told BBC News. "You need to determine what they feed on, when
and where, and whether they are infectious. And where non-house-resting
mosquitoes are contributing to disease transmission, devise effective control
methods that will complement bed-net usage and house spraying. A recent
12M euro [16M USD] multinational project (AvecNET), funded by the European
Union, and led by the Liverpool School of Tropical Medicine has the specific
aims of doing just this."
-
- According to the World Health Organization (WHO), there
are more than 200 million cases of malaria worldwide each year, resulting
in hundreds of thousands of deaths, most of them in Africa.
-
- Malaria is caused by plasmodium parasites. The parasites
are spread to people through the bites of infected female anopheles mosquitoes.
-
- [byline: Jonathan Amos,science correspondent, BBC News]
-
- --
- communicated by:
- ProMED-mail
- promed@promedmail.org
-
- This news report refers to a paper published on 4 Feb
2011 in Science (Riehle MM, et al. A cryptic subgroup of _Anopheles gambiae_
is highly susceptible to human malaria parasites. Science. 2011;331:596-8).
The study was performed in Burkina Faso, West Africa, and shows that sampling
mosquitoes by collecting of indoor resting mosquitoes alone fails to estimate
the contribution to malaria transmission by outdoor resting mosquitoes.
This is important, as pointed out in the study, because previous malaria
control strategies using indoor residual spraying with insecticides will
not kill outdoor resting mosquitoes.
-
- By sampling mosquito larvae the study succeeded in identifying
a new subgroup of _Anopheles gambiae_ mosquitoes, which was found to be
a highly effective vector of _Plasmodium falciparum_. The study also helps
to explain why malaria control using impregnated bed nets are effective
where indoor residual spraying has failed in this part of the world.
-
- A map of the study area is found in the supplementary
material to the paper in Science. - Mod.EP
-
- The interactive HealthMap/ProMED map for Burkina Faso,
West Africa, is available at http://healthmap.org/r/01a6 - CopyEd.EJP
-
-
- Patricia A. Doyle DVM, PhD Bus Admin, Tropical Agricultural
Economics Univ of West Indies Please visit my "Emerging Diseases"
message board at:http://www.emergingdisease.org/phpbb/index.php Also
my new website: http://drpdoyle.tripod.com/ Zhan le Devlesa tai
sastimasa Go with God and in Good Health
-
- Benjamin Franklin said, "They that can give
up essential liberty to obtain a little temporary safety deserve
neither liberty nor safety."
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