New Species of Mosquito Found / W. Africa

Think GE; http://www.trendhunter.com/trends/genetically-modified-mosquitoes

More info on Anopheles; http://www.tinymosquito.com/anopheles.html

MALARIA, NEW ANOPHELES MOSQUITO - WEST AFRICA
**********************************************
A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases


Date: Tue 3 Feb 2011
Source: BBC News [edited]



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


[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 - CopyEd.EJP]

[see also:
2009
---
Malaria - Nigeria, insecticide resistance 20091210.4210
2006
---
Malaria - South Africa: DDT 20060617.1686
2002
---
Malaria: malaria and mosquito genomes decoded 20021003.5450
2001
---
DDT & malaria control - South Africa 20010103.0019]
.................................................ep/ejp/sh
*##########################################################*
************************************************************
ProMED-mail makes every effort to verify the reports that
are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held
responsible for errors or omissions or held liable for any
damages incurred as a result of use or reliance upon posted
or archived material.
************************************************************
Donate to ProMED-mail. Details available at:

************************************************************
Visit ProMED-mail's web site at .
Send all items for posting to: promed@promedmail.org (NOT to
an individual moderator). If you do not give your full name
name and affiliation, it may not be posted. You may unsub-
scribe at .
For assistance from a human being, send mail to:
.
############################################################