A new study in Panama raises concerns over the strategy of
releasing genetically modified (GM) mosquitoes to control diseases.
The study, published in PLoS Neglected Tropical Diseases, maps the expansion of the invasive Asian tiger mosquito,
Aedes albopictus, which carries many viral pathogens including Dengue,
Yellow Fever and Chikungunya and is also implicated in the transmission of
LaCrosse encephalitis virus to humans in the US. Chikungunya virus is native to
tropical regions of Africa but is now considered an emerging global pathogen
since its detection in non-native regions in 2006. Dengue fever is increasingly
common, with global rates rising 30-fold between 1960 and 2010.
Current strategies in dealing with the
spread of these diseases focus on another species of mosquito, the Yellow Fever
mosquito, Aedes aegypti which has been in the Americas since the 1500s
and considered the most common carrier of Dengue as well as Chikungunya and
Yellow fever. The study highlights the limitations of strategies such as GM
mosquito releases to eradicate disease through failure to deal with other
species of mosquito. GM mosquito releases are hence predicted to be ineffective,
costly and certainly not free of biosafety risks.
data used to map spread of disease-carrying Asian tiger mosquito
led by Dr Loaiza at the Smithsonian Tropical Research Institute, Panama aimed
to understand the causes for the expansion of the Tiger
Mosquito in the country. The species is native to South East Asian. It was
first detected in Panama in 2002, but had been in other parts of the Americas
since the 1980s. It had also spread to Europe in the 1970s and Africa in the
Mapping the expansion of its range, the
researchers used models to see which factors promoted the spread of the Asian
tiger mosquito in Panama. By looking at models of road networks, population
density, climate, as well as all these factors combined, they
found that road networks most accurately correlated with Asian tiger mosquito
expansion, while climactic factors correlated most poorly. This may be due to
the fact that the whole country has the right
climate for the mosquito to survive and flourish. As shown in figure 1, since 2002, the Asian tiger mosquito has spread from the eastern
neighbourhood of Panama City to the Caribbean coast and western parts of the
country by 2013. Their modelling data suggests that controlling the
transportation of larval and adult mosquitoes need to be priority if the spread
of the species is to be controlled.
Figure 1 Expansion of
Asian tiger mosquito across Panama from 2002-2013.
From 2002-2005 (a) the species was
detected only in Eastern parts of the capital, Panama City. From 2006-2009 (b)
it expanded out of the city and along the Caribbean coast and by 2009-2013 (c)
it has invaded much of western Panama as well as east of Panama City.
control programs target only Yellow fever mosquito, neglecting Asian tiger
focusing on the Yellow fever mosquito include the British firm Oxitec’s release
of its first batch of GM Yellow Fever mosquitoes in Panama in May 2014. The GM mosquitoes
were engineered to include a sterility gene in the males, which do not bite
with the principle being that GM males will breed with wild-type mosquitoes in
order to bring down overall population numbers. Oxitec have also released their
insects in the Cayman Islands, Malaysia and Brazil, with plans for releases in Florida
later this year. Florida citizens have reacted furiously to this proposal with
a petition against the release drawing over 145 000 signatures on just one day.
Fumigation programs in Panama also preferentially
target the Yellow Fever species, which inhabit densely built-up areas as
opposed to in vegetation outside of buildings, where the Asian tiger mosquito is
more commonly found.
As cautioned by the new study, the major problem with
the current GM and fumigation control programs targeting the Yellow fever
mosquito for disease control, is that the Asian tiger mosquito has been
increasing in population size in many regions of the Americas. In many parts of the US it has even overtaken the Yellow Fever
mosquito as the dominant species. That is indeed the case in much of Florida
where it is now become the most common species to bite humans, making the
proposed release of GM mosquitoes in the State an uninformed and potentially
dangerous approach to effective disease control. In Gabon and Cameroon, the rapid
invasion of the Asian tiger mosquito is thought to be responsible for the 2007
epidemic of dengue and Chikungunya viruses, with local outbreaks
of disease corresponding with high density of this species. Yellow fever
mosquitoes also populate these regions but are thought to have played a
secondary role in that outbreak.
One well-supported mechanism for the
decline in the Yellow Fever mosquito is its intense competition for resources
with the Asian tiger mosquito. The spread of the Asian tiger species makes
control programs targeting only the Yellow Fever mosquito likely ineffective,
and may even exacerbate the spread of the Asian tiger mosquito by leaving
behind an empty ecological niche for them to fill. The authors further warned
that the Yellow fever mosquito could re-establish itself in the absence of
continued release of GM insects, which would prove the GM strategy to be a very
costly, short-term solution.
Commercial releases of Oxitec’s mosquitoes
in Brazil have already coincided with a dengue epidemic that pushed local
authorities to declare a state of emergency. Though the reason behind the
epidemic remains unclear, this highlights the worrying lack of understanding
that these releases have on the local ecosystems and most
importantly, on human diseases which these releases are purportedly aiming to
of risk assessment and proof of efficacy for GM insects
is an additional concern to the lack of risk assessment carried out on the GM insects
made by the British firm Oxitec. Many risks regarding these mosquitoes have
been raised and warrant a complete halt to any
further release until comprehensive data on their biosafety are published. Even
for controlling the Yellow Fever mosquito, the strategy has many flaws that
make it potentially inefficient, ineffective and hazardous (see Transgenic GM
Mosquitoes Not a Solution, SiS 54).
for GM insect release are also lacking, with no specific regulations existing
in any country. The UN Cartagena Protocol on Biosafety states that when
exporting GM insect eggs to another country, the producer is supposed to supply
a risk assessment that meets EU standards and to copy this to the EU and UK
authorities so it can be made public, something which Oxitec has not done. Furthermore,
releases in the Cayman Islands and Malaysia were done without public consent
(see Regulation of Transgenic
Insects Highly Inadequate and Unsafe, SiS 54).
Concerns about fumigating with toxic pesticides is
another problem for disease containment and the least toxic strategy possible must be used in order to protect people
from not just the viruses, but other health problems associated with pesticide
exposure. To date, one of the most effective and also non-toxic control measures
is to target their larval habitats, i.e., any objects or spaces that collect
water such as empty tyres, plant pots, leaking drains, pipes and so on. There
are other new and safer strategies being developed such as the use of a common
symbiotic bacterium Wolbachia
that prevents dengue virus multiplying in the
mosquito host (see Non-transgenic
Mosquitoes to Combat Dengue, SiS 54).
GM strategies have thus far been based on
an over-simplified and short-sighted understanding of how to manage nature, with
its constant ability to adapt and modify to survive. The new study serves as
additional warning that all releases of GM mosquitoes should cease.
Douglas Hinds Comment left 9th February 2015 20:08:09 The new study serves as additional warning that all releases of GM ORGANISMS should cease.
Todd Millions Comment left 11th February 2015 21:09:24 Last(questionable) report I have is that for US release of Oxitec Mossies-'workers are hand separating (what could possibly go wrong?) the males'. I would like this too be confirmed,but the malware levels of terminals available too me are currently running at facebook levels.As well as this-If the Asian tiger mosquito referred too is the same one that arrived from Japan too Texas via car tires in the 1980's-It is cold hardy as well and has being spotted as far north as Montana.I think they have made it across the Canadian border,but my specimens have being lost and Ag canaduh wasn't interested in them when I gathered them a decade ago.I'll look for more.
Patricia P. Tursi, Ph.D. Comment left 16th February 2015 07:07:38 This is another excuse to replace all nature with synthetic life forms, This includes plants, animals, humans and microbial life. AI is being merged with humans via Morgellons (Clifford Carnicom research). NASA scientist, Dr. Steven Dick sees a future where AI will replace biology and that is the plan through DARPA, genetic engineering and other programs. This is one step toward that goal. See the Post Biological Universe.