Finalist-PhilBlogAwards 2010

Finalist-PhilBlogAwards 2010
Finalist for society, politics, history blogs



Friday, September 23, 2011



Erle Frayne D. Argonza

The use of good old chemistry to annihilate malarial and related mosquitoes seems to be running its course down by the day. Reason: after decades of insecticide-based health campaigns, malaria keeps on re-surging back with a vengeance.

Let me add the case of dengue, where the aedes aegpyti mosquito kept on resurging back year after year amid the fogging by insecticide. Akin to the use of insecticide-immersed bednets in Africa, bednets are now being widely disseminated purportedly to stem the attacks of the aedes mosquito. But to no avail! Dengue is back, and it had killed hundreds of patients as of this writing, with tens of thousands of patients recorded.

I am of the opinion that biotech holds the greater salvation value for eradicating malaria, dengue and related mosquitoes that serve as vessels to disease-inducing parasites. Malaysia has already shown the way to breeding genetically modified mosquitoes that can catalyze the sterilization and death of breeder mosquitoes in the field, so it’s really just a matter of emulating the biotech way of Malaysia across nations.

Below is an update report about the insecticide resistance in Africa.

[Philippines, 23 September 2011]


Insecticide resistance linked to malaria resurgence

Emeka Johnkingsley

24 August 2011

[ABUJA] Scientists have linked growing insecticide resistance with a resurgence of malaria in Senegal.

Researchers working in the village of Dielmo warned that new approaches may be needed to fight the malaria scourge on the continent.

They found that in the two years (August 2008–2010) following the distribution of bednets treated with deltamethrin, a long-lasting insecticide recommended by the WHO, malaria cases significantly decreased.

But, in the following four months, cases increased to higher levels than those before the bednets were introduced. This increase in morbidity was therefore likely to be due to increased resistance by malaria-carrying mosquitoes to pyrethroid insecticides, said the authors, whose findings were published online in The Lancet Infectious Diseases last week (18 August).

Thirty-seven per cent of Anopheles gambiae mosquitoes were resistant to deltamethrin in 2010, and the proportion of mosquitoes with the kdr mutation that confers resistance to pyrethroids insecticides in general increased from 8 per cent in 2007 to 48 per cent in 2010.

The authors said that the scale-up of bednet distribution programmes and indoor spraying campaigns has "led to a very rapid spread of pyrethroid resistance in the major malaria vectors".

The study found that malaria resurged, in particular, in older children and adults, who are increasingly susceptible to the disease.

This susceptibility cannot be explained by increasing pyrethroid resistance, the authors said. They suggest that "either a recent increase in exposure to malaria vectors in older age groups or a decrease in protective immunity" could be responsible.

Pierre Druilhe, an author of the research and a researcher at the Malaria Vaccine Development Laboratory at the Pasteur Institute in France, said that the resurgence in malaria morbidity had been foreseen for a long time and goes beyond the problem of insecticide resistance.

He said that in areas that have a high incidence of the disease, exposure to malaria-carrying mosquitoes induces a strong immune response that protects individuals. While insecticide bednets do cut the number of bites from vectors, this in turn reduces acquired immunity — leading to a new equilibrium where the chance of an infectious bite causing malaria increases.

In an accompanying commentary, Joseph Keating and Thomas Eisele warned of the danger of generalising the research to the rest of the continent, particularly because of the short period of the study.

But Druilhe said: "This type of situation [pyrethroid resistance] can happen in all high transmission areas, which corresponds to the vast majority of malaria endemic areas in Africa".

Link to full paper in The Lancet Infectious Diseases



1 comment:

Barsabas Gingrich said...

I sure agree with you Prof Erle. Chemicals have already destroyed our ecology, why persist?