Recent comments

Dear Andre,

Thank you for your reply of 8th May.

I have just entered a blog today "How was malaria of 100 years ago eradicated in Palestine/Israel? And without vaccine?" and which includes a link to the scanned book of Dr Kligler which I have just organised. I hope this is of interest and of use.

Anton.

Hi,

I am an Assistant Professor of Zoology in Kerala, India. I started my career as a researcher at Malaria Research Centre, Goa. I was there for almost  a decade. Then I moved back to my home state Kerala in 2001. For two years I had served as a District Malaria Officer and  in 2003 joined the present position. My areas of research are mosquitoes and mosquito-borne diseases. Since Kerala is almost free of indigenous malaria I had shifted my interest to Dengue, Chikungunya, Japanese Encephalitis and Lymphatic Filariasis. Recently, I have come back to malaria, as sporadic cases of the disease have started appearing in my home town and I have also discovered that the notorious vector Anopheles stephensi is very much prevalent in my town. So let's see------------

What is your problem?

When the target gene (DNA template as example) and the reagents are incubated at a constant temperature between 60-65°C, the following reaction steps proceed:

	STEP1 As double stranded DNA is in the condition of dynamic equilibrium at the temperature around 65°C, one of the LAMP primers can anneal to the complimentary sequence of double stranded target DNA, then initiates DNA synthesis using the DNA polymerase with strand displacement activity, displacing and releasing a single stranded DNA. With the LAMP method, unlike with PCR, there is no need for heat denaturation of the double stranded DNA into a single strand. The following amplification mechanism explains from when the FIP anneals to such released single stranded template DNA.

	STEP2 Through the activity of DNA polymerase with strand displacement activity, a DNA strand complementary to the template DNA is synthesized, starting from the 3' end of the F2 region of the FIP.

	STEP3 The F3 Primer anneals to the F3c region, outside of FIP, on the target DNA and initiates strand displacement DNA synthesis, releasing the FIP-linked complementary strand.

	STEP4 A double strand is formed from the DNA strand synthesized from the F3 Primer and the template DNA strand.

	STEP5 The FIP-linked complementary strand is released as a single strand because of the displacement by the DNA strand synthesized from the F3 Primer. Then, this released single strand forms a stem-loop structure at the 5' end because of the complementary F1c and F1 regions.

	STEP6 This single strand DNA in Step (5) serves as a template for BIP-initiated DNA synthesis and subsequent B3-primed strand displacement DNA synthesis. The BIP anneals to the DNA strand produced in Step (5). Starting from the 3' end of the BIP, synthesis of complementary DNA takes place. Through this process, the DNA reverts from a loop structure into a linear structure. The B3 Primer anneals to the outside of the BIP and then, through the activity of the DNA polymerase and starting at the 3' end, the DNA synthesized from the BIP is displaced and released as a single strand before DNA synthesis from the B3 Primer.

	STEP7 Double stranded DNA is produced through the processes described in Step (6).

	STEP8 The BIP-linked complementary strand displaced in Step (6) forms a structure with stem-loops at each end, which looks like a dumbbell structure. This structure serves as the starting structure for the amplification cycle in the LAMP method (LAMP cycling). The above process can be understood as producing the starting structure for LAMP cycling.

			Basic principle (8) - (11) (Cycling amplification step)

A dumbbell-like DNA structure is quickly converted into a stem-loop DNA by self-primed DNA synthesis. FIP anneals to the single stranded region in the stem-loop DNA and primes strand displacement DNA synthesis, releasing the previously synthesized strand. This released single strand forms a stem-loop structure at the 3' end because of complementary B1c and B1 regions. Then, starting from the 3' end of the B1 region, DNA synthesis starts using self-structure as a template, and releases FIP-linked complementary strand (Step (9)). The released single strand then forms a dumbbell-like structure as both ends have complementary F1 - F1c and B1c - B1 regions, respectively (Step (11)). This structure is the 'turn over' structure of the structure formed in Step (8). Similar to the Steps from (8) to (11), structure in Step (11) leads to self-primed DNA synthesis starting from the 3' end of the B1 region. Furthermore, BIP anneals to the B2c region and primes strand displacement DNA synthesis, releasing the B1-primed DNA strand. Accordingly, similar structures to Steps (9) and (10) as well as the same structure as Step (8) are produced. With the structure produced in Step (10), the BIP anneals to the single strand B2c region, and DNA synthesis continues by displacing double stranded DNA sequence. As a result of this process, various sized structures consisting of alternately inverted repeats of the target sequence on the same strand are formed.

http://loopamp.eiken.co.jp/e/lamp/

Or send your questions to usakitty.lek@gmail.com

Dear Suleiman

I appreciate your feedback. I agree that all affected communities know about malaria and make use of traditional methods for control or prevention. Some of this traditional knowledge and methods may even be developed further to great value in the global fight against malaria. However, local knowledge is often incomplete, and may contain inaccurate facts on the disease and how it works. By correcting false information/beliefs and improving their malaria knowledge, affected communities will become better equipped to actively participate in the fight against malaria. Improved knowledge could also lead to the better utilization of appropriate traditional methods against malaria, and with the sharing of information on successful control methods.

Andre

Dear Cliff

I am confident that a single person can spark local interest in fighting malaria by starting small and growing from there. Maybe a good starting point would be to reach out to community leaders to assess their knowledge, believes and needs in terms of fighting malaria, and to discuss the possible roles that the community may play.

I am sure that there are many Malaria World members that may provide much better advice from experience, and would encourage them to share their thoughts on the matter.

Andre     

Dear Iwalokun Bamidele,

It is absolutely possible to test crude extract, in fact we already try with this method a cinchona extract and we could see the adducts related with choloquine and its isomers, without any purification step. If you want I send you the full paper, write me to my e mail: kmunos@gmail.com

Sincerely,

Katalina Munoz-Durango

V. valuable work. Hopefully the metabolites of primaquine can be tested in this system, particularly the 6 demethyl and 5-OH (and the double change) which still include the positively-charged side chain.

May give us some ideas on anti-hypnozoite agents for P. vivax.

V. valuable work. Hopefully the metabolites of primaquine can be tested in this system, particularly the 6 demethyl and 5-OH (and the double change) which still include the positively-charged side chain.

May give us some ideas on anti-hypnozoite agents for P. vivax.

Dear colleagues,

In this discussion of larval source management (LSM) relative to other control methods such as IRS and bednets, it is important to:

1.  See the economic development which is triggered thru LSM by land reclamation, and

2.  Recognize that LSM includes several other techniques besides repeated application of Bacillus to larval habitats.

In fact, I would argue that we should realize the very large importance for agricultural and economic development in Africa from the impact of malaria suppression through LSM by land reclamation - 

MALARIA SUPPRESSION THROUGH LARVAL SOURCE MANAGEMENT CAN BE A FIRST STEP IN ECONOMIC DEVELOPMENT FOR AFRICA

There is abundant historical evidence that an important first step in economic development in many tropical and semi-tropical areas was land reclamation, which led to suppression of malaria and then to agricultural development.  Malaria transmission was suppressed by draining and filling of the swampy habitats of the mosquito larvae,  a process called larval source management.  Perhaps the most famous example of larval source management was the drainage of the feverish Pontine Marshes near Rome by Mussolini in the 1930s.  Reclamation of this ancient focus of malaria was successful, and the land was settled by thousands of farmers and their families.  They have made the area the most productive agricultural zone in Italy.  Similar successes have occurred across the globe in Malaysia, Puerto Rico and the Holy Land. 

Larval source management is more than the popular practice of larviciding with biological agents, but should be seen in its broader sense which includes drainage and filling of flooded depressions, flushing of streams, and salinity control in coastal areas.  These are simple methods, accomplished with local labor and resources.  

In contrast, tropical areas where malaria has been suppressed by the current chemically dependent strategy of WHO using mass drug administration, widespread spraying of houses with biocides and lavish distribution of treated bednets, have not led to economic development.  In a larger sense these ephemeral methods for malaria control increasingly drain the local and national economies, and also stress international donors.  Attempts by WHO to control malaria in Africa with these ephemeral methods exceed their own budgetary capacities, and have led to recent donor fatigue in the Global Fund.  This current situation is a repeat of the donor fatigue which caused the failure of the first WHO Global Eradication Program in the 1970s, also based on drugs and biocides.  Current global needs for malaria suppression are over $6 billion annually, while available resources are only a few billion.  This disparity is getting worse, not better.

It is fairly easy to see the positive agricultural and economic effects of mosquito suppression, after simple ditching and drainage convert the land from pestilential marshes into productive farms.  Farmers can then afford to improve their housing, including screening of doors and windows.  They can also afford the necessary health care and medicines needed to diagnose and treat the increasingly rare malaria infections.  Eventually these improvements in human ecology make permanent the suppression of malaria transmission in the agricultural communities.

Conversely, the economic drain increases from expensive drugs, bednets and biocides used in the WHO strategy, as new drugs and new biocides are needed to counter the inevitable chemical resistance in the mosquitoes and the malaria parasite.  This growing economic drain negatively affects individuals, ministries of health, WHO, and international donors alike. 

Not only is the WHO approach to malaria control expensive, it is dangerous because of its ephemeral nature, dependent on fickle cycles of donor support. The costly WHO strategy for ephemeral suppression of malaria is unsustainable by African governments and by the people who have the most at stake - the feverish farmers.  Intermittent failure of programs to suppress malaria due to donor fatigue can lead to fatal epidemics in populations which have lost their immunity during temporary suppression of malaria transmission.

Fortunately the positive and generally beneficial aspects of these links between land reclamation, malaria suppression and agricultural productivity can form a rational basis for economic development in many parts of Africa.  International agencies and donors should recognize the economic value in this positively reinforcing process, based on larval source management. 

Spot on - this is what malaria is all about, not some top-level get together somewhere in Europe or the USA to celebrate World Malaria Day...the gains are fragile, sustaining them will be hard, and defeating malaria in a background of ignorance is hopeless...

A very interesting contribution, certainly the spread of SVMNT is a cause of concern. 

A minor quibble is that the authors have misunderstood or mistated the verapamil reversibility*  data respecting the 2 major CQ-R haplotypes. Verapamil reversibility predicts clinical usefulness of amodiaquine and associates with CVIET, non-reversibility predicts clinical amodiaquine-resistance and associates with SVMNT. See Warhurst, Mal. J. 2003.

The repopulation of CVMNK wild types in, for example, Malawi, after withdrawal of chloroquine is possible because wild types are prevalent in the area and fitter than CVIET, thus repopulated on withdrawal of chloroquine.

 As they point out, wild type PfCRT haplotypes are relatively rare in S. America, and the predominant haplotype is , as well as being less CQ-resistant (without the accompanying Pfmdr1 mutations) than CVIET,  is also probably intrinsically closer in fitness to the wild-type.

*(ability to render CQ-r parasites CQ-s when the two drugs are used together in vitro)

David Warhurst

I am glad that Rob Newman has taken to heart the article by Justin Cohen and colleagues about the resurgences in malaria.  But I disagree with Rob's solution, which is to appeal for more funding at a time of a global economic recession and obvious donor fatigue.

Also I am unable to comprehend the statement that $6 billion is needed annually, when WHO proposes a goal of near zero deaths by 2015.

Firstly, the Solution for resurgence due to donor fatigue.  The solution is to suppress malaria in parallel with agricultural and economic development which will then pay for the attack on malaria.

FIRST CASE IN POINT - the Zambian copper belt (Utzinger et al in Trop Med Int Health 2002)  Protection of the workforce and their families in the copper belt by environmental management of mosquito breeding and an integrated strategy, quickly led to the area becoming the leading copper producer in Africa and the ability to sustain the suppression of malaria.

SECOND CASE - the rubber and tea plantations and tin mines of Malaysia.  By instituting environmental management of mosquito habitats in 1938, Malaysia has gradually reduced malaria transmission - even through the disruption of the Second World War  - until the current incidence is a few thousand cases per year.  In the meantime Malaysia has become a beacon of economic stability in the region with an outstanding program of integrated vector control.

In contrast, the current WHO strategy uses costly drugs, bednets and biocides which have already led to donor fatigue, and entirely omits environmental managment methods such as land reclamation which are durable and lead to economic development.

Perhaps another cause of donor fatigue is the confusing figures being released by WHO.  Rob said that $6 billion is needed annually to stay the course.  WHO has a stated goal of near zero deaths by 2015, but Ray Chalmers, the UN malaria ambassador says $2.5 billion is needed (Huffington Post of 23 April).   To further confuse the WHO statements,  Chris Murray and colleagues recently said in the Lancet that the number of malaria deaths in 2010 was 1.2 million, compared to 1.8 million in 2004.  I project that slow decline to reach 0.7 million deaths in 2015.  Is that near zero?  

Perhaps WHO should develop more realistic goals and more durable strategies.