Monday is World Malaria Day; watch out for the pro-DDT hoaxes

April 23, 2011

A letter to the editor of the Cape Cod Times:

DDT unnecessary to fight malaria

April 23, 2011

Monday, April 25,is World Malaria Day. Across the globe, public health and malaria experts will be highlighting the urgent need to do more to tackle this preventable disease that kills more than 800,000 people (mostly in Africa) every year.

Here in the United States, a small group of advocates will, once again, use the day to call for widespread use of the pesticide DDT to control malaria. This despite broad, global agreement that widespread spraying of DDT inside people’s homes is not the best way to tackle malaria and can harm human health.

Those pressing for DDT’s widespread use are few, but they are loud and persistent. They are not public health experts, and they are all closely affiliated with right-wing think tanks. These calls to “bring back DDT” are a dangerous distraction from true malaria prevention.

Debbie West
Barnstable

Ms. West is right.


Anecdotal evidence: Malaria spreads to Tanzania highlands, warming climate blamed

April 16, 2011

Here’s one story that critics of science and scientists who study global warming will try to avoid mentioning:  Malaria’s spread in Tanzania appears to be due to deforestation plus a warming climate that altered historic rainfall patterns.

It’s anecdotal evidence, partly.  The case reinforces the point Al Gore made in An Inconvenient Truth, that climate change can smooth the path for the spread of diseases like malaria.

Via AllAfrica.com, from The Citizen in Dar es Salaam (Sunday Citizen News):

Malaria Threatens Nation’s Highlands

Felix Mwakyembe, 6 March 2011

Opinion

Mbeya — Tanzania’s southern highlanders have long worried about pneumonia and other respiratory illnesses brought on by the cool, wet weather. But as climate change contributes to warmer temperatures in the region, residents are facing a new health threat: malaria.

In Rungwe, a highland district in the south-western Mbeya region bordering Malawi and Zambia, malaria is fast replacing coughs, fever and pneumonia as the most serious local health problem. The change has taken by surprise the region’s residents, who live over 1,000 metres (3,200 feet) above sea level and outside Tanzania’s traditional malarial zones.

Ms Asha Nsasu, 32, of Isebe village, had no idea she had contracted malaria when she was sent to Makandana District Hospital in late December. “I felt weak. I thought it was pneumonia,” Nsasu said. “Then they told me it was malaria.”

In 2009, health centres in Rungwe district reported 100,966 malaria cases, a jump of 25 per cent from 2006, hospital records show.

Malaria is now the biggest public health threat facing Rungwe district, which lies about 940 kilometres (590 miles) southwest of Dar es Salaam, according to the Tukuyu Medical Research Centre, part of the National Institute for Medical Research. One third of outpatients visiting the hospital were diagnosed with the mosquito-borne illness in 2007, according to records from that year, making it the most common disease for outpatients.

Most highland areas in Tanzania are experiencing a growing burden of malaria cases, officials at the Tukuyu Centre said. Climatic changes brought on in part by local environmental degradation are contributing to the growing prevalence of malaria in the district, said Mr Gideon Ndawala, Rungwe district’s malaria coordinator.

“People have cleared the forests, rain has decreased, temperatures have risen,” Mr Ndawala said in an interview. “(When) I first reported on the district in 1983, it was very cold and it rained throughout the year except from mid-September to early November. The weather was not favourable for mosquito breeding,” he said.

Now, however, temperatures are higher and rain more erratic, he said, and mosquito populations – which thrive on warmer temperatures and breed in pools of stagnant water – are on the rise. Worst hit by the surge in malaria are Tukuyu district town, Ikuti, Rungwe Mission and Ilolo, according to district health officials.

Half a century ago, these traditionally cool areas saw no mosquitoes and did not register any malaria cases, but now the weather is warmer, said Mr Ambakisye Mwakatobe, a 76-year-old man from Bulyaga village in Rungwe.

“In the past, we never saw mosquito nets here. I saw a net for the first time at the age of 20, when I joined Butimba Teachers College in 1957,” he said, in an interview at his village home.

Mzee Mwakatobe said cases of malaria began to appear several decades ago but residents did not relate them to warming temperatures, believing the mosquitoes instead were arriving on buses from lower regions.

“It was in the 1970s when we started getting malaria here. I thought it was the buses from Kyela and Usangu that brought mosquitoes,” he admitted. But “the weather also started to change in those years,” he said.

A half-century ago, “it was very cold here and it rained throughout the year. Three things were compulsory: a sweater, pullover or heavy jacket; an umbrella or raincoat; and gumboots,” he added. “There was frost all day long and cars had to put their lights on.

“But today things have changed,” he said. “Look, now we even put on light shirts. There is no need for sweaters, gumboots or umbrellas.”

Scientists agree that the changing weather is feeding into Rungwe’s worsening malaria problem.

“Up until 1960, districts like Rungwe, Mbeya, Mufindi, Njombe, Makete and Iringa in the southern highland regions were malaria free. Today is quite different – malaria prevalence is high,” said Mr Akili Kalinga, a research scientist at Tukuyu Medical Research Centre.

Malaria accounts for 30 per cent of the burden of disease in Tanzania and is a huge drain on productivity, according to a report produced by research scientists for the Sixth Africa Malaria Day in 2006. In response to the rising malaria caseload, the government is taking steps to stem the disease’s expansion.

Measures include public health education in newly vulnerable districts on home cleanliness and water storage, how to eliminate the places of still water where mosquitoes live and breed, and the use of mosquito nets and fumigation, said Dr Sungwa Ndagabwene, Rungwe’s medical officer.

“The government is taking serious measures to fight malaria. We started with a ‘mosquito nets for all’ campaign – saying every person should sleep under bed nets,” Mr Ndagabwene said.

The government also has begun spraying the inside of homes with insecticide, first in the Kagera Region and now throughout the Lake zone, near Lake Victoria, he said. It plans to expand the spraying programme, which has helped cut malaria transmission in Zanzibar, to the rest of the Tanzania’s malaria-affected regions.

Such spraying programmes aim to kill mosquitoes that land on the inside walls of homes. Spraying can protect homes for between four to ten months depending on the insecticide, according to the World Health Organisation (WHO).

WHO has approved 12 insecticides it considers safe for such spraying programmes, including DDT – a controversial endocrine disruptor that has proved one of the most effective ways to control mosquito populations but that has also been linked to environmental damage and health problems including cancer.

Mr Ndagabwene said spraying the chemical only indoors limited its environmental impact. WHO officials have said they believe the benefits of using the pesticide outweigh its risks. The Stockholm Convention bans the use of DDT but exempts countries that choose to use the chemical to control malaria.

Tanzania is one of the world’s worst malaria-affected countries, recording 14 to 18 million clinical cases annually and 60,000 deaths, 80 per cent of them in children under five years old, according to a 2010 malaria reduction plan put together by USAID.

Children under five and pregnant women are most affected by the disease, official health figures show. (AlertNet)

The author is a freelance writer based in Dar es Salaam

More:


WHO, DDT and the Persistent Organic Pesticides Treaty: Historic view from the inside

March 19, 2011

Rollback Malaria (RBM) was established in 1998 in part to reinvigorate the worldwide fight against malaria, and in part to facilitate the negotiations for what became the Stockholm Convention, the Persistent Organic Pesticides Treaty of 2001.

RBM World Malaria Day 2011

That’s about the time the ungodly assault on WHO and Rachel Carson started, by hysterical DDT advocates.  We now know that Roger Bate, Richard Tren, Donald Roberts and their comrades in pens are stuck in that 1998 fight.

Here’s a short account, from RBM, about just what happened:

The DDT Controversy

In 1999 the RBM Secretariat was called upon to help resolve a controversy emerging from intergovernmental negotiations to establish an international environmental treaty. At the centre of this controversy was DDT, former hero of the malaria eradication campaign and current totemic villain of the environmental movement. The treaty being negotiated was intended to eliminate the production and use of twelve persistent organic pollutants. DDT, still used for malaria control in over 20 countries, was included among ‘the dirty dozen’ chemicals slated for elimination, eliciting a strong reaction from public health activists and malaria specialists who claimed that its elimination would result in unacceptable increases in malaria morbidity and mortality. Environmental specialists and others claimed that environmentally friendly alternatives to DDT, although more expensive, could easily be deployed to guard against such a negative impact.

The controversy over the role of DDT in malaria vector control and the dangers posed to the environment escalated and attracted considerable media attention. The controversy was perpetuated in part because of a relatively weak evidence base on the human toxicity of DDT, the cost-effectiveness of proposed alternatives, and the probable impact of public health use of DDT (compared to agricultural use) on the environment. Resolution was also hampered by the relative lack of public health expertise among the Intergovernmental Negotiating Committee delegates, who were primarily active in the fields of foreign and environmental policy.

The challenges presented to the RBM Secretariat in responding to the controversy were many and varied. They included: evaluation of the evidence base and the drafting of policy guidance (a WHO normative role); a major communications effort; and the establishment of new cross-sectoral partnerships and working relationships. In the process, RBM formed new and highly effective ‘partnerships’ or ‘working relations’ with the United Nations Environment Programme (UNEP), the US Environmental Protection Agency, the environmental policy apparatus of core RBM partners, as well as a variety of health and environmental NGOs. RBM conducted country and informal expert consultations and convened and chaired a special working group on DDT which was able to establish a position on the use of the insecticide in public health and the process for evaluating and moving to alternatives. The weight of WHO’s technical authority contributed greatly toward establishing the credibility of the working group. Information about the treaty negotiations and the WHO position on DDT was disseminated to health specialists via the WHO regional networks and to treaty focal points via UNEP.

The RBM Secretariat led the WHO delegation to all meetings of the Intergovernmental Negotiating Committee and prepared information and media events for each, supporting the participation of health/malaria specialists from a number of countries. The RBM Secretariat also served as the media focal point on malaria and DDT and provided interviews and information to all major media, as well as presentations to professional meetings and interest groups.

RBM’s objectives throughout this process were:

  • to establish consensus on the present and future role of DDT and alternatives in malaria control;
  • to encourage greater involvement of public health specialists in country-level discussions about the treaty and in country delegations to the negotiating sessions;
  • to provide information to negotiators and others that would reduce controversy and result in a win-win situation for public health and the environment (in which the longer term goal of DDT elimination is achieved through strengthened, more robust malaria control);
  • to benefit from the media attention to inform the public about malaria; and
  • to mobilize resources to support malaria control from outside the health sector.

All of these objectives have been met and the final treaty, known as the ‘Stockholm Convention on Persistent Organic Pollutants’ provides for the continued public health use of DDT and international assistance for the development and implementation of alternatives.

Resources to support the initial work of the RBM Secretariat were provided by environmental agencies/offices. In addition, the Pan American Health Organization (PAHO) and the WHO Regional Office for the Americas (AMRO) and most recently the WHO Regional Office for Africa (AFRO) have been awarded project development grants from the Global Environment Facility (GEF) to promote regional efforts to strengthen malaria control and reduce reliance on DDT.

From Final Report of the External Evaluation of RBM, Roll Back Malaria to Date, Chapter 2, page 15 (circa 2001).


George Clooney’s malaria? DDT didn’t cure it

January 25, 2011

Not sure why, but pro-DDT sites have been harping about George Clooney’s having contracted malaria, a second time, while performing one of his humanitarian acts in southern Sudan.

George Clooney in Sudan, Time Magazine photo

George Clooney in Sudan, Time Magazine photo

True, Clooney got malaria.  His take?

“This illustrates how with proper medication, the most lethal condition in Africa can be reduced to bad ten days instead of a death sentence.”

Sometimes it may pay to remember that malaria is disease caused by a parasite who must live part of its life cycle in humans, and part of its life in mosquitoes.  Killing mosquitoes only works until the next susceptible mosquito comes along to bite an infected human.

The goal of malaria prevention and eradication campaigns generally is to cure the humans, so regardless how many mosquitoes may be in a given location and regardless how many people they may bite, there is no malaria pool for the mosquitoes to draw from, to spread to other humans.

To beat malaria, we need to prevent the spread of the disease.  At some point that requires providing quick and accurate diagnoses of which parasites cause the infection, and a complete and completed regimen of therapeutic pharmaceuticals to actuall cure the human victims.  DDT is mostly a bystander in that crucial part of the fight.

What was Clooney doing in Sudan?  According to the New York Daily News:

Clooney was in Sudan in December to work with Google and the UN on a human rights project that combines satellite imagery analysis and field reports to prevent a new war from occurring in the troubled country.

“We want to let potential perpetrators of genocide and other war crimes know that we’re watching, the world is watching,” he said in a statement at the time. “War criminals thrive in the dark. It’s a lot harder to commit mass atrocities in the glare of the media spotlight.”

Do you consider it odd that Clooney’s contracting malaria might gather more news in western outlets than his actual trip to Sudan, to call attention to the campaign against genocide?

World Blog – The race to contain drug-resistant malaria

January 23, 2011

NBC News’s World Blog carried a series on malaria and fighting it around the world.  Here’s part I:

PAILIN, Cambodia – The border crossing between Thailand and Cambodia at Pailin has a rather bleak feel about it at the best of times. In the heavy monsoon rain, the dingy checkpoints are reduced to gray smudges.

Vodpod videos no longer available.

World Blog – The race to contain drug-resistant…, posted with vodpod

 

See more video information from NBC, here.


President’s Malaria Initiative: Plans for FY 2011

December 14, 2010

Barack Obama continued George W. Bush’s Africa-oriented fight against malaria.  The President’s Malaria Initiative (PMI)continues to target malaria for control and, if possible, eradication.

PMI announced today plans for work in 2011, country by country:

Malaria Operational Plans for Fiscal Year 2011

These Malaria Operational Plans have been endorsed by the U.S. Global Malaria Coordinator and reflect collaborative discussions with the national malaria control programs and partners in country. If any further changes are made to these plans, it will be reflected in revised postings.

How long before some wag complains that Obama’s program is anti-Africa because it doesn’t propose enough poisoning of the place?  “Not enough DDT!” they will complain, I wager.  And, for the record, I make this prediction not having read any of the country operational plans — in nearly complete ignorance of what the plans actually propose.  Can you find “enough” DDT in any country’s plan?

More:


Mandy Moore Talks Mosquito Nets – ABC News

December 13, 2010

Don’t ask me what work she’s done, because I couldn’t tell you.  I can tell — based on the headlines of the clipping services — that Mandy Moore is popular.

Ironically, in her brief tour of Africa and — shall we label it? — probably-shallow understanding of the issues, Ms. Moore has a deeper understanding of malaria and how to fight it than the most erudite of the DDT denialists, like Michael Crichton, or Rutledge Taylor.  Innocence wins.

For ABC News, the actress talked about charity work in Africa:

Vodpod videos no longer available.

Mandy Moore Talks Mosquito Nets – ABC News, posted with vodpod

It’s a case of a celebrity doing “Do a Good Deed” duty, most likely.  In the video, Mandy Moore puts DDT denialists to shame.  In writing?  Moore doesn’t come off as well.  (Did she write that piece herself?  Maybe she should write what she talks.)


BBC News – Malaria ‘cannot be eradicated’

November 29, 2010

BBC report: Experts say control, not eradication of malaria (short advertisement precedes news video):

Vodpod videos no longer available.

BBC News – Malaria ‘cannot be eradicated’, posted with vodpod

More, and resources:

Lancet map, showing nations where  malaria eradication may be possible, and those where control may be the best solution

Map from The Lancet, accompanying article: "Malaria is caused by five species of a parasite that can be carried from human to human by mosquitoes. Over the last 150 years, the portion of the world where malaria is still endemic has shrunk, but the disease is still endemic in 99 countries. However 32 of these countries, most of them on the edges of the endemic zone, are attempting to eradicate the disease, while the rest are trying to reduce infections and deaths though control measures."


Lancet special issue on malaria eradication: No call for more DDT

October 30, 2010

Lancet is one of the premiere research journals in the world for all of science, but especially for issues of health and medicine.

Image from Lancet illustrating malaria story

Image from Lancet –
Mother and child under a mosquito bite-preventing bednet.

On October 29, 2010, Lancet published a special report, “Malaria Elimination.”  Much science.  Much history.  No call for more DDT.

A plan for research is laid out.  Plans to eradicate malaria from more than 90 nations are laid out, explained and debated.  Calls for more research are made.  Calls for disciplined action from nations and health care organizations, and donor organizations.

But no call for more DDT.

Go take a look at the issue.  Several of the articles are available for no charge, out from behind the usual Lancet paywall.

Get the real science, real history, real policy.  Environmentalists are not evil villains there.  malaria is the villain in that story, and serious health care researchers and deliverers discuss serious methods to beat the disease.  Consequently, DDT has only a bit part.

Resources:


DDT hoaxsters predictably spinning India/malaria deaths story — wrongly

October 28, 2010

People so wedded to a hoax, or just wrong, view of events cannot be swayed away from their convictions easily.

Elizabeth Whelan’s hoax science policy group, the American Council on Science and Health (ACSH), put out a press release taking note of the study published in Lancet that calls into question the count of malaria deaths in India promulgated by the World Health Organization (WHO).  You remember, the study suggests the malaria death toll among adults in India may be as high as 200,000 annually, compared to the 15,000 estimated by WHO.

ACSH can’t resist the spin.  Implicit the debunking may be, but the study thoroughly debunks ACSH’s claim that more DDT will help defeat malaria.  India is the world’s greatest user of DDT, using more than all the rest of the world together.  Clearly a surplus usage of DDT has not created the miracle end to malaria that ACSH and other hoaxsters claim it would.

Still, ACSH sticks to their views, even when those views are grossly wrong.  ACSH said, “ACSH has called for resumed use of indoor residual spraying of small amounts of DDT to prevent mosquito bites, repel mosquitoes, and reduce malaria deaths.”

No word from India on whether it will dramatically reduce DDT use to meet ACSH’s call for “small amounts.”

ACSH’s press release calls attention to a Wall Street Journal Blog article describing WHO’s response to the Lancet-published study of India malaria deaths — WHO questions the “verbal autopsy” methodology, and says it stands by its estimates of malaria deaths in the nation:

“The new study uses verbal autopsy method which is suitable only for diseases with distinctive symptoms and not for malaria,” WHO’s India representative Nata Menabde said in an email statement Thursday.

The WHO says it takes into account only confirmed cases of malaria and surveys those using healthcare facilities.

Malaria symptoms include fever, flu-like illness and muscle aches. Malaria is endemic to parts of India, where many people live in mosquito-infested areas. Confirming the presence of malaria requires tests like the “Peripheral Smear for Malarial Parasite” and “Rapid Malaria Antigen”.

Lancet said the determinations made by its field researchers were reviewed by two of 130 trained doctors for all the 6,671 districts who determined whether or not the person had died from malaria.

The data concluded that 205,000 deaths before the age of 70, mainly in rural areas, were caused by malaria each year – 55,000 in early childhood, 30,000 among children ages five to 14 and 120,000 people 15 and older.

The WHO called for further review of the study.

“Malaria has symptoms common with many other diseases and cannot be correctly identified by the local population,” Dr. Menabde said, adding: “The findings of the study cannot be accepted without further validation.”


Malaria deaths in India under-reported? Bad news for pro-DDT partisans

October 22, 2010

Malaria hotspots in India. Image from Nature magazine, 2010. News report on Lancet study that suggests mortality from malaria in India may be significantly higher than WHO reports indicate.

Good news from the war on malaria has been that annual deaths are calculated to be fewer than 1 million annually, as low as 880,000 a year — the lowest human death toll from malaria in human history.

Researchers in India suggest that deaths there are grossly underreported, however — not the 15,000 estimated by the World Health Organization, but closer to 200,000 deaths a year, nearly 15 times as great.

Reading that news, DDT partisans might get a little race of the pulse thinking that this might improve the urgency for the case for using more DDT, as advocated in several hoax health campaigns and media, such as the recent film “3 Billion and Counting.”

The problem, though, is that India is one of the few places where DDT manufacturing continues today, and India is one of the nations where DDT use is relatively unregulated and heavy.  In short, if DDT were the miracle powder it’s claimed to be, any finding that malaria deaths are 15 times greater than reported by WHO is nails in the coffin of DDT advocacy.

Bloomberg News reported:

Researchers based their estimate on interviews with family members of more than 122,000 people who died between 2001 and 2003. The numbers “greatly exceed” the WHO estimates of 15,000 malaria deaths in India each year, the researchers wrote in the study, published today in the journal The Lancet.

“It shows that malaria kills far more people than previously supposed,” said one of the study authors, Prabhat Jha of the Center for Global Health Research in Toronto, in a statement. “This is the first nationwide study that has collected information on causes of death directly from communities.”

Remote regions may have an undocumented malaria burden, because conventional methods of tracking the disease are flawed, according to the authors. In India, the government malaria data, which is used by the Geneva-based WHO, only counts patients who had tested positive for the disease at a hospital or clinic. Others who died of symptoms closely resembling the malady but didn’t get a blood test aren’t included, co-author Vinod Sharma of the Indian Institute of Technology in New Delhi said in an interview today.

The lack of accurate data may hinder efforts by governments and aid organizations to provide diagnosis and treatment to the population at risk, the authors said.

Watch.  Advocates of poisoning Africa and Asia will claim scientists and environmental activists are somehow to blame for any underreporting, and they will call for more DDT use, claiming a ban has made India a refuge for malaria.  Those reports will fail to mention India’s heavy DDT use already, nor will they suggest an ineffectiveness of the nearly-sacred powder.

The article in the Lancet became available on-line on October 21 — it’s a 4.5 megabyte .pdf document:  “Adult and child malaria mortality in India: a nationally representative mortality survey.” A team of researchers is listed as authors of the study:  Neeraj Dhingra, Prabhat Jha, Vinod P Sharma, Alan A Cohen, Raju M Jotkar, Peter S Rodriguez, Diego G Bassani, Wilson Suraweera,Ramanan Laxminarayan, Richard Peto, for the Million Death Study Collaborators.

Accurate counts of infections and deaths provide essential information for effective programming of the fight against the disease.  Researchers point no particular fingers, but make the case in the article that better methods of counting and estimating malaria deaths must be found.

There are about 1·3 million deaths from infectious diseases before age 70 in rural areas in which fever is the main symptom. If there are large numbers of deaths from undiagnosed and untreated malaria in some parts of rural India then any method of estimating overall malaria deaths must rely, directly or indirectly, on evidence of uncertain reliability from non-medical informants and, although our method of estimating malaria mortality has weaknesses, indirect methods may be even less reliable. The major source of uncertainty in our estimates arises from the possible misclassifi cation of malaria deaths as deaths from other diseases, and vice versa. There is no wholly satisfactory method to quantify the inherent uncertainty in this, and indeed the use of statistical methods to quantify uncertainty can convey a false precision. However, even if we restrict our analyses to deaths immediately classifi ed by both physician coders as malaria, WHO estimates (15 000 deaths per year at all ages)1 are only one-eighth of our lower bound of malaria deaths in India (125 000 deaths below the age of 70 years; of which about 18 000 would have been in health-care facilities).

Our study suggests that the low WHO estimate of malaria deaths in India (and only 100 000 adult malaria deaths per year worldwide) should be reconsidered. If WHO estimates of malaria deaths in India or among adults worldwide are likely to be serious underestimates, this could substantially change disease control strategies, particularly in the rural parts of states with high malaria burden. Better estimates of malaria incidence and of malaria mortality in India, Africa, and elsewhere will provide a more rational foundation for the current debates about funding for preventive measures, about the need for more rapid access to malaria diagnosis, and about affordable access in the community to effective antimalarial drugs for children and adults.

More:


Truth in a fair fight: Eli Rabett explains Gates Foundation’s good work against malaria

September 21, 2010

Good works are oft’ interred with the bones of the good workers, according to that Brutus Mark Antony guy — and at Watts Up With That, many work to bury any good workers, too.

So, a specially-scrubbed carrot is due Eli Rabett, who details the good works of the Gates Foundation against malaria, just to counteract the clamor of the howling at WUWT.

. . . since this started with an attack on Bill Gates, it is important to understand at least some of the interesting things that the Gates Foundation is doing to help fight malaria.

Among these, Affordable Medicines for Malaria (AMFM), is one of the cleverest, and may even work. The idea is that AMFM will buy ACT (artemisinin combination therapy – something else the Wattoids didn’t know about) drugs directly from the manufacturers in huge amounts at deep discount, and pass the drugs on to the distributors, public health agencies, private wholesale pharmacies, and NGOs at so far below cost that even counterfeit drugs cost more. The private wholesalers can take their profit.

One may hope someone will find the magic bullet to fight malaria.  There’s the Ghost of Santayana pacing the chalkboard again, however:  Our experience shows that magic is not real, no magic bullet has ever existed against malaria, and DDT is not now the magic bullet it never was in the first place.  “Those who cannot remember the past are condemned to repeat it,” Ghost of Santayana mutters.

A special place in hell is reserved for those who remember the past, but tell false tales about it instead.


DDT and birth defects: South African television asks questions

July 23, 2010

Steven Milloy, Roger Bate, and Richard Tren hope you never see this television production — they hope you never even hear about it.  It’s one more indication that Rachel Carson was right.

They hope you never even hear about it.  It’s set for telecast in South Africa next Tuesday:

Special Assignment to broadcast episode on ‘Collateral Damage’

Published: 22 July 2010

This week, Special Assignment looks at those affected by the dangerous DDT chemical and also those who say it is a necessary evil to prevent many South Africans from dying.

“I have problems with my balls,” says ‘George’. “I was born without testicles,” adds ‘Joseph’, yet another man born in the Limpopo area. These two and many other young men in Venda share a common story.

Each year, South Africa sprays more than 90 tonnes of the toxic DDT chemical in homesteads in KwaZulu-Natal and Limpopo areas. Though DDT, a persistent organic chemical which can remain in the environment for as much as 40 years is banned across the world, South Africa still uses it to control malaria in the country. Recent studies have however showed that DDT is harmful to humans with hundreds of kids born in the Venda area showing signs of genital deformities. The chemical has also been associated with breast cancer; diabetes; and spontaneous abortion. Yet it remains South Africa’s best option for the prevention of malaria which kills millions of people each year across Africa. This week, Special Assignment looks at those affected by this chemical and also those who say it is a necessary evil to prevent many other South Africans from dying.

‘Collateral Damage’ will be broadcast on Special Assignment on Tuesday, 27 July, at 20:31 on SABC3.


University of Arizona’s “malaria-proof” mosquito

July 15, 2010

This could be good news:  A genetically-altered mosquito that doesn’t harbor the malaria parasite, and so cannot pass it along to humans it bites in its later life.

One more way to end the use and production of DDT.

Press release from the University of Arizona (one of my alma mater schools):

The first malaria-proof mosquito

Scientists at the University of Arizona have achieved a breakthrough in the fight against malaria: a mosquito that can no longer give the disease to humans

IMAGE: Michael Riehle, holding genetically altered mosquitoes, and his team work in a highly secure lab environment to prevent genetically altered mosquitoes from escaping.

Click here for more information.

For years, researchers worldwide have attempted to create genetically altered mosquitoes that cannot infect humans with malaria. Those efforts fell short because the mosquitoes still were capable of transmitting the disease-causing pathogen, only in lower numbers.

Now for the first time, University of Arizona entomologists have succeeded in genetically altering mosquitoes in a way that renders them completely immune to the parasite, a single-celled organism called Plasmodium. Someday researchers hope to replace wild mosquitoes with lab-bred populations unable to act as vectors, i.e. transmit the malaria-causing parasite.

“If you want to effectively stop the spreading of the malaria parasite, you need mosquitoes that are no less than 100 percent resistant to it. If a single parasite slips through and infects a human, the whole approach will be doomed to fail,” said Michael Riehle, who led the research effort, the results of which will be published July 15 in the journal Public Library of Science Pathogens. Riehle is a professor of entomology in the UA’s College of Agriculture and Life Sciences and is a member of the BIO5 Institute.

Riehle’s team used molecular biology techniques to design a piece of genetic information capable of inserting itself into a mosquito’s genome. This construct was then injected into the eggs of the mosquitoes. The emerging generation carries the altered genetic information and passes it on to future generations. For their experiments, the scientists used Anopheles stephensi, a mosquito species that is an important malaria vector throughout the Indian subcontinent.

The researchers targeted one of the many biochemical pathways inside the mosquito’s cells. Specifically, they engineered a piece of genetic code acting as a molecular switch in the complex control of metabolic functions inside the cell. The genetic construct acts like a switch that is always set to “on,” leading to the permanent activity of a signaling enzyme called Akt. Akt functions as a messenger molecule in several metabolic functions, including larval development, immune response and lifespan.

When Riehle and his co-workers studied the genetically modified mosquitoes after feeding them malaria-infested blood, they noticed that the Plasmodium parasites did not infect a single study animal.

IMAGE: Under UV light, this mosquito larva reveals a red fluorescent marker in its nervous system, causing eyes and nerves to glow. The marker’s presence tells the researchers in Riehle’s…

Click here for more information.

“We were surprised how well this works,” said Riehle. “We were just hoping to see some effect on the mosquitoes’ growth rate, lifespan or their susceptibility to the parasite, but it was great to see that our construct blocked the infection process completely.”

Of the estimated 250 million people who contract malaria each year, 1 million – mostly children – do not survive. Ninety percent of the number of fatalities, which Riehle suspects to be underreported, occur in Sub-Saharan Africa.

Each new malaria case starts with a bite from a vector – a mosquito belonging to the genus Anopheles. About 25 species of Anopheles are significant vectors of the disease.

Only the female Anopheles mosquitoes feed on blood, which they need to produce eggs. When they bite an infected human or animal, they ingest the malaria parasite.

Once the Plasmodium cells find themselves in the insect’s midgut, they spring into action. They leave the insect’s digestive tract by squeezing through the midgut lining. The vast majority of Plasmodium cells do not survive this journey and are eliminated by the mosquito’s immune cells. A tiny fraction of parasite cells, usually not more than a handful, make it and attach themselves on the outside of the midgut wall where they develop into brooding cells called oocysts.

Within 10-12 days, thousands of new Plasmodium cells, so-called sporozoites, sprout inside the oocyst. After hatching from the oocyst, the sporozoites make their way into the insect’s salivary glands where they lie in wait until the mosquito finds a victim for a blood meal. When the mosquito bites, some sporozoites are flushed into the victim’s bloodstream.

“The average mosquito transmits about 40 sporozoites when it bites,” said Riehle, “but it takes only one to infect a human and make a new malaria victim.”

Several species of Plasmodium exist in different parts of the world, all of which are microscopically small single-celled organisms that live in their hosts’ red blood cells. Each time the parasites undergo a round of multiplication, their host cells burst and release the progeny into the bloodstream, causing the painful bouts of fever that malaria is known and feared for.

Malaria killed more soldiers in the Civil War than the fighting, according to Riehle. In fact, malaria was prevalent in most parts of the U.S. until the late 1940s and early 1950, when DDT spraying campaigns wiped the vectors off the map. Today, a new case of malaria occurs in the U.S. only on rare occasions.

The severity of the disease depends very largely on the species of the Plasmodium parasite the patient happens to contract.

“Only two species of Plasmodium cause the dreaded relapses of the disease,” said Riehle. “One of them, Plasmodium vivax, can lie dormant in the liver for 10 to 15 years, but now drugs have become available that target the parasites in the liver as well as those in the blood cells.”

That said, there are no effective or approved malaria vaccines. A few vaccine candidates have gone to clinical trials but they were shown to either be ineffective or provide only short-term protection. If an effective vaccine were to be developed, distribution would be a major problem, Riehle said.

Researchers and health officials put higher hopes into eradication programs, which aim at the disease-transmitting mosquitoes rather than the pathogens that cause it.

“The question is ‘What can we do to turn a good vector into a bad vector?'” Riehle said.

“The eradication scenario requires three things: A gene that disrupts the development of the parasite inside the mosquito, a genetic technique to bring that gene into the mosquito genome and a mechanism that gives the modified mosquito an edge over the natural populations so they can displace them over time.”

“The third requirement is going to be the most difficult of the three to realize,” he added, which is why his team decided to tackle the other two first.

“It was known that the Akt enzyme is involved in the mosquito’s growth rate and immune response, among other things,” Riehle said. “So we went ahead with this genetic construct to see if we can ramp up Akt function and help the insects’ immune system fight off the malaria parasite.”

The second rationale behind this approach was to use Akt signaling to stunt the mosquitoes’ growth and cut down on its lifespan.

“In the wild, a mosquito lives for an average of two weeks,” Riehle explained. “Only the oldest mosquitoes are able to transmit the parasite. If we can reduce the lifespan of the mosquitoes, we can reduce the number of infections.”

His research team discovered that mosquitoes carrying two copies of the altered gene had lost their ability to act as malaria vectors altogether.

“In that group of mosquitoes, not a single Plasmodium oocyst managed to form.”

At this point, the modified mosquitoes exist in a highly secured lab environment with no chance of escape. Once researchers find a way to replace wild mosquito populations with lab-bred ones, breakthroughs like the one achieved by Riehle’s group could pave the way toward a world in which malaria is all but history.

###

This study was funded by the National Institutes of Health.

Reference: Corby-Harris et al. Activation of Akt Signaling Reduces the Prevalence and Intensity of Malaria Parasite Infection and Lifespan in Anopheles stephensi Mosquitoes. Public Library of Science (PLoS) Pathogens, July 2010 issue: www.plospathogens.org

How do you like them genetic engineering guys now?


Another study on human health and DDT: ADHD linked to DDT and other pesticides

July 7, 2010

Extravagant and way-too-enthusiastic claims that DDT is “harmless” to human health keep getting marginalized by new studies on the topic.

This week the Journal of the American Medical Association (JAMA) reported another study that links DDT to Attention Deficit Hyperactivity Disorder, “Increased Risk of ADHD Associated With Early Exposure to Pesticides, PCBs.”

I don’t have a full copy of the report yet.  Here is what is publicly available for free:

Individuals who are exposed early in life to organophosphates or organochlorine compounds, widely used as pesticides or for industrial applications, are at greater risk of developing attention-deficit/hyperactivity disorder (ADHD), according to recent studies. Previous studies had linked ADHD with very high levels of childhood exposure to organophosphate pesticides, such as levels experienced by children living in farming communities that used these chemicals. But a recent study using data from the National Health and Nutrition Examination Survey (NHANES) found that even children who experience more typical levels of pesticide exposure, such as from eating pesticide-treated fruits and vegetables, have a higher risk of developing the disorder.

JAMA. 2010;304(1):27-28.

Many of the chief junk science promoters will ignore this study, as they ignore almost all others — Steven Milloy, Roger Bate, Richard Tren, CEI, etc., etc.  How often does the junk science apple have to hit people before they figure out these people are malificent actors, when they claim DDT is harmless and we need more?

See also: