“They found that mosquitoes seemed to change their hours of “peak aggression” from 2 or 3 a.m. to around 5 a.m. three years after nets were put up. And in one village, the proportion of mosquito bites inflicted outdoors rose.
Posts Tagged ‘Africa’
Nigerians have become so at home with malaria that they feel it is no longer a threat but scientists believe that it is still a very big threat to man today. Statistics show that worldwide, it kills more than 1.2 million people annually.
Prevention, they say, is better than cure so researchers at the Department of Public Health, Nigerian Institute of Medical Research (NIMR) are working hard to see that malaria is eradicated by eliminating the vehicle through which the malaria parasite is transmitted to man, the female anopheles mosquito. In this chat with Dr. Sam Awolola, head of the Department of Public Health, NIMR, he says all the efforts will come to naught if proper policies are not put in place. Excerpts:
According to Dr Awolola, the three main processes in malaria control are prevention, treatment and the possibility of having a vaccine against malaria but in NIMR, the focus is on prevention.
“When you talk of prevention, you are talking of how to prevent people from getting infected with malaria; how to prevent transmission from mosquito to human. We focus on preventing mosquitoes from infecting people with malaria through three major ways: Use of long-lasting insecticide-treated nets impregnated with insecticide. They can last up to three years; spraying the houses with WHO-approved insecticides done by trained personnel. When a house is adequately sprayed, the insecticide repels mosquitoes because it has excito-repellent effect.
It also kills those that are stubborn and land on the sprayed wall. This is done every six months or at least once a year depending on the epidemiology of malaria in that environment. The third aspect is larva source management. Mosquitoes breed in stagnant water and before they become adults, they pass through some phases and at that level, you can catch them. Larva source management has two portions – larviciding, ie applying insecticide to the larva and pupa stages.
The other aspect is environmental management. Mosquitoes breed in stagnant water and such water can be cleared or made to flow and all the larvae will be killed. If your gutters are flowing, the water will carry the larvae along and destroy them. Also, some areas of vegetation support the breeding of mosquitoes. We clear those vegetations. All these make up environmental management. So environmental management plus larviciding are put together as larva source management,” he stated.
He said using protective clothing or aerosol in houses do not make much impact when it comes to reducing malaria morbidity and mortality.
Awolola noted that their research in the last 10 years has shown clearly that there is a lot of resistance to public health insecticides used for malaria vector control in Nigeria. Due to continuous use of the four classes of chemical insecticides (pyrethroids, carbamates, organophosphates and organochlorines), the mosquitoes were subjected to a lot of pressure and over the years, they adapted to the environment so well that they have now become resistant to the insecticides.
“Mosquitoes react to an insecticide in two main ways: One is by trying to metabolise (decay) it using some chemical enzymes so that it becomes non-toxic. Another way is mutation. The mosquito gets in touch with the insecticide through its integument (legs, wings), it then changes the configuration of the gene that recognises the insecticide so that the site of recognition of the mosquito changes and the insecticide becomes ineffective.
For the insecticide to be effective, the site of recognition with the mosquito must be identical. So immediately the mosquito changes the site of recognition, the whole system changes and the mosquito is able to survive. If that happens, the mosquito has mutated because genes are involved.
The gene is a heritable material which means that the next generation of mosquitoes will be resistant to the insecticide because it has passed the gene to them and that gene will continue in that population. We, therefore, have an insecticide-resistant gene in the population and the next set of mosquitoes from that line, whether they have been exposed before or not, will be resistant to insecticides.
You know that 350 mosquitoes can come out from one set of eggs. So if out of the 350, 100 survive and have a blood meal and are able to lay eggs, they will go on to produce another 350 mosquitoes each, and there will be an exponential increment in the number of mosquitoes that will be resistant in that population. That is how resistance spreads.
Dr. Awolola advised that all interventions must be evidence-based for them to be effective. “This means that before the intervention, you must have sufficient evidence to show that it will work. You must have collected some baseline information prior to the intervention, but unfortunately, that is not done inNigeria. But things have started changing at the national level because people have seen that you can spend millions of naira and it goes down the drain if you don’t do these things.
We want to scale up our intervention, to have an ambitious coverage. So if you don’t get these fundamental bases of malaria control, then you are running your programme on a faulty start and you will end up having faulty results and faulty intervention and then malaria continues to stay with us. “With insecticide resistance, we are in for it unless we put our house in order to ensure that our interventions are evidence-based.”
He advocated the practice of rotational use of insecticide, saying that “when you identify that the mosquito is resistant to a particular insecticide, you use another class of insecticides becuse the classes have different target sites. But that can be done when you have a programme that is systematic, pragmatic and evidence-based where information are gathered by think-tanks and fuelled into the national bowl for use to formulate policies.”
He noted that there is still a gap between research and policy which needs to be bridged. Harping on the need for surveillance systems that will be able to monitor resistance, he said: “By now, we should have in each geopolitical zone, a centre where they monitor mosquito resistance because malaria is a big issue.
People say that all the time but the will to actually do something about it is not there so we need to put that in place because if that is not in place, sooner or later, these chemicals will become useless, worthless and the issue of malaria becomes more difficult to control, the intervention will no longer be effective and it will be rejected.
“Our research has shown clearly that the resistance issue has continued to increase in Nigeria and if measures are not in place to ensure that it is curtailed, sooner or later, you will see that all these interventions will fail so government needs to put a structure in place, a structure which I refer to as a roadmap to malaria elimination.
That roadmap should be a policy statement from the Federal Government, through the Federal Ministry of Health and the National Malaria Control Programme and we will have a policy in place towards malaria elimination and this roadmap has to be well structured.
It is not something that will happen in two or five years, it might not happen in 10 years but you have timelines and milestones and indicators to show progress. Insecticide resistance is one key issue here; you cannot get malaria eliminated without focusing more on the vectors,” he said.
By Ed Cropley
Besides the huge human cost imposed on the continent – 90 percent of the 655,000 deaths estimated worldwide in 2010 – the mosquito-borne disease is an economic millstone, draining public and private resources and hammering productivity.
According to a 2001 study co-authored by U.S. economist Jeffrey Sachs, the disease imposes an annual “growth penalty” of 1.3 percentage points on afflicted states, which includes most of those south of the Sahara apart from South Africa.
In Nigeria, Africa’s most populous nation and its biggest oil producer, malaria is responsible for up to 25 worker days lost per person per year, or two a month, due to direct infection or the need to stay at home to nurse a sick family member, often for a week or more.
In Zambia, it is the leading cause of absenteeism, accounting for more than twice as many days off as HIV/AIDS, and can consume up to 40 percent of the public health budget in cash-strapped frontline states.
It may not always be thus.
The number of malaria deaths has fallen dramatically in the last decade due to increased aid spending on basic items such as insecticide-treated bed nets and drugs, the World Health Organization (WHO) says.
More excitingly, the holy grail of a vaccine against a notoriously adaptable parasite no longer appears unobtainable after an experimental vaccine from GlaxoSmithKline was shown last year to halve the risk of African children getting the disease.
Even before the prospect of a vaccine, companies across Africa were waking up to the commercial sense of investing in a malaria-free workforce – and the results are encouraging governments to get in on the act.
Faced with endemic malaria in the 240,000 population town around its Obuasi gold mine in Ghana, AngloGold Ashanti, the world’s third largest bullion producer, launched a multi-pronged campaign of bed-nets, indoor insecticide spraying and drugs that cut infections from 79,237 in 2005 to fewer than 16,000 in 2008.
The program cost the Johannesburg-based firm $1.3 million a year, but over that time the malaria drug bill at the mine’s hospital dropped from $55,000 to $9,800 a month, while work days lost each month fell from 6,983 to just 282.
“It really made economic sense because of the absenteeism and the cost of medication,” said Steve Knowles, the head of AngloGold’s anti-malaria operations.
The Ghana model is now being extended to communities around its mines in Democratic Republic of Congo, Tanzania, Mali and Guinea, bringing as many as 500,000 people under its umbrella.
Europe’s financial crisis and relatively sluggish rich-world growth have left a question mark over cash pools such as the Global Fund to Fight AIDS, Tuberculosis and Malaria that have been complementing state and private sector efforts, threatening to unravel the gains made.
But Knowles said many governments were becoming increasingly aware of the mathematics of beating malaria and starting to put their own programs in place.
The prospect of an affordable vaccine is only going to increase the power of that argument for a region forecast to grow at 5.4 percent this year – even with malaria. Without it, that figure could be knocking on 7 percent.
“Now that they’re seeing the aid funding may not be there, it’s a bit of a wake-up call and governments are looking to do it themselves,” Knowles said. “What difference will a vaccine make? If it comes through, it’s going to be huge.”
(Editing by Ed Stoddard and Ron Askew)
Dengue-malaria scare looms, health dept has no
plans or enough staff
The fear of malaria and dengue is looming large over the city this year as well. Besides, the health department
claims lack of manpower to carry out any preventive measures such as fogging and others to check this menace.
A large number of city residents fall prey to malaria and dengue every year.
In 2011, the city reported 153 cases of dengue. Nine people lost their lives. The city also reported 526 malaria
And this year, as summer is approaching, the department has again showed its helplessness citing lack of
manpower to carry out fogging in the city. At present, the malarial wing of the department has 16 people and the
district health department has written a letter to the state health department for an additional 120 people.
“We have shortage ofstaff in the district. But we willstill carry out fogging and other measures to control the
problem. We are waiting for additional manpower,” said Dr Parveen Garg, chief medical officer.
Residents allege that the health department has not initiated fogging and other preventive measures till now. Last
year, the department was avoiding fogging and other measures saying that fogging was ‘not good’ for health and
was expensive. But this year they do not have manpower.
Riti Singal, resident of Kendriya Vihar said, “These things should have been done well in advance. Now when
mosquitoes have started ruling, the department realised that they do not have manpower. By now things would
have been clear how to control this menace. But they are waiting for some positive cases.”
© Copyright © 2012 HT Media Limited. AllRights Reserved.
Drug-resistant Malaria Spreads
Almost all malaria-related deaths are caused by the drug-resistant plasmodium falciparum version. Scientists believe the spread is fueled by the incorrect use of artemisinin and fake versions of the drug, White told Reuters.
BY: TALEA MILLER
Wormwood plants growing in China. Photo by Flickr user Novartis AG.
A synthetic biology breakthrough, achieved at laboratories in northern California, could expand access to malaria treatment around the globe beginning in 2012.
Scientists at the University of California, Berkeley, and the biotech start-up Amyris developed a process to manufacture artemisinin, a crucial ingredient in first-line malaria drugs that until now had to be extracted from a natural crop called sweet wormwood.
Nearly one million people die each year around the world from malaria, despite the existence of effective drugs against the disease. One reason is the lack of access to affordable treatment with artemisinin combination therapy.
Fluctuations in the annual crop output of sweet wormwood, a fern-like plant grown mostly in China and Vietnam, have caused instability in the market price for these malaria drugs. Shortages of the crop can also lead to shortages of the medicine.
Fermentation tank photo courtesy Sanofi-aventis.
The new semi-synthetic artemisinin, produced in large-scale fermintation tanks (pictured to the right) from engineered synthetic microbes, successfully entered the production phase through a public-private partnership with the drug company Sanofi-aventis earlier this year. It is considered “semi-synthetic” because it is uses natural substances in the process.
It will hit the market beginning in 2012, and those involved with the research hope it will stabilize prices and take the boom and bust nature of artemisinin production out of the malaria treatment equation.
Richard Chin, CEO of the non-profit drug development organization OneWorld Health, said production will ramp up from 20 tons in the first year to 40 tons annually in 2013. His organization coordinated the public-private partnership and development of the technology with funding from the Bill and Melinda Gates Foundation*.
“It will be about half, a little less than half, of the world’s supply and it will alleviate the shortage predicted for next year,” said Chin.
The influx of artemisinin will help make the best quality malaria treatment more affordable for governments and consumers in poor countries, said Dr. Olusoji Adeyi, who runs the affordable malaria medication program at the Global Fund to Fight AIDS, Tuberculosis and Malaria, and is not involved in the research.
“This is a benefit to the consumer, at the country level, and the resources that governments and donors provide can cover more treatments,” said Adeyi.
The project is aiming for an artemisinin market price of about $350 a kilo so that farmers can also stay in business growing sweet wormwood. Currently, Chin said, artemisinin is priced higher than $500 a kilo and climbing because of an anticipated shortage in the crop for next year.
“The price is rising as we speak,” he said.
The high price of artemisinin has played a big role in the lack of access to the combination therapies, Adeyi said, leaving many in malaria endemic areas to turn to the cheap — but now mostly ineffective — chloroquine malaria treatments.
In many countries, artemisinin combination therapy can still cost anywhere between $4 and $10 for the consumer, while chloroquine costs around 50 cents. The difference in price makes the higher quality drug prohibitively expensive to most people in malaria endemic areas, Adeyi said.
The Global Fund has designed a financing mechanism to reduce those prices, which is showing good success so far in its pilot stage, but Adeyi said any expansion of access to medication will require a steady dependable supply of artemisinin like what the semi-synthetic roll out could provide.
The project intends to be a complimentary source of artemisinin for malaria drugs, not to edge natural artemisinin out of the market.
“We are not trying to make it a monopoly,” Chin said. “We don’t want to lower [the price] below a point where it is fair to the farmers.”
Through the partnership, Sanofi-aventis is producing the artemisinin on a large scale, and has agreed to sell it at production price in a fair manner to any qualified drug producer who promises to use it in combination therapy.
The company will also be able to use the ingredient for its own manufacturing purposes. Amyris has also benefited from the project, and is now using the technology developed for the malaria project for work on synthetic fuels. But, says Chin, the real payoff for all the groups involved will come when effective treatment starts to drive down transmission of new malaria cases, and he hopes it will encourage other drug companies and institutions to get involved in global health research down the road.
“The ultimate goal is eradication,” Chin said. “To make malaria a forgotten disease would be incredible.”
*For the record, the PBS NewsHour‘s global health unit is funded by the Bill and Melinda Gates Foundation.
Published online 5 July 2011 | Nature 475, 19 (2011) | doi:10.1038/475019a
Mosquitoes score in chemical war
Growing resistance is threatening global malaria-control efforts.
Key weapons in the fight against malaria, pyrethroid insecticides, are losing their edge. Over the past decade, billions of dollars have been spent on distributing long-lasting pyrethroid-treated bed nets and on indoor spraying. Focused in Africa, where most malaria deaths occur, these efforts have greatly reduced the disease’s toll. But they have also created intense selection pressure for mosquitoes to develop resistance.
“Data are coming in thick and fast indicating increasing levels of resistance, and also of resistance in new places,” says Jo Lines, an entomological epidemiologist and head of vector control at the Global Malaria Programme of the World Health Organization (WHO) in Geneva, Switzerland. The WHO now intends to launch a global strategy to tackle the problem by the end of the year.
Pyrethroids are the mainstay of malaria control because they are safe, cheap, effective and long-lasting. Alternatives such as organophosphates and carbamates are available for indoor spraying, although they cost more and are less effective. But pyrethroids are the only insecticides approved by the WHO for use in bed nets. “We have lots of our eggs in the pyrethroid basket,” says Robert Newman, director of the Global Malaria Programme.
The international community has been slow to respond to the threat despite warnings, says Janet Hemingway, director of the Liverpool School of Tropical Medicine, UK, and chief executive of the non-profit Innovative Vector Control Consortium, a public–private venture set up in 2005 to develop new insecticides and monitoring tools. “A number of us had been banging the drums, saying: ‘As soon as you scale up you are going to get resistance.’” But Lines says that the malaria-control community felt too many lives were at stake to let the threat of resistance stand in the way of massively scaling up the bed-net and spraying campaigns.
Teasing out the impact of resistance on the success of malaria-control interventions is difficult because so many other factors influence their outcome. More systematic and more sophisticated monitoring of resistance is also vital, says Lines. The best surveillance data (see ‘Resistance on the rise’), although useful, do not give a complete picture of where resistance is emerging and how prevalent it is, he says. Malaria-control programmes often lack insect-resistance monitoring, and detection of all forms of resistance is not easy. Quick, cheap tests can pick out gene mutations that help the mosquitoes’ nerve cells withstand pyrethroid attack. But other forms of resistance, which depend on increased levels of mosquito enzymes that can destroy pyrethroids before they reach their target, require more complex tests to detect (H. Ranson et al. Trends Parasitol. 27, 91–98; 2011).
But uncertainties about the extent of resistance or its impact are “no excuse for inaction”, says Newman, arguing that the proposed WHO strategy needs to be urgently implemented, and also rolled out preemptively in places where resistance has yet to be detected. The WHO’s plan will recommend, for example, that control programmes rotate insecticides sprayed indoors, using pyrethroids one year and a different class the next. This would be more costly and less effective than relying only on pyrethroids, however, so control programmes may be reluctant to adopt this measure.
Lines says that new combinations of insecticides also need to be developed, so that mosquitoes resistant to one would be killed by the other. In areas where pyrethroid bed nets are used, a different class of insecticides should be used for wall spraying, he adds.
Ultimately, entirely new classes of insecticides — particularly those that can be applied to bed nets — are needed to alleviate the dependence of malaria-control efforts on pyrethroids. For indoor spraying, some longer-lasting and more cost-effective non-pyrethroid insecticides should be available by next year, Hemingway says, although developing wholly new classes will take five to seven years. Repurposed agricultural insecticides might also act as a stopgap were resistance to pyrethroids to develop rapidly. Research targeting mosquito control is “grossly underfunded” compared with that on malaria drugs and vaccines, she adds, which is why control efforts have had so few options to call on.
Amid all the gloomy talk of economic recession and dire warnings that the amount of money available for development aid is going to shrink, a report on the state of malaria research out on Tuesday is refreshingly upbeat. Investment has more than quadrupled in the past 16 years, it says, from $121m in 1993 to $612m in 2009. Yes, malaria is a massive health burden in many countries and was neglected for decades. But, it goes on – and this is worth quoting because it’s a rare moment of good news:
Fortunately, a dramatic increase in support for R&D since the mid-1990s means funders are now well on the way to achieving global malaria control, treatment and elimination goals and, with maintained commitment, should reap the rewards in the next five to six years.
The report comes from six different major organisations, including the Malaria Vaccine Initiative and Medicines for Malaria Venture. Speaking to Professor Awa Marie Coll-Seck, executive director of the Roll Back Malaria partnership, which co-ordinates the global effort, I was keen to know whether this means that the mosquito-borne disease that kills 750,000 a year – mostly small children – in developing countries is on the way out.
In the last few years, she said, the roll-out of bed nets to protect against mosquito bites at night, indoor spraying with insecticide, and better access to good treatment has enabled 40 countries to cut malaria deaths and cases by 50%. “This has put it in the minds of all people that it is possible to defeat this disease and have, one day, a malaria-free world,” she said.
Some countries have eliminated malaria completely – such as Morocco in the last two years. Others are making impressive progress, such as South Africa and Swaziland, where cases have dropped by 90%. This is the way it has to happen, with one region or country after another eliminating the disease. It will take time. “We will one day go towards eradication, but it is not now,” said Coll-Seck. “We are not saying tomorrow we will eradicate malaria. We have a long way to go. We need new tools and the financing of malaria must be sustained.”
Of course, the only disease the world has managed to eradicate is smallpox and that was thanks to a vaccine. Polio is forever tantalisingly close and never quite there, because not only a vaccine is needed but the capacity and will and money to reach all children with the vaccine. Huge efforts continue to be made in the remaining pockets – I saw the impressive mobilisation myself in India a year and a half ago(this is the piece I wrote). But even where eradication is elusive, vaccines can drastically cut the death toll of infectious diseases.
So one of the tools Coll-Seck mentions is indeed a vaccine. One of the big surges in malaria research funding has been for the development of GlaxoSmithKline‘s RTS,S vaccine, which is now in final trials in Africa and may give children 50% to 60% protection, we hope. Between 2004 and 2009, says the report, 28% of malaria research funding has gone into vaccines, with 38% into drugs, 23% to basic research but only 4% into vector control products – essentially new insecticides to replace the cheap but controversial DDT, which causes environmental damage if used outside – and 1% into new diagnostics. That reflects “donor funding preferences”, the report says. The two latter areas badly need more money, says Coll-Seck.
Once again, it is the Bill and Melinda Gates Foundation that has led from the wallet. Two organisations – the foundation and the US National Institutes of Health – “provided a striking half of global malaria R&D funding in 2007-09, and were responsible for 85% of the global increase in malaria funding”, says the report.
So what are the hurdles ahead, I asked Coll-Seck. Sustained finance is still the number one priority, she says. Funding overall for malaria (not just research) plateaued in 2010. Some 70% of it comes through the the Global Fund to Fight Aids, Tuberculosis and Malaria, which is struggling to keep donations up. The second issue is resistance to the only drug that works well – artemisinin – which has been found on the Thai/Cambodia border, underlining the need for new drugs and the importance of using those we have properly. And the third, she says, is maintaining a strong and well co-ordinated partnership between all the countries and organisations involved in the fight against malaria.
So there is much more to do and much further to go, and eradication may be no more than a distant dream – but heartening to see such progress.
Malaria Fight Hits Snag
Amos Nyambane | 29 Jun 2011
AllAfrica.comAn NGO yesterday said mosquito nets are being misused in Kisii and Nyamira counties. The organisation said this is hampering the campaign against malaria in the areas. “The misuse of mosquito nets is greatly affecting the malaria campaigns in the regions. People must understand that they are issued with the nets to protect themselves from the disease not as chicken cages or garden fences,” said Douglas Mobasi, Perlin Project manager.
Mobasi said the predominance rate of malaria in the region declined with 86 percent of children below five years and 73 percent of pregnant women sleeping under the nets in that order. Addressing a one day stakeholder’s workshop at Dado Hotel in Kisii, the manager challenged the locals having the nets to use them for the prevention of malaria.