Insecticide treated mosquito nets Archives

June 1, 2011

Mosquitoes are Suckered in New Malaria Research

(AFP) –

PARIS — In the biggest lab breakthrough against malaria in years, scientists on Wednesday said they had identified odour molecules that baffle blood-thirsty mosquitoes.

The molecules disrupt carbon-dioxide sensors that alert mosquitoes to exhaled breath, which signals the presence of a human nearby, the team reported.

The work could lead to revolutionary but low-cost chemicals to confuse, deter or trap mosquitoes, it said.

They could be invaluable in poor tropical countries, providing an alternative to DEET, a skin repellent that is expensive, needs repeat applications and is showing worrying signs of resistance.

“These chemicals offer powerful advantages as potential tools for reducing mosquito-human contact and can lead to the development of new generations of insect repellents and lures,” said Anandasankar Ray, an assistant professor of entomology at the University of California at Riverside, who led the study.

Traps for mosquitoes already exist, in the form of dry ice, gas cylinders of carbon dioxide or propane combustion.

But these gadgets are too bulky and far too expensive to be used for mosquito control, especially in poor settings.

Future mosquito traps, Ray predicted, could be “highly portable, convenient and easily replenishable.”

Malaria claimed 781,000 lives in 2009, according to the UN’s World Health Organisation (WHO), which is heading efforts to distribute insecticide-treated mosquito nets and to spray reproduction sites.

About 90 percent of malaria deaths each year occur in Africa and 92 percent of those are children aged under five.

Other mosquito-borne diseases are dengue, which sickens around 50 million people each year, yellow fever, filariasis and West Nile virus.

Building on research on fruitflies, a common laboratory tool, Ray’s team looked at three of mosquito species whose females are disease vectors: Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus.

The odour molecules that they identified disrupt receptor cells for carbon dioxide located in tiny, antennae-like appendages close to the mosquito’s mouth.

These receptors are activated by a whiff of carbon dioxide, triggering a signal in the brain that prompts the insect to fly upwind, following the puffs of CO2 until they reach its source. Mosquito also use heat sensors and sight to home in on their meal.

The findings have been tested in a small-scale experiment in Kenya, using huts where alluring plumes of CO2 were released to attract mosquitoes and odour molecules were released to bamboozle them.

Mark Stopfer, a specialist at the US National Institutes of Health (NIH), said the results opened up “a promising line of defence.”

He added some words of caution, saying that mosquitoes were attracted to other odours in human sweat and skin. In addition, the chemicals that have been tested on insects so far have not yet been tested for safety on humans, he noted.

March 8, 2011April 1, 2011

Fighting Malaria With Nets Nets, Mandy Moore

Mandy Moore

Singer-songwriter, actress and PSI Ambassador

I’m extremely grateful to be invited to share my voice alongside all these incredible women on International Women’s Day. As an ambassador for the global health organization PSI (Population Services International), I’ve been fortunate to have traveled to places like the Central African Republic and Southern Sudan where I have met amazing women who rival the likes of the women on this site today.

Last fall, I traveled to the Central African Republic — a country where malaria is responsible for approximately half of all hospital visits. I was there to help launch a United Nations Foundation’s Nothing But Nets campaign that would provide a net to every family in need in the country.

As part of the trip, I visited a local health clinic in a rural part of the capital city, Bangui. There, I met a woman named Sophie who was with her husband and newborn baby. Her baby was inconsolable, crying from pain and hot to touch with a high fever. This was the second time Sophie had been at the clinic with her daughter. The first time her daughter she was only mildly ill, but the health clinic didn’t have any anti-malaria treatment in stock. So they referred her to the local hospital, which was an expensive bus ride away. When Sophie arrived at the hospital she realized that they couldn’t afford the medication. So she took the little remaining money she had and purchased syringes. Then she walked back to the rural health clinic and begged the doctor there to give them the medication for free. Sophie was willing to inject her daughter herself if she thought it could save her life.

Many Moore — Mandy Moore in the Central African Republic

That’s when I met them. The health clinic had no medication, Sophie had no money, and her daughter’s fever was worsening by the minute. Luckily, in her case, we were able to give her the money needed to return to the hospital by cab and purchase the right treatments.

That was the last time I saw Sophie and her baby. I often think of them and hope that they’re okay. But I can’t help but wonder what will happen the next time her daughter is bitten by a malaria-carrying mosquito, when there’s no group of Westerners at the clinic willing to pay her way.

Thankfully, there’s hope for mothers like her. Long-lasting, insecticide-treated mosquito nets are one of the most cost-effective and cost-efficient ways of preventing malaria. Nets can prevent malaria transmission by up to 90 percent, and through the Nothing But Nets campaign that I helped launch, the government of Central African Republic and its partners at PSI and UNICEF were able to distribute nearly 1 million mosquito nets — one for every family in need.

At the same time, thanks to a grant from the Global Fund to Fight AIDS, Tuberculosis and Malaria, the local health clinic where I met Sophie is now able to provide preventative malaria treatment to pregnant women, free of charge. Malaria contributes to the deaths of an estimated 10,000 pregnant women and 200,000 infants each year in Africa, so early and effective treatment can prevent a great majority of deaths.

But tackling malaria in a country like the Central African Republic is a huge uphill battle, and my experiences there have been a healthy dose of reality, fueling my own sense of urgency to do my part in reducing the preventable suffering of the incredible women I met. This year, I will be attending the Clinton Global Initiative University, a meeting for students and national youth organizations to tackle pressing global issues. I am excited about being a part of this growing community of young leaders who don’t just discuss the world’s challenges, but take real, concrete steps toward solving them — real, concrete steps to empower women like Sophie to protect herself and her family.

[ad#Adsense-200by200sq]

February 10, 2011January 3, 2013

Malaria: What is it and Why I Believe Our Generation Can Defeat it

By Kwabena Amponsah-Manager

What is Malaria?

Malaria is a tropical disease that is caused by the bite from the female Anopheles mosquito. The parasite is known as Plasmodium. Globally about 22 countries are plagued by malaria, most of them in the tropical regions and a few sub-tropical countries.

Symptoms of Malaria:

The symptoms of malaria include fever, anemia, chills, lost of appetite, general body weakness, nausea, convulsions and headache. The most characteristic symptom of malaria is the cycle of sudden chills followed by fever and sweating.

Occurrence:

There are more than 400 million cases of malaria annually. If not treated, the infection can be fatal, especially in infants, pregnant mothers and seniors. Malaria kills between one and three million people, the majority of whom are young children in sub-Saharan Africa, where 90% of malaria-related deaths occur.

The most serious form of the disease is caused by Plasmodium falciparum which is one of several species of the parasite that cause the disease. A milder form of the disease results from the species Plasmodium vivax, Plasmodium ovale and Plasmodium malariae.

Prevention and Treatment of Malaria:

The most effective means of preventing the disease is to prevent the bite from the mosquito. Insecticide treated mosquito nets and insect repellents are first line preventive measures. Mass preventive measures such as spraying insecticides inside houses and draining standing water where mosquitoes lay their eggs are also employed by governments and institutions.

Currently there is no effective vaccine against malaria though a few are in development (GSK is a leader in this aspect). A variety of antimalarial medications are available. In the last 5 years, treatment of P. falciparum infections in endemic countries has been altered by the use of combinations of drugs containing an artemisinin derivative. Severe malaria is treated with intravenous or intramuscular quinine or, increasingly, the artemisinin derivative artesunate. Several drugs are also available to prevent malaria in travelers to malaria-endemic countries (prophylaxis). An example of prophylactic malaria drug is Malarone. Chloroquine used to be most commonly prescribed medicine against malaria but the parasite developed resistance to the drug. It is still being used to treat and prevent malaria though not as effective as it used to be. In places where drug resistance parasites have not yet been confirmed, such as Central America and parts of the Middle East, Chloroquine is still the drug of choice prevent and treat P. falciparum and P. vivax infections.

For reasons not fully understood, a number of diseases appear to provide some resistance to malaria. Notable ones include sickle cell disease, thalassaemias, glucose-6-phosphate dehydrogenase, Duffy antigens. Some people have red blood cells that lack proteins called Duffy antigens on their surface. Duffy antigens act as receptors for Plasmodium vivax merozoites, so people without Duffy antigens are resistant to infection from this parasite. Again, individuals who live in malaria-endemic regions acquire immunity to malaria through natural exposure to malaria parasites. In fact, naturally acquired immunity to falciparum malaria protects millions of people routinely exposed to Plasmodium falciparum infection from the disease.

Even though malaria has not received the global attention required for a killer of such profile, wealthy foundations, some private companies, and smart governments across the world are beginning to wake and make malaria a priority. However, there are still skeptics who doubt humans’ ability to eradicate malaria. Early November of 2010 a series of papers published in a respected scientific journal, the Lancet cast a gloomy cloud over any hope of dealing with malaria, at least in our lifetime. The papers concluded by urging governments, donor agencies and foundations to focus more on minimizing the prevalence of malaria and not on eradicating the killer.

Generally speaking, and not necessarily referring to the Lancet papers, considering mankind’s quest to conquer the universe, occupy Space, and pursue every kind of technology to make life easier and better, it would be intellectuality dishonest and morally criminal for humans to accept the theory that malaria is ineradicable.

A few decades ago, significant portion of North America was plagued with malaria in the same fashion as African countries are going through. In fact, it was not until the late 1890′s that scientists even learnt that the disease is caused by a parasite and that it is a mosquito that transmits the parasite from person to person. The assumption in those days was that malaria was caused by some environmental factors. The word malaria actually comes from the Italian “mala aria”, meaning “bad air” because it was generally believed that malaria was caused by breathing in bad or foul air and vapors emanating from swamps, marshy lands and latrines.

It is important to remember that 70 to 80 years ago, Americans traveling to the Eastern Tennessee Valleys had the same fear they now have when traveling to Togo or Ivory Coast because of malaria. With the creation of the U.S. Tennessee Valley Authority (TVA) in 1933 which established an organized malaria control program, the doubts began to fade. At the time, malaria affected 30 percent of the population in the region where the TVA was incorporated. After implementing aggressive research and control operations, the disease was essentially eradicated in the TVA region by 1947.

The US did not win the battle over malaria overnight. Efforts to control malaria became national focus as far back as the early 20th century during the occupation of American military in Cuba and the construction of the Panama Canal. It is recorded that malaria (and yellow fever) caused significant number of deaths among the workers of the canal. This triggered an aggressive program of malaria control which in 10 years had already made remarkable progress.

Malaria can be defeated, albeit, not overnight. The funding available for anti-malaria campaigns, and research and development is tiny compared to the challenges.

In the long run, I believe that prevention of malaria is the cost-effective route to take rather than treatment of the disease. However, for preventive measures to make the required impact, funding would have to be ramped up.

Current statistics show that in many of the malaria endemic countries, funding is less than US$1 per capita, and in fact it is less than US$0.5 in 16 malaria endemic countries, making up about 710 million people.

Much as I wanted this to be educational rather than political, I cannot help but state that malaria could be eradicated from the earth at negligible percentage of the cost of the Iraq war. It has been estimated by Economist Jeffrey Sachs that malaria can be controlled for US$3 billion in aid per year. (The cost of the Iraq war stands at $774 billion at the time of writing this article)

Our generation must stand trial for genocide for inaction on a problem that kills a child every 30-40 seconds. It is every 30-40 seconds!