New mosquito patch in fight against malaria and West Nile virus

A new mosquito-beating patch is being developed in California that, if successfully rolled out in Africa, could help prevent illnesses such as malaria, West Nile virus and dengue fever.
The Kite patch adheres to clothing, much like a sticker, and uses FDA-approved, non-toxic compounds that block a mosquito's ability to track humans for 48 hours.
The sticker was created by a team based in Riverside, CA, after 7 years of research and development by Olfactor Laboratories, Inc. and the University of California, Riverside.
The company behind the patch, ieCrowd, employed designers to make it withstand tough conditions. The product website for the sticker claims it is "perfectly suited for children in Uganda, professional athletes, families on the soccer field, outdoor enthusiasts, and workers in the suburbs of Manila."
Since mosquitos track humans through carbon dioxide release, the company notes that the Kite should work on all types of mosquitos, citing preliminary field trials that show the patch's effectiveness on many different species of mosquitos.
Though the patch should not replace mosquito nets at night in high-risk areas, the patch is being promoted as a replacement for sprays or lotions currently on the market.

Malaria is a global problem

Humans become infected with malaria when a mosquito carrying the parasite transfers it to the bloodstream through a bite in the skin.

The Kite adheres to clothing like a sticker. For up to 48 hours it can block mosquitos' ability to track humans via carbon dioxide.

According to the Centers for Disease Control and Prevention (CDC), around 219 million people had malaria in 2010 and 660,000 of these people died. Africa was hit the hardest, with 91% of all malaria deaths happening on that continent.
In the US, there are around 1,500 cases of malaria each year, most of which involve people who have traveled to Africa and South Asia.
Symptoms of malaria infection includefever, chills and flu-like illness. If left untreated, sufferers of malaria can eventually die from complications.
The direct costs of malaria - those relating to illness, treatment and premature death - are around $12 billion each year, according to the makers of the Kite. The company claims that costs relating to lost economic growth "are many times more."

Prevention is key for mosquito-borne illnesses

While malaria kills a large number of people each year, it is easily preventable. We know where it comes from (mosquitoes) and we know how to avoid these insects (using nets and repellants).
Grey Frandsen, the project lead and chief marketing officer at ieCrowd, is a surviver of malaria himself. He says:

"We want this small patch to change people's lives. We're designing Kite to deliver everyone protection from mosquitoes, no matter where they are in the world.
It will provide a new level of protection for children in Uganda, for young families in South Africa, and hikers in Seattle or Wyoming or Florida seeking a safer, socially-responsible solution.
We built Kite to be simple and affordable - a small colorful sticker that will appeal to children and adults and survive the rigors of extreme climates, play time, or outdoor recreation."

The company recently launched a crowdfunding campaign to help their first roll out of the potentially life-saving product in Uganda. They will continue to test the patch there, where communities have the highest need for a solution.
A recent study showed that malaria-carrying mosquitos are more strongly attracted to the smell of humans, which is why a patch that blocks their ability to find us in the first place could be an effective weapon against malaria.

Mosquitoes With Altered Smell Gene Lose Preference For Humans

By changing one gene, scientists have bred a mosquito that does not seek out the smell of humans in preference to other animals. The team behind one of the first successful attempts to genetically engineer mosquitoes believes their work not only shows what can be done with the latest genetic techniques, but also helps us better understand the insect's attraction to humans and therefore how to block it.
Lead researcher Leslie Vosshall, a Howard Hughes Medical Institute (HHMI) investigator at The Rockefeller University in New York, says in a statement:

"The time has come now to do genetics in these important disease-vector insects. I think our new work is a great example that you can do it."

"By disrupting a single gene, we can fundamentally confuse the mosquito from its task of seeking humans," she adds.

Vosshall and colleagues write about their work in a paper published online in Nature on 29 May.

Their report follows another study published recently in PLOS ONE, where researchers from the London School of Hygiene & Tropical Medicine in the UK describe how malaria-carrying mosquitoes are more strongly attracted to the smell of humans.

Starting Point Was a Gene in Flies

After scientists in 2007 announced they had sequenced the complete genome of Aedes aegypti, the mosquito that carries dengue and yellow fever, Vosshall switched her lab's focus from Drosophila flies to mosquitoes and set about trying to alter their genes.

From working with genetically engineered flies, she and her team already knew of a gene called orco that was important for the fly's sense of smell. So, as Vosshall explains, they started working on this gene in mosquitoes:

" ... we had some hints that mosquitoes interact with smells in their environment, so it was a good bet that something would interact with orco in mosquitoes."

Genetic Engineering Tools

To mutate the orco gene in Aedes aegypti, the team used "zinc-finger nucleases" (ZFNs), powerful tools that can be designed to target and cleave specific sequences of genomic DNA.

First, they injected ZFNs into mosquito embryos and when these matured, they sought out mutant individuals and used them to generate mutant strains so they could study the behavior of the orco gene in mosquitoes.

They discovered that brain cells linked to sensing odors were not as active in the genetically engineered mosquitoes. But they also found some other interesting changes.

Less Preference for Human Odor

Normally, when presented with a choice between humans and other animals, non-mutant Aedes aegypti mosquitoes fly toward humans, attracted by their smell.

But when Vosshall and colleagues gave their mutant mosquitoes a choice between human scent and that of guinea pigs, they did not show a preference for humans. This was the case even in the presence of carbon dioxide, which is supposed to enhance the attraction of mosquito to humans.

It appears that changing a single gene, the orco gene, disrupts the mosquito's ability to seek human prey.

However, this experiment did not establish precisely how the mutated mosquito lost the preference for human smell.

For example, did the mutated insect lose its ability detect that the guinea pig smell is not a preferred one, or did it lose the ability to discriminate that the human smell is the one to go for? Or did the altered gene cause both these changes?

Response to DEET

In a second part of their study, Vosshall and colleagues found that the mosquitoes with orco mutations were attracted to human skin even when it was protected by the common insect repellant DEET.

They exposed them to two human arms: one slathered in a solution of 10% DEET, and the other untreated. The insects flew equally to both arms, showing therefore that they could not smell the DEET.

However, once the mutant mosquitoes landed on the arms, they quickly flew away from the one slathered in DEET solution.

Two Different Odor-Sensing Mechanisms Identified

The team concluded that their experiments with DEET on human arms showed the mosquitoes are using two separate mechanisms to sense the DEET.

"One is what's happening in the air, and the other only comes into action when the mosquito is touching the skin," Vosshall explains.

There has been talk of a dual mechanism, but this is the first experiment to show it.

Vosshall's team now wants to explore how the orco protein interacts with the mosquito's smell receptors to shape its sense of smell.

"We want to know what it is about these mosquitoes that makes them so specialized for humans," she says.

"And if we can also provide insights into how existing repellants are working, then we can start having some ideas about what a next-generation repellant would look like," she adds.

In another recently published study, US researchers suggest it may be possible to use a bacterium that stops malaria parasites developing in mosquitoes.

IPhone Microscope Helps Diagnose Intestinal Worms

smart phones are transforming the way that people communicate throughout the world. Now scientists are using them in an innovative way to help diagnose intestinal worm infections in school children living in rural Tanzania.

The scientists have developed an inexpensive microscope using a glass lens costing $8 USD, a strip of double-sided tape, and a cheap flashlight - altering an iPhone 4s into a device that can detect intestinal worm infections; parasites that infect two billion people and result in malnutrition.

Isaac Bogoch, MD, an infectious disease specialist at Toronto General Hospital and the study's lead author explained:

"There's been a lot of tinkering in the lab with mobile phone microscopes, but this is the first time the technology has been used in the field to diagnose intestinal parasites."

The scientists' findings were published in the American Journal of Tropical Medicine and Hygiene, and evaluated 199 stool samples of children using their unique device.

Along with a standard light microscope the researchers examined the samples with the cell phone microscopes and a regular laboratory slide. The kids participating in the trial on Pemba Island, Tanzania, were undergoing different treatments for eliminating intestinal worms.

Scientists first covered the slide in cellophane, then used the double-sided tape to attach it to the camera, lit it from underneath with the flashlight and finally took a picture.

The iPhone microscope was found to be not as sensitive as a light microscope, however, the scientists believe that with some changes it will come close. Bogoch commented, "We think cell phone microscopes could soon become a valuable diagnostic tool in poor, remote regions where intestinal worms are a serious health problem, particularly in children."

Intestinal Worms - A Global Issue

The cell phone microscope sensitivity was dependent on the type of worm and the strength of the infection.

Scientists have developed the camera on an iPhone into a microscope that can detect intestinal worm infections.
Photo Credit: Isaac Bogoch

For example, the cellphone found 81 percent of infections of giant roundworm (A. lumbricoides) and 54 percent of roundworm infections (T. trichiura ). But, it only detected 14 percent of all hookworm infections; the researchers say that this is due to the much smaller number of eggs present than with the other parasites.

"It was quite successful at detecting moderate to heavy infections, but not very good at detecting mild infections where there might be only a few eggs in the sample," Bogoch said.

Worms that infect the intestines, such as roundworms and hookworms - or soil-transmitted helminths - harm nearly two billion people worldwide. In isolated, poor regions of developing nations rates of this disease are particularly high and can result in chronic malnutrition and anemia in kids.

Bogoch and his team aimed to find an alternative tool by taping a 3 millimeter ball lens to the camera of Bogoch's Apple iPhone 4S - one he already owned. However, the researchers noted that any phone that has a camera with a zoom option could work effectively. Ball lenses are normally used in the telecommunications field in couplings for optical fiber cable. They are inexpensive - generally $8 to $10 USD.

Instead of an electric light, they used a small flashlight that just needs a single battery for many hours of operation. The entire set-up can be developed for $15 USD, in addition to the cost of the phone, and can be assembled in five minutes.

Cell Phone Microscope - Several Implications

The authors believe that the "mobile phone microscope would likely be of clinical use when it is sensitive enough to detect 80 percent of infections," and note that even now there are new developments underway to improve the current cell phone microscopes.

Bogoch said, "I'm confident that in the near future we will see cell phone microscopes widely used in low-resource settings. They're easy to make, portable, and today, you can find mobile phones with cameras even in some of the most remote regions in the world."

The cell microscope can be used for treating and diagnosing people with worm infections as well as observing the prevalence of disease amongst the broader population.

One example could be when administering drug treatment to large populations. Cell phone microscopes could serve as cheap and effective tools to calculate the effectiveness of these mass drug administration campaigns.

David H. Walker, MD, president of the American Society of Tropical Medicine and Hygiene said:

"I have nothing but praise for the ingenuity of scientists using all available tools to solve pressing health problems in some of the poorest parts of the world. This study is an illustration of how a modest investment in tropical disease research can help reap enormous health benefits for children."

Mosquito Repellent DEET Is Becoming Less Effective

Mosquitos are now able to ignore the scent of the insect repellent DEET three hours after being exposed to it.
The finding, published in PLoS One, suggests that even though historically, insects have been strongly repelled by the scent of DEET, other studies by Dr.James Logan reveal that some mosquitoes and flies carry a genetic alteration in their aroma receptors rendering them insensitive to the smell.

DEET is one of the most successful protectors against mosquito bites that can transmit deadly diseases, such as:

• West Nile Virus
• Malaria
• Dengue fever
• Encephalitis
• Yellow fever

Products that have DEET come in many different forms including liquids, sprays, lotions, wristbands. DEET has been in use by the public since 1957.

In this latest study, Dr. Logan and his peers from the London School of Hygiene & Tropical Medicine discovered a response in mosquitoes that occurred due to short-term changes (not genetic ones).

The investigators examined changes in responses to DEET in Aedes aegypti mosquitoes - which are well known for biting during the day and transmit deadly diseases, such as yellow fever and dengue fever.

They discovered that a slight exposure to DEET was enough to make some mosquitoes less sensitive to the repellent.

Three hours following exposure, the mosquitoes were put off seeking out attractants like human skin and heat even though they had been previously exposed to DEET.

The investigators also saw that this ineffectiveness of the odor could be linked to a fall in the sensitivity of smell receptors on the mosquito's antennae after an earlier exposure.

Dr Logan, medical entomologist and Chief Scientific Officer for the Arthropod Control Product Test Centre, said:

"We think that the mosquitoes are habituating to the repellent, similar to a phenomenon seen with the human sense of smell also. However, the human olfactory system is very different from a mosquito's so the mechanism involved in this case is likely to be very different.

Our study shows that the effects of this exposure last up to three hours. We will be doing further research to determine how long the effect lasts. This doesn't mean that we should stop using repellents - on the contrary, DEET is a very good repellent, and is still recommended for use in high risk areas. However, we are keeping a close eye on how mosquitoes can overcome the repellent and ways in which we can combat this."

In 2008, a new class of bug repellent was found to be effective for three times longer than DEET, which is the quality standard of all repellents.

More Funding Needed For Tropical Diseases, WHO Says

Tropical diseases that were once overlooked, are now receiving more attention from pharmaceutical companies and the government, but also require more funding and innovation.
Diseases that are uncommon in the U.S. such as:

• lymphatic filariasis (elephantiasis)
• onchocerciasis (river blindness)
• schistosomiasis (a parasite)
• soil-transmitted helminthiasis (intestinal worms)

...can cause many deaths and complicate lives in underdeveloped nations.

In a new report, the WHO (World Health Organization) announces that they have seen groundbreaking progress in regards to these tropical disease, thanks to an international strategy that includes a regular supply of inexpensive, quality-assured medicines, and support from international partners.

The new strategies have brought us closer to the complete removal of many of these illnesses that are particularly devastating in the world's poorest regions.

Reports Show Progress As Well As New Goals

The report reveals significant progress in combating, terminating and eradicating these neglected tropical diseases. Specifically, dracunculiasis (guinea worm disease) and yaws, are due for global eradication in 2015 and 2020 respectively.

In addition, there are six goals set for the removal of five diseases in 2015 and 10 more goals for nine diseases for 2020, either internationally, or in specific geographical regions.

Dr Margaret Chan, Director-General of WHO commented:

"With this new phase in the control of these diseases, we are moving ahead towards achieving universal health coverage with essential interventions. The challenge now is to strengthen capacity of national disease programs in endemic countries and streamline supply chains to get the drugs to the people who need them, when they need them."

Medicine donations and extra funding by several global partners have aided in swift action and measures that are now having a considerable impact in affected countries with a broader scale of precautionary chemotherapy interventions. Of note is the universal delivery of single-dose, safe, quality medications as preventive treatments against five helminthiases and trachoma (chlamydial infection).

In 2010, 711 million people had treatment for at least one of the four diseases covered by preventive chemotherapy.

Coverage Planned to Increase

The WHO believes that treatment for schistosomiasis (bilharzia) will expand to 235 million people over the next five years. This will be achieved through better availability of treatments with donated medicines, as well as organized distribution on regional levels.

Dr. Chan adds:

"The prospects for success have never been so strong. "Many millions of people are being freed from the misery and disability that have kept populations mired in poverty, generation after generation, for centuries."

Other report highlights include:

• Elimination of guinea worm. There has been a decrease in the number cases, with just 521 between January and September 2012, compared to 1006 for the same time period in 2011. Also human African trypanosomiasis (sleeping sickness) is down to fewer than 7,000 in 2011, from a high of 30,000 cases at the beginning of this century.
• Rabies has been removed from many countries and the WHO believes this disease will be eradicated on a regional basis by 2020. Antibiotics are now available for buruli ulcer, a chronic and severely disabling skin condition.r
• In 2012, dengue was the fastest spreading vector-bone viral disease, with the potential to become an epidemic. The WHO suggested an immediate change in approach and put into effect sustainable preventive care.

The report also touches on some challenges that are still present at country levels. It stresses the need for national disease control plans to implement organization, integration, and coordination. It also recommends the use of other sectors like education, agriculture and veterinary public health, as well as strengthening human resources.

'Exhausted' T Cells Lead To Chronic Viral Infection

When you get an acute infection, such as influenza, the body generally responds with a coordinated response of immune-cell proliferation and attack that rapidly clears the pathogen. Then, their mission done, the immune system stands down, leaving a population of sentinel memory cells to rapidly redeploy the immune system in the event of reinfection.

This is why vaccination works, and it's why, in theory at least, people who have had the chicken pox once will never get it again.

But what about chronic infection? In the case of such pathogens as hepatitis C, HIV, and malaria, the body and the pathogen essentially fight to a prolonged stalemate, neither able to gain an advantage. Over time, however, the cells become "exhausted" and the immune system can collapse, giving the pathogen the edge.

Now, a new study by researchers at the Perelman School of Medicine, University of Pennsylvania, is showing just how that happens. The findings also suggest a novel therapeutical approach that might be used to shift the balance of power in chronic infections. The study appears in Science.

The team, led by E. John Wherry, PhD, associate professor of Microbiology and Director of the Institute for Immunology, used a mouse model of chronic viral infection to map the T-cell response that arises when the immune system is on an extended war footing. They found that two distinct classes of virus-specific CD8+ T cells - one expressing high levels of the protein T-bet, the other expressing high levels of the protein Eomes, work together to keep the infection in check.

Specifically, they found that the two cell populations appear to have a progenitor-mature cell relationship. The T-bet-expressing cells appear to function as the progenitor cells - that is, stem cells. These cells divide both to regenerate and maintain the pool of virus-specific T cells. But they also divide and differentiate to form mature, terminally differentiated Eomes-expressing cells. These cells are more effective at fighting the virus itself, but cannot replicate.

"There's a balance, an equilibrium, which allows you to maintain control over the infection but is insufficient to give you complete clearance," Wherry explains.

These two cell subpopulations tend to confine themselves to different anatomic regions in the infected animals, the researchers found. T-bet-positive cells were found in the blood and spleen, whereas Eomes cells were found in the liver, bone marrow, and gut.

Loss of either subpopulation, which the researchers modeled by deleting one or the other protein, reduces the immune system's ability to fight the infection, leading to a shift in favor of the pathogen.

According to Wherry, these data can help explain the gradual loss of virus-specific T cells observed in such chronic infections as hepatitis C.

"Our data suggest the reason for loss of immune control during some chronic infections is that the long-term pressure on this progenitor-mature cell relationship depletes the progenitor pool," he says.

What's more, the study suggests new therapeutic avenues that can be used to fight, or at least better control, chronic infections. For instance, he says, "If we can maintain these progenitor cells longer, or coax the terminal progeny to divide further, we may be able to shift the balance and maintain control of the infection," he says.

Wherry's lab is now studying candidate molecular pathways to determine their efficacy in controlling, and perhaps modulating, these two T-cell populations.