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The Problem of Insecticide Resistance in Anopheles Mosquitoes

Insecticide Resistance in Anopheles MosquitoesThe consistent and widespread use of insecticides has significantly reduced the incidence of malaria by eliminating the disease’s vector, Anopheles mosquitoes. Unfortunately, this progress is threatened, as 60 countries have reported the existence of insecticide resistance in Anopheles mosquitoes. In 2012, the World Health Organization launched the Global Plan for Insecticide Resistance Management in Malaria Vectors to monitor this problem and try to generate solutions.

Some Anopheles mosquitoes have changed to better withstand the effects of insecticides. This resistance can be passed from one generation to the next, increasing the prevalence of resistant mosquitoes. These mosquitoes can come in contact with treated bed nets or homes and proceed to infect people with malaria.

Scientists have observed resistance to insecticides since the introduction of malaria vector control methods in the 1940s. However, the impact of this resistance has become greater. Over the past decade, global health workers have relied on one type of insecticide, pyrethroids, because it is safe and affordable. This reliance has led to the prominence of mosquitoes resistant to this particular type of insecticide.

Many scientists are developing new vector control methods that do not involve pyrethroids. The Innovative Vector Control Consortium, for example, is inventing non-pyrethroid, long-lasting insecticide nets which may be available in two to five years.

Researchers are also testing attract-and-kill trapping systems with different repellents and attractants. The purpose of these traps is to kill pregnant female mosquitoes before they can lay their eggs. Scientists at the London School of Hygiene and Tropical Medicine found that cedrol, a naturally occurring compound, attracts pregnant mosquitoes to egg-laying sites. In the future scientist can develop traps utilizing this compound.

The full effects of insecticide resistance in Anopheles mosquitoes are not yet known. It is crucial for countries to continue monitoring their prevalence and whether traditional vector control methods are still as effective as they once were. Development of new control methods takes time, but many promising ideas are in the pipeline.

– Sarah Denning

Photo: Google

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EU Takes a Swat at Yellow Fever in the DRC Using Mobile Labs

Yellow Fever in the DRC
While mosquito bites are rarely more than a summer nuisance for the average American, they can be carriers of dangerous illnesses. This year, the Democratic Republic of Congo (DRC) is facing an outbreak of yellow fever.

By August, there were 5,000 suspected cases and 400 reported deaths across the DRC and Angola. Yellow fever is difficult to diagnose because symptoms closely resemble other illnesses and vary from patient to patient.

Fortunately, World Health Organization (WHO) and the European Union announced that they have created a mobile lab to quickly diagnose and vaccinate people to stop the disease in the DRC.

The mobile lab was dispatched in mid-July with five technicians from Italy and Germany. Quick, accurate blood tests are crucial.

This mosquito-transmitted disease can become so prolific because most infected people never show symptoms, and risk exporting the illness or continuing to allow mosquitoes to spread it in crowded subtropical areas. Now tests can be done on site, which reduces the time wasted for transporting samples.

Those who develop symptoms after the incubation period experience fever, chills, aches, nausea and weakness. Unfortunately, 15 percent of people develop a serious form of the disease that leads to bleeding, jaundice, organ failure and death in 20 to 50 percent of cases. There is no cure, only prevention and palliative treatment.

The technicians have a tough job because of the sheer number of people affected by yellow fever in the DRC. Unfortunately, preventative measures like bug repellent and protective clothing only go so far against the persistent parasite.

The good news is a vaccine that provides lifelong immunity exists. To keep the disease out of the DRC, visitors are required to get the vaccine before entering the country.

The bad news is that the vaccine is expensive and the epidemic is straining the supply. Currently, there are only 6 million doses of the vaccine and it will take a year to make more. Reuters ominously reports that time and resources are not on the EU’s side in the face of this epidemic.

WHO and the EU remain positive. The mobile labs can get results to 50 to 100 people in a day. WHO is training lab technicians in DRC and Angola to continue accurate testing after the EU’s program ends.

Dr. Formerly explains, “Aside from getting patients on the right treatment, faster diagnosis helps to plan the response better, such as identifying where to conduct mass vaccination campaigns in the affected countries.”

Mass vaccinations have been effective in slowing the spread and tests will help. Without a cure, prevention is the only way to stop the disease.

The EU and WHO have been splitting each dose into fifths. While this does not provide lifelong immunity to yellow fever that the full vaccine provides, it does protect recipients for a year. The mobile lab program is a great step towards ending this epidemic.

– Jeanette I. Burke

Photo: Flickr

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Fighting Malaria with Genetically Modified Mosquitoes

genetically_modified_mosquitoes
Scientists have genetically modified mosquitoes in an effort to combat the spread of malaria globally. This technological advancement could substantially reduce the transmission of malaria which continues to have devasting impacts especially in developing countries.

Malaria Facts

According to the World Health Organization (WHO):

  • In 2015, there were 214 million malaria cases across the globe and approximately 438,000 deaths.
  • Sub-Saharan African countries, such as Chad, Sudan, and Angola, are the most at risk for contracting malaria and 90 percent of all malaria deaths occur in these areas.
  • Children are one of the most high-risk groups – 482,000 children under the age of five died from malaria in 2012 alone.

Researchers affiliated with Imperial College London will seek to genetically modify Anopheles gambiae, the mosquito species most responsible for malaria transmission. Using a technology called “gene drive,” the researchers will use a modified gene to “disrupt” the egg production in female mosquitoes, making them sexually unable to reproduce.

However, some mosquitoes will simply become carriers of the modified gene. The gene will then be passed down “at an accelerated rate to offspring,” slowly discontinuing the spread of malaria throughout the population over time.genetically_modified_mosquitoes

In order to test the gene drive, the team identified three genes that were important in female fertility. After diagnosing those genes, they altered them, resulting in an adjustment that “disrupted the activity.”

The genes were modified with the CRISPR/Cas9 endonuclease, a special type of tool that is able to cut designated parts of the genetic code. Having the enabled ability to cut DNA at an exact location, researchers could then mutate them, rendering female mosquitoes infertile.

The researchers are optimistic that the spread could not only drastically reduce the number of malaria cases, but, in three years’ time, local populations of malaria-carrying mosquitoes could be eliminated.

“If successful, this technology has the potential to substantially reduce the transmission of malaria,” said co-author Andrea Crisanti from the Department of Life Sciences at Imperial.

The technique, although only targeting the Anopheles gambiae, could be tested on other mosquito species as well. The team did target other species while conducting their research; however, they decided to focus their efforts on Anopheles gambaie. Their range of testing proves that their “gene drive” is flexible and can be applied to a range of varied genes.

However, it will still be a substantial amount of time before the gene-altered mosquitoes will be ready. Professor Austin Burt from Imperial’s Department of Life Sciences told The Economic Times that he expects it will be “at least 10 more years before gene drive malaria mosquitoes could be a working intervention”.

Naturally, there is more work that needs to be accomplished before genetically modified mosquitoes can be introduced. Safety assessments and extensive reports must be generated before field trials can take place. However, the futuristic technology is encouraging and could dramatically alter the spread of malaria, as well as change the way scientists will attack other diseases.

– Alyson Atondo

Sources: WHO 1, WHO 2, IFLScience, India
Picture: Flickr1, Flickr2

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What is Dengue Hemorrhagic Fever?

Dengue Hemorrhagic Fever
The National Institute of Health defines dengue hemorrhagic fever as “a severe, potentially deadly infection spread by mosquitoes, mainly the species Aedes aegypti.” After being bitten by Aedes aegypti, the fever can originate from any one of four dengue viruses. Recovery is possible if the patient’s body has remaining dengue antibodies.

The onset of dengue hemorrhagic fever feels very similar to that of typical dengue, and the symptoms are largely the same. The experience diverges with the appearance of tiny spots of blood on the skin and can ultimately culminate in seizures and lasting brain and liver damage.

What makes dengue hemorrhagic fever so problematic is the lack of a vaccine or cure. The symptoms, however, can be treated. These treatments include blood and platelet transfusions, IV fluids that combat electrolyte imbalances and dehydration and oxygen therapy. If a patient has access to a hospital ICU, they can typically receive treatment.

But what is so important about dengue hemorrhagic fever?

In recent years, the incidence of dengue hemorrhagic fever has grown sharply. The World Health Organization (WHO) now estimates there to be between 50 million and 100 million cases of the disease every year worldwide. Yet prior to 1970, there had been only nine countries which had experienced large outbreaks of the disease. Now, it can be found in over 100 African countries, in Southeast Asia and on the Western Pacific coast.

This means 40 percent of the word is at risk of getting the disease. Women and people of European ancestry are at a higher risk. After contracting the disease, 2.5 percent of infected people die, many of them children.

With this in mind, the prognosis looks bleak, but the disease is not without dedicated researchers working to defeat it. Currently, the WHO supports countries as they attempt to confirm outbreaks of the disease, providing valuable data on the subject. They also provide guidance and technical support in the management of an outbreak, and they train professionals in clinical management, vector control and diagnosis of the disease.

Dengue hemorrhagic fever may be strong, but with treatments already available and research turning up crucial information, the risk it poses is certain to halt in the foreseeable future.

– Rachel Davis

Sources: MedlinePlus, World Health Organization
Photo: Examiner

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The Dangers of Dengue Fever

dengue fever
Within tropic and sub-tropic regions, as well as the urban and semi-urban areas of these regions, dengue fever is a leading cause of death. It is transmitted by mosquitoes and affects approximately 400 million people annually.

First discovered in the 1950s, dengue fever is also known as dengue haemorrhagic fever, and was more closely studied during an epidemic in both Thailand and the Philippines. The past decade has seen an increase in the outbreaks of the disease. While dengue fever used to be limited to specific regions, it is now spreading from south-east Asia and the western pacific to regions in Europe, China and the United States.

The most common transmitter is named the Aedes Aegypti mosquito. After an infected mosquito bites and infects a human, other mosquitoes who bite the same human also become carriers of the disease.

As an urban-dwelling creature, this type of mosquito thrives in a man-made environment. The Aedes albopictus, another carrier, has been identified as one of the causes for the increase in dengue fever across the globe. With its ability to adapt to survive in both freezing and scorching temperatures, and its affinity to breed in goods typically traded internationally, this type of mosquito has been able to travel overseas to inflict new populations.

A vaccine to combat dengue fever is currently in development, although researchers are skeptical about its success rate. In a recent trial in Asia, the vaccine was only effective 56.5 percent of the time. While the vaccine has the chance to reduce the frequency of the disease by about half, the vaccine has not been successful in protecting against all four strains of the virus.

Researcher at the Nanyang Technological University in Singapore, Annelies Wilder-Smith, asserts that at this stage, it is impossible to know the lasting effects of the vaccine and that children who receive the vaccine will need to be closely observed for a minimum of three years.

Most successful methods of prevention for the time being, therefore, have proven to be those involving avoiding a mosquito bite altogether.

– Jordyn Horowitz

Sources: Centers for Disease Control, Deutsche Welle, Focus Taiwan, World Health Organization
Photo: NPR

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How to Stop Malaria

stop_malaria
Malaria seems to be a disease out of sight for most of us, affecting far away people. Malaria used to be present in the United States, but it was wiped out in the 1950s. The mosquitoes, carrying the malaria parasite, are making people very sick and taking lives in the countries where this dangerous disease still exists, but in order to stop malaria, certain precautions and steps must be taken.

What is the current situation?

In 2012, there were about 207 million people diagnosed with malaria, and an estimated 627,000 malaria deaths. About 3.4 billion people — half of the world’s population — are at risk of contracting malaria. Most cases incur in Sub-Saharan Africa, greatly affecting children under age five.

How to prevent and stop malaria

Prevention of malaria includes preventing people from acquiring mosquito bites and giving people the appropriate medicine. Wearing protective clothing, staying inside when it is dark outside, using mosquito spray indoors if possible and avoiding going to region with a high number of cases of malaria if vulnerable (pregnant, under age five, etc…) are also effective in malaria prevention. Using long-lasting mosquito nets is one of the most effective methods to prevent mosquito bites. If traveling to regions where malaria is present, taking preventative medicine is strongly recommend. Most people who are infected do not take the proper medicine or follow the right schedule.

What we need to do

We have already achieved huge success. Fewer people are getting sick, thanks to the effects of the U.N., local government and nonprofit organizations. We need to keep up the fight against malaria. Most cases occur in Sub-Saharan Africa, where people lack certain preventive materials such as bed nets and insect spray. We need to make sure people sleep under bed nets and have access to basic malaria diagnosis and treatment.

There are no certain vaccines that can prevent people from getting malaria. Scientists still continue with their research to develop effective vaccines. We also need to find innovative ways and methods to stop malaria.

– Jing Xu

Sources: ImpatientOptimists, WHO, WebMD
Photo: AAAAI

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Chickungunya Virus Spreading Fast

Chickungunya

North Carolina’s first case of the Chickungunya virus was confirmed on June 12. Seven days later Georgia confirmed its first case. Two days after that Tennessee confirmed its second. With over 30 cases already confirmed in Florida, this mosquito-borne virus is quickly spreading.

Until 2007, Chickungunya was only found in Africa, Asia and the Indian subcontinent. Then it appeared in Italy and slowly made its way throughout Europe. In December of this past year the first case of Chickungunya was reported in the Caribbean. Now, barely six months later, the Pan American Health Organization has confirmed 5,000 cases of the virus and suspects another 160,000 cases in the region.

There is currently no vaccine for the virus or treatment for the symptoms. Those symptoms include fever, rash, nausea, chronic joint pain, swelling and headache. They usually first appear within three to seven days after infection with most symptoms abating after about a week’s time. However, the joint pain often lasts for months.

There are now 20 afflicted states and islands in the Caribbean, with Cuba being the most recent. The Center for Disease Control has reported approximately 60 total cases in the continental United States thus far. All such cases have included patients who have made recent trips to the Caribbean. The virus has been linked to the Aedes aegypti and Aedes albopictus mosquitoes, both of which are fairly common in the U.S. The CDC has recommended that people who are traveling to the Caribbean use bug spray and dress in long sleeves and pants to avoid being bitten by either kind.

Despite rising concerns about possible contraction of the Chickungunya virus, trips to the Caribbean remain popular among American tourists. With cruise season currently in full swing, the number of cases in the U.S. is sure to rise.

— Taylor Dow

Sources: LA Times, Island Gazette, CNN, AJC, Medpage Today
Photo: Wageningen Ur

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Mosquito-borne Virus and Health Concerns

mosquito_borne_virus
Chikungunya is not a term commonly recognized by the average American. The mosquito-borne virus was originally found in Tanzania in 1952, though it is suspected to have been circulating in the region for many centuries. Chikungunya is transmitted to humans by mosquitoes, and has been predominately concentrated in countries in Africa, Asia and the Indian subcontinent until quite recently.

Within the past week, the virus has been diagnosed in patients from several states in the U.S., including Indiana, Florida and North Carolina. These cases appeared after a major outbreak in the Caribbean that has affected thousands in the past few months.

While chikungunya is rarely a fatal disease, it can cause intense pain, which sometimes lasts for months. The main symptoms are fever and joint pain, though it can be accompanied by nausea, headache and fatigue as well. The World Health Organization states, “the disease shares some clinical signs with dengue (fever), and can be misdiagnosed in areas where dengue is common.”

The mosquito-borne virus is most common in areas close to mosquito breeding sites. The New York Daily News says that cases of the virus will continue to rise in Haiti due to large amounts of standing water left in open containers, which are “used in many Haitian homes that lack running water.” The WHO says that the virus spreads by bites from infected female mosquitoes. Symptoms usually begin to show four to eight days after the bite.

CNN reports that 25 to 28 American travelers bring the virus back to the U.S. after traveling to high-risk areas abroad. The New York Daily News affirms that the latest cases in the U.S. were not from local mosquitoes, but were “carried by recent travelers to the Caribbean where the virus is raging.”

The outbreak in the Caribbean has been troubling internationally, as tourist destinations like St. Martin could act as a hub for this epidemic, says The New York Times.

The Oxford Journals recognize that though the disease does not typically have a high death toll, in developing nations, “the epidemics resulted in significant morbidity and taxed the health care and public health infrastructure.”

Reducing the outbreak of chikungunya presents a challenge to the global community. Rural villages in African and Caribbean countries do not have access to running water, which creates the need for standing water sources. The risk of attracting mosquitoes increases under these conditions, and therefore the risk of disease goes up as well.

There is currently no vaccine or cure for chikungunya. According to the WHO, treatment aims to alleviate symptoms, usually using anti-pyretics (fever reducers), optimal analgesics (painkillers) and fluids. Travelers to high-risk areas are told to be cautious and protect exposed skin with clothing and bug spray. However, very few recommendations have been made for those who live in the afflicted areas. Unfortunately, reducing the number of cases in such areas would require major overhaul of health care systems and vast improvement of living conditions. Hopefully, the future will bring a vaccine and the social change needed to reduce the spread of this epidemic.

— Bridget Tobin

Sources: CNN, NY Daily News, NY Times, Oxford Journals, WHO
Photo: USA Today

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Anti-Mosquito Patch Hides Users from Detection

Mosquito_Patch
A new stick-on anti-mosquito patch hides users from mosquito detection for 48 hours. Although such a product has high potential, it must first undergo trials in Ugandav. The Kite Patch (referred to as “Kites”), is a small patch that sticks to clothing and hides wearers from mosquito detection.

It works by neutralizing two key attractants for mosquitoes: exhaled carbon dioxide, and human odor. Mosquitoes are able to detect exhaled carbon dioxide from more than a football field away, while human odor is used for short range detection.

Olfactor Laboratories, an innovative company focused on developing products related to disease prevention, has developed the patch to prevent diseases from being transmitted by mosquitoes. They are currently working to prevent other mosquito-borne illnesses as well, including the West Nile Virus, Dengue Fever, Rift Valley Fever, and Yellow Fever.

By shielding humans from mosquito detection, the Kite Patch will protect users from insect-borne infections. This will save lives and bring about a reduction in the incidence of insect-transmitted diseases.

Uganda has been chosen as the testing site for the patches because it is is home to some of the largest percentages of malaria transmittance in the world. This provides a unique opportunity to test the life-saving capabilities of Kites in a real-world environment where anti-mosquito measures are most needed.

Kites also provide an alternative in the Americas and other developed nations, where mosquitoes are often little more than an annoyance, and yet potentially dangerous anti-mosquito sprays are commonly used. They are safer and more effective than these sprays, offering further health and environmental benefits even in areas where the risk of life-threatening disease is much lower.

Although a market price is yet to be determined, project leader Grey Frandsen has announced that the patch is likely to be subsidized to a price lower than repellents and cheap enough for consumers to buy regularly.

– Michael Carney

Sources: SciDev Center for Disease Control
Photo: Dude, I want that

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Irrigation Infrastructure and Malaria, An Interesting Correlation

Irrigation_infrastructure
Irrigation, known for improving crops and overall increasing capabilities of life for centuries, may have one major drawback. With an increase in water abundance through irrigation, infrastructure such as irrigation canals are proving to be havens for mosquito growth.

Recent research shows that newly constructed irrigation infrastructure in malaria prone areas can increase the risk of malaria in the local community.

Research was conducted in the northwest region of India known as Gujarat. The research project found that when irrigation infrastructure was already established in sub-districts, such as Banaskantha and Patan, the monsoon rain influx had less of a malarial increase than sub-districts with early and transitional irrigation systems.

These transitional irrigation systems, known as “low irrigated,” were found to be the most susceptible to malaria that comes after the rainy monsoon season. In comparison, “mature irrigated” areas that had established wells and canals for over thirty years, were less affected by the mosquitoes and the disease they carry.

Led by University of Michigan graduate student, Andres Baeza, the team of researchers monitored the methods and results of a large irrigation project that was set to irrigate 47 million acres of farmland.

“In these dry, fragile ecosystems, where increase in water availability from rainfall is the limiting factor for malaria transmission, irrigation infrastructure can drastically alter mosquito population abundance to levels above the threshold needed to maintain malaria transmission” according to Baeza.

Although it has been known that malaria increases and new irrigation improvements are correlated, this new research shows that the improvements to land that eventually reduce malaria may take longer than expected for farmers in malaria prevalent regions.

This is not to persuade readers that irrigation is not worth it. On the contrary, with irrigation improvements come improved farm yields, food security, better incomes and increased access to finance and healthcare. With improved farmland, malaria is deterred and over the course of a few decades will be much lower as long as farming improvements are made accordingly.

– Michael Carney

Sources: Humanosphere, Proceedings of the National Academy of the Scienes (PNAS)
Photo: The Gef

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