Findings Could Lead To A Safer And More Effective Method To Control Mosquito-caused Malaria

Science Daily— A Mayo Clinic researcher has discovered a target site within malaria-carrying mosquitoes that could be used to develop pesticides that are toxic to the Anopheles gambiae mosquito and other mosquito species. It would not affect humans and other mammals. If supported by further studies, the findings could offer a safer and more effective control of mosquito-borne diseases such as malaria.

Yuan-Ping Pang, Ph.D., a chemist and expert in computer-aided molecular design at Mayo Clinic, identified two unique amino acid residues called cysteine (286) and arginine (339). These exist in three mosquito species and the German cockroach.

Dr. Pang's findings are significant because the residues could potentially be used as a target site for a pesticide that would incapacitate only insects that carry these residues, which do not exist in mammals. The findings appear in the current issue of PLoS ONE, a new, peer-reviewed, open-access journal published by the Public Library of Science.

"These findings suggest that new pesticides can be designed to target only the mosquito enzyme. Such pesticides could be used in small quantities to harm mosquitoes, but not mammals," Dr. Pang says. "We've developed a blueprint for a pesticide that could incapacitate malaria-carrying mosquitoes. We are currently making a prototype of the new pesticide."

Most pesticides today work by crippling the serine residue, which is another amino acid of the enzyme acetylcholinesterase and is located at the active site of the enzyme. This serine residue is present in both insects and mammals and therefore, any pesticide targeting this amino acid affects both insects and mammals.

Acetylcholinesterase is a vital enzyme to both insects and mammals. It breaks down the neurotransmitter acetylcholine, which is a primary neurotransmitter in the brain that is associated with memory and cognition.

Dr. Pang, director of Mayo Clinic's Computer-Aided Molecular Design Laboratory, studied the genetic makeup of all known acetylcholinesterases in 73 species, including humans. He identified residues that only exist in the mosquito version of the acetylcholinesterase. To identify which of these residues is susceptible to pesticides, he developed a three-dimensional model of mosquito acetylcholinesterase. With this three-dimensional model in hand, Dr. Pang learned how residues function in a way never before possible.

He found that the cysteine and arginine residues were located at the opening of the active site of the mosquito acetylcholinesterase. An active site is a pocket in an enzyme where a fast chemical reaction takes place to break down a molecule or build a new molecule.

Previous studies by Dr. Pang and researchers elsewhere found that the cysteine residue acts as a hook that could tether a small molecule in the active site of an enzyme and permanently damage the enzyme. This led Dr. Pang to believe the cysteine and arginine residues could be targeted by a pesticide that would not affect humans and other mammals.

"While a three-dimensional model of the mosquito enzyme acetylcholinesterase has been reported by other scientists, no mosquito-specific residue at the active site of acetylcholinesterase has been reported until now," Dr. Pang says. "These findings suggest that a chemically stable molecule (to be used as a safer pesticide) could be made to react with the cysteine residue in the mosquito enzyme acetylcholinesterase and irreversibly inhibit the enzyme."

The three-dimensional model Dr. Pang developed was created with a powerful computing system called a terascale system. He built the system with 590 personal computers. Terascale refers to computational power measured in the unit of teraflops, which is a processor capable of a speed of one trillion floating-point operations per second. A single teraflops computer is comparable to a computer that can search at least 50,000 Manhattan phonebooks in one second. Terascale systems are among the most powerful computers available today.

Dr. Pang published similar findings in October 2006 in which he described a potentially safer and more effective method for controlling crop-destroying aphids. The study was published in the journal Bioorganic & Medicinal Chemistry Letters.

Background on pesticides and malaria
DDT has been banned in most parts of the world for decades, but approximately 20 countries currently use the pesticide to control malaria and others are considering its use. DDT use remains controversial, as some studies have linked its use to environmental and health problems. Still, it is largely believed to be among the most effective methods to kill malaria-carrying mosquitoes.

Malaria continues to be the leading cause of death and morbidity in poor countries, according to the World Health Organization (WHO). More than one million deaths and up to 500 million clinical cases are reported each year. Most of the 3,000 deaths that occur each day worldwide are of children in Africa. More than one-third of the world's population lives in malaria-endemic areas. According to a 2006 report by the Centers for Disease Control and Prevention, there were outbreaks of locally acquired mosquito-transmitted malaria in the United States.
The research funding for Dr. Pang's study was provided by Mayo Clinic.

Note: This story has been adapted from a news release issued by Mayo Clinic.

Science Daily — A Mayo Clinic researcher has discovered a target site within malaria-carrying mosquitoes that could be used to develop pesticides that are toxic to the Anopheles gambiae mosquito and other mosquito species. It would not affect humans and other mammals. If supported by further studies, the findings could offer a safer and more effective control of mosquito-borne diseases such as malaria.

Yuan-Ping Pang, Ph.D., a chemist and expert in computer-aided molecular design at Mayo Clinic, identified two unique amino acid residues called cysteine (286) and arginine (339). These exist in three mosquito species and the German cockroach.

Dr. Pang's findings are significant because the residues could potentially be used as a target site for a pesticide that would incapacitate only insects that carry these residues, which do not exist in mammals. The findings appear in the current issue of PLoS ONE, a new, peer-reviewed, open-access journal published by the Public Library of Science.

"These findings suggest that new pesticides can be designed to target only the mosquito enzyme. Such pesticides could be used in small quantities to harm mosquitoes, but not mammals," Dr. Pang says. "We've developed a blueprint for a pesticide that could incapacitate malaria-carrying mosquitoes. We are currently making a prototype of the new pesticide."

Most pesticides today work by crippling the serine residue, which is another amino acid of the enzyme acetylcholinesterase and is located at the active site of the enzyme. This serine residue is present in both insects and mammals and therefore, any pesticide targeting this amino acid affects both insects and mammals.

Acetylcholinesterase is a vital enzyme to both insects and mammals. It breaks down the neurotransmitter acetylcholine, which is a primary neurotransmitter in the brain that is associated with memory and cognition.

Dr. Pang, director of Mayo Clinic's Computer-Aided Molecular Design Laboratory, studied the genetic makeup of all known acetylcholinesterases in 73 species, including humans. He identified residues that only exist in the mosquito version of the acetylcholinesterase. To identify which of these residues is susceptible to pesticides, he developed a three-dimensional model of mosquito acetylcholinesterase. With this three-dimensional model in hand, Dr. Pang learned how residues function in a way never before possible.

He found that the cysteine and arginine residues were located at the opening of the active site of the mosquito acetylcholinesterase. An active site is a pocket in an enzyme where a fast chemical reaction takes place to break down a molecule or build a new molecule.

Previous studies by Dr. Pang and researchers elsewhere found that the cysteine residue acts as a hook that could tether a small molecule in the active site of an enzyme and permanently damage the enzyme. This led Dr. Pang to believe the cysteine and arginine residues could be targeted by a pesticide that would not affect humans and other mammals.

"While a three-dimensional model of the mosquito enzyme acetylcholinesterase has been reported by other scientists, no mosquito-specific residue at the active site of acetylcholinesterase has been reported until now," Dr. Pang says. "These findings suggest that a chemically stable molecule (to be used as a safer pesticide) could be made to react with the cysteine residue in the mosquito enzyme acetylcholinesterase and irreversibly inhibit the enzyme."

The three-dimensional model Dr. Pang developed was created with a powerful computing system called a terascale system. He built the system with 590 personal computers. Terascale refers to computational power measured in the unit of teraflops, which is a processor capable of a speed of one trillion floating-point operations per second. A single teraflops computer is comparable to a computer that can search at least 50,000 Manhattan phonebooks in one s

second. Terascale systems are among the most powerful computers available today.

Dr. Pang published similar findings in October 2006 in which he described a potentially safer and more effective method for controlling crop-destroying aphids. The study was published in the journal Bioorganic & Medicinal Chemistry Letters.

Background on pesticides and malaria
DDT has been banned in most parts of the world for decades, but approximately 20 countries currently use the pesticide to control malaria and others are considering its use. DDT use remains controversial, as some studies have linked its use to environmental and health problems. Still, it is largely believed to be among the most effective methods to kill malaria-carrying mosquitoes.

Malaria continues to be the leading cause of death and morbidity in poor countries, according to the World Health Organization (WHO). More than one million deaths and up to 500 million clinical cases are reported each year. Most of the 3,000 deaths that occur each day worldwide are of children in Africa. More than one-third of the world's population lives in malaria-endemic areas. According to a 2006 report by the Centers for Disease Control and Prevention, there were outbreaks of locally acquired mosquito-transmitted malaria in the United States.

The research funding for Dr. Pang's study was provided by Mayo Clinic.
Note: This story has been adapted from a news release issued by Mayo Clinic.

Source:www.sciencedaily.com

Mosquito Control Program to Repeat in 2007, More Prevention May Mean Less Spraying

By Shayla Ashmore

Lassen County Agriculture Commissioner Ken Smith won another state grant to conduct mosquito abatement in 2007 to control deadly West Nile Virus.

“We’re hopeful that maybe with the larviciding and the mosquito fish, that perhaps Susanville might not warrant (spraying) and it would remain in the outlying areas which are so heavily infested with the West Nile.”

WNV is now a threat all over the country, Smith told the Board of Supervisors at its Dec. 19 meeting, with 270 human cases reported in California last year.“

Some fairly close by, Butte County reported 31, Tehama County 3, Shasta County 4, Modoc County 2 and over in Nevada, it’s not an exact number, but around 15,” Smith said.

The median age of those who contracted WNV was 50.

“Which means half the people who contracted West Nile Virus were over 50 and half were under 50,” he said. “Previously most people assumed that West Nile Virus was a condition that would affect mostly elderly people, but the median age is 50, so, that’s not necessarily so good.”

Lassen County reported positive tests for WNV in 2006 on seven horses, three dead birds and three mosquito samples. When the WNV control program began in the county in 2006, Smith said, his staff was learning the process.“

We were purchasing the equipment and the materials and being trained and so the larviciding program wasn’t as good as it could be,” Smith said. “The mosquito fish program needs to be improved.”

Lassen County will receive $25,000 and Smith will hire a seasonal employee. The board unanimously approved a cooperative agreement with the California Department of Health Services, allowing Smith to receive the money.“

So, we’ll have somebody out almost every day addressing these issues,” he told the board. “Last year, by the time we got to do some of the larviciding, the storm drains in Susanville were dried up.”

During the 2007 mosquito season, Smith and his staff plan to improve the larvicide’s program, buy mosquito fish and “perhaps treat Barry Reservoir and places like that.”

The program the board approved last year will continue. It includes monitoring by trapping larval and adult mosquitoes, larval mosquito control in Susanville and Westwood and spraying for adult mosquitoes throughout the county when conditions warrant or when trapping indicates the presence of target mosquito populations and WNV.

A county crew conducts spraying at dusk or later at night on predetermined dates using the lowest volume of pesticides that still yield effective control and ultra-low volume techniques.

Pyrethrins are used in rural areas and synthetically produced pyrethroids are used in more populated areas.

The mosquito eating minnow fish are used to control larval insects “where they will not impact native fish,” Smith said in May 2006. Spraying is only used as a last resort and requires approval by the supervisors.

In late August 2006, the board gave Smith permission to spray pesticides to kill mosquitoes in an area bounded by Mapes Road on the east and south, Standish Buntingville Road on the south, Highway 395 on the west and Center Road on the North. Smith said spraying would occur in the more populated areas around Standish, Litchfield and some fringe areas of Johnstonville and Janesville.

After trapping a high number of culex tarsalis, the mosquito that carries WNV, Smith’s staff sprayed the safest pesticide pyrethroids at the least toxic, lowest effective rate starting at Leavitt Lake.

They also sprayed in Susanville north of Main Street and east of Ash Street. Smith said his staff couldn’t trap enough mosquitoes in Westwood to send a sample to the state for testing.

Once again, Smith will develop call and shutoff lists for those who wish to be notified before spraying occurs near their homes or wish to request their residence not be sprayed. Call 251-8110 for more information about the call and shutoff lists.

Smith said he will announce areas to be sprayed in the local media at least 24 hours in advance.

To protect themselves from the effects of WNV residents may:

•Drain any standing water near their homes,•Stay indoors at dusk and dawn,

•Wear long, loose-fitting clothes while outdoors,

•Wear insect repellent containing DEET, Picaridin, oil of lemon, Eucalyptus, and

•Repair or replace any damaged window or door screens to exclude mosquitoes.

Sourcehttp://www.lassennews.com

Malaria Carrying Mosquito Restricted To One Area

By Khalil Goodman

There is only one mosquito that can transmit malaria in Barbados and thankfully it is only found in one area on the island.

The mosquito, Anopheles aquasalis is one species of the 400 variants of the Anopheles mosquito. Of these only 40 can transmit the four different species of parasites known to cause malaria.

Ronald Chapman, Environmental Health Specialist with the Epidemiology Department in the Ministry of Health, explained yesterday that the Anopheles aquasalis prefers to live in water with a higher than average salt density in the water. Thus, for years they have only lived in the brackish water of the Graeme Hall Swamp.

Referencing Jamaica where over 100 cases were reported in the last month, Chapman noted that it is unclear what type of anopheles mosquito has caused the outbreak there, but noted that the species Anopheles gambiae is the type that is most known to transmit the dangerous malaria parasite plasmodium falciparum.

He disclosed that the few cases of malaria reported in Barbados have originated outside Barbados and no evidence of any of the four malaria parasites have been discovered. Chapman also revealed that the Anopheles aquasalis mosquito is distinct from the Aedes aegypti which spreads dengue and the culex which is more common, in that the latter two feed with their bodies perpendicular to the hosts, while the aquasalis feeds at a 45 degree angle and sometimes almost perpendicular.

Explaining, that since the mosquito needs a safe place to lay its eggs after ingesting a blood meal, Chapman explained that this would mean the mosquito could only travel back to the swamp, this would inhibit any long scale travel. Speaking to the media after presenting on vector control at a special seminar Strengthening the Laboratory Diagnosis of Malaria, Chapman revealed that the Epidemiology department is dedicated to constant vigilance of the swamp. Chapman explained that should it be found that anyone has contracted malaria, it is first ascertained if they are residing near the area of the swamp. He explained that such a person would be evacuated from the area, to prevent the mosquito drinking from that host and thereby becoming a vector for the malaria parasite.

Chapman stated that along with constant dipping and testing of the water, cleaning of the area is undertaken and where larvae eating fish are depleted, the department replenishes the fish community.

Source:http://www.barbadosadvocate.com

14 Tips for home control mosquitoes

Here are some tips for controlling mosquito breeding areas around your home or business:
• Empty water from old tires, tin cans, buckets, drums, bottles or other places mosquitoes could breed.
• Clean rain gutters and downspouts.
• Empty plastic wading pools at least once per week and store inside when not in use.
• Change the water in bird baths and plant pots or drip trays at least once per week.
• Store boats covered or upside down or remove accumulated rain water every week.
• Empty pets' water bowls daily.
• Level the ground around your home so water won't collect in low spots.
• Fill in holes or depressions in the ground around your home if they collect water.
• Cut weeds and grass where adult mosquitoes seek refuge from the heat during the day.
To protect yourself:
• Stay indoors during the peak biting periods of dawn and dusk.
• Make sure door and window screens fit tight and are in good condition.
• Wear long-sleeved shirts and long pants of tightly woven fabric.
• Use mosquito netting when sleeping outdoors or in an unscreened structure and to protect babies.
• Use insect repellent with DEET that have a concentration of 25-30 percent for adults and lower levels for children.

Rain puddles bring mosquito infestation - what to do about it

By Brennan Purtzer

With record rainfall flooding Kaunakaka'i and other areas of the island, much of the wet stuff ended up in ponds, swamps and bogs across Moloka'i.

hile frogs are enjoying the ponds, you may have noticed they have also become hatcheries to thousands, if not millions of mosquitoes.

As mad as we get at the whalers who brought them here, the fact remains they are here to stay, and we've got to learn to live with the bloodsuckers.

Here are some tips to dealing with these parasitic pests.

* Avoid swampy areas if you can.

* If you're in a swampy area, try to avoid being there at dawn or dusk.

* Wear long, heavy pants and shirts.

* Tuck your pants into your boots.

* Wear light colored clothing so ticks and bugs show up easily.

* Spray pesticides on your clothing (NOT on your skin).

Even more effective - don't be a mosquito breeding ground.

Try to prevent mosquitoes from breeding in the first place. Replacing your outdoor lights with yellow lights and using citronella candles and torches can help drive the mosquitoes away from your immediate area, but they will simply go elsewhere to attack birds and humans. So your most proactive means of helping with the current panic would be to ensure that any and all breeding waters within your control or on your property are taken care of.

Products that work to keep them off you:
Anything with DEET as an ingredient works best, but some may feel uncomfortable with putting such a powerful chemical on them (or anywhere else). Other, natural, repellants are "Skeeter skatter," which is an effective concoction made of natural oils that are displeaseing to mosquitoes. You can buy that at http://www.simmonsnaturals.com/ for just $7.00 a bottle.

Also effective are citronella candles, which give off displeasing scents to the bugs.
The best natural method of mosquito control is promoting a healthy bat population. Opeapea, the Hawaiian Hoary bat, lives only on the islands of Hawaii, Maui and Lana'i. We might want to consider importing the small Opeapea, as they are the largest eaters of mosquitoes and other annoying bugs.

Remember, mosquitoes are more than pests, they carry deadly diseases such as malaria, west nile virus and hepetitus.Some information for this story was gathered at: http://www.lisashea.com/

http://www.molokaitimes.com

Taming Your Outdoors

by Bill Hanckel

Slapping yourself silly trying to keep mosquitoes from biting you? Besides causing irritating itching bites, mosquitoes can also carry and transmit several diseases including the West Nile Virus. Although you cannot get rid of every mosquito, there are many ways to protect yourself and those around you.

The most important way to help fight mosquitoes is by breaking their breeding cycle. Mosquitoes lay their eggs in stagnant water and those eggs hatch within 48 hours. Once hatched, the larvae feed on debris in the stagnant water until they move into the resting stage. In this stage, the larvae become pupae. The mosquito begins to develop and finally emerges as an adult mosquito. All this can happen in less than 5 days!

Be pro-active and check the area around your home for places where standing water may accumulate such as birdbaths, clogged gutters, buckets, kiddie pools, toys, even bottle caps – mosquitoes can breed in just a thimble full of water. Change water often in birdbaths. Empty kiddy pools and turn them upside down when not in use so they do not collect water. Keep your gutters clear of debris.

If you have done your best to help prevent breeding and are still being bothered by mosquitoes, there are many products on the market to repel or kill mosquitoes. The available products range from low-cost items such as lotions and sprays to higher priced solutions such as traps and misters. Along with a range in cost comes a range in effectiveness.

Citronella candles and torches are ineffective except in very small areas. One study showed that use of citronella candles resulted in people still being bitten by mosquitoes, but they had half as many bites as those who were not around the candles. Other products that do not perform well are ‘sonic’ repelling systems. While these products are inexpensive, laboratory studies have shown that they do not work.

When looking for lotions or sprays, the Center for Disease Control recommends selecting those, which contain DEET, picaridin, or lemon eucalyptus. Products containing these ingredients can be obtained from most drug stores or home and garden stores. In addition to the products recommended by the CDC, there are also all natural products available. Lewey’s Eco-Blends offers an all-natural product that contains essential oils such as rosemary and thyme, which have shown repellent properties. Eco-blend comes in bottles for human use and spray bottles for equine use. Always be sure to read the label instructions and follow these instructions carefully.

If you would rather choose a more high-tech solution which helps reduce the population of mosquitoes, then you may want to investigate a propane based collection system or a mosquito misting system. The propane collection system works by converting the propane to carbon dioxide. The carbon dioxide draws the mosquitoes to the unit in the same way your exhaled breath draws mosquitoes to you. In the collection system, the mosquito is ‘trapped’ in a bag when the pest enters the unit. These units need to have their collection bag cleaned frequently and you must change/refill the propane tank. Placement is critical. The units need to be placed downwind of your area and must be moved every time the wind direction shifts. These types of units require a fair amount of human intervention to operate at peak performance so the cost vs. the price should be weighed accordingly.

Another high-tech solution that is fairly new to the market, the mosquito mister system is permanently installed around your home. The system is comprised of a reservoir, pump, timer, and nozzles. Once the system is installed, it is set to mist a diluted Pyrethrum concentrate, at specified intervals – usually 4 times per day for about 30 seconds each period. The active ingredient in Pyrethrum is Pyrethrin, which is a natural pesticide made by crushing a special type of chrysanthemum flower into powder form. The powder is then added to an insecticide, commonly referred to as PBO, to increase the effectiveness of the solution. Misting Systems require only occasional maintenance and refilling, but are priced higher than other options. More advanced mister systems can be equipped with a remote control and variable timing functions in addition to automatic weather control options.

Now that you know how mosquitoes breed and how to protect against their bites, don’t let them run your life. Take action, tame your outdoors and enjoy your summer!

Bill Hackel is General Manager of http://www.MosquitoMister.com, the top supplier of mosquito misting systems for the do-it-yourself consumer.

Article Source: http://EzineArticles.com/?expert=Bill_Hackel

Guidelines To Buying Mosquito Netting

By Mark Jansen

Mosquitoes can carry diseases like malaria, yellow fever, many types of encephalitis and dengue. Almost 600 million people die each year with mosquito-born diseases. What can you do to prevent getting bitten?

Mosquito netting is important because it prevents an insect bite that carries infectious diseases. It comes in a variety of shapes, color and purposes. Here are some guidelines for you to choose the perfect mosquito netting.

1) Size and shape: The size of the net should be spacious. It should have enough space to cover your whole body while sleeping. The mosquito netting should provide you with your needed air circulation. A mosquito net with holes of 1.2mm x 1.2mm is the most used and the most recommended. Rectangular mosquito nettings are more advisable to use because it provides much needed space for you and your friends. Pyramid shaped mosquito nets could be used for individual purposes.

2) Material: There are two most common material used in mosquito netting – polyester and cotton. Mosquito netting made of polyester is lightweight that could be used for camping and other traveling needs. It lasts longer than cotton nets because cotton is not water-resistant and weighs more when wet. But cotton mosquito netting could offer a more comfortable rest when used outdoors. Both of these kinds of netting are available in different sizes and thickness of the thread used. For a more efficient mosquito net, it is recommended to purchase a net that has been sprayed with high quality insecticides. If the nets are pre-treated with insecticides, the mosquito net repellant could be useful at least for a year depending on heat and rain exposure. If insecticide is no longer there, you could always buy from your nearest store.

3) Purpose: The mosquito netting is perfect for a number of situations. It could be used outside of your backyard as gazebos and umbrellas. It could be used in your house as doors, windows and balconies. It could be used in traveling and in camping. Whatever the case may be, it could be used anywhere you may go.

4) Variety: The mosquito netting could be purchased in a number of styles and shapes for your preference. Here are some of the basic kinds of mosquito nets available in stores.

* Head and body nets: These kinds of nets are usually used outdoors in camping and in dealing with swarms of mosquitoes. There are nets available to cover any part of the body, or the whole body itself.

* Indoor nets: Indoor nets are used in the repelling of insects inside the house. It is to protect your children and yourself from future insect bites. It is used in screening the doors, windows, as draperies, and many more.

* Hanging nets: These kinds of mosquito nets are hanged from the top of your house and tucked into the floor. They are the types of nets that are best used as umbrella, for balconies, and for larger areas to cover.

* Equipment nets: These are specialty equipments produced with mosquito netting. Samples of this include a baby stroller net, bed canopies, and many more. Now that you know how to buy the perfect mosquito netting for you, invest now and experience the protection your family would maintain.

About the Author: For more great netting info and advice check out: http://www.netting-advisor.com
Source: www.isnare.com