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Sept 26 (Reuters) - More than 400 new U.S. cases of West Nile virus emerged in the last week, in an outbreak that remains the second worst on record but has begun to show signs of slowing.

So far this year, 3,545 cases have been reported to federal health officials as of Sept. 25, up from 3,142 reported the week before, the Centers for Disease Control and Prevention (CDC) said in its weekly update of outbreak data.

That marked a rise of nearly 13 percent, down considerably from a 30 percent weekly jump witnessed earlier this month.

About 38 percent of all cases have been reported in Texas. Other states with large number of cases include Mississippi, Michigan, South Dakota, Louisiana, Oklahoma, and California.

A total of 147 people have died from the disease, compared with 134 reported one week ago. Just over half of the cases reported to the CDC this year have been of the severe neuroinvasive form of the disease, which can lead to meningitis and encephalitis.

The milder form of the disease causes flu-like symptoms and is rarely lethal.

Experts believe the disease originated in Africa and was first detected in New York City in 1999. Outbreaks tend to be unpredictable. Hot temperatures, rainfall amounts and ecological factors such as bird and mosquito populations have to align just right to trigger an outbreak such as the one this year.

The CDC said the number of cases this year is the highest reported to federal health officials through the last week in September since 2003, the year with the most cases. (Reporting by Paul Thomasch; Editing by Sandra Maler and Vicki Allen)

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  • Avoid Dusk And Dawn

    The evening and early morning hours are <a href="http://www.cdc.gov/ncidod/dvbid/westnile/prevention_info.htm" target="_hplink">peak biting times for many mosquito species</a>, according to the CDC, so consider ramping up your protection or staying inside at these times if you can. <br><br> But, Conlon warns, other species bite during the day, too. "Whenever you're present, you're on the menu," he says. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/activesteve/5628626857/" target="_hplink">ActiveSteve</a></em>

  • Eat Garlic

    Garlic has long been rumored to ward off mosquitoes, but there isn't much research to back up the claims. However, <a href="http://www.sciencedaily.com/releases/2009/01/090130154901.htm" target="_hplink">garlic does have some healthy benefits</a>, thanks to the powerful antioxidant allicin that gives it its smell and flavor. Adding a little extra garlic to your summer diet certainly won't hurt! <br><br> Pure garlic oil, on the other hand, when rubbed on the skin <em>will</em> repel mosquitos -- for around 20 minutes -- but it will probably repel everyone around you as well, jokes Conlon. <br><br> There is one ingestible to avoid, however. The <em>New York Times</em> reports that alcohol is just about the <a href="http://www.nytimes.com/2007/07/24/health/24real.html" target="_hplink">only food or beverage proven to have a true effect on mosquitos</a>, and the bad news is it attracts them. A small 2002 study showed that more mosquitoes landed on beer drinkers than tee-totalers. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/jenorton/2212742541/" target="_hplink">lowjumpingfrog</a></em>

  • Avoid Scented Shampoos, Soaps And Perfumes

    This one is mostly rumor, says Conlon. When they're not feasting on humans, mosquitos obtain some nourishment from plants, so the thinking goes that if you smell like a pretty flower, a bug might mistake you for one, but it's never been proven, he says.

  • Citronella

    A small study from 2002 found that <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa011699#t=articleResults" target="_hplink">citronella-based repellents</a> keep bugs away for about 20 minutes or less. <br><br> While the plant-based oil is thought to smell bad to mosquitoes, it's not highly unpleasant to humans, so if you feel like it works, there's no reason to stop using it, says Conlon, but there may be a bit of a placebo effect going on, he says. <br><br> The same study found that other plant-based repellents, like geranium oil, didn't provide lasting protection either. However, protection from <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa011699#t=articleResults" target="_hplink">soybean-oil-based repellents</a> lasted about 90 minutes. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/elwillo/5021856163/" target="_hplink">Keith Williamson</a></em>

  • Burn A Candle

    Whether you light citronella candles or decorative patio torches, smoke will keep mosquitos at bay, says Conlon. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/tedsblog/904732/" target="_hplink">TedsBlog</a></em>

  • Cover Up

    The CDC recommends wearing long sleeves, pants, hats and closed-toed shoes instead of sandals to <a href="http://wwwnc.cdc.gov/travel/page/mosquito-tick.htm" target="_hplink">cover exposed skin</a>. In the dead of summer, this might not always be appropriate, but if you have to be outside during dusk or dawn, when temperatures are likely to be cooler, long sleeves may be more practical. <br><br> "Any exposed skin is 'fair game,'" says Conlon.

  • B Vitamins

    According to the Mayo Clinic, taking a daily dose of <a href="http://www.mayoclinic.com/health/mosquito-bites/DS01075/DSECTION=alternative-medicine" target="_hplink">75 to 150 milligrams of vitamin B-1</a> (thiamin) could slightly change your scent in a way that might keep mosquitoes away, but the research isn't conclusive. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/seanmichaelragan/6254362902/" target="_hplink">seanmichaelragan</a></em>

  • Eliminate Standing Water

    Any pools or puddles around your home or yard can quickly become mosquito breeding ground. The Mayo Clinic recommends unclogging roof gutters, emptying any kids' pools, changing the water in any bird baths weekly, making sure rain is not accumulating in trash can lids and storing flower pots or any other unused containers upside down, <a href="http://www.mayoclinic.com/health/mosquito-bites/ds01075/dsection=prevention" target="_hplink">among other tips you can see here</a>. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/elias_daniel/281970867/" target="_hplink">elias_daniel</a></em>

  • Stay Close To The Fan

    "Mosquitoes are bad fliers," <a href="http://www.cleveland.com/insideout/index.ssf/2010/06/preventing_mosquito_bites_so_b.html" target="_hplink">Dave Shetlar, an Ohio State University professor of urban landscape entomology</a> told Cleveland.com. Perch yourself near ceiling fans on patios, porches or open-air restaurants that have them. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/lipstickproject/4637258947/" target="_hplink">JMacPherson</a></em>

  • Ditch The Bug Zapper

    These electronic gadgets will wind up killing bigger bugs, like moths, rather than mosquitoes, says Conlon. <br><br> In fact, an entomology professor from the University of Delaware published a study in 1996 showing that out of nearly 14,000 insects killed by six zappers in one summer, <a href="http://www.popularmechanics.com/home/improvement/4323044" target="_hplink">only 31 were biting fliers</a>, <em>Popular Mechanics</em> reported. Another 2,000 were beneficial bugs that keep real pests at bay, and the others were harmless species. <br><br> Plus, mosquitoes are <a href="http://www.cleveland.com/insideout/index.ssf/2010/06/preventing_mosquito_bites_so_b.html" target="_hplink">attracted to <em>dim</em> light</a>, so they may fly toward the zapper initially, but they'll likely turn away from the thing when they get too close, according to Cleveland.com. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/hfb/182343058/" target="_hplink">hfb</a></em>

  • Lemon Eucalyptus Oil

    The CDC, <em>Consumer Reports</em> and other outlets recommend this "very good repellent" Conlon says, which, at 40 percent concentration will ward off mosquitoes and ticks. <br><br> However, it isn't recommended for <a href="http://www.consumerreports.org/health/healthy-living/beauty-personal-care/insect-repellent/overview/index.htm" target="_hplink">children under 3</a>, according to <em>Consumer Reports</em>. Conlon explains that isn't necessarily because of toxicity, however. "I think they probably haven't taken the time to get the [EPA] registration," he says, a timely and costly process, when children under 3 can be protected in other ways, like dressing them appropriately, he says. <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/fairfaxcounty/7352235208/" target="_hplink">fairfaxcounty</a></em>

  • Catnip Oil

    According to a 2001 study, this natural repellent is <a href="http://www.sciencedaily.com/releases/2001/08/010828075659.htm" target="_hplink">10 times more effective than DEET</a>. Since then, scientists have been studying its repellency, and Dow Chemical is in the process of getting EPA registration for a new catnip-based product, says Conlon. Of course, every consumer will have to weigh the cost and the benefits, he jokes. You'll repel mosquitoes wearing the stuff, but you're likely to attract cats! <br><br> <em>Flickr photo by <a href="http://www.flickr.com/photos/cygnus921/2598483750/" target="_hplink">cygnus921</a> </em>

  • IR3535

    This cryptically-named repellent, most well-known as the active ingredient in Avon Skin So Soft, is characterized by the EPA as a "biopesticide repellent," meaning it is in fact derived from natural materials. However, the same 2002 study found this compound <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa011699#t=articleResults" target="_hplink">protects against mosquitoes for only about 23 minutes</a>. <br><br> <em>Photo from <a href="http://www.amazon.com/Avon-Guard-IR3535-EXPEDITION-Spray/dp/B00199RQ5S/ref=sr_1_1?s=hpc&ie=UTF8&qid=1339188213&sr=1-1" target="_hplink">Amazon.com</a></em>

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