Friday, July 16, 2010

Mosquito Infection Rates

Jonathan F. Day, Professor of Medical Entomology, University of Florida, Florida Medical Entomology Laboratory, Vero Beach
What is your real risk of contracting a mosquito transmitted disease like West Nile virus? The answer depends on three factors: where you live, your daily mosquito exposure rate and, most importantly, local mosquito infection rates.
Where you live is important because of the geographic distribution of WNV and other mosquito-transmitted diseases. There are regions of the United States where the virus is common and other regions where WNV is rare. If you live in California, Texas, Nebraska or Colorado where the virus is seasonally common, your risk of infection is higher than if you live in Maine or New Hampshire where the virus is rare.
Likewise, mosquito exposure rate is an important risk factor. People who live in homes without window screens or air conditioning are at a much higher risk of infection than people who live in mosquito-proof homes. Individuals such as night watchmen and emergency responders who work outdoors at night are at higher risk of infection than individuals who work in air conditioned buildings.
Finally, the local mosquito infection rate is the most important risk factor. During most summers, mosquito infection rates are extremely low. For example, a typical WNV mosquito infection rate in Florida is one in 10,000 (that is, one WNV-positive female mosquito is found in every 10,000 females that are sampled). The likelihood of a human WN infection under these conditions is very low. Contrast this with the mosquito infection rate of 1 in 100 observed in Colorado during the 2003 WN epidemic. If one out of every 100 female mosquitoes can transmit WNV, the risk of human disease, especially in humans with high mosquito exposure rates, increases tremendously.
Risk of WNV exposure can be reduced by avoiding mosquitoes and preventing them from biting, especially when mosquito infection rates are known to be high. The best ways to avoid mosquito bites are to avoid infested areas, wear protective clothing and wear insect repellent.
UPDATE: Due to current environmental conditions, FMEL has released the sixth FMEL Arboviral Epidemic Risk Assessment for Florida of 2010. Details can be found in the latest update (PDF) at my lab's website at http://fmel.ifas.ufl.edu. Go to the Mosquito Information Web Site and look in "MWTD Risk Analysis."

Tuesday, June 15, 2010


The year my life changed forever
Mel Lacy
Life was good for me in 2006. I was 49, successful, wealthy and healthy, with great endurance. I had the world by the tail—with a lovely wife and family, a great career as a builder and a zest for living.

Suddenly, without warning, toward the last week in July, my health deteriorated rapidly. By early August, I had severe headaches, muscle weakness, and disorientation. In each of four separate doctor visits, I was told bed rest and fluids were the best treatment for whatever it was I had (no one knew.)

I continued to deteriorate and by Aug. 5 I could not stop vomiting. Going to the emergency room is the last thing I remember until Oct. 17, when I regained consciousness. The news was horrific. I was paralyzed from the neck down. Lucky to have survived, I had a tracheotomy, was hooked to a ventilator and had a stomach feeding tube. I had lost 45 lbs. of muscle. I looked like a concentration camp survivor. I was flooded by anxiety—what would happen to me, to my family?

In mid-August, while I was still unconscious, physicians had finally concluded that I had West Nile Virus neuroinvasive encephalitis, which was causing the paralysis. West Nile virus is transmitted to people from infected mosquitoes. Who would have thought that something as tiny as a mosquito weighing less than an ounce could have felled a big healthy guy like me with just one bite? Before this happened, mosquito bites were just an annoyance. They had never been life-threatening. I suspect I was bitten in my own back yard in mid-July. Who would have thought?

After weeks in intensive care, I was transferred to a rehabilitation facility. Rehab for someone in my condition, it turns out, was not a good idea. They sent me home after six weeks and four days later, I had respiratory failure. On the way to the emergency room, my heart stopped. I was revived and spent the next 30 days in intensive care.

During that period, one of the physicians thought I had been misdiagnosed. He sent me to a teaching hospital in Portland, Ore., nearly 500 miles from home. The WNV diagnosis was confirmed. My attending physician said he thought that my head movement was about all I could ever expect. It was a devastating realization. This was, without doubt, one of the lowest of low points.

I was transferred at my own expense to a hospital near my home in Idaho and was finally released on Dec. 26, 2006, still on a ventilator. My wife became my primary caregiver as I lay in a hospital bed in our dining room. A physical therapist visited twice weekly during February. And my wife and I worked at the rehabilitation ourselves. I slowly improved enough so that I could to go to a rehabilitation clinic as an outpatient. The tracheotomy apparatus was finally removed in April.

Progress, when you get WNV neuroinvasive disease like I have, is hard to come by. But in the past three years, I have recovered some movement in my lower arms and hands but not full strength. My shoulders don’t function properly—I cannot raise my arms when they are extended straight out. I have good movement in my right leg and ankle, but not much in my left leg and my left arm is stronger than my right, which is unusual, because I am right-handed. My body core is still weak and I have poor lung function.

Despite the setbacks and the negative prognosis from the outset, there have been some minor victories. These are hard won. I have gained enough overall strength to transfer myself using a slide board which helps me to be a little more independent in my daily routines than in the past. I use a sophisticated, motorized wheelchair, which make a huge difference.

One of the main achievements of the past year is that, thankfully, I am able to drive again. Being given this freedom is a miracle. I transfer to and from the van seat from my wheelchair. I use my right leg for regular pedal controls and have good movement with my arm for steering.

But working harder and longer in rehabilitation, which is effective for most folks with disabilities, is not the right thing to do for anyone stricken by WNV. My doctor informed me that, with this virus, there is a very fine line beyond which I may actually be doing more harm than good. This was tough to hear, having worked so hard and come this far.

So, with that in mind, I no longer go to rehab, but I am able to go to the local YMCA, which has a great pool. There’s a swing chair that lowers down in the water, so I can transfer myself into water and do my therapy. This is wonderful, because once in the water I can walk and am slowly gaining strength.

One of the biggest challenges to overcome these days is muscle fatigue, so I do not have much endurance. As my doctor says, "After you have done your pool workout, that’s the equivalent of a runner having run a marathon."

Will I continue to work to regain mobility and strength? Absolutely. But it will be a long journey and who knows how much more motion I can gain.

My hope is that others will not have to go through something like this. My ability to speak has not been compromised, so I tell everyone I know to take personal precautions to prevent being bitten by infected mosquitoes. Everyone needs to dress appropriately when outside and they need to use an EPA-registered mosquito repellent, like the ones that contain the ingredient DEET, faithfully if you are outside when mosquitoes are biting (typically dawn and dusk).

I never knew this simple information…and often think about the “what ifs” in my life. What if I had used repellent and that mosquito had not bitten me? What if I had not been outside after dark? What if…I had never gotten West Nile virus?

So, I encourage everyone to take precautions. West Nile virus could change your life forever. Don’t let that happen to your family, your friends or yourself. This is a chance you can’t afford to take.

Mel Lacy

Friday, February 26, 2010

Fight the Bite Poster Contest

Greetings!

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While it’s still a bit dreary and cold here in the East, and across much of America, lots of kids are stuck inside due to the winter weather. Here’s a suggestion for fifth and sixth graders seeking an indoor activity during the next two months: create an entry for the Fight the Bite poster contest.

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The CDC and DEET Education Program are once again co-sponsoring the contest, which is open to all fifth and sixth graders in the U.S., including those who are home-schooled. Entries must be postmarked by April 5. Helpful hints, the entry form and rules are at http://www.fightthebitecontest.org/, plus winning posters from prior years, which I’m sure you’ll agree are amazingly good.

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The contest encourages students to illustrate ways to protect themselves and their families from diseases spread by mosquitoes and ticks by using repellent while outdoors. Two winners from each state—one fifth grader and one in sixth—will receive a $50 U.S. Savings Bond and an award certificate. Two Grand Prize winners—one from each grade—will receive a $1,000 U.S. Savings Bond, a plaque and a trip to CDC offices and laboratories in Fort Collins, Colo. (airfare and lodging provided) with their parents for the awards presentation.

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I’ve co-hosted the ceremony the past three years and I can say it’s a fun event that the winners and their families seem to enjoy greatly. There’s even an educational component to the trip, courtesy of our CDC partners.

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“Tips for Teachers” also have been added, based on input from a Missouri teacher who has assisted two national winners. Public health and mosquito control professionals are encouraged to use any of the winning posters for educational outreach, public service materials and similar purposes.

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Keep in mind that tick season is upon us, especially in states that have an early spring. The new ticks, known as nymphs, are really hard to see but they carry diseases like Lyme, Rocky Mountain spotted fever and the like. So, be sure to dress appropriately and use repellent to protect yourselves when you venture into the woods.

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You can post questions, suggestions and comments below, or via info@deetonline.org.

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Best wishes for a wonderful and healthy spring and summer!

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Susan E. Little

Executive Director, DEET Education Program

Wednesday, August 19, 2009

EEE: Rare But Serious

I recently visited my son up in New Hampshire. While not bad yet, the mosquitoes were just getting started. Because of the risk of both eastern equine encephalitis (EEE) and West Nile, my son was concerned about the risk of disease to his son (my 15-month-old grandson). For both of these diseases, the real risk of being bitten by an infected mosquito and then developing the disease is very low. Unfortunately, if you are the one who does become ill, the consequences can be very grave. More than half of the people who get sick with EEE will likely die. To reduce the risk of infection, I suggested that the family wear clothing that covered most of the body, avoid times outside when mosquitoes are particularly bad, and wear a repellent, such as DEET. My son was concerned about any potential health risks associated with DEET and small children, so I checked with the American Academy of Pediatrics (see http://aapnews.aappublications.org/cgi/content/full/e200399v1), and they recommended use of a product containing 10-30% DEET on children at least 2 months old to protect them against mosquito bites and the diseases that mosquitoes can transmit. As an added safety precaution, always follow label directions. An adult should always apply the repellent to the child, being careful to avoid the mouth and eyes as well as the hands, as the child is likely to rub their eyes or stick their hands in their mouths. While the risk of catching a mosquito-transmitted disease is rare, the consequences can be severe, and we should try to limit exposure to mosquitoes whenever possible.

Wednesday, August 5, 2009

Independent Experts Dispute Study on DEET Neurotoxicity

A European study using lab animals to examine the possibility that DEET is a neurotoxin produced misleading results and fails to accurately reflect the way that consumers use insect repellents containing DEET, experts say.
DEET is the world’s most popular insect repellent active ingredient and has been used reliably by consumers for more than 50 years.
“The incidence of exposures resulting in neurotoxic effects is very low, when considered in the context of the millions of people around the world who have used insect repellents containing DEET, ” said Daniel Sudakin, M.D., M.P.H., WITH the U.S. National Pesticide Information Center in a BBC News story (http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/8182052.stm).
The BBC News story is a balanced report on the study. A news release issued by the study published and other news stories provide a misleading picture. For more, please visit www.deetonline.org

Tuesday, July 7, 2009

Eastern Equine Encephalitis Virus

Eastern equine encephalitis is a viral infection that is transmitted to humans, horses, other domestic animals (including dogs and pigs), and wild birds through the bite of an infected mosquito. Because of this “mosquito connection,” the eastern equine encephalitis virus (EEEV) is commonly referred to as an arbovirus (arthropod-borne virus). The EEEV has been reported throughout the eastern half of North America (which is the reason for its name), but is particularly prevalent in coastal cedar and hardwood swamps from New Hampshire to peninsular Florida.

The EEEV is normally transmitted between mosquitoes and wild birds in freshwater swamps. This bird-to-mosquito-to-bird transmission cycle is commonly referred to as amplification because it can result in a large number of infected mosquitoes and birds. During most years infected birds and mosquitoes remain in the swamps. During years with wet spring and summer conditions infected mosquitoes disperse from the swamps and carry the EEEV to horses and humans in distant locations. Most wild and domestic animals are not susceptible to infection and do not suffer clinical signs of infection. Some animals (particularly humans and horses) are highly susceptible to EEE infection and these individuals may suffer severe clinical symptoms, often ending in death.

Environmental conditions are extremely important to the EEEV cycle in nature and certain rainfall patterns predispose a region to EEEV transmission. At the University of Florida, Florida Medical Entomology Laboratory, we track these conditions and periodically issue releases explaining and updating the current EEEV situation in Florida. To view the most recent information about EEEV in Florida visit:

http://mosquito.ifas.ufl.edu/Documents/MWTD/EEE_Analysis_Florida_June_2009.pdf

and http://eis.ifas.ufl.edu/eis1.htm.

Best wishes for an enjoyable and healthy summer,
Jonathan F. Day, Ph.D.
Professor of Medical Entomology
University of Florida, Florida Medical Entomology Laboratory, Vero Beach


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Friday, June 12, 2009

Working for CDC has afforded me with opportunities to develop health messages that are read by people throughout the world, which is pretty exciting. It’s a wonderful opportunity to meet people who hear and use those messages.

For that reason one of my greatest rewards has been my involvement with the “Fight the Bite” poster contest that CDC co-sponsors with the DEET Education Program. This is the third year we’ve held the contest and it was the best yet. It was a treat to meet national contest winners Meghan Zengel and Richard Schleicher. The students and their families came together recently for the “Fight the Bite” Poster Contest award ceremony at the Atlanta headquarters of the Centers for Disease Control and Prevention. Those of us with the CDC and the DEET Education Program, which sponsor the contest, had a great time meeting the students and hearing about their artwork and their interesting plans for the future.
Meghan, a fifth grader, and Richard, a sixth grader, both received a $1,000 U.S. Savings Bond and an award certificate. Plus they won an all-expense-paid trip to Atlanta with their parents (and Meghan’s brother).

Students from New Hampshire to Washington State entered the third annual “Fight the Bite” poster contest. What pleased us most here at CDC was the quality of entries, with their young artists accurately conveying important prevention messages in attractive and creative ways. We can really get some insight into what young people hear from our bug-bite prevention messages, and we always take some new ideas for prevention and promotion away from the event. You can see the list of winners and their posters at http://www.fightthebitecontest.org/.
Richard, who competes in rodeos as a bull rider (what courage! So glad he uses a helmet!), used that thrilling sport as his theme. Meghan, who enjoys reading mystery novels, created a fun and clever poster around a detective with a magnifying glass.

Our contest invites fifth and sixth grade student to create posters encouraging children and adults to protect against mosquito and tick bites and the diseases they can cause. (Please visit http://www.cdc.gov/ for more). A panel of judges, including two top public health leaders, chose two Grand Prize winners—one from each grade—and they selected state winners for fifth grade and sixth grade, who each will receive a $50 savings bond and certificate.
Please tell youngsters who will be in those two grades next year about our contest. Of course, if you’re one, please enter! You’ll have fun, learn some valuable information and get a shot at some nice prizes.

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