Thanks for including my writing!

I wanted to post a thank-you to the people on the web who are including some examples of articles I’ve written:

Grand Rounds is a very cool collection of medical related blogs, gathered into a nice and easy to read format.  Thanks to HighlightHealth.com for including my post about Rock climbing and finger injuries!

Matador Travel is an on-line traveler community with loads of information for travelers, adventurers, travel writers and those who enjoy other cultures.  I am very happy they chose to publish an article I wrote about Malaria Vaccines and What Travelers Need to Know.

World Nomads is a travel and health insurance company specializing in international and extreme sport coverage.  Their blog, Travel Safety Hub, helps travelers stay safe.  I am very proud they included a post I made on Mosquitoes and Bite Prevention.

Happy Holidays to everybody and thanks for stopping by!

Oral and Topical Mosquito Repellents

I was recently asked, by a favorite target of mosquitoes, about using oral or pill form mosquito repellents.  Great question!  You can see the question posted here.

A very well written and informative article titled Mosquitoes and Mosquito Repellents: A Clinician’s Guide is a fantastic resource for most information about “all things mosquito repellent”. The short answer to the question of oral mosquito repellents is, simply, no.

DEET(N, N-diethyl-meta-tolumide) is the most studied, effective and advised method of preventing mosquito bites. An oral or transdermal (skin patch) method of mosquito bite prevention has been the “holy grail” of vector borne disease prevention for many years. To date, there is not an effective product.

There have been attempts to show that garlic, bananas and vitamin B can be taken orally and prevent mosquitoes. This is not true. There are numerous and respected studies that have looked at these methods and all have shown that there is no protection from Garlic, Vitamin B or any other ingested methods of bite prevention. The university of Wisconsin conducted a good study that showed vitamin B was ineffective. Several good sites can be found here:

Natural Mosquito Repellents

Mosquito Repellents (general)

There are a few things that are proven to work, in decreasing mosquito bites:

Use DEET as directed and do not exceed 30-35% concentration for adults and 10% for children

Avoid being outside during traditional peak mosquito hours (dusk and dawn)

Long sleeves and pants, with a mesh hat/veil if needed!

Permethrin impregnated clothing and bed nets

An original post on this subject can be found here:
http://adventuredoc.wordpress.com/2007/11/06/mosquito-bite-prevention/

Mosquitoes and Mosquito Bite Prevention: Review

There is a very good article, from 1998 Annals of Internal Medicine called Mosquitoes and Mosquito Repellents: A Clinician’s Guide written by Mark S. Fradin, MD.

This article, while 10 years old, still gives a great deal of information on prevention of mosquito bites and debunks some myths about what does and does not work.

Mosquito Bite Prevention

Mosquito Bite Prevention

700,000,000 people get a disease from a mosquito, each year. Of those diseases, 1 out of 17 people currently alive will die from the disease.

The species to know about are Aedes, Culex and Anopheles. These are the bad girls that carry diseases such as malaria, yellow fever, dengue fever and filariasis. I say “bad girls” because on the female mosquito bites mammals. The growth on new mosquitoes requires a blood meal. The males are content to only feed from flowers. Certain types of mosquitoes prefer animals, some prefer humans and some feed from both.

Attraction:

What attracts mosquitoes is not fully clear, yet. Mosquitoes do have developed senses of vision, thermal/heat sense and smell. They use all of their senses to find food. It is believed that the olfactory (smell) sense is the most important in finding victims.

During the daytime, dark colored clothing and movement help a female mosquito “lock on” to its target, at long range. As the mosquito nears her prey, the senses of smell and thermal sense take over. Carbon Dioxide and Lactic Acid are two of the most studied mosquito attractants. CO2 is mainly found in exhaled breaths and lactic acid can be found on the skin when muscles are being used, as in exercise. Lastly, skin temperature and skin moisture guide the mosquito to where they want to bite, on the body. It is widely assumed that certain species of mosquito prefer different body parts; hands, face, feet, etc. This could be due to the differences in local skin temperatures. Scented soaps, cologne, lotions and hair products can also attract mosquitoes.

As for personal preference, adults are preferred over children. Men are more commonly bitten than women and larger people get bit more than smaller people, possible due to their increased CO2 output. It also appears my wife is preferred over to me.

Chemical Repellents:

DEET (N,N Diethyl 3 Methylbenzamide) is the gold standard of insect repellent. It has been well studied for over 50 years and provides protection not only against mosquitoes but also flies, chiggers, ticks and fleas. The concentrations of DEET available range from 5% to 100% and the higher the concentration of DEET, the longer the time of protection. Concerns over long term exposure to high doses of DEET have led to the US Military to adopt a 35% slow release formula. The medical literature disagrees over a formula that accurately predicts number of hours of protection and DEET percentage. One study indicates a 4 hour protection with 50% DEET while another indicates 12.5% DEET protected for 6 hours. Products with 20-35% DEET generally provide adequate coverage for most instances. There are reports of skin irritation occurring more frequently with percentages greater than 35%. The Pediatricians advise nothing more than 10% DEET for children less than 12 years old. Use of DEET with sun-block lowers the efficacy of the sun-block. So, more frequent applications of sunscreen will be needed for adequate solar protection. The DEET spray is applied to the skin, first. Sunscreen is applied over the top of the DEET spray. I remember this because the DEET protects your blood and stays the closest. Sunscreen protects against the sun, which is further away. DEET is a well studied and commonly used chemical. High dose DEET has been shown to not be a neuro-toxin. There have been several cases of encephalopathy (brain swelling), mostly in children, with prolonged exposure and inappropriate use of DEET. DEET works by inhibiting signals from the mosquitoes’ antennae and making it hard for them to find you.

Avon Skin-So-Soft is known to be a mosquito repellent. Lab studies showed a 30-minute protection time against Aedes mosquitoes. Ideas as to why it is a repellent center around either fragrance of the cream or the chemicals it contains, benzophenone and diisopropyl adipate.

Permethrin is an insecticide that kills or stuns bugs. Permethrin is effective against mosquitoes, ticks, flies, chiggers and fleas. The chemical does not easily absorb into the skin. This is applied to clothing, bed nets or screens, as a spray.

Citronella is known as the “natural” mosquito repellent. Derived from a plant, Cymbopogon Nardus, the oil has a lemon-like scent. Studies have shown that burning citronella candles and/or incense decrease the number of insect bites, for those near to the candles or incense.

Timing is Everything

Most species of mosquitoes bite at dawn and dusk. Avoiding being outside will lessen your chances of bites. When you are sleeping at night, in open air environments, a bed net is definitely shown to decrease bites. Often, those staying in nicer hotel rooms, with climate control, do not need netting. Open windows mean a need for netting.

Learn more about mosquito carried diseases such as Malaria, Dengue Fever and Yellow Fever over at www.AdventureDoc.org

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