Trip Preparation Update - Insect Precautions

Howdy all. This will be a mixed post today. The first part will cover a quick update to all the things I previously had in flight preparing for my trip, and the second part will be a summary of the intensive research I’ve done on insect and mosquito repellents and other precautions. Several folks on the RY Facebook groups have been asking questions about what to do for mosquitos while in South America, and I have also fielded some direct questions from folks about the Permethrin-embedded clothing that I bought. In addition, I’ve now agreed to join a hike of the Inca Trail to Machu Picchu while we’re in Peru, which means I need to step up my research game and be definitively sure of my choices before I leave. But first, the update.

Since this post is pretty long, I’m providing a simple table of contents to help you get around.

Table of Contents
  • Trip Preparation Update
  • Insect Precautions
    • A Word on Mosquito-Borne Illnesses
    • Types of Repellents
      • Permethrin
      • DEET
      • Picaridin
      • Oil of Eucalyptus(PMD)
      • IR3535®
    • More Recommended Reading
    • My Disclaimer and Conclusions

The Update

Global Entry

I’ve completed my interview, been fingerprinted, photographed, and received my Global Entry card in the mail. After much deliberation, I’ve decided to forgo getting a Form 4457 for each of my gear items, because I already have receipts for each I’m taking with me, as well as my insurance schedule that has descriptions and serial numbers. Since I have Global Entry, there should be no need to interact with the Custom’s folks if I have nothing to declare on entry into the US. Since I don’t need to declare items I left the US with, it should all be a non-issue hopefully.

Meeting Some Early RY Folks and Spreading Advice

I had the pleasure of meeting up with Martin Smith and some other Rackers while he was here in San Antonio for some Rackspace-related meetings. It was great to find out that some other Rackers were going to be participating in RY soon and to get to hear some stories. I also got some great useful advice, which I’ve shared with the RY - Darien Facebook group, and I’ll summarize in bullets below.

  • The radiators in most buildings have been around longer than you have, lock your stuff to them with a chain when you leave your room.
  • Take way less stuff than you think you need, because a lot of travel is on busses which have different baggage rules than airplanes.
  • Remember anything you bring you /will/ be lugging around.
  • Bring your own high-quality sunscreen to South America. It’s essential and very expensive locally.
  • Take insect precautions seriously
  • Watch out for the food/water contamination, a lot of RY folks got sick in Bolivia

The last point segues well into my next section…

Vaccines and Prevention of Infectious Diseases

I need to get my second booster (1 month interval) of Hepatitis B vaccine, but I’m currently at the tail end of a bout of Bronchitis which started while I was in Michigan. Unfortunately, I can’t take the vaccine while under treatment or while ill, either one. So I have to wait it out and get it before I leave.

Regarding general prevention of infectious diseases I am going to write a much longer and more detailed blog post summarizing my research, much in the same vein as this one. To summarize the summary though, I’ve invested in a few different forms of water filtration and purification which are easily portable, will be taking precautions for water and food safety, and am going to request to be prescribed several effective dosing cycles of antibiotics for my trip to be taken at my own discretion if I get TD (traveler’s diarrhea). Currently, it seems most likely I’ll have to be prescribed Cipro or a derivative fluoroquinolone because unfortunately I’m allergic to Zithromax (azythromycin) which is the only other quick-acting antibiotic effective against TD and despite the fact that fluroquinolones are increasingly finding resistances especially among E. Coli, the number one cause of TD.

Insurance and Will/Estate Planning

I’ve paid the bills for all the insurance on this trip and should be good to go here. I met with an attorney to draft a will, create an estate trust, and a charitable trust before I leave. It’s currently in the works and should be completed before I depart so that the vast majority of my assets go to charities I’ve predefined if for some reason I don’t make it back out the other side alive :)

Insect Precautions

A Word on Mosquito-Borne Illnesses

I wasn’t sure whether to put this under the Vaccines update section or not. I want to clarify for my readers that I’ve chosen to not get the Malaria vaccine, for a few reasons. Chief among those reasons is that the Malaria vaccine is less a vaccine and more a prophylaxis, which must be taken before, during, and after any potential exposure activities for quite some time, it’s very expensive, and has potentially disastrous and permanent life-altering side effects. The reasoning for this is that Malaria isn’t a virus, it’s actually a parasite, so if you stop taking the prophylaxis you become vulnerable again. Meanwhile, Malaria isn’t the only issue and perhaps even the least of your worries when it comes to mosquito-borne illnesses.

In Summary, the following diseases (and more) can be acquired from mosquitos:

  • Malaria
    • Occurs anywhere mosquitos live, including in South Texas where I live
    • Deadliest disease in history
    • Treatable and preventable via prophylaxis
  • Zika
    • Is in South America and spreading
    • Currently developing world-wide health crisis, which started in Brazil and has now reached Texas and Florida
    • No known cure
    • No known vaccine
    • After exposure, can be sexually transmitted and you may be a carrier for life
    • Causes micro-encephalits in infants born of women exposed to Zika with high mortality rates
  • Chikungunya
    • Is in Asia, Africa, and now spread to some parts of South America
    • No known cure
    • No known vaccine
    • Requires IMMEDIATE medical treatment or death will occur
    • After exposure, negative effects can be permanent
  • Dengue
    • Is in Asia and South America
    • No known cure
    • No known vaccine
    • Requires IMMEDIATE medical treatment or death will occur
    • After exposure, negative effects can be permanent
  • West Nile Virus
    • Occurs anywhere mosquitos live, including in all US states.
    • No known cure
    • No known vaccine
    • Only 1/5 people who contract it will have symptoms
    • Most people have mild symptoms, but some die or have severe permanent life-altering consequences
  • Yellow Fever
  • Multiple Types of Encephalitis
    • All are found under various conditions worldwide, including in the US
    • No known cure
    • No known vaccine
    • Requires IMMEDIATE medical treatment or death will occur
    • After exposure, negative effects can be permanent

These are just the ones I could Google lots of information on quickly that are common mosquito-borne illnesses. There’s numerous others, many of which don’t occur in South America or the US, so won’t be things I’ll be exposed to on this trip (Africa has some scary mosquitos). The key thing to note is most of these are viruses, meaning there’s no effective cure or treatment, almost none of them have a vaccine, and most of them cause death without IMMEDIATE medical treatment and are definitely life-threatening and/or life-altering. Which is why I arrived at the conclusion I should get my Yellow Fever vaccine and otherwise invest my time, energy, and money into preventing exposure to mosquito-borne illnesses. This is the major motivator for the research and conclusions that follow.

Types of Repellents


The Basics

Permethrin is an organic neurotoxin derived from the Chrysanthemum plant. It has low skin absorption after drying and is moisure resistant, this makes it long-acting and safe for use on humans and many other mammals, however it is highly toxic to cats and fish. It is on the World Health Organization’s List of Essential Medicines as being one of the most important medicines needed for a basic health system. It is commonly used as an insect repellent, insecticide, and to treat scabies, lice, and fleas in humans.

The Good
  • Highly effective against all manner of biting insects, including mosquitos, biting flies, ticks, chiggers, and fleas.
  • Recommended by the CDC for travel in tropical climates
  • Used by the US Military in the new ACU combat uniform (as well as by other militaries)
  • Extremely safe for humans compared to alternatives
  • Doesn’t just repel insects, it kills them
The Bad
  • Needs to be pre-applied to clothing or embedded in clothing
  • Applications are only effective for 20-30 days and minimal washing, or for longer + washings when embedded
  • Only effective on contact, will not prevent insects from landing on you, but will prevent them from biting and may kill on contact
  • Can only protect areas of your body which are covered
  • Application process is somewhat complex and an inappropriate application can be ineffective or dangerous
More Information


The Basics

N,N-Diethyl-meta-toluamide, more commonly known as DEET, is a synthetic compound developed in 1944 by the USDA and the US Army for military use as an insect repellent during jungle warfare in response to experiences the US military had in World War II. It’s been in military use since 1946 and civilian use since 1957, and was deployed widely by the US military during Korea and Vietnam. It’s considered effective, however is toxic, and is an active solvent so has some definite downsides. More on that in a moment.

The Good
  • High effectiveness against mosquitos
  • Is inexpensive and widely available
  • Can be applied in multiple different forms and is available as aerosol and non-aerosol sprays, liquids, lotions, creams, and wipes
  • Can be embedded in polymers to delay release and mixed into creams to extent effective duration at lower concentrations
The Bad
  • DEET is toxic to humans, however actual direct effects seem to be limited to about 1 out of every 100 million individuals exposed
  • Negative side effects can be seizures, cancer, or death
  • Toxicity is directly related to concentration, unfortunately so is effectiveness and longevity
  • DEET is a solvent and will dissolve many fabrics used in clothing such as spandex, rayon, and other plastic-based synthetic fabrics
More Information


The Basics

Hydroxyethyl isobutyl piperidine carboxylate, more commonly known as Picaridin and officially given the INN by the World Health Organization of Icaridin, is an organic chemical pesticide originally creater by Bayer in Germany as Bayrepel, but is now off patent and widely available. This is a newer pesticide, but is exciting because it has similar effectiveness at similar concentrations to DEET without the whole melting plastics thing.

The Good
  • High effectiveness against mosquitos
  • Also is effective against many types of biting insects other than mosquitos, including some types of biting flies that are unaffected by DEET.
  • Doesn’t melt plastics
  • While studies are still being done, appears to be low in toxicity to humans
The Bad
  • Not as widely available as DEET
  • Effectiveness against some specific types of mosquitos falls off on quicker timelines than DEET.
  • Difficult to find in high concentrations, and it is generally understood to require a minimum concentration of 20% to be effective
  • Can mix with sweat and get in your eyes causing intense irritation/stinging due to the piperidine
More Information

Oil of Lemon Eucalyptus (PMD)

The Basics

Oil of Lemon Eucalyptus, also known as OLE, is the essential oil from the tree Corymbia citriodora, known commonly as lemon-scented gum eucalyptus. This essential oil contains para-menthane-3,8-diol also known as PMD, which the active ingredient in the essential oil for repelling insects. Raw OLE contains very small quantities of PMD, so it must be refined before being used in insect repellents. Typical OLE used has 64% concentration of PMD after refinement. OLE is the ONLY effective active ingredient for repelling insects which naturally occurs and is legal to use in the US and Europe, as well as being recommended by the CDC for preventing mosquito bites.

The Good
  • Moderate effectiveness against mosquitos
  • Is produced by extracting the oil from naturally occurring botanicals
  • Has extremely low toxicity
  • Very inexpensive (about half the cost of other options for a 4oz spray pump)
The Bad
  • Very new, so research is still out on its effectiveness compared to DEET and other synthetic options
  • There’s only a handful of reputable vendors you can acquire it from
  • It’s hard to find good information about the substance
  • Is only effective in very high concentrations
  • Needs to be re-applied more often than DEET
More Information


The Basics

Insect Repellent 3535, or IR3535, is a registered trademark of Merck and is a patented synthetic biopesticide product rather than a chemical in and of itself. It is based on the biochemical beta-alanine, and has similar properties. It’s relatively new which is why its still covered by the patent, however it has been accepted by the CDC and WHO as being an effective pesticide for repelling mosquitos.

The Good
  • Moderate to high effectiveness against mosquitos
  • Requires relatively low concentrations to be effective (10-20%)
  • In theory may be more effective when mixed with sunscreen, but the jury is still out
The Bad
  • Hard to find, especially in effective concentrations
  • Hard to find good information about it
  • Needs to be re-applied more often than DEET
More Information

My Decision(s) and Conclusions


I am not a doctor. I am not a chemist. I am not an entomologist. In fact, I know effectively nothing about the topic at hand other than what I’ve learned by reading about it on the Internet, mostly through links I’ve provided above. I have performed some minimal testing of my own here in South Texas (which is very much not South America), but I don’t consider it conclusive or scientific in any way. I evaluated the information to the best of my abilities and I am going to present my findings as my personal opinion, not as a statement of fact, and you are free to follow or ignore this advice as your own prerogative.


I intentionally didn’t bother listing any of the research I did into “alternative” options because the body of evidence available shows them to be ineffective. If you’re reading this and you got this far, do yourself the favor and don’t risk your health on something random you heard of the Internet or you found at your local health-food store. If you are determined to use something naturally sourced and don’t mind some loss of effectiveness, use Oil of Lemon Eucalyptus (PMD), as its the best option on that front.

Briefly here’s a not even remotely exhaustive list of things I found people recommending online that have been proven to be ineffective and functionally useless:

  • Vitamin B1 patches
  • Sulfur tablets
  • Eating Garlic
  • Eating Bananas
  • Oil of Citronella
  • Lemongrass Oil
  • Cedar Oil
  • Peppermint Oil
  • Skin Moisturizer (e.g. Avon Skin So Soft)
  • Strong perfume
  • Not Showering (eww gross)

Down to Brass Tacks

There is really no good reason to not be wearing as much permethrin treated clothing as you can while in areas at high risk for mosquito-borne diseases. This is my planned first line of defense, and in my opinion should be something every person who travels to a high-risk area considers. If the skin is covered and the clothing is treated, the risk of a mosquito bite to that area of skin is extremely low.

Basic Precautions to Take:

  • Minimize exposure times to high-risk areas
  • Avoid standing water, swamps, and similar
  • Avoid going outside from dusk to dawn as this is when most species of mosquitos are most active (the exception is the Dengue-carriers are day biters)
  • Wear long-sleeved shirts, full-length pants, long socks, and boots when outside the city
  • Leave a fan turned on in the room where you sleep
  • Use air-conditioning when possible
  • Consider getting mosquito netting (permethrin treated if possible) to sleep inside of or to cover your head while sleeping
  • Ensure doors and windows are closed or screened and seal any cracks with duct tape
  • Try to keep your body temperature down and try not to sweat (a big ask I know)

In the end, here’s my plan:

That was a LOT of text to convey what ended up being a rather short conclusion, but hopefully this helps somebody else out in the process too and I certainly learned a lot this weekend reading through all of this information.

If you find any errors that need correcting or have any suggestions for additions/changes to this post, please let me know via email. Till next time, thanks for reading!