I’ve been doing a lot of research on future trips that focus on outdoor adventures. Part of that research is knowing what to expect as far as potential risks and hazards in the places that we go, and that includes the wildlife.

To be honest, the only wildlife I find scary are the pesky little bugs that can carry really terrifying diseases. Unlike large animals that we can see and evade with a modicum of effort, insects of varying types seek us out with maniacal intensity. And even if they don’t transmit diseases, the hoards of flying insects can make any beautiful spot intolerable.

These photos may not show it but in each of these scenes we were trying to have fun while being feasted upon by mosquitoes or biting flies. In every case we quickly abandoned our location to avoid additional misery. I remember once being at Effigy Mounds in Iowa and never getting more than a few seconds to look at each of the mounds before having to run madly for the safety of the car because of the dense swarms of mosquitos.

With that in mind I decided it was time to discuss the nasty little nasties that can take the fun out of any outdoor occasion.

Mosquitoes

For most people, mosquitoes are the number one source of aggravation outdoors. Mosquitoes are going to be present everywhere there is sufficient water and where the temperatures are warm enough for their survival.

We’ve encountered voracious swarms in all of the obvious places: temperate woodlands, by mountain lakes and rivers, in swamps and bayous, and in the rainforests. Mosquitoes tend to be seasonal in most locations north of the tropics, but even in the tropics their numbers rise during the ‘rainy’ seasons and become more manageable in the ‘dry’ seasons.

For the most part, mosquitoes are just an annoyance and their bites are typically pretty mild. North of the tropics mosquitoes don’t tend to transmit any serious diseases. In places like Alaska, mosquitoes can be quite large and their bites can become more aggravating, but by applying mosquito repellant (DEET is the best in my experience) it’s pretty easy to keep them largely at bay.

When you apply mosquito repellant it helps to reapply every couple hours and don’t neglect places like your scalp. Mosquitoes have evolved alongside furry mammals and do not have any difficulty biting beneath your hair. Also they are far and away the most active at sunrise and particularly at sunset. If you venture out at these hours try to cover more of your skin (pants and long sleeve shirts).

In the tropics and Middle East the dangers brought by mosquitoes become much more serious, and most of the attention is on malaria. Many countries which once had endemic malaria have made significant strides in controlling it, but it is still present and a risk in vast swaths of the more remote regions of the world.

Places like Costa Rica and Peru are practically malaria-free, while in Bolivia the disease is still a present danger. Yellow fever, dengue, chikungunya, West Nile virus, zika, etc are also spread by mosquitos and usually in the same areas that remain higher risk for malaria. All are spread primarily by the Aedes Aegypti species.

Fortunately, the danger presented by any of these illnesses is not particularly great for most healthy people. There is a widely available yellow fever vaccine that confers 100% immunity. Chikungunya, West Nile fever, and dengue will present as asymptomatic or with a mild illness for most people (fevers and malaise that passes over the course of a few days). Severe illness is pretty rare but with proper medical care most can expect to recover without longterm effects.

There are effective antimalarials available as well, including antibiotic quinalones and doxycycline. If you are traveling into a region where malaria is known to exist, taking a prophylactic anti-malarial would be wise. Even then, most people that contract malaria will recover with a mild illness.

Biting Flies

Starting with the simple nuisance: black flies. Many times when we’ve been trying to enjoy the outdoors black flies have pestered us and eventually forced us inside after trying to ignore and tolerate them as long as possible. What’s worse: they simply do not care about repellant. Or at least I’ve never seen any personal evidence that they are actually repelled by mosquito repellent.

Fortunately black fly bites rarely itch and though often painful at the moment the longterm effects are negligible. While they are indeed annoying as heck (the sound of the buzzing alone will make you crazy) they are mostly harmless.

Sand Flies

While black flies are annoying, sand flies are much more a concern if you travel into warmer climates. Sand flies are about 1/3 the size of mosquitos and tend to congregate near the ground in rainforests, beaches, and around lakes and streams.

Phlebotomine sand flies tend to swarm and bite quickly and painlessly. Unlike a mosquito that sits on the skin and injects its proboscis into the skin, sand flies make shallow bites at the skin surface. They leave a salivary residue at the site of the bite that causes intense itching that can last for weeks.

The itchy, painful bites are bad enough, but it is a very serious tropical disease that is the much greater concern: leishmaniasis.

I first learned about leishmaniasis from the book “The Lost City of the Monkey God“, by Douglas Preston. It’s a terrific book that I highly recommend to anyone interested in archaeology and the rainforests of Central America. It’s a true story about a group of archaeologists accompanied by the writer Douglas Preston who travel to Honduras to begin excavating a lost city that was discovered by lidar (which can penetrate the rainforest canopy and map the topography of the rainforest floor).

After returning home, Douglas Preston and a large number of the research team had developed cutaneous leishmaniasis from sand fly bites. Unfortunately the drug regimen necessary to cure cutaneous leishmaniasis is long and difficult with many possible and serious side-effects. Even after recovery scars are likely to be left behind.

And if leishmaniasis is not cured it can lead to mucosal leishmaniasis which is horribly disfiguring with people’s faces literally being eaten away from the nose. The Spanish explorers in the 1500s even wrote about the disease and the effect it had on the local population.

On top of all of that, doctors in the US rarely even know what it is and only certain facilities can even test for it. And because of that difficultly getting treated early can be a challenge.

Fortunately, it can be mostly prevented with precautions. Sand flies cannot bite through clothing (at least most clothing) so wearing long pants, long sleeves, thick socks, and shoes helps. Spray all exposed skin (and clothing too) with heavy DEET repellant. Sleep under fine mesh mosquito nets (remember they are only 1/3 the size of mosquitos so it requires a finer mesh). And don’t wander the beach or rainforest at dawn or dusk when they are most active. Also, they can’t fly far so you are actually safer in the middle of a lake than on shore.

Sand flies and leishmaniasis aren’t prevalent everywhere. The tropics of South and Central America, the Middle East, South Asia, and to a lesser extent the Mediterranean coast are the primary locations where it is reported to exist. Certain species of sand fly also don’t typically spread the disease. The most dangerous varieties are found in the Amazon Basin of Brazil, Peru, Colombia, Ecuador and in pockets of remote Central America. If you are going to these regions at least be aware of the presence of the disease so you can take necessary precautions.

I want to go to Peru but I might leave off the Amazon basin or change how I travel there. I’m still investigating this to decide whether I want to take that small chance of such a serious disease.

On another note, the disease is spreading even into the southern United States (a few cases happened recently in Texas that are known to have been to people that never traveled outside the US). With the disease spreading into areas it never before existed it is possible new treatments and even a vaccine may be developed.

Ticks

Another vector of serious diseases are ticks. Ticks are found in woodlands all across the world and in more northerly climates. They tend to latch on relatively easily and once attached can transmit a number of diseases.

Most people have learned abut Lime Disease and unfortunately it is a pretty harsh illness that takes many months and even years to recover from. A lot of people, myself included, like to wear shorts while hiking but anytime you will be in dense forests you should opt for hiking pants. Many people also get bitten by ticks while horseback riding and for the reason you should always look over the horse on both sides before climbing onto the saddle and wear long pants (jeans are the best option).

There are many diseases spread by ticks and rather than list them out I’ll simply link to the CDC website: https://www.cdc.gov/ticks/diseases/index.html

Avoiding ticks can be hard enough for humans, but don’t forget to check your pets if you live in areas that border woodlands. They can easily hide in a dense fur coat and unfortunately a tick may have been attached for days or weeks before it is discovered by its owner.

It’s also a matter of debate as to whether ticks are repelled by the same DEET and permethrin repellants used for mosquitos. But certainly there is no harm in applying the repellant, at least for mosquitos and flies. Your best protection is clothing and surveying your pants and skin after traversing through foliage.

In most cases a tick bite will be nothing but a reminder that the wild is a wild. But if you do begin to feel ill (fevers, malaise, etc) in the days after a tick bite, and especially if you see redness near the bite it is best to seek medical attention.

Spiders

So, sand flies and ticks are worrisome. But what about spiders? Well, finally some good news. Outside of a couple species you have very little to worry about.

Living in Colorado, my sons and I get bitten by spiders almost yearly. In most cases we just have a red mark with two little holes where the fangs penetrated the skin. Other than a possible secondary infection, the bites are nothing more than a little irritating.

There are only two varieties that are of any concern in the US and much of the world and they are the widow spiders and the brown recluse. Both spiders tend to hide out in dark places and avoid people and attention. Always shine a flashlight into crevices in garages and sheds before putting your hand into these places to retrieve something. Chances are good that a spider might have made it’s home in these recesses.

Even if you were to be bitten by these two poisonous spider varieties, you are not likely to suffer any serious effects. Necrosis of the skin at the site is rare, and (gasp) death is very, very rare for most healthy people. Certainly you should seek medical attention regardless.

There is one variety that you ought to worry about if you travel to Amazonia, however: the Brazilian Wandering Spider (this spider is also known as the Banana Spider).

The Wandering Spider injects a very potent venom and unlike the widows and recluse spiders, it is aggressive. The odds of a bite are not particularly high even when trekking through the rainforest, but always check bedding in lodges (beds are actually a common place for bites), check shoes before wearing, wear long pants, and be careful about grabbing onto branches and vines without first checking your potential handhold.