Wikivoyage articles have a Stay Healthy section with location-specific advice. This article contains general information relevant to many destinations.
Those who sleep with dogs will rise with fleas.International proverb

Travellers may encounter animal pests that they are not familiar with in their home regions. Pests can spoil food, cause irritation, or in a worse case cause allergic reactions, spread venom, or transmit infections. Infectious diseases themselves, or dangerous animals that can injure or kill people by force, do not usually qualify as pests. There is a separate article on poisonous plants.


Long mandibles and big eyes of a bull ant

The common black ants are a problem mainly because they get into food. However, there are types of ants that can make for an uncomfortable or even dangerous encounter. The three types of stinging ants are:

Ant stings can really hurt, and accidentally walking on a fire ant nest can give a person - especially a toddler - an experience they won't soon forget. Though painful, bites will usually clear up within a couple of days if left alone. For cases where there are multiple bites, hydrocortizone or aloe vera is sometimes applied topically, or antihistamines may be taken orally. A few unfortunate people are allergic, and for such people stings may lead to anaphylactic shock, which can be lethal.

#Permethrin-treated_fabrics kill ants, as well as other insects, that crawl on them.


These tiny nuisances tend to nest under beds or in other furniture, coming out at night to feed on the blood of unsuspecting victims who typically do not feel bites at the time. Infestation can be found almost anywhere in the world - they are most common in less developed areas but are becoming an increasingly common problem in the developed world as well. Bites are typically nothing serious and may be hardly noticeable, but can sometimes provoke rashes, allergic reactions, or other skin irritations. If you are travelling cheap and happen to detect a faint odor of rotten raspberries in your hotel room, or if you find small, mysterious red bites on your skin in the morning, you might consider changing your choice of accommodations. Sleep tight!

You do not want to take these home with you. Avoid unpacking into places where the bugs may be dwelling and wash your spare clothes before the bugs have a chance to hide away.

Bees, hornets and wasps

Spider wasp common to India
Asian Giant Hornet

Hornets and wasps sting more readily than bees because stinging is fatal for bees and not the other two types of insects. Wasp stings can be very painful, but unless you are allergic to the stings of any of these insects or are stung by an entire hive, there is usually very little chance of serious complications. However, varieties such as the 'Asian Giant Hornet' (found in Japan, Korea and China) can be extremely dangerous, even to people without an allergy. People who are allergic to bee stings need to exercise great caution, because one sting can be fatal for them. Yellowjackets, though similar to bees in appearance, are actually a type of wasp. They probably won't sting you for no reason, but if you are eating or drinking outside and a swarm of yellowjackets decides they want what you're having, you're best off letting them have it.


Cockroaches are common carriers of disease and you surely do not want to handle them or allow them to get into your food. Quite a few people are allergic to cockroaches, and this allergy is a major cause of asthma in places with large roach infestations, like poor areas of American cities. In some parts of the world, such as Thailand, large roaches called waterbugs are considered a delicacy and are for sale in markets for human consumption.


Tsetse flies fold their wings on top of each other when resting.

It pays to check on what kind of flies are present where you are visiting. House flies can spread infection and are a common contaminator of food. In some countries exposed waste makes flies particularly dangerous by what they can spread.

Some types of flies bite but, unlike female mosquitoes, have many sources of food other than blood, so they may leave you alone and are mostly just a nuisance. However, horseflies have a particularly annoying bite, and there are parts of the world where black flies are a horrible scourge. Even worse, certain types of flies are very dangerous, like the tsetse flies that spread sleeping sickness, which kills tens of thousands of people or more every year in East Africa. In Australia, non-biting flies can swarm and simply make it difficult to do anything without whisking them away from the face, leading to various nets and hat attachments as essential clothing.

#Permethrin-treated_fabrics kill flies, as well as other insects, that crawl on them.

Tiny biting flies (aka midges) are not unknown in remoter parts of the Scottish Highlands, Northern Europe, Scandanavia and Russia.


Main article: Jellyfish

Jellyfish are found the world over in many shapes and sizes. Some are harmless but many are venomous and will sting you. A few species are incredibly dangerous and in some cases can kill a human.


Mites are similar to ticks and tend to be much smaller. They can be hard to see with the naked eye and be very uncomfortable if you are covered by some. See a doctor if you are affected.

#Permethrin-treated_fabrics kill mites as well as other arthropods.


The Aedes or Asian tiger mosquito that spreads dengue, Zika virus and Yellow fever has a recognizable stance and appearance.
Prevalence of the Aedes aegypti mosquito
Mosquito net on a tent frame

Mosquitoes exist around the world, especially in wetlands. In parts of the tropics, mosquitoes carry malaria, dengue fever, Zika virus, or yellow fever. Other diseases, including West Nile virus, can be spread by mosquitoes in some temperate latitudes.

Prevention is better than cure: cover arms and legs as much as possible, and use repellents. Use insect screens or insect nets where you sleep. For areas where mosquitoes are known to carry diseases you should check in advance whether preventive medication is recommended. There are vaccines for Yellow fever and dengue fever, but not for other mosquito-borne diseases. The vaccine against Yellow Fever has been around for decades now whereas the vaccine against Dengue is still in the process of getting approved in most countries as of 2016.

There are several drugs which will prevent malaria, but which one to use varies by region. Some of these drugs may be unsuitable for pregnant women or for patients who react badly to a particular drug. In areas with lower malaria risks taking preventive medicine can actually do more harm than good. Always talk to your doctor – or better yet, a specialist for tropical medicine – before traveling to any malaria endemic region.

In areas where mosquitoes are a problem, typical precautions include:

#Permethrin-treated_fabrics are a good defense against mosquitoes as well as other insects.

Sleeping in rooms that are either air-conditioned (so that you can close the windows and doors), or have insect screens over the windows, will help prevent mosquitoes from entering the room. Be sure to check the screens for defects before relying on them. Having a fan switched on can help, as the moving air makes it more difficult for mosquitoes to land.

Repellents are available in various forms, including lotions and aerosols that can be applied to the skin, and others that can be applied to clothing. There are also devices that generate repelling scent, such as mosquito coils and citronella candles.

A mosquito coil

Mosquito coils, usually permethrin-based, provide effective protection for up to 8 hours in spaces up to 30 cubic meters (a small room). They usually come with little stands: bend the center part upwards, slot the middle of the coil on the pointy bit, heat the other end with a flame until it catches fire, then blow it out and let the end smoulder. The main danger with these is the risk of fire: place the coil on a ceramic plate or other fireproof platform and extinguish it before going out or going to sleep. The smell will also stick to your clothes and other belongings for a while, although it usually fades pretty fast. For indoor use, there are also plug-in electrical devices that dispense an insecticide and/or a repellent into the air.

Most electronic bug zappers are not effective against mosquitoes since mosquitoes are not attracted to light. There are some models which emit carbon dioxide or octenol (found in the breath of mammals) so they do attract mosquitoes.

A major method of controlling mosquito population is to eliminate standing water where they breed. They do not need much; even a bit of water around the base of a flower pot is enough. In some countries there are substantial fines for anyone found to have standing water on their property; this is one reason that Singapore is now low-risk for both dengue and malaria.

When camping, it may be wise to avoid setting up near areas with stagnant or standing water. When camping or sleeping indoors without screens, use a mosquito net that has been treated with permethrin. As mosquitoes are very persistent insects that will keep trying to find a way to reach you, make sure the net is securely tucked under your bed or sleeping mat.


Rats, mice and other rodents are as prolific as humans; rats have colonized the world during the last centuries as stowaways on ships. They cause trouble by eating human food, as well as chewing through clothing and other equipment. Rodent-proofing a building can be difficult.

Rats can enter buildings through a toilet. Make sure the trap is filled with water, and close the lid. Dumping food (even rotten food) through the toilet attracts rats and should therefore be avoided.

Rats can also carry other pests such as fleas, many of which carry diseases as well. A good example is the plague, also known as "black death", which wiped out more than half of Europe's population in the 14th century. It was caused by the spread of lice that may or may not have come from rats.


Snakes are covered in our article on Dangerous animals#Snakes.


There are many spiders, especially in the tropics, with poisonous bites that can be fatal. Many spiders, such as the Huntsman, can give you a strong bite but are not venomous. The two most dangerous spider species in the world are endemic to Australia, although fatalities are very rare.


A tick in the grass
Tick compared to head of match

Ticks are small, eight-leg arachnids (sharing ancestry with spiders and mites) that prey on large animals, such as humans. They are among the most common visible parasites in temperate areas such as Europe and North America. However you may encounter ticks in the tropical regions as well, for instance in the Amazon rainforest. In Australia kangaroo ticks are very common and require checking for in areas frequented by kangaroos.

Ticks can be a nuisance in outdoor life, especially when hiking and travelling with pets, and in some parts of the world, certain kinds of ticks can carry nasty diseases, including Lyme disease (borreliosis), TBE (tick-borne meningoencephalitis), RMSF (Rocky Mountain Spotted Fever), and CCHF (Crimean-Congo hemorrhagic fever). Young ticks, nymphs, are barely visible to the naked eye; when fed with blood, they can become as big as a pin head.

TBE is a serious disease which requires hospitalization and can be fatal. There is no specific treatment against TBE and it reduces to a symptomatic therapy. There is vaccination available, relevant if staying a longer time in the riskiest environments.

Borreliosis can often be noticed by a red ring forming on the skin, a week or so after the bite. In the beginning, when symptoms are mild and temporary, it is easily treated with antibiotics. Untreated borreliosis can give serious neurological symptoms later. Treatment at this stage is difficult and rehabilitation not guaranteed.

RMSF is a bacterial infection and responds well to treatment with antibiotics. Usually the first symptoms are a high fever and splitting headache, often followed a few days later by a rash that starts around the wrists and ankles. If you are in North America, have been exposed to ticks, and have any of those symptoms, see a doctor immediately; the disease is not very dangerous with proper treatment but can be fatal if not treated promptly.

CCHF leads to severe infection in humans with a mortality rate of 10-40% within a week. Despite its name, it is prevalent in much of the Old World and it requires immediate hospitalization — effective treatment against it exists but preventative vaccines are in an experimental stage.

How to prevent tick bites

#Permethrin-treated_fabrics provide a partial defense against ticks, but not a complete defense since ticks may land on exposed skin or crawl around without making enough contact with clothing for the poison to get them.

How to remove a tick

Care must be taken when removing ticks to prevent the mouth parts from breaking off under the skin and to avoid squeezing the tick, as that would increase the risk of infection. You can buy special fine-tipped tick tweezers from the pharmacy, which can be used to remove a tick safely if you happen to get bitten. You should remove the tick from your skin without unnecessary delay (leaving it over the night will drastically augment the risks) and preferably with the tick tweezers to reduce the infection risk. After removal, wash the bite with alcohol, iodine, or soap and water.

If you experience symptoms relating to the bite, you should go visit a doctor as soon as possible. Similarly, if you develop a rash or fever within weeks, seek prompt medical attention and remember to tell about the tick.


If you see a scorpion, watch out. At best, their sting is very painful. At worst, in some parts of the world, a scorpion strike can be fatal. In general, scorpions are more interested in smaller creatures they can eat than they are in you, but they do need to be respected. If you are travelling in an area where scorpions are endemic, take special care not to leave your luggage open overnight, and check inside your shoes before putting them on, in case a scorpion has decided to make its home there.

Permethrin-treated fabrics

Permethrin is an insecticide used to treat fabrics. Permethrin-treated equipment is widely used by professional travellers military, Peace Corps, NGO workers, ... and is something any traveller wanting protection against arthropods either insects (6-legged) such as mosquitoes and lice or 8-legged species such as ticks, mites and spiders should consider.

Permethrin-treated fabric kills all types of arthropods, but it does not repel them, so it is often used along with an insect repellent. The usual pattern is to apply permethrin to clothing and other gear and use a repellent on any exposed skin.

Permethrin is not suitable for application to the skin (it is used in anti-lice shampoo, but that is soon rinsed out) and does not work well on hard surfaces. Fabrics are often impregnated by soaking in a permethrin solution, but aerosol sprays are also available and some mosquito nets are treated at the factory.

For most clothing, a single application will last several washes. Treated clothing should be washed separately from other clothing; hand washing and air drying are recommended. For things that are not washed often tents, mosquito nets, backpacks, jackets, etc. the effect lasts for about six weeks if the item is exposed to sun and rain, otherwise longer.

Permethrin is toxic to fish and the liquid form (though not the treated clothing) is dangerous for cats, so some caution is needed.

See also

This article is issued from Wikivoyage - version of the Thursday, March 17, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.