Dengue and Mosquitoes in Bali

Dengue is the mosquito-borne illness a visitor to Bali should plan for, and there is no pill or routine vaccine for an American traveler to take against it. Protection is repellent, clothing and where you sleep. The CDC reports no malaria transmission in the resort areas of Bali, in Ubud, or in the Gili Islands, so on a normal Bali trip the mosquito question is about dengue and Zika.

What dengue is

Dengue is a viral illness spread to people mainly through the bite of an infected Aedes mosquito. The CDC lists dengue among the diseases a traveler to Indonesia can get from a mosquito bite, and its advice against it is the same two words it gives for every such disease: avoid bug bites.

These mosquitoes bite in the daytime too

The CDC states that the mosquitoes that spread dengue bite during the day and at night. That is the detail that changes behavior. Repellent put on only at dusk leaves the whole day uncovered, including breakfast on a terrace and an afternoon in a garden cafe.

No vaccine for most travelers

The CDC says no dengue vaccine is currently available in the United States. An American preparing for Bali cannot add dengue to the list of travel shots. The CDC also notes that many of the diseases spread by bugs in Indonesia cannot be prevented with a vaccine or medicine, which is why bite prevention carries the whole load.

How to prevent mosquito bites in Bali

Preventing mosquito bites in Bali comes down to the steps the CDC lists for Indonesia. Cover exposed skin with long-sleeved shirts and long pants, use an appropriate insect repellent, and stay and sleep in air-conditioned or screened rooms. Where the place you sleep is open to the outdoors, the CDC says to use a bed net.

Which repellent

The CDC names the active ingredients that work against mosquitoes: DEET, picaridin, oil of lemon eucalyptus or PMD, IR3535 and 2-undecanone. Higher percentages of the active ingredient give longer protection, and the CDC notes that a repellent with 20% or more DEET lasts up to several hours. Always use repellent as directed on the label.

Clothing

The CDC also recommends clothing and gear treated with permethrin, and it warns never to put permethrin directly on skin. Loose, long, light clothing is comfortable in Bali's heat in the evening and does part of the job on its own. Ankles and feet under a dinner table are worth a second layer of repellent.

Where you sleep

Many Bali villas and bungalows have open-air living rooms and bathrooms, which is part of their appeal. The CDC's advice points the other way: air-conditioned or screened rooms, or a bed net when the sleeping area is exposed. When you book, our advice is to check that the bedroom itself can be closed and cooled, or that the bed has a net.

Symptoms of dengue

Dengue's most common symptom is a fever, together with aches and pains. The CDC describes eye pain, typically behind the eyes, along with muscle, joint or bone pain, and lists nausea, vomiting, rash and headache as further symptoms. The illness typically lasts 2 to 7 days, and most people recover in about a week.

The warning signs

Severe dengue is a medical emergency. The CDC lists the warning signs: belly pain or tenderness, vomiting at least three times in 24 hours, bleeding from the nose or gums, vomiting blood or blood in the stool, and feeling extremely tired or restless. Anyone with one of these signs should go to a clinic or emergency room immediately.

The danger comes after the fever

The CDC says the warning signs usually begin in the 24 to 48 hours after the fever has gone away. Feeling better is therefore the wrong moment to stop paying attention. Someone who has had a fever in Bali should be watched for two days after it breaks.

What to do if you get a fever in Bali

A fever in Bali is a reason to see a doctor, because a blood test is the only way to confirm dengue. The State Department says routine medical care is available in Indonesia's major cities, and that hospitals and doctors often require payment or a sizable deposit before service. Take your passport, your insurance details and a payment card.

Getting there

The State Department notes that ambulance services in Indonesia are not widely available and can take 45 minutes or longer to arrive, and that travelers may prefer a taxi or private vehicle to the hospital. In an emergency the numbers are 112 for the unified emergency line, 110 for police, 119 for an ambulance and 113 for fire.

After you fly home

The CDC advises travelers returning from an area with dengue to keep preventing mosquito bites for three weeks, even without symptoms, so the virus is not passed to mosquitoes at home. If you fall ill after the trip, tell your doctor where you traveled.

Zika in Bali

Zika is spread by mosquito bites as well, and the CDC currently has a Level 2 travel health notice for Zika in Bali, based on cases in travelers returning from the island. The notice tells all travelers to Bali to prevent mosquito bites and sexual transmission of the virus during and after travel.

Pregnancy

The CDC notes that a pregnant woman infected with Zika can pass it to her unborn baby. Anyone who is pregnant, or who may become pregnant around the time of the trip, should read the current CDC notice and talk to a doctor before booking. Health notices change, so check the date on the one you read.

What a mosquito kit looks like

Our own packing suggestion follows from the CDC's list: a repellent with one of the named active ingredients, bought at home so you know what is in it; one long-sleeved shirt and one pair of long trousers per person; and a thermometer. Apply repellent after sunscreen, and reapply after swimming.