The infection may present with some or all of the following symptoms: sudden onset of high-grade fever, chills, headache, redness of eyes, muscle and joint pain, and rash. The rash usually occurs after the onset of fever and typically involves the trunk and extremities, but can also include the palms, soles of the feet, and the face.
Often fever occurs in two phases of up to one week duration, with an interval of one to two fever-free days in between. The second phase may present with much more intense muscle and joint pain, which can be severe and debilitating. These symptoms are typically bilateral and symmetric and mainly involve hands and feet, but may also involve the larger joints, such as the knees or shoulders.
About 5-10% of infected people continue to experience severe joint pain even after the fever has subsided, in some cases lasting up to several months or, albeit rare, even years.
Dengue fever is the most common insect-borne infectious disease worldwide. There are 4 known serotypes of dengue virus, so it is possible to be infected with dengue more than once. Approximately 1 in 4 infected individuals develop symptoms of dengue, resulting in high fever, muscle and joint pain, and skin rash. In rare cases, most often after a second infection, life-threatening bleeding and shock (severe drop of blood pressure) may occur.
In 3 out of 4 cases, an infection with the virus remains asymptomatic. After a short incubation period (5-8 days), 1 out of 4 infected people present an abrupt onset of fever, headache, joint, limb and muscle pain, as well as nausea and vomiting. Eye movement pain is also typical. A rash usually appears on the 3rd or 4th day of illness. After 4 to 7 days, the fever finally subsides but fatigue may persist for several days or weeks.
In rare cases, severe dengue can occur. Particularly susceptible are local children and seniors as well as people who have experienced a prior dengue infection. Tourists extremely rarely present with severe dengue. In the first days, the disease resembles the course of classic dengue fever, but on the 4th/5th day, and usually after the fever has subsided, the condition worsens. Blood pressure drops, and patients complain of shortness of breath, abdominal discomfort, nosebleeds, and mild skin or mucosal hemorrhages. In the most severe cases, life-threatening shock may occur.
There is no specific treatment for dengue virus infection. Treatment is limited to mitigation and monitoring of symptoms: fever reduction, relief of eye, back, muscle and joint pain, and monitoring of blood clotting and blood volume. Patients with severe symptoms must be hospitalised.
For treatment of fever or pain, paracetamol or acetaminophen are recommended (e.g. Acetalgin® Dafalgan®). Drugs containing the active ingredient acetylsalicylic acid (e.g. Aspirin®, Alcacyl®, Aspégic®) must be avoided.
Effective mosquito protection during the day and especially during twilight hours (i.e. sunset) is the best preventive measure:
No vaccination against dengue virus is currently available for travellers.
Hepatitis A occurs all over the world, but the risk of infection is higher in countries with poor hygiene standards. There is an increased risk in most tropical and subtropical countries, as well as in some countries in Eastern Europe and around the Mediterranean.
In recent years, there have also been increasing cases in North America and Europe, including Switzerland, especially among men who have sex with men (MSM). Outbreaks in northern European countries can also occur when unvaccinated children become infected during family visits to tropical and subtropical countries. Upon return, they may transmit the virus within their care facilities.
There is a safe and very effective vaccine that consists of two injections at least 6 months apart. It provides lifelong protection after the second dose. Hepatitis A vaccination can also be given in combination with hepatitis B vaccination (3 doses required).
Vaccination against hepatitis A is recommended for all travellers to risk areas, as well as for persons at increased personal risk: persons with chronic liver disease, men who have sex with men, people who use or inject drug, persons with increased occupational contact with persons from high-risk areas or populations, and others.
Fever during or after a stay in a malaria-endemic area is an emergency! Prompt diagnosis and treatment are required as the health of people with malaria can deteriorate very quickly. That means: if you have fever >37.5° (use a thermometer!) you need to test for malaria within a maximum time-frame of 24 hours, regardless of whether or not you have used prophylactic medication (malaria chemoprophylaxis). Try to reach a doctor or hospital where you can reliably receive such a test. If the first test is negative, it should be repeated on the following day if the fever persists.
Prevention of malaria requires a combination of approaches:
For travellers, there is currently no malaria vaccination available.
Vaccination is recommended for stays in the meningitis belt:
Meningococcal vaccination is recommended in Switzerland as a complementary vaccination for children between 2 – 4 years and for adolescents between 11 – 15 years. Furthermore, it is recommended as a risk group vaccination for persons with certain medical conditions, for persons with close contact to a patient with meningococcal disease and for travelers to endemic areas.
For more detailed information on the disease and Swiss national recommendations (in German, French, Italian) see: https://www.bag.admin.ch/bag/de/home/krankheiten/krankheiten-im-ueberblick/meningokokken-erkrankungen.html
Regular hand washing after using the bathroom and before eating or preparing food. Avoidance of undercooked or raw food that is potentially contaminated with fecal material.
The most important prevention is vaccination. A very effective and well-tolerated vaccine against polio is available (inactivated (killed) polio vaccine (IPV)), which is part of the basic vaccination schedule during childhood. Combination vaccines (e.g. with diphtheria and tetanus) are also available. After basic vaccination, a booster dose is recommended every 10 years for travel to certain countries (see country page recommendations). WHO recommends a yearly vaccination for residents or long-stay visitors (minimum 4 weeks) in a country with ongoing polio infections or circulating vaccine-derived polio viruses. This recommendation not only targets individual protection, but aims to prevent the international spread of the virus.
No reliable treatment of rabies disease exists!
Stroking cute pets is not a good idea; refrain from touching wild or unfamiliar or dead animals.
All travellers to places where rabies may occur and who are likely to take repeated trips to areas where rabies occurs should have a pre-exposure vaccination. In addition, pre-exposure vaccination is highly recommended for travellers at particular risk:
The shortened vaccination schedule can be proposed to most travellers: 2 shots, the first one at one month before departure if possible (minimum: 8 days before departure). A single third rabies booster vaccination is recommended before the next trip, at least after one year.
There is a risk of arthropod-borne diseases other than malaria, dengue, chikungunya or zika in sub-/tropical regions, and some areas of Southern Europe. These include the following diseases [and their vectors]:
“Cook it, boil it, peel it or forget it” – this simple slogan would be sufficient to prevent typhoid fever nearly entirely. However, only few travelers fully adhere to this advice. Nevertheless, the value of food and water hygiene cannot be stressed enough: avoid buying water bottles without proper sealing, avoid drinking tap water from unknown sources, avoid eating cooled / frozen foods (i.e. ice cubes in water or ice cream) and avoid eating raw fruits and vegetables that you yourself have not peeled and washed with clean drinking water.
Two types of vaccines are available:
As against all mosquito-borne diseases, prevention from mosquito bites is during day and night (see “Insect and tick bite protection” factsheet). The available vaccine is highly efficacious and provides a long-term protection. It is recommended for people aged 9 months or older who are travelling to yellow fever endemic areas. In addition, providing proof of vaccination may be mandatory for entry into certain countries.
The vaccine is a live-attenuated form of the virus. In immunocompetent persons, protection starts about 10 days after the first vaccination. Reactions to yellow fever vaccine are generally mild and include headache, muscle aches, and low-grade fevers. Side effects can be treated with paracetamol but aspirin and other nonsteroidal anti-inflammatory drugs, for example ibuprofen or naproxen, should be avoided. On extremely rare occasions, people may develop severe, sometimes life-threatening reactions to the yellow fever vaccine – which is why this vaccine is used with caution in immunocompromised individuals, pregnant women and the elderly for safety reasons. Talk to your travel health advisor if you belong to this group.
The Zika virus was identified in 1947 in monkeys from the Zika forest in Uganda. Virus circulation has long been limited (a few cases each year) in Africa and South-East Asia. In May 2015, the American continent was affected for the first time, with an epidemic in Brazil that rapidly spread to South America, Central America, and the Caribbean. Since then, the disease has been reported in most tropical and subtropical regions.
The risk of infection is currently low in most regions and does not require specific measures. However, epidemics may occasionally reappear. During epidemics, the risk of transmission is high, and specific recommendations for the traveller are necessary.
In case of fever, it is recommended to consult a doctor. The symptoms of a Zika virus infection may seem similar to those of malaria, for which urgent treatment is necessary, or dengue fever. Treatment for Zika aims for reduction of fever and joint pain (paracetamol). Avoid aspirin and anti-inflammatory drugs (e.g. ibuprofen) as long as dengue fever is not excluded. There is no vaccine available.
In case of pregnancy and fever during or upon return from a Zika virus transmission area, blood and/or urine tests are indicated. In case of confirmed infection, the medical management should be discussed with the gynecologist and infectious/travel medicine specialists.
The risk of infection can be reduced by effective protection from mosquito bites during the day and in the early evening (long clothing, mosquito repellents, mosquito net).
When travelling in an area of increased risk (= declared epidemic) and in order to prevent possible sexual transmission of the virus, it is recommended to use a condom / Femidom during the trip and at least 2 months after return.
Due to the risk of fetal malformation, pregnant women are advised against travelling to areas at increased risk (= declared as epidemic) of Zika transmission at any time during pregnancy (in case of essential travel, a consultation with a travel medicine specialist is advised before departure). Women who wish to become pregnant should wait at least 2 months after their return (or that of their partner) from an area at increased risk of Zika transmission.