Chikungunya, Zika and Yellow Fever: How They Differ, Who Is at Risk and How to Protect Yourself

Why mosquito-borne diseases matter for travellers

City trips to Rio, island hopping in Thailand or business travel to West Africa – long-haul journeys have become part of everyday life. At the same time, mosquito-borne viruses such as chikungunya, Zika and yellow fever are spreading in many tropical and subtropical regions. For general information about fever after travel, see our Fever After Travel guide.

For travellers from Europe, the UK, the US or Australia these infections are still relatively rare, but they can cause severe illness and, in the case of yellow fever and Zika in pregnancy, even life-threatening complications. This guide explains the key differences between the three diseases, outlines who is most at risk and summarises evidence-based prevention strategies according to WHO, CDC and other leading health authorities. For information on Dengue fever and Malaria, see our separate guides.

Overview: chikungunya, Zika and yellow fever

All three infections are transmitted mainly by day-biting Aedes mosquitoes. However, they differ in their typical symptoms, severity and the options available for vaccination and prevention.

Chikungunya – intense joint pain after a mosquito bite

Chikungunya is caused by a virus transmitted mainly by Aedes aegypti and Aedes albopictus mosquitoes. The illness typically starts abruptly with high fever and very painful joints, often in the hands and feet. Headache, muscle pain, swollen joints and rash are also common. The incubation period is usually 4–8 days.

Most people recover fully, but joint pain can persist for weeks, months or even years and significantly affect quality of life. Deaths are rare but can occur in older adults and people with serious underlying conditions.

There is no specific antiviral treatment. Management is supportive, focusing on adequate fluid intake and pain relief, usually with paracetamol. Non-steroidal anti-inflammatory drugs (NSAIDs) are often avoided in the early phase until dengue has been ruled out because of the risk of bleeding.

A chikungunya vaccine has recently become available and is recommended for certain high-risk travellers to areas with ongoing outbreaks. Talk to a travel medicine clinic to assess whether vaccination is appropriate for your itinerary.

Zika – mild in most adults, dangerous in pregnancy

Zika virus is also spread by Aedes mosquitoes and can additionally be transmitted through sexual contact. Around 80% of infections cause no symptoms at all. When symptoms occur, they are usually mild and include low-grade fever, rash, joint and muscle pain and red eyes.

The major concern is infection during pregnancy. Zika can cross the placenta and damage the developing foetus, leading to microcephaly (abnormally small head size) and other severe brain and eye defects. The virus has also been linked to Guillain-Barré syndrome in adults.

Currently, there is no licensed vaccine and no specific antiviral treatment for Zika. Prevention relies entirely on mosquito bite protection and safer sex practices. Many health authorities advise pregnant women and those planning a pregnancy to avoid non-essential travel to areas with active Zika transmission.

Yellow fever – preventable with a single shot

Yellow fever is a viral haemorrhagic disease endemic in parts of Africa and South America. It is transmitted by Aedes aegypti in urban settings and by other mosquito species in jungle areas. After an incubation period of 3–6 days, patients develop fever, chills, headache, muscle and back pain, nausea and loss of appetite.

Many patients recover after this initial phase. However, about 15% progress to a toxic phase with jaundice (yellowing of the skin and eyes), abdominal pain, bleeding and multi-organ failure. In this phase, the case-fatality rate can be very high.

There is no specific antiviral therapy. Treatment is supportive and often requires intensive care. The most important preventive measure is vaccination: a single dose of a WHO-approved yellow fever vaccine usually provides life-long protection.

Who is at highest risk?

The overall risk depends on the destination, season, length of stay and type of activities. The following groups deserve particular attention:

• Pregnant women and those planning a pregnancy (especially for Zika)
• Infants and young children
• Older adults
• People with chronic illnesses such as heart, lung or liver disease
• Travellers staying for several weeks or months in endemic areas
• Backpackers and adventure travellers with basic accommodation and outdoor activities
• Travellers with limited access to high-quality medical care

How to protect yourself from mosquito bites

Effective mosquito protection is the cornerstone of preventing chikungunya, Zika and yellow fever – whether or not a vaccine is available.

Repellents

Choose an EPA-registered repellent with proven active ingredients such as DEET, picaridin (icaridin), IR3535 or oil of lemon eucalyptus (PMD). Consider the following tips:

• Use products with adequate concentration (for example 20–30% DEET for high-risk exposure).
• Reapply as directed, especially after swimming, sweating or towel-drying.
• Apply sunscreen first, repellent second.
• Follow age-specific recommendations for children and seek advice for use in pregnancy.

Clothing, nets and environment

In addition to repellents, simple behavioural measures help to cut down the number of bites:

• Wear long-sleeved shirts and long trousers made from tightly woven, light-coloured fabric.
• Use bed nets, ideally insecticide-treated, in rooms without air conditioning or intact screens.
• Keep windows and doors closed or screened; use air conditioning where available.
• Eliminate standing water around your accommodation (buckets, plant saucers, open tanks).
• Choose accommodation with good mosquito control measures.

Vaccination: yellow fever and chikungunya

Discuss your itinerary with a travel medicine specialist well before departure:

• Yellow fever: a single dose of vaccine usually provides life-long protection. It is recommended for, and sometimes required by, countries with yellow fever risk.
• Chikungunya: a vaccine is available in some regions and may be recommended for travellers at increased risk during outbreaks or long stays in endemic areas.
• Zika: there is currently no licensed vaccine – meticulous mosquito protection and pregnancy planning remain essential.

What to do if you feel unwell during or after travel

Seek medical care promptly if you develop symptoms such as fever, severe joint or muscle pain, rash or jaundice during travel or within a few weeks after return. Always mention your recent travel history.

• Avoid self-medicating with aspirin or other NSAIDs until dengue and other haemorrhagic fevers have been excluded.
• Drink plenty of fluids and rest.
• Pregnant travellers or those who may be pregnant should seek urgent advice after potential Zika exposure, even if they feel well.

Frequently asked questions

Do I need yellow fever vaccination for every trip to the tropics?

No. Yellow fever vaccination is recommended only for travel to specific high-risk areas in Africa and South America and may be required for entry into certain countries.

Can I be tested for chikungunya, Zika or yellow fever?

Yes. Specialised laboratories can detect the viruses by PCR or antibody testing. The usefulness of testing depends on the timing of your illness and exposure.

When should I schedule a travel clinic appointment?

Ideally 4–6 weeks before departure, so that all recommended vaccines can be administered in time.

References

• World Health Organization (WHO) fact sheets on chikungunya, Zika virus and yellow fever (latest updates 2025).
• CDC Yellow Book and travel health advisories on mosquito-borne diseases.
• Recent peer-reviewed research on the global overlap of dengue, chikungunya, Zika and yellow fever.
• National public health guidance from European, UK, US and Australian authorities (2024–2025).