Chikungunya and Zika: Mosquito-Borne Illness Prevention for UK Travellers

While many UK travellers are familiar with malaria, other mosquito-borne viruses like Chikungunya and Zika are increasingly common in tropical and subtropical regions. Both are transmitted by the Aedes mosquito, which is distinct because it primarily bites during daylight hours, particularly at dawn and dusk.

Chikungunya is characterised by the sudden onset of fever and debilitating joint pain. The name translates to 'that which bends up,' referring to the stooped posture of sufferers. Zika virus often causes milder symptoms, such as a rash or low-grade fever, but it gained international attention due to its link to microcephaly in newborns and Guillain-Barré syndrome. Understanding these risks is essential for anyone planning a trip to Southeast Asia, Africa, or Central and South America.

Most people infected with these viruses will develop symptoms within 3 to 12 days of being bitten. While they share similarities with the flu, there are specific markers to look out for:

• Chikungunya: Intense joint pain (often in the hands and feet), high fever, muscle pain, and headache. The joint pain can sometimes persist for months after the initial infection.
• Zika: A flat, red rash covered with small bumps, fever, joint pain, and conjunctivitis (red eyes). Many people with Zika may have no symptoms at all.

According to NICE guidelines, diagnosis is usually confirmed through blood or urine tests once you return to the UK. Treatment is supportive, focusing on hydration and paracetamol to manage fever and pain; aspirin and ibuprofen should be avoided until dengue fever is ruled out, as they can increase bleeding risks.

As there are no specific antiviral treatments or widely available vaccines for Chikungunya and Zika for the general public, bite prevention is your only line of defence. The NHS recommends a multi-layered approach to 'bite avoidance'.

Effective Repellents

Ensure your repellent contains at least 50% DEET. If you are sensitive to DEET, Icaridin (Picaridin) or Lemon Eucalyptus oil (PMD) are suitable alternatives. These must be reapplied frequently, especially after swimming or heavy sweating.

Protective Clothing

Covering up is vital. Wear loose-fitting, long-sleeved shirts and long trousers. Aedes mosquitoes can bite through tight leggings. For added protection, treat your clothes with permethrin, an insecticide that kills mosquitoes on contact. However, nunca apply permethrin directly to your skin.

Environment Control

Stay in accommodation with air conditioning and intact insect screens on windows. If you are sleeping in a high-risk area without these facilities, use a mosquito net treated with insecticide.

The UK Health Security Agency (UKHSA) provides strict guidance regarding Zika virus and pregnancy. If you are pregnant or planning to conceive, you are advised to avoid non-essential travel to areas with a high risk of Zika transmission. The virus can be passed from a mother to her foetus, potentially causing serious birth defects.

Furthermore, Zika can be sexually transmitted. The NHS recommends that men returning from Zika-affected areas use condoms for three months, while women should wait at least two months before trying to conceive, even if they did not experience any symptoms during their trip.

Preparing for a trip can be overwhelming, particularly when navigating the differing risks of tropical diseases. Using a UK online doctor service allows you to discuss your itinerary from the comfort of your home. A GP can review your medical history and provide tailored advice on:

• Which specific mosquito-borne risks are prevalent in your destination.
• Managing pre-existing conditions while dealing with potential tropical illnesses.
• Appropriate medications for your travel kit, such as high-strength analgesics for joint pain.
• Documentation for carrying medications through customs (sick notes or GP letters).

By speaking to a GP online before you fly, you ensure that your travel health kit is evidence-based and aligned with current NICE clinical knowledge summaries.

If you return to the UK and develop a fever, joint pain, or a rash within a few weeks of your trip, it is important to seek medical advice. You should inform the healthcare provider exactly where you have travelled. While Chikungunya and Zika are rarely fatal, they can mimic other serious conditions like malaria or meningitis which require urgent intervention.

An online consultation is an excellent first step for non-emergency symptoms to determine if you need specialised blood tests at a local hospital or a referral to a tropical medicine specialist.