Joint Pain in Travelers: Comprehensive Guide on Chikungunya Risk and Mosquito Prevention - The Dual Threat Carried by Mosquitoes and Midges

The UK's public health authorities have issued a red alert for "invisible risks" in line with the summer travel season. The UKHSA (UK Health Security Agency) announced that travel-related chikungunya cases reached 73 in the first half of 2025, a significant increase from 27 cases in the same period last year. Travelers are urged to "use repellents, wear clothing that reduces skin exposure, and utilize mosquito nets or insect screens." While the number of imported cases is rising, the risk of sustained transmission within the UK remains low. However, early medical consultation is advised for those experiencing fever or severe joint pain after returning home. GOV.UK

A breakdown of the statistics shows that many reports were linked to travel history to Sri Lanka, India, and Mauritius. These figures indicate that the risk of mosquito-borne infections remains significant for travelers, against the backdrop of resurgent travel and localized outbreaks. Furthermore, the UKHSA report states, "The first three imported cases of Oropouche fever in the UK have been confirmed, all related to travel to Brazil." GOV.UK

What about the concern of "secondary infections" within the UK? The UKHSA explains that the two mosquito species that transmit chikungunya (Aedes aegypti and Aedes albopictus) are not established in the UK, so the risk of sustained onward transmission domestically is currently low. Therefore, the key points are "not getting bitten abroad" and "noticing any changes in health after returning home." The Independent

Oropouche fever, newly confirmed in the UK, is a viral infection mainly transmitted by biting midges (Culicoides) and some mosquitoes. Symptoms resemble influenza, including fever, headache, joint pain, muscle pain, chills, and nausea. In severe cases, it can progress to meningitis or encephalitis. While the Amazon basin has been the primary endemic area, autochthonous cases were reported in seven Latin American countries in 2024, and traveler cases have been identified in Western countries in recent years. There is no vaccine or specific treatment, making prevention crucial. World Health Organization

Vaccines: Two for chikungunya, none for Oropouche

There is some good news. For chikungunya, the number of approved vaccines in the UK has increased to two. Valneva's live vaccine "IXCHIQ" was approved for adults in February 2025, and Bavarian Nordic's VLP vaccine "Vimkunya" was approved for those aged 12 and over in May. The decision to vaccinate and its suitability depend on age, constitution, and underlying conditions, so consult a specialized travel clinic before traveling. GOV.UK

However, there are points to note. For IXCHIQ, the UK regulatory authorities have imposed temporary use restrictions (license restrictions) due to safety concerns in the elderly (generally 65 and over). Policies may be updated following reviews, so check the latest public information and medical guidance. Reuters

The positioning, target age, and immunogenicity data of both vaccines are summarized by the UK's JCVI (Joint Committee on Vaccination and Immunisation), and risk-stratified use is proposed for travelers. Particularly for those in an immunosuppressed state, the live vaccine (IXCHIQ) may be unsuitable, making the VLP vaccine (Vimkunya) a viable alternative. GOV.UK

Symptoms and "What Comes After"—Be Aware of Prolonged Joint Pain

Chikungunya fever is characterized by sudden high fever and severe joint pain, rash, photosensitivity, and headache. While most recover within two weeks, joint pain can persist for months in some cases. Fatal outcomes are rare in younger populations, but infants, the elderly, and those with underlying conditions are at higher risk of severe illness. Oropouche fever is generally mild to moderate "flu-like," but can occasionally lead to central nervous system complications, making it important to consider in febrile patients with a travel history. The IndependentWorld Health Organization

Reasons for the Increase: The "Multiplication" of Travel and Environment

While the resumption of international travel brings imported cases into communities, sporadic outbreaks continue to occur in tropical and subtropical regions. Climate changes and extreme rainfall and high temperatures affect the distribution and breeding of vectors (mosquitoes and midges), increasing exposure opportunities for travelers. This backdrop is directly linked to the increase in travel-related reports in the UK and the "first confirmation" of Oropouche. paho.org

Reactions on Social Media (Summary)

The following points have been prominent on social media regarding this issue (summarized without specifying individual posts).

• "Should I get vaccinated against chikungunya before traveling? I don't know which vaccine suits me."

• "Is it safe for the elderly?"—Voices reconsidering family vaccination plans following reports of IXCHIQ usage restrictions.

• "DEET or Icaridin for repellents? Which products work locally?"—Choosing repellents and reapplication frequency are popular topics.

• "I developed a fever after returning home. When should I see a doctor?"—Posts sharing the importance of declaring "travel history."

• "Is climate change causing mosquitoes to migrate north?"—Discussions on the relationship between outbreaks and the environment.

Traveler's Self-Checklist

• Before Departure: Check the outbreak status of your destination (health authorities, foreign ministry, travel clinics). Consult a doctor about the suitability of chikungunya vaccines if necessary. Be especially cautious if you have underlying conditions or are potentially pregnant. GOV.UK

• On-Site: Use repellents containing DEET or Icaridin appropriately. Wear clothing that reduces skin exposure, use air conditioning or screens, and utilize insecticide-treated mosquito nets. Avoid creating standing water. GOV.UK

• After Returning: Monitor your health for about three weeks. If you develop a fever, severe joint pain, rash, or headache, be sure to report your travel history (country, city, date) when seeking medical attention. Since there is no specific treatment for Oropouche fever, early diagnosis and supportive care are crucial. World Health Organization

Q&A: Chikungunya vs. Oropouche

• Vaccines: Chikungunya = Available (IXCHIQ, Vimkunya / suitability varies by age and constitution). Oropouche = None. GOV.UK+1

• Main Vectors: Chikungunya = Aedes aegypti, etc. Oropouche = Mainly biting midges + some mosquitoes. World Health Organization

• Risk in the UK: Currently, the risk of sustained mosquito-borne transmission is low (the vector mosquitoes are not established). However, imported cases may continue. The Independent

• Typical Symptoms: Chikungunya = High fever + severe joint pain, rash, etc. Oropouche = Flu-like, occasionally meningitis or encephalitis. The IndependentWorld Health Organization

• Vaccination for the Elderly: Temporary usage restriction on IXCHIQ. Make decisions based on the latest information. Reuters

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