January 9, 2025 Author : Saraiva da Cunha Chikungunya is the name of the disease, infection or fever caused by the chikungunya virus . The first case of chikungunya fever occurred on the Makonde Plateau, in Tanzania, in 1952. The name chikungunya originated from a verb in the local dialect that means to be bent or to walk hunched over and is related to the posture adopted by patients resulting from the joint pain caused by the infection. The chikungunya virus is transmitted by mosquitoes of the Aedes genus , mainly those of the Aedes aegypti and Aedes albopictus species. Chikungunya infection is not transmitted directly from person to person. However, mother-to-child transmission during pregnancy and peripartum and following contaminated blood transfusions are documented. Chikungunya, Aedes aegypti and Aedes albopictus Mosquitoes of the genus Aedes are particularly important for public health. The species Aedes aegypti and Aedes albopictus are exotic in Europe, that is, they are from other regions of the planet. However, they are already well established in Europe . They live close to human habitats and their activity is more intense during the day, mainly at dawn and dusk. They are the transmission vectors of several microorganisms that are cause of disease in humans and domestic animals , including chikungunya, dengue, zika, yellow fever, West Nile and Japanese encephalitis viruses. Globalization and climate changes have some role in the spread of the chikungunya virus, because environmental conditions favorable to the development of Aedes mosquitoes are expanding, putting populations at greater risk of infection. Simultaneously, Aedes albopictus adapted to temperatures colder than those of its region of origin. Man is the main reservoir of the chikungunya virus and transmission occurs when female Aedes aegypti and Aedes albopictus bite to feed on the blood they need to complete their life cycle. If they are already infected with the chikungunya virus, they can transmit the infection when they bite; When they feed on people infected with chikungunya, they can become infected and can transmit the disease to other people. Currently the chikungunya virus is present in more than 60 countries, mainly in tropical climate regions, especially in Southwest Asia, Africa and South America, but also in temperate regions, such as Europe or the USA. Aedes albopictus was first identified in European countries in Albania, in 1979. Since 2010 there have been outbreaks of chikungunya associated with this species of mosquito in Europe, which previously preferred to feed on non-human blood. In 2005-2007 there was an epidemic of around 1.25 million cases of chikungunya on islands in the Indian Ocean and in India. In Europe, there were outbreaks in Italy in 2007 and 2017 and cases of infection contracted outside Europe were also diagnosed in Spain, the United Kingdom, Switzerland, Belgium, the Czech Republic, Germany, Norway and France. In France there are records of cases of local infection. In Portugal : The presence of Aedes aegypti has been recorded on the island of Madeira since 2005; In continental Portugal, the Aedes albopictus mosquito was identified in 2017 in the municipality of Penafiel, in 2018 in Loulé, and in 2022 in several municipalities in the Algarve and in Mértola and in 2023 in Lisbon; No cases of chikungunya have been reported yet. The pandemic potential of the chikungunya virus is known and, therefore, the disease is considered a priority for vaccine development. The first chikungunya vaccine was approved in 2023 by the Food and Drug Administration (FDA) in the US. The risk of increasing cases of chikungunya infection in Europe is real, although low, as the necessary conditions are met, particularly in the countries of the Mediterranean basin. In 2024 : As of November 30, 480,000 cases had been reported worldwide in 23 countries (1 in Europe: France), causing more than 200 deaths. The countries with the most cases are Brazil (407,250 cases and 203 deaths) and India (69,544), Argentina, Paraguay and Bolivia. Symptoms and diagnosis of chikungunya After an incubation period of 3-7 days (but which can vary between 1 and 12 days), the most important and characteristic symptoms of acute chikungunya infection are : Sudden onset fever, often high, accompanied by headache, chills, intolerance to light, nausea and vomiting and skin rash; Disabling joint and muscle pain beginning 2-5 days after fever, particularly affecting the most distal joints. The severity of chikungunya infection can range from asymptomatic (in 10%-15% of cases), to a mild and self-limited disease, and even severe neurological manifestations and progression to a chronic form with disabling joint pain, which can last months or years and which happens in 30%-40% of cases. The disease is considered chronic when symptoms persist beyond 3 months. The most serious forms of the disease tend to occur in specific risk groups , such as women in advanced stages of pregnancy, older age groups (over 65 years old) and people with other diseases (comorbidities), for example kidney failure. or cardiac. Around 0.6%-13% of those infected require hospitalization. Fatal cases are rare (0.024-0.8%), but in a significant percentage of infected people the disease can become chronic and seriously impair quality of life. The diagnosis of chikungunya is based on examination of the patient and on symptoms, especially fever and joint pain, especially when associated with origin or recent history of travel to areas where the virus is endemic, although confirmation of the diagnosis can only be done through blood tests. Travelers to endemic areas should be particularly alert to symptoms, even after their return, and communicate their destinations and travel details if they seek health services. Treatment and prevention of chikungunya infection There are no specific antiviral medications against the chikungunya virus. Treatment is symptomatic, that is, aimed at relieving symptoms , especially joint pain. A vaccine against chikungunya was approved by European authorities (European Medicines Agency, EMA) in June 2024 and there are no other medicines intended to prevent chikungunya fever. Prevention is carried out also with measures aimed at controlling the mosquito population and with individual care . It is important in areas where there are Aedes mosquitoes, particularly when traveling to regions where the virus is endemic (mainly Africa, Southwest Asia and India). Avoid going outside during periods when mosquitoes are most active (although Aedes mosquitoes are also active inside buildings). Use protective screens on windows . Use fans and air conditioning which contribute to protection because insects move away from the wind. Cover all areas of body when outside by wearing socks and closed shoes, long sleeves, long pants, and a hat. Apply insect repellents to all exposed skin (except around the eyes and mouth) and also to clothing, always following the product's instructions, especially regarding the age range of people in which they can be used. Eliminate any stagnant water near buildings , including swimming pools, buckets of water, potted plant dishes, among others, as these are the places where female mosquitoes lay their eggs. References Bartholomeeusen K, Daniel M, LaBeaud DA, et al. Chikungunya fever . Nat Rev Dis Primers 2023;9:17. European Centre for Disease Prevention and Control. Chikungunya virus disease . World Health Organization. 2022. Chikungunya . Meet the infectious diseases clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
