The chikungunya virus is transmitted to humans by the bite of the tiger mosquito or the Aedes aegypti mosquito. In which countries? In France ? What symptoms? Duration ? Deadly ? Is there a vaccine?
Chikungunya is a viral disease that is transmitted from person to person through mosquitoes of the Aedes genus in particular (tiger mosquito). The infection causes fever, severe joint pain, headaches, nausea, severe fatigue and skin rashes. Where do you get chikungunya? In France ? In which countries? What is the difference between chikungunya and dengue fever? Can chikungunya be cured? What are the sequelae of chikungunya? Lighting of Professor Anna-Bella Faillouxhead of the “Arboviruses and insect vectors” research and expertise unit at the Institut Pasteur
What is chikungunya?
Chikungunya, also called “chik” or “bent man’s disease”, is a tropical infectious disease belonging to the clinical family of arboviruses (diseases transmitted by an arthropod). She is transmitted by mosquitoes belonging to the genus Aedes which mainly bite during the day. Chikungunya affects humans, but also monkeys and other animals. The name “chikungunya” is derived from a word in the Kimakonde language which means “to deform”, can we read on the WHO website.
What is the virus in question?
The chikungunya virus is an arbovirus (virus transmitted by arthropods) whose vectors are female mosquitoes of the genus Aedes which are identifiable by the presence of black and white stripes on the legs. The two incriminated species are Aedes aegypti and Aedes albopictus. The virus is transmitted through blood (through a bite from an infected mosquito).
What are the symptoms of a chikungunya infection?
At first, the infection looks like a flu syndrome with :
- A severe fever
- Joint pain mainly concerning the small articular belts (wrists, fingers, ankles, feet) but also the knees
- Severe muscle pain
- A rash on the trunk and limbs
- Abdominal pain
- Inflammation of one or more cervical lymph node(s)
At an advanced stage, may occur neurological complications serious, especially in newborns and the elderly. Joint pain and severe fatigue may persist for several months after the initial diagnosis. Bleeding from the gums or nose has also been frequently described, mainly in Asia.
What is the incubation time?
The symptoms of Chikungunya appear after a incubation period of 2 to 12 days on average.
Is chikungunia present in France?
Yes. Aedes albopictus is present in the south of France and Aedes aegypti in the overseas departments (Antilles, Guyana), French Polynesia and New Caledonia. In France, the immense majority of cases are imported epidemic foci. In 2010, the first two indigenous cases of chikungunya were identified in France, in the Var, in people bitten by a locally implanted mosquito (Aedes albopictus). Then in October 2014, 12 other autochthonous cases were observed in Montpellier. “As a result, chikungunya infection was added to the list of notifiable diseases and since January 2006, an enhanced surveillance system has been in place”, emphasizes the specialist. Currently in France, 64 departments bring together all the right conditions the emergence of chikungunya: the presence of the vector mosquito in the region, favorable temperature and humidity for egg hatching, many travelers returning from countries where the chikungunya virus circulates.
Where is it present in the world?
The first epidemic due to the chikungunya virus was described on the African continent, Tanzania in 1952. Chikungunya virus infection has since continued to evolve in an endemo-epidemic mode. Chikungunya has raged in the islands of the Indian Ocean (Reunion, Mayotte, Grandes Comoros, Madagascar, Maldives, Mauritius, Seychelles) and in Asia (India, Pakistan, Sri Lanka, Malaysia, Indonesia, Laos, Cambodia, China…) and in the West Indies (Martinique, Guadeloupe, French Guiana). Chikungunya epidemics have also been observed in the past or recently in various countries in North Africa (Egypt), East Africa (Tanzania, Benin, Burundi, Kenya, Sudan, Uganda), West Africa (Nigeria, Senegal), Central (Central African Republic, Congo, Equatorial Guinea, Gabon) as well as in South Africa, Malawi and Zimbabwe. The disease has also hit New Caledonia. Chikungunya does not spare Europe. Cases occurred in northeastern Italy in 2007.
How long does the disease last?
Symptoms usually last a few days, but can persist for weeks, months, or even years. Anyone who has been infected once naturally acquires a lasting immunity (several years). On the other hand, some joint pain (arthralgia) may persist or reappear over varying periods of time. This is a joint reaction independent of reinfection with the virus.
Is it deadly? What are the risks of sequelae?
Severe or fatal cases of chikungunya are very rareand are almost always associated with the existence of other pathologies. “The spontaneous evolution of the disease is most often favorable, but it can progress to a chronic form, with prolonged fatigue for several months and/or the persistence of joint pain (in 20% of cases) for months or years. sometimes very troublesome years in everyday life, observes Professor Failloux.
Involvement of other organs is possible:
- type neurological damage Guillain-Barré syndrome (damage to the peripheral nerves responsible for paralysis, muscle weakness or sensory disturbances with, for example, tingling in the arms and legs). A few cases of meningoencephalitis were observed during the Reunion epidemic.
- Eye damage: conjunctivitis recovering spontaneously, loss of vision.
- THE kidney complicationsliver or heart are exceptional.
It would seem that the pain associated with CHIKV essentially focuses on organs or areas already previously weakened by a pathology, trauma, a previous intervention.
The Chikungunya virus can be detected directly in blood samples taken from the patient during the first week of illness by nucleic acid amplification tests like RT-PCR (reverse transcription and polymerase chain reaction). Other tests can detect a person’s immune response to chikungunya virus infection, which are instead used after the first week of infection to check for the presence of antibodies against the virus. Antibody levels are usually detectable within the first week after illness onset and can still be detected for about 2 months.
What is the treatment for chikungunya?
Treatment is primarily symptomatic and aims to relieve fever and pain with the prescription of antipyretics, appropriate analgesics (paracetamol or acetaminophen), a good fluid intake and rest for the patient. There is no specific antiviral medication for chikungunya infection.
Is there a chikungunya vaccine?
There is currently no licensed vaccine or specific treatment for chikungunya virus infections. Several vaccines are under development. To protect oneself, in addition to the means of physical protection (wearing long clothing covering the arms and legs up to the ankles, mosquito nets in the habitat, etc.), it is strongly recommended to use a repellent product while respecting the precautions of job.
What is the difference between chikungunya and dengue fever?
Dengue fever and Zika virus disease have similar symptoms to chikungunya, which can easily lead to misdiagnosis. The two chikungunya mosquitoes are also implicated in the transmission of other arboviruses, including dengue fever, yellow fever and Zika virus.
What are the risks during pregnancy?
In the case of a pregnant woman who is infected with the virus, the contamination of the baby occurs directly during childbirth in one out of two cases. It generates neurological and/or cardiac disorders in half of infants. It is recommended that pregnant women who travel to regions affected by chikungunya protect themselves by all available means against mosquito bites, especially during the last trimester of pregnancy.
– Chikungunya, World Health Organization, December 8, 2022
– Chikungunya, Pasteur Institute and Pasteur Institute of Lille
– Chikungunya file, Public Health France
Thanks to Professor Anna-Bella Failloux, head of the “Arboviruses and Insect Vectors” research and expertise unit at the Institut Pasteur.