Chikungunya, how to counter tiger mosquitoes with aromatherapy?

What is chikungunya?

In Swahili, “chik” means “to walk hunched over”, illustrating the posture adopted by people suffering from Chikungunya. After an incubation period of two to ten days, a high fever appears, accompanied bysevere muscle and jointpains, particularly in the joints (wrists, ankles, phalanges, etc.). Headaches and skin rashes may also appear, and sometimes bleeding from the gums or nose. Chikungunya disease progresses in a few days, with the fever and skin symptoms disappearing, but the joint pain may last for several weeks.

What is this disease?

Chikungunya is a viral infection transmitted by Aedes mosquitoes, particularly the tiger mosquito, characterised by fever and acute joint pain. Other symptoms include myalgias, headaches, nausea, fatigue and skin rashes. Joint pain, which is particularly disabling, may persist. Diagnostic confusion with dengue fever is possible in regions where the latter is endemic. Treatment is mainly symptomatic, as there is no specific therapy for this disease.

After an incubation period of 2 to 10 days, the infection manifests itself as disabling joint pain, headaches, fever, muscle pain, skin rashes, inflamed lymph nodes and sometimes conjunctivitis. Some patients, mainly in Asia, have reported bleeding from the gums or nose. Serious cases, such as meningoencephalitis, have mainly affected the elderly and immunocompromised, and newborn babies infected in utero.

Prevention is based on personal protection against mosquito bites and limiting their reproduction. Although there is no specific treatment or vaccine, symptom management remains essential.

Mode of transmission

Prevention, diagnosis and treatment

The Regional Health Agencies (ARS), in collaboration with the departmental councils and local authorities, are conducting information and communication campaigns to prevent and manage chikungunya. From 1 May to 30 November, they are stepping up surveillance of human cases in departments where the Aedes albopictus mosquito is present. Travellers returning from endemic areas with symptoms should report them to the ARS for biological confirmation. Suspected cases are advised to protect themselves from mosquito bites and to stay at home to avoid transmission.

Medical management is limited to symptomatic treatment, including analgesics and anti-inflammatories, without preventing chronic forms of the disease. Prevention is based on individual and collective mosquito control. Individuals should limit their exposure to bites by wearing long clothing, using skin repellents and insecticides on clothing and mosquito nets. Collective measures include spraying insecticides and eliminating breeding sites.

The virus can be detected by RT-PCR tests in blood samples during the first week of the disease, and serological tests for antibodies can be used after this period. There is currently no licensed vaccine against the virus.

The best protection is to avoid mosquito bites. Suspect patients should avoid being bitten during the first week of the illness to avoid transmitting the virus. Mosquito control involves reducing breeding sites and using insecticides. During outbreaks, it is advisable to wear covering clothing, use insecticide-impregnated mosquito nets and repellents based on DEET, IR3535 or icaridine. Travellers in high-risk areas should adopt the same precautions and check that their accommodation is equipped with mosquito nets.

What is the epidemiology of chikungunya?

The epidemiology of chikungunya, a disease transmitted by Aedes mosquitoes, has evolved since it was first identified in Tanzania in 1952. The disease, characterised by fever and joint pain, has spread across Africa, Asia and, more recently, Europe and America. This article examines the changes in its geographical distribution, the mechanisms of transmission, and the factors influencing the proliferation of vectors, which are essential to the development of prevention and control strategies.

Worldwide

In 2005, Réunion was hit by a chikungunya epidemic, marking the start of an international spread. In 2007, Europe, particularly Italy, recorded its first cases, linked to tourist travel. Currently, 18 French departments are under increased surveillance for the presence of the tiger mosquito, the vector of this disease. Although native cases in France are rare, particular attention is being paid to immunocompromised and elderly people.

First identified in Tanzania in 1952, chikungunya has long circulated in Africa and Asia, particularly in India, where there have been around 2 million cases since 2006. In 2007, an epidemic hit Italy, and in 2010 and 2014, native cases were reported in France. New Caledonia in 2011, the West Indies in 2013 and French Polynesia in 2014 were also affected.

In Europe, the authorities are actively monitoring the risk of Aedes albopictus spreading chikungunya. Since 2006, they have set up surveillance systems and compulsory reporting of cases.

In Africa, the virus is maintained in a forest cycle involving primates and sylvatic mosquitoes. In Asia, it is mainly urban, involving Aedes aegypti and Aedes albopictus. Epidemics are frequent in these regions, particularly in India.

In the Indian Ocean, the 2005 epidemic in the Comoros spread to Réunion and Madagascar, with a significant impact on the population.

In the Americas, the epidemic began in 2013 in the West Indies, spreading rapidly across the continent. French Guiana had already recorded cases in 2006. Chikungunya, which has become more frequent and widespread since 2004, is present in more than 110 countries, with urban outbreaks reported in Thailand and India since the 1960s and 1970s. Regions where Aedes aegypti or Aedes albopictus are present are now experiencing local transmission.

In France

Since 2006, a plan to combat the spread of chikungunya has been in force in mainland France, combining surveillance of mosquitoes and cases of infection, coordinated by Santé publique France. The plan is based on a number of key elements:

• Mandatory reporting to the Regional Health Agency (ARS) of all confirmed cases of chikungunya.
• Contribution of a network of volunteer laboratories to the diagnosis process, with results sent to Santé publique France.
• Increased surveillance in departments where the mosquito vector is active (from 1 May to 30 November), including rapid notification to the ARS of suspected imported cases (people returning from a high-risk area within the last 15 days), rapid diagnosis and the activation of targeted vector control measures around these cases. In 2021, 58 départements were affected, according to Santé Publique France.

In the French overseas departments, similar measures have been applied since 2006, under the supervision of the Regional Health Agencies and the Interregional Epidemiology Units (Cire).

What does the WHO say?

The World Health Organisation (WHO) supports countries in monitoring and combating arboviruses via the Global Arbovirus Initiative. With regard to chikungunya, the WHO is involved in :

1. Helping countries to confirm epidemics through its network of collaborating laboratories.
2. Providing technical support and guidelines for effective management of mosquito-borne disease outbreaks.
3. Evaluating efforts to develop new tools, including insecticides and application methods.
4. Developing evidence-based outbreak management strategies, policies and plans.
5. Providing technical support for optimal case management and effective epidemic management.
6. Helping countries improve their case notification systems.
7. Organising training in clinical management, diagnosis and vector control in collaboration with its regional centres.
8. Publishing guidelines and manuals for Member States on epidemiological surveillance, laboratory analysis, clinical management and vector control.
9. Promoting integrated multidisciplinary approaches to the management of arboviroses.

The WHO also encourages countries to develop and maintain the necessary capacity to detect and confirm cases, manage patients and implement communication strategies to reduce the presence of mosquito vectors.

What’s the current state of research?

Although there is as yet no specific treatment, knowledge of the virus is progressing. Epidemics of chikungunya in Réunion and the French West Indies have prompted epidemiological and clinical research. These studies have led to a better understanding of the disease, its long-term consequences and the risks of transmission from mother to child.

The DAG2 programme, supported by Aviesan, has collected biological samples in Martinique, Guadeloupe and French Guiana. It has created a cohort covering arboviroses such as Zika and Dengue. The CHIKHITA study observed adults during the acute phase of chikungunya and over three years. However, the decline in the number of cases restricted the completion of this study.

Research has identified potential therapeutic targets, in particular the FHL1 protein, which is essential for the virus to enter human and mouse cells. Blocking FHL1 could inhibit infection.

Vaccine development is also progressing. The CHIKV VLP vaccine candidate, developed by the US NIH, uses virus-like particles to induce an immune response, with no risk of viral replication. After a successful phase 2 clinical trial, its effectiveness in epidemic conditions remains to be assessed.

Research shows that plasmacytoid dendritic cells (pDC) play a crucial role in the immune response against chikungunya and dengue fever. Although in a minority, they rapidly produce type I interferons, which block viral replication and mobilise other immune cells.

Treatment for chikungunya focuses on managing the symptoms. It includes analgesics, non-steroidal anti-inflammatories, corticosteroids and sometimes methotrexate or anti-TNF alpha for chronic forms. Valneva SE’s VLA1553 vaccine, marketed under the name Ixchiq, was approved by the FDA in 2023. It is the first chikungunya vaccine for adults at risk.

How can I prevent myself from catching the tiger mosquito?

So what should you do? For chikungunya, as for malaria, preventing bites is the most effective treatment. Adopt simple measures: wear covering clothing, use natural repellents, install mosquito nets, and avoid stagnant water. If you are travelling to an area considered to be at risk, you can adopt a preventive treatment based onessential oils, in addition to the appropriate protective measures:

Some anti-mosquito essential oils

Lemon Eucalyptus E.O

Lemon eucalyptus is an insecticide. Lemon eucalyptus essential oil is effective against the larvae of mosquitoes that carry dengue fever and chikungunya, as well as mites. Its strong, fresh, lemony scent repels mosquitoes thanks to its citronellal and citronellol molecules. In the event of a bite, this substance provides rapid relief thanks to its strong analgesic and anti-inflammatory properties. It is a repellent in veterinary medicine.

Lemon Litsée E.O

Litsea repels Aedes, Anopheles and Culex mosquitoes.Lemony Litsée, also known as Exotic Verbena, is distinguished by its lemony scent resulting from a high concentration of citrals (geranial and neral isomers), which make up 75% of the composition of its essential oil. This plant is a preferred choice for its dual role as an insect repellent and insecticide, particularly effective against mosquitoes of the Aedes genus.

Ylang-ylang E.O

Ylang-ylang has a powerful repellent effect on mosquitoes, particularly the vector of dengue fever(Aedes aegypti). However, its insecticidal and ovicidal (egg destroying) action is weak on the vector of dengue fever, malaria and culex.

E.O. Ceylon Citronella

Citronella is an insect repellent for mosquitoes. Geraniol combined with citronnellol is an active repellent for two to four hours. It repels mosquitoes and wasps (as a preventive measure) and cures mosquito bites.

Mugwort E.O

White mugwort repels insects, particularly Aedes albopictus (which can transmit dengue fever or chikungunya).

Rose Geranium E.O

What natural treatments are there for Chikungunya?

If the tiger mosquito thwarts your vigilance and you are diagnosed with chikungunya, you can use essential oils to promote the healing process and boost your immunity:

Preparation for local rubbing:

• Ravintsara (Cinnamomum Camphora) 5 ml
• Lemongrass (Cymbopogon citratus) 3 ml
• Palmarosa (Cymbopogon martinii var. motia) 3 ml
• Clove tree (Eugenia caryophyllus) 1 ml
• Katrafay (Cedrelopsis grevei) 2 ml
• Apricot Kernel Oil 16 ml

25 drops of the mixture on the chest and 25 drops on the back, 8 times a day for 48 hours, then 6 times a day for 48 hours, then 4 times a day for 3 days.

Caution: doses should be halved for children aged 6 to 12. From 3 to 6 years, reduce the number of drops to 1/4. Same duration. Do not use on children under 3. Not suitable for pregnant or breast-feeding women.

Other natural remedies for chikungunya :

• A homeopathic protocol defined with your doctor to act on the symptoms is a good complement to this advice
• In gemmotherapy, blackcurrant (Ribes Nigrum), for its anti-inflammatory and general stimulating action, and Virginia creeper (Ampelopsis veitchii), which has a more targeted action on the joints, are remedies to consider

But, as always in naturopathy, acting on symptoms should remain the secondary route. The first priority is to support your body’s immune system.

• Echinacea is a highly effective plant for stimulating the immune system
• Ginger is also an antiviral against the chikungunya virus
• Magnesium chloride remains a particularly effective remedy for boosting your immune system. This remedy plays a key role in the treatment of chikungunya. It is taken in large doses, one sachet diluted in a litre of water, throughout the day. This protocol is applied for a few days as an initial plan of attack. Despite controversy and criticism from the authorities, many testimonials confirm its practical benefits.