OVERVIEW

What is Chikungunya Fever?

Chikungunya fever, also known as Chikungunya fever, Qikungunya fever, or Qu Gong disease in Chinese, are all transliterations of its English name.

This disease is caused by infection with the Chikungunya virus, which is primarily transmitted through mosquito bites. The term "chikungunya" originates from the Makonde language in Africa, meaning "to become contorted," "to bend the body," or "to walk bent over," describing the characteristic posture and movement of infected individuals due to joint pain and restricted mobility.

Currently, there is no specific antiviral treatment for this disease. During the acute phase, management focuses on symptomatic and supportive care, such as rest, hydration, and relief of fever and pain. For chronic or recurrent cases, medications like methotrexate or corticosteroids may be used. Some patients may experience persistent joint pain for years, significantly reducing their quality of life.

Preventive measures for Chikungunya fever mainly involve avoiding mosquito bites. A vaccine is still under development.

How Common is Chikungunya Fever? Where is it Prevalent (Endemic Areas)?

Chikungunya fever is common, with high incidence rates, and can lead to large-scale outbreaks. In areas where the virus circulates, it can infect one-third to three-quarters of the population.

Over the past decade, the number of Chikungunya outbreaks has increased, with the epidemic range expanding. The disease has now been reported in over 100 countries and regions worldwide, causing approximately one million infections annually.

Chikungunya fever outbreaks have occurred in Africa, Asia, Europe, the Indian and Pacific Ocean islands, and the Americas. In Africa, major affected areas include Tanzania, South Africa, Zimbabwe, Zaire, Senegal, Angola, Nigeria, Uganda, Rhodesia, Comoros, Mauritius, Madagascar, Mayotte, Seychelles, and Réunion Island. In Asia, outbreaks have been reported in India, Sri Lanka, Myanmar, Vietnam, Thailand, Laos, Cambodia, the Philippines, and Malaysia.

Have There Been Cases of Chikungunya Fever in China?

Cases of Chikungunya fever have been reported in China, primarily as imported cases.

SYMPTOMS

How long is the incubation period for chikungunya fever?

The incubation period for chikungunya fever is 1–14 days, with an average of 3–7 days.

What symptoms does chikungunya fever cause?

After the incubation period, chikungunya fever typically presents with sudden onset of fever and malaise.

• Fever: May be high-grade (>39°C), usually lasting 3–5 days (range: 1–10 days).
• Polyarthralgia: Begins 2–5 days after fever onset, often affecting multiple joints (≥10 joint groups); typically symmetric and bilateral, with a predilection for distal joints; commonly involved joints include the hands (50%–76%), wrists (29%–81%), and ankles (41%–68%); axial skeleton (spine) involvement occurs in 34%–52% of cases; severe pain may lead to restricted mobility or inability to move.
• Skin manifestations: Occur in 40%–75% of patients, most commonly as maculopapular or morbilliform rashes, usually appearing 3 or more days after symptom onset and lasting 3–7 days; often starts on the limbs and trunk, may spread to the face in a patchy or diffuse pattern; 25%–50% of patients experience pruritus; atypical skin findings include bullous lesions (most common in children) and hyperpigmentation.
• Other symptoms: May include headache, myalgia, facial edema, and gastrointestinal symptoms. Redness of the external ear may suggest chondritis. Ocular manifestations can include iritis, retinitis, episcleritis, macular choroiditis, and uveitis. Auditory symptoms may involve sensorineural hearing loss. Nasal skin necrosis may occur. Rarely, patients may exhibit hemorrhagic symptoms.

What severe complications can chikungunya fever cause?

During outbreaks, chikungunya fever can lead to severe complications and fatalities.

Patients aged 65+ or those with chronic conditions (e.g., diabetes, cardiovascular disease) are at higher risk for severe outcomes.

Severe complications include respiratory failure, heart failure, myocarditis, acute hepatitis, kidney failure, hemorrhage, and meningoencephalitis.

Data from the Réunion outbreak estimated severe complication incidence at 17 per 100,000 people.

What is the mortality risk of chikungunya fever?

Fatal cases have been reported during outbreaks in Mauritius, Réunion, India, and the Caribbean, with Réunion fatalities averaging 78 years of age. During the 2006 Ahmedabad outbreak in India, nearly 3,000 deaths occurred among ~60,000 cases over a 4-month peak period.

CAUSES

What pathogen causes chikungunya fever?

The chikungunya virus, belonging to the genus Alphavirus of the Togaviridae family, is a single-stranded positive-sense RNA virus. It can infect animals such as non-human primates and suckling mice.

The chikungunya virus has weak resistance to physicochemical factors and is sensitive to acids, heat, lipid solvents, detergents, bleaching powder, phenol, 70% alcohol, and formaldehyde.

How does the chikungunya virus make people sick?

• The chikungunya virus can directly invade the human body and cause illness: the virus enters human cells, replicates within them, leading to cell necrosis and apoptosis. The virus can also infect the fetus through the placenta, resulting in miscarriage or fetal death.

• The virus can also trigger immune mechanisms to cause illness: after extensive replication, the virus spreads through the bloodstream to body parts such as the liver and joints (with particularly high concentrations in joint tissues), stimulating the production of large amounts of cytokines and inflammatory factors, triggering inflammatory responses and cell aggregation, leading to symptoms.

How is chikungunya fever transmitted? Can it spread from person to person?

Chikungunya fever can be transmitted in the following ways:

• Mosquito transmission: This is the primary mode of transmission. The main vectors are Aedes aegypti and Aedes albopictus mosquitoes, which primarily bite during the day. After feeding on the blood of an infected individual, the virus reaches the mosquito's salivary glands, and the mosquito then transmits the virus to other humans or animals through bites. Ships and airplanes can also transport mosquito larvae and eggs to new regions with suitable environmental and climatic conditions, initiating new outbreaks. Generally, higher temperatures accelerate viral transmission by mosquitoes, while in cooler temperate climates, mosquitoes may die before completing the extrinsic incubation period, preventing large-scale epidemics.
• Transmission via blood products and organ transplants: Contact with an infected person's blood or blood products can lead to infection. Organ transplants, such as corneas, from infected donors may also transmit the virus.
• Mother-to-child transmission: If a pregnant woman is infected with the chikungunya virus and exhibits symptoms during delivery (2 days before to 2 days after childbirth), the risk of mother-to-child transmission is highest, at approximately 50%. Cesarean section does not prevent vertical transmission.

Patients with chikungunya fever should take preventive measures during the first week of illness (when viremia is likely present) to avoid mosquito bites, thereby reducing the risk of transmitting the virus to others through mosquitoes.

Which populations are more commonly affected by chikungunya fever?

Humans are generally susceptible to the chikungunya virus, and infection can occur at any age without significant differences based on gender, occupation, or race. However, the affected populations differ between new and long-standing endemic areas.

• In new or imported outbreak areas, all age groups can be affected.
• In long-standing endemic areas, such as Africa and Southeast Asia, children are more frequently affected.

DIAGNOSIS

When to Suspect Chikungunya Fever?

Chikungunya fever should be suspected in individuals with an epidemiological history, such as living in or traveling to endemic areas within the past 12 days, or a history of mosquito bites within 12 days before symptom onset, along with typical manifestations. These include acute onset of fever, followed by a rash 2–5 days later, and severe pain in multiple joints.

What Tests Are Needed When Chikungunya Fever Is Suspected?

First, the doctor will perform a physical examination. Periaricular edema or swelling is observed in 32%–95% of cases; peripheral lymphadenopathy (most commonly in the neck) is present in 9%–41% of cases; and conjunctivitis may also be noted in some patients.

Next, the doctor will conduct diagnostic tests, including:

• RT-PCR: Detects Chikungunya virus RNA within 1–7 days of symptom onset. A positive result confirms infection, while a negative result warrants serological testing (ELISA or IFA).
• Serological tests (ELISA/IFA): Performed ≥8 days after symptom onset. A positive result confirms Chikungunya virus infection.
• Antibody testing: IgM antibodies appear around day 5 (range: 1–12 days) post-symptom onset and persist for weeks to 3 months. IgG antibodies emerge around week 2 and may last for years.
• Testing for dengue and Zika virus infections is also recommended to rule out these diseases.

Viral culture is primarily used for research, aiding in strain identification and epidemiological studies.

How Is Chikungunya Fever Diagnosed?

Suspected cases include individuals with an epidemiological history plus fever, rash, and severe polyarthralgia, or those with typical symptoms without such history. Confirmation requires a positive test (RT-PCR, IgM/IgG antibodies, or viral isolation).

What Diseases Mimic Chikungunya Fever? How to Differentiate?

Acute phase:

• Dengue fever: Shares similar symptoms and distribution but more often causes neutropenia, thrombocytopenia, hemorrhage, shock, or death. RT-PCR/serology distinguishes them.
• Zika virus infection: Typically presents with milder fever and arthralgia. Lab tests confirm diagnosis.
• Other viral infections (e.g., rubella, Ross River virus) may also cause arthritis, requiring lab differentiation.

Chronic phase:

• Seronegative rheumatoid arthritis: Resembles Chikungunya arthritis but requires exclusion of other conditions.
• Reactive arthritis: Asymmetric, often linked to extra-articular infections.
• Systemic lupus erythematosus: Features ANA positivity and systemic involvement.
• Hepatitis C infection: Serology helps differentiate.

TREATMENT

Which department should I see for chikungunya fever?

Infectious diseases department, fever clinic.

Can chikungunya fever heal on its own?

Chikungunya fever is a self-limiting disease, and most cases can resolve on their own, so the prognosis is generally good.

Should suspected chikungunya fever patients be isolated?

Patients with chikungunya fever should take precautions to avoid mosquito bites during the first week of illness and be isolated with mosquito prevention measures. The isolation period is 5 days after the onset of symptoms to reduce the risk of virus transmission to others through mosquitoes.

How is chikungunya fever treated?

There is no specific treatment for chikungunya fever during the acute phase. Management mainly involves symptomatic and supportive care, such as rest, hydration, pain relief, and fever reduction. Systemic corticosteroids and other immunosuppressive drugs are generally not used.

For persistent or recurrent chikungunya fever, treatment focuses on addressing joint problems:

• Anti-inflammatory drugs and analgesics can be used to relieve pain in the months following the acute phase. Medications like pregabalin or gabapentin may also be prescribed for further pain control.
• Physical rehabilitation therapy may also be beneficial.
• For patients with inflammatory arthritis, tendinitis, or bursitis who do not respond to conventional pain medications, a short course of systemic corticosteroids (e.g., prednisone 10 mg daily for 5 days, then tapered over 10 days) may be given. More severe cases may require higher doses or longer treatment durations.
• If symptoms persist beyond 3 months, immunosuppressive therapy (e.g., methotrexate) may be considered.

Can chikungunya fever be completely cured? Will it affect the body?

Chikungunya fever is a self-limiting disease, and most cases can be completely cured with a generally good prognosis.

However, some patients may experience persistent joint pain for years after other symptoms subside. Severe cases may result in a bent posture, reduced mobility, and significantly diminished quality of life.

Newborns infected by their mothers may develop cognitive problems later in life.

DIET & LIFESTYLE

What dietary precautions should be taken during chikungunya fever treatment?

There are no special dietary requirements. It is recommended to eat light, easily digestible foods. Drink plenty of fluids during fever to prevent dehydration.

When can chikungunya fever patients be released from isolation?

Isolation is required within 5 days of symptom onset. Patients can be released from isolation after more than 5 days of illness.

Can chikungunya fever patients breastfeed?

Chikungunya virus has not been detected in breast milk, and there have been no reported cases of transmission through breastfeeding. Therefore, mothers are encouraged to breastfeed, even in areas where chikungunya virus is prevalent.

PREVENTION

How to prevent chikungunya fever?

The main approach is to avoid mosquito bites as much as possible, including personal protection and environmental control measures.

• Personal protection measures: For example, installing mosquito nets, window screens, and screen doors indoors.
• Environmental control measures: Such as eliminating mosquitoes and removing their breeding sites.

Is there a vaccine available for chikungunya fever?

Currently, there is no vaccine for chikungunya fever, and it is still under development.

After recovering from chikungunya fever, can one gain lifelong immunity? Will reinfection occur?

People who have been infected with chikungunya fever do not gain lifelong immunity and can be reinfected.