Chikungunya
Chikungunya
Editors: Yamilka Díaz, José Antonio Suárez, Laura Naranjo
Key Points
- Chikungunya virus (CHIKV) is transmitted by the mosquito Aedes.
- During the acute phase, it causes a self-limiting febrile illness with symmetric polyarthralgias.
- A subset of individuals, can progress to chronic rheumatism.
- Depending on the timing, diagnosis is based on serology or PCR.
- Treatment is largely supportive, except when rheumatism is present where it may require drugs with anti-inflammatory effect.
Background
Chikungunya is a mosquito-borne febrile illness caused by the Chikungunya virus (CHIKV) - a member of the Alphavirus family - which is mainly transmitted to humans via the mosquito of the genus Aedes. Its name derives from the Makonde (or Kimakonde) language in Southeast Africa that means “to be contorted” or “that which bends up” describing the appearance of patients with beause of the characteristic polyarthralgias.
- Chikungunya virus
- Mayaro virus
- O’nyong’nyong virus
- Ross River virus
- Equine encephalitis virus (Eastner, Western, Venezuelan)
Transmission & Epidemiology
Transmission occurs primarily in tropical and subtropical areas, and it is most commonly transmitted by bite of the female mosquito Aedes (Ae. aegypti > Ae. albopictus) and probably of smaller importance, the mosquito Culex. Aedes spp. feed in a bimodal rhythm during the day: morning and sunset (daytime biters!). Female mosquitoes lay eggs in containers that hold stagnant water (ie, flower bases, garbage lids, car tires) where they complete their life cycle.
Note: Other viruses transmitted by the genus Aedes:
- Dengue virus
- Chikungunya virus
- Zika virus
- Yellow fever virus
| Aedes aegypti | Aedes albopictus | |
| Behavior | Anthropophilic | Zoophilic>Anthropophilic |
| Habitat | Urban areas/Peri-urban | Peri-urban/Rural areas |
| Local distribution | Indoor = Outdoor | Outdoor > Indoor |
Table 1. Key differences of both Aedes spp.
Figure 1. Aedes aegypti
Clinical Spectrum
- Acute phase: correlates with the duration of the viremia (~7 days). 78-97% of patients develop an asymptomatic or minimally symptomatic disease. After an incubation period of 3-7 days, the acute phase is characterized by high-grade fever (often >39C), rigors, and polyarthralgias (appear 2-5 days after fever, typically symmetric, and distal). Other symptoms include: headache, photophobia, myalgias, pruritic maculopapular rash, or nausea/vomiting. Disease severity varies from mild self-limiting illness to debilitating arthralgias. Laboratory findings: lymphopenia, mild thrombocytopenia, abnormal liver enzymes
Note: Remember that multiple arboviruses, and other respiratory viruses (influenza, SARS CoV-2) co-circulate in endemic regions and clinical presentation varies widely as individuals may be infected with multiple pathogens simultaneously.
- Chronic phase: following an acute infection, in 30-40% of individuals there is long-term rheumatism characterized by recurrent and often debilitating arthropathy that can persist for months to years. Although not fully understood, factors associated with post-chikungunya chronic inflammatory rheumatism include: female sex, >60 years, high level viremia, and genetic predisposition (ie, toll-like receptor polymorphisms).
Differential Diagnosis
CHIKV is clinically indistinguishable from many arbovirosis. Some key differences are outlined below.
| Key differences between common arbovirosis | |||||
| Distribution | Vector | Clinical Presentation ("Buzzwords") | Prevention | Complications | |
| Chikungunya | South America & the Caribbean, Africa, Asia | Aedes | Polyarthralgias | Mosquito avoidance and control | Post-chikungunya inflammatory rheumatism |
| Dengue | South America & the Caribbean, Africa, Asia | Aedes | Retro-orbital pain | Mosquito avoidance and control, Vaccination | Severe dengue, bleeding diathesis, multiorgan failure |
| Zika | South America & the Caribbean, Africa, Asia | Aedes | Conjunctivitis, limb edema | Mosquito avoidance and control, Safe sex practices | Guillain Barre Syndrome, Microcephaly |
| Yellow Fever | South America & Africa | Aedes | Bi-phastic fever, Liver and Renal Failure | Vaccination, Mosquito avoidance and control | High mortality. Careful with viscero- and neutropic disease after vaccination |
Diagnosis
Most arboviruses that generate a fever-rash syndrome are clinically indistinguishable, therefore specific molecular or serological tests are needed to establish a final diagnosis. Options include:
- RT-PCR: preferred testing modality within one week of symptom onset
- Serology: IgM first appears by the end of the first week and may remain detectable for about 2 months. Seroconversion or four-fold rise in IgG between acute and convalescent plasma is also diagnostic in the right clinical setting. Be careful as serologic testing can cross-react with other Alphaviruses and Flaviviruses.
- Rapid Diagnostic Testing (RDTs): useful during epidemics as a rapid turnout time of 20 minutes. Sensitivity is highly variable 20-100%.
Treatment & Management
There is no targeted antiviral treatment for Chikingunya fever. Treatment options may vary depending on the phase of the disease:
- Acute phase: supportive - rest, hydration, antipyretics. Some practitioners would avoid NSAIDs and/or aspirin due to risk of hemorrhage.
- Chronic phase: analgesia is the cornerstone therapy (ie, NSAIDs). Some practitioners would use corticosteroids if symptoms are disabling, unresponsive/contraindications to NSAIDs, but regimens vary widely among providers. If unresponsive to steroids (based on limited evidence), and the diagnosis for post-chikungunya chronic inflammatory rheumatism is certain, consider disease-modifying anti-rheumatic drugs (DMARDs).
Prevention
There is no targeted antiviral treatment for Chikungunya fever. Treatment options may vary depending on the phase of the disease:
- Vector prevention: use insect repellents, permethrin-sprayed clothes, protective clothing (long pants & sleeves), and nets - if no contraindications.
- Vector control: decrease mosquito breeding sites (dump stagnant water), mosquito traps.
- Vaccination: for high-risk travelers, there are two vaccine options to prevent Chikungunya fever - a live-attenuated option (IXCHIQ) and a virus-like particle option (VIMKUNYA). Both are administered intramuscularly and as a single dose. For more information on these vaccines, we recommend reviewing the CDC Yellow Book!
References
This lesson was built in partnership with Infectotrópico and was last updated August 22 2025