Chikungunya virus (CHIKV) is an enveloped, positive-sense single-stranded RNA virus belonging to the genus Alphavirus in the family Togaviridae. The name “chikungunya” derives from the Swahili word meaning “that which bends up,” referring to the characteristic stooped posture caused by severe joint pain.
Main systemic symptoms include sudden high fever (≥39°C), joint pain, muscle pain, headache, and rash. Up to 50% of patients develop persistent arthritis.
In recent years, intraocular inflammatory diseases caused by CHIKV have become more widely recognized. Uveitis in particular may appear simultaneously with systemic symptoms or develop late after an asymptomatic period.
Main ocular complications of CHIKV
Anterior uveitis: Most commonly reported ocular complication
Intermediate, posterior, and panuveitis: Higher severity
Keratitis: epithelial or stromal
Optic neuropathy: occurs in up to 10% of ocular symptoms
Conjunctivitis: usually resolves within one week
Viral characteristics
Classification: Togaviridae family, Alphavirus genus
Vector arthropod: Aedes mosquitoes (Aedes aegypti, Ae. albopictus)
Endemic areas: Africa, India, Southeast Asia, Central and South America
Seasonality: Frequent during monsoon season
Incubation period: Usually 1–12 days
Ocular subjective symptoms vary depending on the site of inflammation.
Acute phase (up to 3 weeks after infection):
Delayed symptoms (weeks to months after systemic symptoms subside):
In one case series, 60% of patients developed ocular symptoms during the course of systemic disease, and 40% developed them within 6 weeks after the resolution of acute symptoms [1, 2]. A systematic review by da Silva et al. reported that eye pain, inflammation, and decreased vision were the most frequent subjective symptoms [5].
Features of anterior uveitis:
Features of posterior uveitis and panuveitis:
Optic neuropathy [1, 2, 5]:
Other ocular findings:
Yes. Ocular complications of CHIKV can occur concurrently with systemic symptoms (direct viral involvement) or appear late after the acute phase symptoms subside (due to delayed immune response). Salceanu et al. reported a late-onset case of retinitis that developed about one year after infection and relapsed after steroid treatment [4]. It is important to consider CHIKV in the differential diagnosis of late-onset uveitis in patients with a history of travel to endemic areas and prior fever and joint pain.
Transmission route:
The main route of infection is through the bite of mosquitoes of the genus Aedes (Aedes aegypti, Aedes albopictus). The viremic phase (within one week after onset) carries the highest risk of transmission. Perinatal transmission can occur if the mother is viremic, but intrauterine infection is rare. No detection of CHIKV in breast milk has been reported.
Risk factors:
| Risk factor | Details |
|---|---|
| Travel history | Travel to endemic areas (Africa, India, Southeast Asia, Central and South America) |
| Mosquito exposure | Environments and seasons with high Aedes mosquito activity |
| Immune status | Immunocompromised individuals have increased risk of multi-organ involvement and severe disease |
| Age | Infants and the elderly have higher mortality rates |
| Season | Monsoon season (coinciding with vector increase) |
Diagnosis is made by combining a history of travel or residence in an endemic area, typical systemic symptoms (fever, joint pain), and test results.
Virological testing:
| Timing | Test method |
|---|---|
| Acute phase (within 8 days of onset) | Detection of viral RNA by blood PCR |
| From day 8 onward | Serological tests (IgM ELISA, IgG paired sera) |
| Gold standard | Virus isolation in mosquito or mammalian cell culture (usually difficult to perform) |
PAHO/WHO diagnostic guidelines recommend IgM ELISA/rapid diagnostic test or IgG paired sera from day 8 onward.
Ophthalmic examination:
Differential diagnosis:
Requires differentiation from many diseases including arboviruses (dengue, Zika, West Nile), herpesviruses, syphilis, tuberculosis, sarcoidosis, etc. [3]. Travel history to endemic areas, history of fever and joint pain are important for differentiation.
No specific antiviral drug currently exists. Treatment is entirely symptomatic and supportive [1, 2, 5].
Systemic treatment:
Local ocular treatment:
| Condition | Treatment |
|---|---|
| Anterior segment inflammation | Topical nonsteroidal anti-inflammatory drugs, steroid eye drops, cycloplegics |
| Elevated intraocular pressure | Topical antihypertensives (beta-blockers, carbonic anhydrase inhibitors, etc.) |
| Posterior segment lesions (risk of vision loss) | Systemic steroid therapy |
| Chronic uveitis | Systemic immunomodulatory therapy |
Intraocular target cells of CHIKV:
CHIKV has been found to target the following tissues and cells:
CHIKV antigen has also been identified in fibroblasts at these sites in human tissues.
Two mechanisms of ocular symptom onset:
It is currently unknown whether active viral particles persist in the eye long-term and contribute to late-onset inflammatory recurrence.
Viremia and infection spread:
The viremic phase within one week of onset is the most infectious to mosquitoes. Mosquitoes feeding during this period maintain the infection cycle.
Vaccine development:
Currently, there is no approved vaccine for CHIKV, but two phase 1 clinical trials have shown good safety and immunogenicity. Developing an approved vaccine is a key public health priority.
Improving diagnostic accuracy:
Most data on CHIKV-associated uveitis are based on case reports without unified diagnostic criteria. Standardization of diagnostic methods and multicenter prospective studies are needed.
Climate change and CHIKV spread:
Due to climate change expanding the habitat of Aedes mosquitoes, the risk of CHIKV infection is increasing in previously non-endemic regions such as Europe, the United States, and Japan. Along with increased international travel, ophthalmologists need to raise awareness of this disease.
Corneal donor safety:
Reports have confirmed evidence of the virus in corneal specimens from CHIKV IgM/IgG-positive donors even after conventional eye bank preservation, posing challenges for risk management of infection transmission in corneal transplantation.
Mahendradas P, Avadhani K, Shetty R. Chikungunya and the eye: a review. J Ophthalmic Inflamm Infect. 2013;3(1):35. PMID: 23514031.
Martínez-Pulgarín DF, Chowdhury FR, Villamil-Gomez WE, et al. Ophthalmologic aspects of chikungunya infection. Travel Med Infect Dis. 2016;14(5):451-457. PMID: 27238905.
Merle H, Donnio A, Jean-Charles A, et al. Ocular manifestations of emerging arboviruses: Dengue fever, Chikungunya, Zika virus, West Nile virus, and yellow fever. J Fr Ophtalmol. 2018;41(6):e235-e243. PMID: 29929827.
Salceanu SO, Raman V. Recurrent chikungunya retinitis. BMJ Case Rep. 2018;2018:bcr2017222864. PMID: 30150331.
da Silva LCM, Platner FDS, Fonseca LDS, et al. Ocular Manifestations of Chikungunya Infection: A Systematic Review. Pathogens. 2022;11(4):412. PMID: 35456087.
