Chikungunya virus
From IDWiki
Background
Microbiology
- Member of the Alphavirus genus within the Togaviridae family
- Closely related to o’nyong-nyong virus
- Four genotypes: East-Central-South African, West African, Indian Ocean, and Asian
Epidemiology
- The primary vectors are Aedes aegypti and Aedes albopictus mosquitoes
- Endemic in most of Africa, Southeast Asia, the Philippines, and South and Central America
- There has been autochthonous transmission in Italy and Frace
Clinical Manifestations
- Incubation period of 1 to 12 days
- Fever, rash, and arthralgias
- Fever may be "saddleback", with remittance at 4 to 8 days followed by recrudescence for 2 weeks
- Arthritis is typically a symmetrical polyarticular arthritis that involves small joints and knees
- Resolves over months to a year (sometimes longer), but arthralgias (± arthritis) can persist for years
- Rash is macular or maculopapular, and more often central but can involve palms and soles
- Other common symptoms include headache, fatigue, nausea, vomiting, and conjunctivitis
- Bloodwork shows leukopenia, thrombocytopenia, hypocalcemia, and mild to moderate transaminase elevation
- Children are more likely to develop neurological symptoms (status epilepticus, complex seizures, and encephalitis) and dermatologic symptoms (bullous rash)
Differential Diagnosis
| Feature | Dengue | Zika | Chikungunya |
|---|---|---|---|
| Asymptomatic | 40-80% | 35-85% | 3-28% |
| Fever | +++ | ++ | +++ |
| Rash | + | +++ | ++ |
| Conjunctivitis | – | ++ | + |
| Arthralgia | + | ++ | +++ |
| Myalgia | ++ | + | + |
| Headache | ++ | + | ++ |
| Hemorrhage | ++ | – | – |
| Shock | + | – | – |
| Thrombocytopenia | +++ | + | – |
| Leukopenia | ++ | – | ++ |
Management
- High-dose NSAIDs
- May need aggressive rheumatologic medications for arthritis
- Supportive treatment
Prognosis
- 12% risk of chronic arthralgias up to 3 years post-infection
- Neonates and elderly at highest risk for neurological sequelae
