Chikungunya virus

From IDWiki

Background

Microbiology

  • Member of the Alphavirus genus within the Togaviridae family
  • 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