Chikungunya fever

Overview

Chikungunya fever is an acute febrile disease caused by the chikungunya virus.

Pathogen(s)

Chikungunya virus.

Transmission

Transmitted by the bite of infected Aedes mosquitoes, predominantly Aedes aegypti and Aedes albopictus mosquitoes.

Incubation period: Typically 3 to 7 days; range is 1 to 12 days.

Infectious period: Usually infectious to mosquitoes during days 2 to 6 of illness, when the patient is viraemic.

Clinical features

The disease is typically characterised by high fever, joint pain, and rash:

• Fever – high with acute onset; maybe biphasic. Usually lasts 3 to 4 days

• Joint pain, with or without swelling or erythema, is a prominent distinguishing feature

  • Initial severe eruptive polyarthritis/arthralgia with classical history of painful walking

  • Typically followed by protracted peripheral arthropathy that can last for months

  • Commonly affects the knees, ankles and wrists; also, the small joints of hands and feet

• Rash

  • Maculopapular or mobiliform (older children/adults); may be pruritic

  • Vesiculobullous eruptions described in infants.

  • Typically on trunk and limbs

  • Uncommon haemorrhagic manifestations

Other reported symptoms include headache, conjunctival injection, nausea, vomiting, and fatigue.

Severe complications are more common in those aged above 65 years and with underlying medical conditions. Complications include respiratory failure, bleeding, meningoencephalitis, acute hepatitis, and ocular manifestations (iridocyclitis, retinitis and episcleritis).

Risk factors

Risk factors include:

• Living in or travelling to Chikungunya-affected areas 

Diagnosis

PCR for chikungunya virus within 5 days of onset may give a more rapid diagnosis.

Serology: Positive chikungunya IgM on acute serum sample. IgM antibodies appear on approximately the fifth day of illness and last for 2 months.

Treatment and management

Symptomatic treatment including paracetamol for fever, aches and pains and non-steroidal anti-inflammatory drugs may be considered for joint pains.

Precaution, prevention, and control

Standard precautions apply in healthcare settings.

Vector control remains the mainstay in reducing the spread of mosquito-borne diseases. Individuals can also take precautions against mosquito bites, such as:

• Staying in rooms which are well-screened or air-conditioned

• Wearing long, covered clothing that cover most of one’s body

• Applying an effective insect repellent, such as those containing DEET, Picaridin or IR3535 as the active ingredient regularly

Notification

Who should notify:

• Medical practitioners

• Laboratories

When to notify:

• On clinical suspicion or laboratory confirmation

How to notify:

• Please refer to the Infectious Disease Notification for more information. 

Notification timeline:

• As soon as possible. No later than 24 hours from the time of diagnosis.

Resources

Please refer to the Weekly Infectious Diseases Bulletin for the number of confirmed chikungunya fever cases in Singapore.