Chikungunya fever

What is chikungunya fever?

Chikungunya is an arthropod-borne alphavirus transmitted by mosquitos. It causes an acute febrile illness accompanied by a rash, joint pain, and muscle pain.

Where does chikungunya virus come from?

Chikungunya virus (CHIK V) was first reported in Tanzania in 1952. Following the initial outbreaks in Africa and after more than three decades of quiescence, it made a resurgence and is currently endemic in several regions in Africa, India, South-East Asia, and the Western Pacific. Outbreaks have also become more frequent in the Indian Ocean and Pacific Island nations [1,2]. There have been no locally acquired cases in New Zealand or Australia; however, travellers can transport the virus after visiting endemic areas [3,4].

How is chikungunya spread?

Chikungunya virus is transmitted to humans through the bite of an infected mosquito, mainly Aedes aegypti or A. albopictus. Mosquitos that are capable of spreading chikungunya virus exist in some parts of Australia but are not normally found in New Zealand [3,4].

Rarely, chikungunya spreads via the maternal-fetal route, through blood products, or organ transplantation [5].

What are the clinical features of chikungunya fever?

Chikungunya virus typically has an incubation period of 3–7 days (range 1–12 days) [6,7].

The first clinical manifestations are sudden-onset high fever and chills followed by severe polyarthralgia.

• Classically, there is symmetrical involvement of several joints, especially the small joints of the hands and feet.
• The arthralgia may persist for several months [6,7].
• Other common non-specific symptoms include a headache, myalgia, nausea, and lethargy.

Cutaneous manifestations of chikungunya

A wide range of mucocutaneous manifestations occurs, affecting up to 75% of patients with chikungunya during the disease course [6,7].

These have mainly been reported during chikungunya outbreaks in India.

• An erythematous macular or maculopapular rash usually appears in the first 2–3 days of the illness and subsides within 7–10 days. It can be patchy or diffuse on the face, trunk and limbs. It is typically asymptomatic but may be pruritic [6–12].
• The rash may result in postinflammatory macules or diffuse pigmentation. Pigmentation is most common on the face, characteristically affecting the nose [8–12].
• Painful aphthous-like ulcers that predominantly involve the oral mucosa and groin are also common [8–12].

Other cutaneous features of chikungunya may include:

• A vesiculobullous eruption (which most often affects children) [12]
• Haemorrhagic lesions
• Desquamation
• A lichenoid eruption
• Secondary bacterial infection (crusting and ulcers)
• Exacerbation of a pre-existing skin disorder such as psoriasis or lichen planus [8–12].

How is chikungunya fever diagnosed?

Chikungunya fever should be suspected in a patient with acute-onset fever and polyarthralgia when living in an endemic area or following recent travel to an area where mosquito-borne transmission of chikungunya virus has been reported.

• The diagnosis is confirmed by detection of viral RNA on polymerase chain reaction (PCR) testing or by positive viral serology.
• Testing for dengue virus and zika virus should also be undertaken.

What is the treatment for chikungunya fever?

Chikungunya fever is usually self-limiting and no specific therapy is required or available.

• Supportive treatment may include rehydration, rest, and anti-inflammatory or analgesic medication.
• Symptomatic relief from itch may be achieved with emollients, low potency topical steroids, or calamine lotion.
• Secondary bacterial infection should be treated with oral antibiotics.

How is chikungunya virus infection prevented?

No vaccine against chikungunya virus is currently available. Prevention relies primarily on avoidance of mosquitos (long-sleeved clothing, DEET insect repellents, insect screens and bed netting) [16].

What is the outcome of chikungunya fever?

The cutaneous manifestations of chikungunya typically resolve spontaneously within several weeks, without any need for specific dermatological treatment [8,9].

Patients with persistent arthralgia should be referred to a rheumatologist for additional workup and treatment [14].