Aiding in the diagnosis of recent infection with Chikungunya virus in patients with recent travel to endemic areas and a compatible clinical syndrome

Testing Algorithm

See Mosquito-borne Disease Laboratory Testing in Special Instructions.

Clinical Information

Chikungunya virus (ChikV) is a single-stranded RNA alphavirus and a member of the Togaviridae family of viruses. The name Chikungunya is derived from the language of the Makonde ethnic groups in southeast Africa and means "that which bends" or "stooped walk." This is in reference to the hunched-over appearance of infected individuals due to the characteristically painful and incapacitating arthralgia caused by the virus. ChikV is endemic throughout Africa, India, and more recently the Caribbean islands. In 2014, the first case of autochthonous or local transmission in the United States occurred in Florida.

Humans are the primary reservoir for ChikV and Aedes species mosquitos are the primary vectors for transmission. Unlike other mosquito-borne viruses such as West Nile virus (WNV) and Dengue, the majority of individuals who are exposed to ChikV become symptomatic, with the most severe manifestations observed at the extremes of age and in those with suppressed immunity. Once exposed to ChikV, individuals develop lasting immunity and protection from reinfection.

Prior to the development of symptoms, the incubation period ranges, on average, from 3 to 7 days. Infected patients typically present with sudden onset high fever, incapacitating joint pain, and often a maculopapular rash lasting anywhere from 3 to 10 days. Notably, symptom relapse can occur in some individuals 2 to 3 months following the resolution of initial symptoms. Currently, there are no licensed vaccines and treatment is strictly supportive care.

Interpretation

IgM and IgG Negative:
- No serologic evidence of exposure to the Chikungunya virus. Repeat testing on a new specimen collected in 5 to 10 days is recommended if clinical suspicion persists.

IgM and IgG Positive:
- IgM and IgG antibodies to the Chikungunya virus were detected, suggesting recent or past infection. IgM antibodies to the Chikungunya virus may remain detectable for 3 to 4 months post-infection.

IgM Positive, IgG Negative:
- IgM antibodies to the Chikungunya virus were detected, suggesting recent infection. Repeat testing in 5 to 10 days is recommended to demonstrate anti-Chikungunya virus IgG seroconversion to confirm current infection.

IgM Negative, IgG Positive:
- IgG antibodies to the Chikungunya virus were detected, suggesting past infection.

IgM and/or IgG Borderline:
- Repeat testing in 10 to 14 days is recommended.

Cautions

Specimens collected too early following infection may be negative for antibodies to the Chikungunya virus.

Chikungunya and Dengue viruses currently co-circulate in endemic areas and infections can present similarly in symptomatic patients. It is therefore recommended to evaluate at-risk patients for infection with both viruses.