Intro

Chikungunya virus (CHIKV) is an insect-borne virus, of the genus, Alphavirus, that is transmitted to humans by virus-carrying Aedes mosquitoes. There have been recent outbreaks of CHIKV associated with severe morbidity. CHIKV causes an illness with symptoms similar to dengue fever. CHIKV manifests itself with an acute febrile phase of the illness lasts only two to five days. Followed by a prolonged arthralgic disease that affects the joints of the extremities. The pain associated with CHIKV infection of the joints persists for weeks or months.

Signs and symptoms

The incubation period of Chikungunya disease is from two to four days. Symptoms of the disease include a fever up to 39 ℃ (102.2 ℉), a petechial or maculopapular rash of the trunk and occasionally the limbs, and arthralgia or Osteoarthritis affecting multiple joints. Other nonspecific symptoms can include headaches , conjunctival injection, and slight photophobia. Typically, the fever lasts for two days and then ends abruptly. However, other symptoms, namely joint pain, intense headaches , insomnia and an extreme degree of prostration last for a variable period; usually for about 5 to 7 days. Patients have complained of joint pains for much longer time periods depending on their age.

Diagnosis

Common laboratory tests for chikungunya include RT-PCR, virus isolation, and serological tests.

• Virus isolation provides the most definitive diganosis but takes 1-2 weeks for completion and must be carried out in Biosafety level 3 laboratories. The technique involves exposing specific cell lines to samples from whole blood and identifying chikungunya virus-specific responses.
• RT-PCR using nested primer pairs to amplify several Chikungunya-specific genes from whole blood. Results can be determined in 1-2 days.
• Serological diagnosis requires a larger amount of blood than the other methods and uses an ELISA assay to measure Chikungunya-specific IgM levels. Results require 2-3 days and false positives can occur with infection via other related viruses such as O'nyong'nyong virus and Semliki Forest Virus.