Chronic recurrent polyarthralgia occurs in at least 20% of chikungunya patients one year after infection, whereas such symptoms are uncommon in dengue.Virus isolation provides the most definitive diagnosis, but takes one to two weeks for completion and must be carried out in biosafety level III 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 is used to amplify several chikungunya-specific genes from whole blood, generating thousands to millions of copies of the genes in order to identify them. RT-PCR can also be used to quantify the viral load in the blood. Using RT-PCR, diagnostic results can be available in one to two days. Serological diagnosis requires a larger amount of blood than the other methods, and uses an ELISA assay to measure chikungunya-specific IgM levels in the blood serum. One advantage offered by serological diagnosis is that serum IgM is detectable from 5 days to months after the onset of symptoms, but drawbacks are that results may require two to three days, and false positives can occur with infection due to other related viruses, such as onyongnyong virus and Semliki Forest virus.Presently, there is no specific way to test for chronic signs and symptoms associated with Chikungunya fever although nonspecific laboratory findings such as C reactive protein and elevated cytokines can correlate with disease activity. Prevention
Because no approved vaccine exists, the most effective means of prevention are protection against contact with the disease-carrying mosquitoes and controlling mosquito populations by limiting their habitat.
In particularly rare cases, people may develop behavioral changes, seizures, irritation of the cerebellum or meninges, oculomotor nerve palsy, or paralysis of the eye muscles.Newborns are susceptible to particularly severe effects of Chikungunya infection. Signs of infection typically begin with fever, rash, and swelling at the extremities. Around half of newborns have a mild case of the disease that resolves on its own; the other half have severe disease with inflammation of the brain and seizures. In severe cases, affected newborns may also have issues with bleeding and bloodflow, and problems with heart function.In addition to newborns, the elderly, and those with diabetes, heart disease, liver and kidney diseases, and human immunodeficiency virus infection tend to have more severe cases of Chikungunya. Around 1 to 5 in 1,000 people with symptomatic Chikungunya die of the disease. Cause
Virology
Chikungunya virus (CHIKV), is a member of the genus Alphavirus, and family Togaviridae. It was first isolated in 1953 in Tanzania and is an RNA virus with a positive-sense single-stranded genome of about 11.6kb. It is a member of the Semliki Forest virus complex and is closely related to Ross River virus, Onyongnyong virus, and Semliki Forest virus. Because it is transmitted by arthropods, namely mosquitoes, it can also be referred to as an arbovirus (arthropod-borne virus). In the United States, it is classified as a category B priority pathogen, and work requires biosafety level III precautions. Transmission
Chikungunya is generally transmitted from mosquitoes to humans.