Observations during recent epidemics have suggested chikungunya may cause long-term symptoms following acute infection. During the La Reunion outbreak in 2006, greater than 50% of subjects over the age of 45 reported long term musculoskeletal pain[12] with up to 60% of patients reporting prolonged arthralgia 3 years following initial infection.[13] A study of imported cases in France reported that 59% of patients still suffered from arthralgia two years after acute infection.[14] Following a local epidemic of chikungunya in Italy, 66% of patients reported myalgia, arthralgia, or asthenia at one year postacute infection.[15] Long-term symptoms are not an entirely new observation; long-term arthritis was observed following an outbreak in 1979.[16] Common predictors of prolonged symptoms are increased age and prior rheumatological disease.[12][13][15][17] The cause of these chronic symptoms is currently not fully known. Markers of autoimmune or rheumatoid disease have not been found in patients reporting chronic symptoms.[13][18] However, some evidence from human patients and animal models suggest that chikungunya may be able to establish chronic infections within the host. Viral antigen was detected in a muscle biopsy of a patient suffering a recurrent episode of disease three months after initial onset.[19] Additionally, viral antigen and RNA were found in synovial macrophages of a patient during a relapse of musculoskeletal disease 18 months post initial infection.[20] Several animal models have also suggested that chikungunya virus may establish persistent infections. In a mouse model, viral RNA was detected specifically in joint-associated tissue for at least 16 weeks post-inoculation, and was associated with chronic synovitis.[21] Similarly, another study reported detection of a viral reporter gene in joint tissue of mice for weeks post-inoculation.[22] In a non-human primate model, chikungunya virus was found to persist in the spleen for at least 6 weeks.[23] en.wikipedia.org/wiki/Chikungunya
Posted on: Sun, 15 Jun 2014 02:56:50 +0000
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