CHIKV : The "New" Rheumatologic Disease

Chikungunya virus, aka CHIKV, is an emerging "new" rheumatologic disease according to this morning's speaker from India, Dr. A. Chopra. Dr. Chopra detailed the results of his internationally recognized work studying the impact of the 2006 Chikungunya epidemic in Pune, India. Carried in the day mosquito vectors of Aedes aegypti and Aedes albopictus (same vector as Dengue virus), this single stranded RNA virus belonging to the family Togaviridae, genus Alphavirus, causes an explosive onset of high fever, excruciating body pain with peripheral small and large joint arthritis. Patients often suffer with headache and less commonly, rash and gastrointestinal symptoms including diarrhea. The fever settles within two to five days followed by complete resolution of arthritis within weeks. Rarely fatal, a subset of patients can be crippled with chronic CHIKV musculoskeletal pains, truly living up to its Makonde (Swahili) name - "that which bends up".

Dr. Chopra's work in India demonstrated that patients infected with CHIKV have a confusing immunologic and cytokine profile, but there is little evidence to presume this is an "autoimmune" or reactive disease. Limited results with low patient numbers have demonstrated persistent CHIKV antigen in synovial biopsy of patients eighteen months after infection, speaking to the possibility of a chronic, persistently active disease.

Recommendations for treatment were disappointing. A study from South Africa had previously suggested benefit from chloroquine. However, Dr. Chopra's group conducted a single center, blinded randomized study comparing chloroquine and meloxicam and showed no difference in treatment response between these agents. In fact, the best agent in his clinical experience was intermittent steroid use but he acknowledged the need for disease modifying anti-rheumatic and biologic drugs in a subset of chronic patients.

Dr. Chopra's work reflects his experience in India - but remember that large outbreaks are currently ongoing in the Carribean, French Polynesia and concerns of the same exist for North, South and Central America. We should remember CHIKV in the differential diagnosis of acute polyarthritis in returning travellers. Testing can be conducted in Canada; however, given the delay in an answer, clinical suspicion will likely weigh in heavily to diagnosis and initial management.

More reports from ACR 2015