U.S. chikungunya epidemic would likely put rheumatologists on front line
Treatment
No evidence-based treatment for chikungunya exists. Treatment in the acute phase is primarily supportive care. Rheumatologists on the Caribbean island of Martinique have reported a favorable experience using methotrexate at doses up to 25 mg/week or with standard doses of anti–tumor necrosis factor agents in chikungunya patients with severe bilateral symmetric chronic inflammatory joint disease arising during the 2013-2015 epidemic. The treatment response and tolerability were comparable with the results typically obtained in rheumatoid arthritis patients, according to the rheumatologists (Arthritis Rheumatol. 2016 Nov;68[11]:2817-24).
Dr. Schoen found the report from Martinique to be reassuring. He too has resorted to familiar rheumatologic medications in his severely affected patients. Anecdotally, his greatest success involved a patient with a 5-year history of disabling chikungunya polyarthritis who showed marked improvement after several months on hydroxychloroquine.
The Martinique investigators also reported on 22 patients who developed chikungunya while on biologic agents for rheumatoid arthritis, Crohn’s disease, psoriatic arthritis, or systemic lupus erythematosus. The biologics weren’t protective against the viral disease in these patients. All 22 of them developed severe acute chikungunya polyarthritis with a mean swollen joint count of 9.6 (Joint Bone Spine. 2016 Mar;83[2]:245-6).
Infection during pregnancy
There is a legitimate concern about chikungunya infection occurring during pregnancy, but, based on the experiences documented on Reunion Island, the risk to the baby is confined to intrapartum exposure in a viremic mother.
Reunion Island is a French region in the Indian Ocean off the eastern coast of Africa. It has first-world medical care. Much of the best documented early work on chikungunya outbreaks grew out of the 2005-2006 epidemic there, which affected more than one-third of the island’s 800,000-plus residents.
In a prospective study of 7,504 deliveries on the island during a 22-month period, mother-to-child transmission of chikungunya occurred only in the context of intrapartum viremia, with 19 cases of vertical transmission occurring among 39 affected mothers who delivered at a median 38 weeks of gestation. Cesarean section had no protective effect. All 19 infected neonates were asymptomatic at birth, with median onset of pain, fever, and thrombocytopenia on day 4. Nine of the 19 infected neonates developed encephalopathy with pathologic MRI findings, including cerebral hemorrhage in two cases (PLoS Med. 2008 Mar 18;5[3]:e60).
The case fatality rate for chikungunya is low at 0.1%. Most deaths occur in young children or elderly individuals with major comorbid conditions. Despite this low mortality, interest in chikungunya vaccine development is being driven by the infection’s impact on tourism, its spread to temperate climates, the economic impact of the considerable time lost from work, and military need. A promising attenuated, virus-like, particle-based vaccine is currently in phase II testing in the Caribbean.
Dr. Schoen reported having no financial conflicts.
