James Gathany/CDC
Chikungunya virus: A female Aedes aegypti mosquito in the process of acquiring a blood meal from a human host.
The patient was ultimately diagnosed with chikungunya, a single-strand RNA mosquito-borne virus with the same vectors as dengue. “This has been wreaking havoc across the Caribbean in the past few years,” Dr. Ahronowitz said. “Chikungunya was first identified in the Americas in 2013, and there have been hundreds of thousands of cases in the Caribbean.” The first case acquired in the United States occurred in Florida in the summer of 2014. As of January 2016 there were 679 imported cases of the infection in the United States. “Fortunately, this most recent epidemic is slowing down a bit, but it’s important to be aware of,” she said.
Clinical presentation of chikungunya includes an incubation period of 3-7 days, acute onset of high fevers, chills, and myalgia. Nonspecific exanthem around 3 days occurs in 40%-75% of cases, and symmetric polyarthralgias are common in the fingers, wrists, and ankles. Labs may reveal lymphopenia, AKI, and elevated AST/ALT. Acute symptoms resolve within 7-10 days.
Besides the rash, other cutaneous signs of the disease include aphthous-like ulcers and anogenital ulcers, particularly around the scrotum. Other patients may present with controfacial hyperpigmentation, also known as “brownie nose,” that appears with the rash. In babies, bullous lesions can occur. More than 20% of patients who acquire chikungunya still have severe joint pain 1 year after initial presentation. “This can be really debilitating,” she said. “A subset of patients will develop an inflammatory seronegative rheumatoid-like arthritis. It’s generally not a fatal condition except in the extremes of age and in people with a lot of comorbidities. Most people recover fully.”
As in dengue, clinicians can diagnose chikungunya by viral culture in the first 3 days of illness, and by RT-PCR in the first 8 days of illness. On serology, IgM is positive by 5 days of symptom onset.
“If testing is not available locally, contact the [Centers for Disease Control and Prevention],” Dr. Ahronowitz said. “Treatment is supportive. Evaluate for and treat potential coinfections, including dengue, malaria, and bacterial infections. If dengue is in the differential diagnosis, avoid NSAIDs.” A new vaccine for chikungunya is currently in phase II trials.
Dr. Ahronowitz reported having no relevant disclosures.