RA or Chikungunya? The Rheumatologist’s Primer on Tropical Mosquito-Related Viruses

By Leonard Calabrese, DO, and Elizabeth Kirchner, CNP

Rheumatologists are seeing an increase in patients with mild to severe rheumatic symptoms upon returning from tropical areas. Many of their afflictions fall within the category of arboviruses or arthropod-borne viruses ‒ infections carried by insects. Until a few years ago, the majority of these viral infections were rare and typically only seen in patients who had traveled to Pacific islands or parts of Africa. Since the fall of 2013, however, the Western Hemisphere has seen a wave of such infections, with more than 1 million cases reported.1[i]

Zika virus has recently attracted worldwide concern and attention due to its rapid spread, association with serious birth defects, prevalence in Latin America and the Caribbean and recent local transmission in Florida. Chikungunya is another common virus that can debilitate patients with arthritis and rheumatism for several weeks, with some symptoms persisting much longer. Chikungunya is a strong mimic for dengue, which is fatal in rare cases, so proper diagnosis is essential.

The spread of these infections poses a global public health problem and warrants inclusion of arboviruses in differential diagnoses throughout the country.

Include arboviruses in your differential diagnosis

Health care providers in the U.S. understandably gravitate toward a diagnosis of rheumatic conditions, such as rheumatoid arthritis or systemic lupus erythematosus (SLE), when indicative symptoms manifest (see Table). Correct diagnosis is essential, however, as treating arboviruses with immunosuppressants hinders patient recovery. In most cases, the only treatment for arboviruses is symptomatic relief such as analgesics and NSAIDs.

The diagnosis of one of these mosquito-borne diseases is based on clinical criteria and laboratory testing when possible. First, a clinician must establish an epidemiological basis for the diagnosis through questions about a patient’s recent travel to endemic areas.

Zika, dengue and chikungunya viruses are primarily transmitted through the bite of an infected Aedes genus mosquito in tropical areas (A. aegypti and A. albopictus). They propagate by infecting animals within a zoonotic cycle. However, mosquitoes are increasingly able to transmit the viruses directly between people, eliminating the need for an animal host. Zika virus can also be vertically and sexually transmitted. The CDC has released recommendations for prevention of sexual transmission of Zika (cdc.gov/zika). This human-to-human transmission warrants ongoing concern and vigilance since it is possible to establish the disease anywhere there is an infected patient and a capable vector.

Because these viruses thrive in daytime-biting mosquitoes, it is also important to urge patients in infected areas to use adequate repellants, in addition to nighttime mosquito netting. These viruses will be with us for a long time, so it is crucial that we enter them into our clinical decision-making routines.

Dr. Calabrese (calabrl@ccf.org; 216.444.5258) is Director of the R.J Fasenmyer Center for Clinical Immunology in the Department of Rheumatic and Immunologic Diseases.

Ms. Kirchner (kirchne@ccf.org; 216.445.7280) is a certified nurse practitioner in the Department of Rheumatic and Immunologic Diseases.