A 34-year-old man returns from Kerala with high fever, severe arthralgia of wrists and small joints of the hands, and a maculopapular rash. Fever subsided in four days but joint pain and stiffness persist into the third week. Serology shows anti-chikungunya IgM. Which statement about this agent is correct?

• A It is a flavivirus transmitted by Culex tritaeniorhynchus
• B It is an alphavirus of the family Togaviridae transmitted by Aedes mosquitoes ✓
• C It is a bunyavirus causing recurrent polyarthritis through immune complex deposition
• D It is an orthobunyavirus with a segmented genome requiring reassortment for epidemics

Explanation

Chikungunya virus is an alphavirus (family Togaviridae) with a single-stranded positive-sense RNA genome, transmitted by Aedes aegypti and Aedes albopictus. Prolonged, sometimes chronic, symmetric polyarthritis distinguishes it clinically from dengue, in which severe myalgia and bleeding dominate and joint involvement is mild. Distractor A wrongly assigns it the vector and family of Japanese encephalitis virus. Persistent arthritis reflects direct viral persistence in synovial macrophages rather than classic immune complex disease.

Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.