Snapshot A 33-year-old man presents to the emergency department for headache and joint pain. His symptoms are associated with symmetric arthralgias involving the ankles, knees, and wrists bilaterally, myalgias, and facial puffiness. He returned from West Africa approximately 4 days ago. His temperature is 103.1°F (39.5°C), blood pressure is 135/90 mmHg, pulse is 102/min, and respirations are 19/min. Physical examination is notable for periarticular swelling at the wrist, ankles, and knees, along with a maculopapular rash involving the trunk and extremities. Serologic testing via reverse transcription polymerase chain reaction demonstrates chikungunya viral RNA. Introduction Classification icosahedral capid, enveloped, linear, non-segmented, positive sense, single-stranded RNA viruses viruses western equine encephalitis virus eastern equine encephalitis virus chikungunya virus rubella virus Diseases Togaviruses Disease Presentation Diagnostic Studies Treatment Rubella Caused by the rubivirus can be vertically transmitted to the fetus, causing congenital defects congenital deficits include heart patent ductus arteriosus interventricular septal defect pulmonary artery stenosis eyes cataracts chorioretinitis brain developmental delay microcephaly deafness skin "blueberry muffin" rash caused by dermal extramedullary hematopoiesis Symptoms headache nausea vomiting Physical exam lymphadenopathy red maculopapular rash spreads from the forehead to the face, torso, and then to the extremities the rash typically lasts 3 days arthralgia can be seen in young women Rubella-specific IgM antibodies Supportive treatment Preventative live-attenuated vaccine note, it is not recommended for pregnant women Eastern equine encephalitis Symptoms headache myalgias malaise arthralgias Physical exam fever seizures arthralgia myalgia convulsions Eastern equine encephalitis virus-specific IgM antibody in serum or CSF Supportive treatment Western equine encephalitis Symptoms headache myalgias malaise arthralgias Physical exam fever erythematous oropharynx palatal petechiae IgM detected in the cerebrospinal fluid Isolation of the viral antibodies in the serum Viral antigen or genomic sequences in the tissue, blood, or CSF Supportive treatment Chikungunya fever Symptoms headache facial puffiness polyarthralgia Physical exam fever macular or maculopapular rash Chikungunya viral RNA via RT-PCR Chikungunya virus serology Supportive treatment Rubella-specific IgM antibodies Supportive treatment