Zika Virus Infection in Patient with No Known Risk Factors, Utah, USA, 2016

Abstract

In 2016, Zika virus disease developed in a man (patient A) who had no known risk factors beyond caring for a relative who died of this disease (index patient). We investigated the source of infection for patient A by surveying other family contacts, healthcare personnel, and community members, and testing samples for Zika virus. We identified 19 family contacts who had similar exposures to the index patient; 86 healthcare personnel had contact with the index patient, including 57 (66%) who had contact with body fluids. Of 218 community members interviewed, 28 (13%) reported signs/symptoms and 132 (61%) provided a sample. Except for patient A, no other persons tested had laboratory evidence of recent Zika virus infection. Of 5,875 mosquitoes collected, none were known vectors of Zika virus and all were negative for Zika virus. The mechanism of transmission to patient A remains unknown but was likely person-to-person contact with the index patient.

Keywords: United States; Utah; Zika virus; Zika virus disease; arbovirus; exposure; healthcare; infection; local transmission; person-to-person transmission; symptomatic; transmission; vector-borne infections; viruses; zoonoses.

Figure 1

Timeline of events for investigation of Zika virus infection in patient with no known risk factors, Utah, USA, 2016. CDC, Centers for Disease Control and Prevention; DOH, Department of Health.

Figure 2

Characteristics of clinical course investigation of Zika virus infection in patient with no known risk factors, Utah, USA, 2016. Patient location, procedures, and body fluid output are as documented in medical records by day of treatment or observation of index patient. Body fluid output is separate from potential exposures generated by procedures. CRRT, continuous renal replacement therapy; ED, emergency department; ICU, intensive care unit; IV, intravenous line; ✓, recorded output (frequency).