Zika Virus Infection in the Department of Veterans Affairs (VA)

Abstract

Background. Zika virus, transmitted by Anopheles mosquitoes, has emerged as an important flavivirus in the Americas. Cases have now been reported in the United States. We characterized the first endemic Zika infection in Puerto Rico (PR) in December 2015, an Asian strain closely aligned with strains from Brazil (1). Herein we report on Zika infections in VA. Methods. Serum samples submitted to the VA Public Health Reference Laboratory (PHRL) for clinical testing were analyzed initially for Zika virus using a modified CDC RT-PCR assay, and then subsequently using the Trioplex RT-PCR (Zika, Dengue, Chikungunya [CHIK] viruses), and CDC Zika MAC-ELISA, dengue and CHIK EIA IgM assays. VA data warehouses were queried to identify cases not tested at PHRL. Zikapositive cases were chart reviewed for demographic and clinical information. Results. One hundred eighty unique samples from 19 VA medical centers were submitted for testing between 7 December 2015 and 13 May 2016, of which 48 (26.7%) were positive for Zika virus (25 RT-PCR and 23 IgM presumptive positive) in 47 unique patients; 43 were from PR, 4 from other VA facilities (traveled to Dominican Republic, Haiti, Honduras and PR); 42 males, 5 females (1 pregnant at time of infection); mean age was 60 years (range 25-89). Six (13%) were hospitalized, 3 in intensive care; no Guillain-Barre syndrome or deaths were documented. Documented fever, rash, myalgia/arthralgia, conjunctivitis, leukopenia (<4.3 x 103) and thrombocytopenia (<155 x 103) occurred in 66%, 81%, 79%, 32%, 36% and 32%, respectively. Five patients were also dengue IgM positive (4 Zika IgM+ , 1 Zika RT-PCR+) and none were CHIK IgM or RT-PCR positive for dengue or CHIK. Confirmatory Zika antibody plaque reduction neutralization testing is being performed. Conclusion. Zika infection has rapidly become endemic in PR (2). Compared to reported Zika infections in PR, Veterans demonstrated similar signs and symptoms, but were older, predominantly male and associated with higher than expected numbers of hospitalizations.