High Incidence of Chikungunya Virus and Frequency of Viremic Blood Donations during Epidemic, Puerto Rico, USA, 2014

Abstract

Deaths were rarely observed, but newborns and other vulnerable populations are at risk for severe complications.

Viremia and Clinical Presentation in Nicaraguan Patients Infected With Zika Virus, Chikungunya Virus, and Dengue Virus

“…Patients with low-positive CHIKV viremia have been identified in other series, but the clinical presentation of and outcomes for such cases have not been evaluated [17–20, 25]. In our study, 57.1% of CHIKV-positive patients had viremia that was below the quantifiable range in the ZCD assay.…”

Evaluating Vaccination Strategies for Zika Virus in the Americas

“…For example, if 25% of the population in Puerto Rico is already immune to Zika (27), coverage of 50% or 90% of women 9–49 would reduce prenatal infections in a subsequent outbreak to 5 or 2, respectively, per 1000 pregnancies (Figure 3B–C), compared with 192 in an unvaccinated, immunologically naive Puerto Rican population (Figure 3A). The expected impact under reduced vaccine coverage represented in this sensitivity analysis also approximates the impact under reduced vaccine efficacy.…”

“…Third, we determined the best fit parameter sets for the epidemiological variables using a least-squares approach. For Puerto Rico, we computed the human-to-mosquito transmission rate that produced a 23.5% attack rate, as observed during the Puerto Rico Chikungunya outbreak (27), and computed the mosquito seasonality parameters which best fit the observed Zika epidemic trajectory over the period January 17, 2016 through July 21, 2017 (28,29) (Figure S2). When not otherwise specified, we used the Puerto Rico best-fit attack rate as our base case.…”

Screening of Blood Donations for Zika Virus Infection — Puerto Rico, April 3–June 11, 2016

“…Retrospective screening for chikungunya virus nucleic acid was performed on blood donations collected during June-December 2014, and the estimated detectable viremia was 0.65%, with a peak of 2.1% in October. Testing for chikungunya virus immunoglobulin M antibody of retained individual blood donation samples obtained during March 1-9, 2015, suggested that nearly 25% of the Puerto Rico population became infected during the previous year's epidemic (7). Because viremia is only present days after acute infection, immunoglobulin M antibody can provide a more precise estimate of the burden of recent infection.…”