Ability to serologically confirm recent Zika virus infection in areas with varying past incidence of dengue virus infection - United States and territories, 2016.

Ability to serologically confirm recent Zika virus infection in areas with varying past incidence of dengue virus infection - United States and territories, 2016.

J Clin Microbiol. 2017 Nov 01;:

Authors: Lindsey NP, Staples JE, Powell K, Rabe IB, Fischer M, Powers AM, Kosoy OI, Mossel EC, Munoz-Jordan JL, Beltran M, Hancock WT, Toews KE, Ellis EM, Ellis BR, Panella AJ, Basile AJ, Calvert AE, Laven J, Goodman CH, Gould CV, Martin SW, Thomas JD, Villanueva J, Mataia ML, Sciulli R, Gose R, Whelen AC, Hills SL

Abstract
Background. Cross-reactivity within flavivirus antibody assays, produced by shared epitopes in the envelope proteins, can complicate serological diagnosis of Zika virus (ZIKAV) infection. We assessed the utility of the plaque reduction neutralization test (PRNT) to confirm recent ZIKAV infections and rule out misleading positive IgM results in areas with varying past dengue virus (DENV) infection incidence. Methods. We reviewed PRNT results of sera collected for diagnosis of ZIKAV infection from January 1 through August 31, 2016 with positive ZIKAV IgM results and ZIKAV and DENV PRNT performed. PRNT result interpretations included ZIKAV, unspecified flavivirus, DENV infection, or negative. For this analysis, ZIKAV IgM was considered false-positive for samples interpreted as DENV infection or negative. Results. In US states, 208 (27%) of 759 IgM positives were confirmed as ZIKAV, compared to 11 (21%) of 52 in the US Virgin Islands (USVI), 15 (15%) of 103 in American Samoa, and 13 (11%) of 123 in Puerto Rico. In American Samoa and Puerto Rico, more than 80% of IgM positives were unspecified flavivirus infections. The false-positivity rate was 27% in US states, 18% in USVI, 2% in American Samoa, and 6% in Puerto Rico. Conclusions. In US states, PRNT provided a virus-specific diagnosis or ruled out infection in the majority of IgM positive samples. Almost a third of ZIKAV IgM positive results did not confirm; therefore, providers and patients must understand that IgM results are preliminary. In territories with historically higher DENV transmission, PRNT usually could not differentiate between ZIKAV and DENV infections.

PMID: 29093104 [PubMed - as supplied by publisher]

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