Results presented in Table 1 showed that the RapidWN test produced 100% agreement of serological sensitivity for acute, CDC WNV IgM and IgG ELISA-positive and plaque neutralization reduction test (PRNT
In the United States, testing of samples by hemagglutination inhibition (HAI), ELISA, and/or PRNT
is commonly undertaken by state reference laboratories or by the CDC.
While being a valuable tool in the diagnosis of WNV infection and being the most specific of any of the flavivirus serological assays, PRNT
exhibits a number of limitations, which restrict the test's capacity to be exploited for high-volume measurement of antibody against WNV.
We performed plaque reduction neutralization tests (PRNTs
) on a subgroup of samples to detect neutralizing antibodies against 4 DENV serotypes (DENV-1, strain Hawaii; DENV-2, strain 16681; DENV-3, strain H87; DENV-4, strain H241) and 2 Zika virus strains (strain MR766 and 1 clinical isolate from a patient who acquired infection in Thailand).
Laboratory evidence of congenital Zika virus infection includes a positive Zika virus NAT or a nonnegative Zika virus IgM with confirmatory neutralizing antibody testing, if PRNT
confirmation is performed.
CHIKV, chikungunya virus; dpo, days post-symptom onset; E, envelope; NS, nonstructural protein; PRNT
, plaque reduction neutralization test.
Testing is not routinely recommended for pregnant women with a previous diagnosis of laboratory-confirmed Zika virus infection by either NAT or serology (positive/equivocal Zika virus or dengue virus IgM and Zika virus PRNT
>10 and dengue virus PRNT
Twelve serum specimens were positive for IgG against Heartland virus, and 7 of those were confirmed for Heartland virus neutralizing antibodies by PRNT
. For the 7 donors with Heartland virus neutralizing antibodies, median age was 33 years (range 30-78 years) and 4 (57%) were men.
* Excludes live births with confirmed recent maternal Zika virus infection (positive Zika virus RT-PCR, or Zika or dengue virus IgM-positive or equivocal with Zika virus PRNT
titer [greater than or equal to] 10 and dengue virus PRNT
titer <10) or no evidence of Zika virus infection (Zika or dengue virus IgM positive or equivocal with Zika virus PRNT
titer <10 regardless of dengue PRNT
titer, or Zika virus IgM negative where all possible exposure occurred within 2-12 weeks of serum collection date), or confirmed congenital Zika virus infection based on infant testing (positive Zika virus RT-PCR or Zika virus IgM positive and Zika virus PRNT
titer [greater than or equal to] 10 with dengue virus PRNT
Because we used an isolate from West Africa in our PRNT
, our results are probably an underestimate of the true percentage of samples specific for CCHFV.
The USZPR defines laboratory evidence of possible recent Zika virus infection as 1) recent Zika virus infection detected by a Zika virus RNA nucleic acid test (NAT, e.g., reverse transcription-polymerase chain reaction [RT-PCR]) on any maternal, placental, or fetal/infant specimen or 2) detection of recent Zika virus infection or recent unspecified flavivirus infection by serologic tests on a maternal or infant specimen (i.e., either positive or equivocal Zika virus immunoglobulin M [IgM] AND Zika virus plaque reduction neutralization test [PRNT] titer [greater than or equal to] 10, regardless of dengue virus PRNT
value; or negative Zika virus IgM, AND positive or equivocal dengue virus IgM, AND Zika virus PRNT
titer [greater than or equal to] 10, regardless of dengue virus PRNT