Enzyme-linked immunosorbent assays using virus-like particles containing mutations of conserved residues on envelope protein can distinguish three flavivirus infections.

The recent outbreaks of Zika virus (ZIKV) in flavivirus-endemic regions highlight the need for sensitive and specific serological tests. Previously we and others reported key fusion loop (FL) residues and/or BC loop (BCL) residues on dengue virus (DENV) envelope protein recognized by flavivirus cross-reactive human monoclonal antibodies and polyclonal sera. To improve ZIKV serodiagnosis, we employed wild type (WT) and FL or FL/BCL mutant virus-like particles (VLP) of ZIKV, DENV1 and West Nile virus (WNV) in enzyme linked immunosorbent assays (ELISA), and tested convalescent-phase serum or plasma samples from reverse-transcription PCR-confirmed cases with different ZIKV, DENV and WNV infections. For IgG ELISA, ZIKV WT-VLP had a sensitivity of 100% and specificity of 52.9%, which was improved to 83.3% by FL/BCL mutant VLP and 92.2% by the ratio of relative optical density of mutant to WT VLP. Similarly, DENV1 and WNV WT-VLP had a sensitivity/specificity of 100%/70.0% and 100%/56.3%, respectively; the specificity was improved to 93.3% and 83.0% by FL mutant VLP. For IgM ELISA, ZIKV, DENV1 and WNV WT-VLP had a specificity of 96.4%, 92.3% and 91.4%, respectively, for primary infection; the specificity was improved to 93.7-99.3% by FL or FL/BCL mutant VLP. An algorithm based on a combination of mutant and WT-VLP IgG ELISA is proposed to discriminate primary ZIKV, DENV and WNV infections as well as secondary DENV and ZIKV infection with previous DENV infections; this could be a powerful tool to better understand the seroprevalence and pathogenesis of ZIKV in regions where multiple flaviviruses co-circulate.

A Pilot Dental Survey on Maui.

Routine dental screening surveys of third graders have proven to be a useful tool to monitor the dental health of a community, especially those of highest risk. In 2010 the PEW Charitable Trust (PEW) conducted state-by-state oral hygiene assessments, giving Hawai'i a poor grade, with routine dental surveys of children one of several criteria not met. The Maui Oral Health Task Force piloted its own survey for the island of Maui to assess the challenges in implementing a dental screening and to gain an understanding as to how obstacles might be addressed. Three issues were identified: technical (sampling methodology, data interpretation, and analysis), administrative (approvals of protocols, consent forms, and confidentiality), and operational (participation rates, dental referrals, and missing data of socio-economic status). These issues were relatively easy to resolve over the course of a few months due to the public's and providers' outcry over the negative findings of the PEW report. Two hundred and eighty-one students were surveyed, which represents 46% of the children whose forms were sent home for parental consent and approval. Of those returning the forms, 77% had parent's consent to participate. Based on our island survey, the estimated sample size and participation rate for the State of Hawai'i would be comparable to those of other states, which had met the PEW survey criteria. Comparative exploratory analysis between Maui and survey data from other states underscores the value of prevention in averting dental treatment.