The spread of Zika virus (ZIKV) in endemic areas and modes of transmission and symptoms pretty much comparable to those of Dengue virus makes it important to a proper differential diagnosis and the correct identification of the viral agent, for formidable potential neurological complications fetal (see articles 30 March, May 4, June 13, August 2, 12 September) related to ZIKV. As they are available in molecular biology tests for the detection of the viral genome (RT-PCR), very often it can not be used for diagnostic purpose since patients come late to the observation, and then in the absence of detectable viremia. The anti-IgM ZIKV can be researched on samples obtained at least 4 days of onset of symptoms, but, as recommended by the Food and Drug Administration (FDA), because to false positives due to cross-reactivity, it is necessary execution of a confirmatory test (neutralization with reduction of the plate, PRNT), not to quick access and execution.
The development, therefore, of an easily available serological tests and with wide diagnostic window, able to differentiate ZIKV and Dengue, is fundamental. For this, plays great interest the Brief Communication published a few days ago online by the prestigious journal Nature Medicine, whose authors describe the development of a diagnostic test based on a multiplex nanotechnology platform (ie with the use of gold nanoparticles with oscillating electrons – plasmons, pGOLD) can measure IgG and IgA and avidity of these antibodies against ZIKV and Dengue viruses. Unlike the highly cross-reactive IgM, the IgG and IgA antibodies against the antigen NS1 protein (non-structural protein1) are considerably specific for ZIKV and the IgG avidity test distinguishes recent infection from a ZIKV respect to previous Dengue virus infection in regions where both viruses are endemic. The test, which takes just 1 µl of serum, and gives results in two hours, it is ready to be validated through large scale trials and has been submitted to the FDA for permission to use in an emergency.
Nat Med. 2017 Mar 6. doi: 10.1038/nm.4302. [Epub ahead of print]
Diagnosis of Zika virus infection on a nanotechnology platform.
Zhang B1, Pinsky BA2,3, Ananta JS1, Zhao S1, Arulkumar S1, Wan H4, Sahoo MK2, Abeynayake J5, Waggoner JJ6, Hopes C1, Tang M1, Dai H7.