As reports of Zika virus infections continue to spread through the Americas, countless questions loom. Chief among them is about the relationship between infection during pregnancy and microcephaly in babies, which has been difficult to pin down given the limitations of current diagnostics. A number of researchers are working at breakneck speed to develop immunological reagents and assays that could confirm whether a person has had a Zika infection.
Currently, the standard assay for Zika viral infection is a PCR test that probes for the presence of viral RNA in a sample.
More user-friendly serologic tests, which measure the presence of antibodies against a particular pathogen, would be a better alternative, but in the case of Zika it’s been difficult to tell which flavivirus a person has encountered—whether dengue, Zika, or another. “And the problem is, where Zika is occurring is the same place dengue is occurring,” said immunobiologist Mike Diamond of Washington University in St. Louis.
Several commercial outfits are selling serologic Zika tests. For instance, San Diego–based MyBioSource sells an IgM ELISA to test for Zika. Biocan Diagnostics, based in Canada, is selling a finger-prick assay that can detect IgM and IgG antibodies (which are elevated even longer after an infection than IgM antibodies) against Zika and give results in five to 10 minutes. “It can be used in field settings or mobile clinics, and doesn’t need any special equipment,” said Bhavjit Jauhar, the vice president of sales and development for Biocan. He said his firm’s screening test is 99 percent specific, with no cross-reactivity with dengue or chikungunya.
New Tests for Zika in the Works
Source: TheScientist Magazine