NEW ORLEANS -- The Zika virus has struck fear throughout the
Here’s why: Most infected people don’t display symptoms or they choose to tough out what may seem like nothing more than influenza instead of seeking medical help. Moreover, infected people don’t have much detectable virus, and what’s in the body doesn’t linger.
There is no commercial test approved by the
Researchers are seeking to streamline the process. Among them is Robert Garry, a
The procedure Garry and his colleagues want to develop will look for antibodies because, Garry said, they stay in the body longer, especially in urine.
“The virus goes away quickly, but the damage can be done,” said Garry, a professor of microbiology and immunology.
According to the CDC, Zika antibodies show up in the blood four to five days after the onset of illness and can last 12 weeks -- or longer.
Garry said the CDC’s test looks for immunoglobulin M, or IgM, antibodies that show up relatively early in an infection.
“They wouldn’t detect a longer-term infection,” said Garry, adding that the test he and his colleagues want to develop would find antibodies that appear later.
The Zika virus, which now has a toehold in the United States after sweeping through Brazil and other Latin American countries, is most commonly spread by mosquitoes but can also be transmitted via blood, sexual contact and by mother to fetus.
The CDC has logged more than 2,900 cases in the United States and since July reported that cases in Florida that were likely caused locally by mosquito bites. Nearly 16,000 cases have been reported in
Symptoms can include fever, rash, joint and muscle pain, and nausea, but most infected people may not realize they have the virus. There is no specific medicine or vaccine. The CDC recommends rest and plenty of fluids.
The virus is most dangerous when transmitted to a pregnant woman because it can cause microcephaly, a condition in which the brain does not develop properly in the fetus, resulting in a smaller-than-normal head.
In addition to the CDC’s antibody-detection test, which is known as Zika MAC-ELISA, another test from the CDC is designed to distinguish the Zika virus from closely related microorganisms that cause dengue and chikungunya.
In both, a specimen of blood, serum or urine is put onto a plastic plate and subjected to several hours of incubation and washing, followed by the addition of a reagent that will produce a color pattern. An instrument that measures colors is then used to confirm the presence of the virus, said Randall Kincaid, the senior scientific officer at the
The turnaround time on each should be about a day, he said.
“It isn’t my favorite or anyone’s favorite type of an assay,” Kincaid said, “but it’s what the CDC had available as a template for evaluating infections by endemic virus.”
Acknowledging that this takes time, Kincaid said, “If your concern is knowing that you’ve been infected, you’re willing to sacrifice a day to get the most reliable answer.”
The other procedures also use blood, serum or urine samples to look for the Zika virus’ RNA, a molecule that is important to genetic coding. Each test, Kincaid said, teases out the virus -- if it’s there. The result should be available within hours.
The confidence in these tests is “quite different, based on the virological truths that underlie these tests,” Kincaid said.