Once You Zika Can You Get It Again
Story highlights
- Study shows male and not-pregnant monkeys could non exist reinfected with Zika
- Merely meaning monkeys stayed infected 30 to 70 days longer
- Researchers worry that Zika could be passed back from fetus to mother
(CNN)Once you lot've had Zika, can you lot become it again? Scientists don't recall and so, merely it's never been proved. Researchers from the University of Wisconsin say they are one step closer to answering that question afterward studying how the virus affects rhesus macaque monkeys.
"It'southward important for the states to show in a lab setting what people have expected in humans: that you lot clear infection past the Zika virus inside a week, and you are protected from future infections by the same virus," said Emma Mohr, a pediatric infectious disease fellow at UW-Madison and 1 of the lead authors of the study, published in Nature.
Eight animals, ii of whom were significant, were infected with the Asian strain of Zika, currently circulating in much of Central and Due south American and the Caribbean. It's the strain associated with serious nascency defects, such as microcephaly, and an increased hazard for Guillain-Barré, a disorder in which the trunk'south own immune system attacks nerve cells.
The monkeys that were non meaning showed that the virus stayed active in claret for upwards to 10 days and lasted upwardly to 17 days in urine and saliva. Then the virus appeared to go away and stay away, fifty-fifty after the animals were reinfected with the same strain 10 weeks later.
"When we gave the aforementioned virus dorsum to the animals, there was no sign of disease in their blood," said biologist Dawn Dudley, another author of the report. "We saw complete protection for up to 28 days following the exposure."
"And it goes down to zero levels or at least below our threshold of detection," added co-author David O'Connor, chairman of the Global Infectious disease division of the Wisconsin National Primate Research Center.
O'Connor and his team had seen like results earlier in the yr when they infected some other grouping of monkeys with the African strain and then introduced the Asian variation.
"It's pretty solid evidence that the initial infection provides some protection from reinfection from either strain," he said. "The reason I'm hedging that a niggling bit is because we don't know how long. Information technology could be a year; it could be three years, 5 years. Information technology could be lifetime amnesty. We just don't know correct now, and the studies are so new that we can't have that data nonetheless."
Simply there were likewise some startling findings. The virus appears to stay longer in pregnant monkeys, much longer than the 10-day average in males and not-meaning monkeys. In results published online in an open up inquiry portal, O'Connor's grouping found that the virus lasted approximately thirty days in one pregnant female and 75 in another.
"In this latest study, we infected two females in their 3rd trimester," O'Connor said. "In one animal, the infection wasn't extended at all, and in the other, the amount of virus in the claret stayed relatively constant out to 50 days."
O'Connor says these data advise that every pregnancy is different in terms of how long the virus persists, at least in monkeys.
"Our running hypothesis is, nosotros're actually seeing the virus being given from the fetus back into the mother," O'Connor said. "And we believe that the longer this happens, the greater the probability of fetus abnormality there volition be. Again, that's a hypothesis right now, but that's what we're currently testing."
O'Connor says his findings are particularly meaning in calorie-free of a recent case report published in the New England Journal of Medicine that describes what happened to a 33-twelvemonth-old Finnish woman who developed Zika while pregnant.
"She had the same thing," he explained, "where the virus persisted until the woman terminated her pregnancy, at which point, the virus went completely away. So that's another reason nosotros believe this might actually be a virus that is coming back into the mother from the fetus and not but the mother being infected and not being able to fight it off herself."
O'Connor'south group is using a strain of Zika that came from French Polynesia, site of the first large outbreak of Zika in humans. Some other research grouping at the UC Davis primate inquiry center is also infecting iii pregnant macaques but using a sub-strain of the virus from a patient in Brazil. And their study involves a unique twist.
"In improver to infecting the significant monkey, nosotros are also infecting the fetus via the amniotic fluid," said Dr. Koen Van Rompay, Zika project leader at the heart. "To make absolutely sure that the infant has Zika."
But ane calendar week subsequently the mothers were infected, one of the fetuses died, and an dissection showed massive amounts of the virus in bodily tissues. The other ii monkeys are still advancing in their pregnancies and at this time prove no show of the virus in their blood.
"Simply nosotros do see large amounts of the virus in amniotic fluids," Van Rompay said. "What all of this means, it's simply as well before long to tell. And you lot have to remember, these are studies in only a few animals. We may need to replicate in a larger group."
Van Rompay and his colleagues hope to do just that this fall, when breeding flavor for the rhesus macaque is at its pinnacle.
"Our hope is that once we have a better understanding of the brute model of the Zika virus, we can test multiple strategies to gainsay the virus in a very curt period of fourth dimension, using a very small number of monkeys," Van Rompay said. "This can provide the information doctors need to start clinical trials in humans."
Source: https://www.cnn.com/2016/06/29/health/zika-immunity/index.html
0 Response to "Once You Zika Can You Get It Again"
Post a Comment