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Zika Infection Now Linked|to Host of Birth Defects

(CN) - Infants risk developing birth defects other than microcephaly when their mothers have a Zika infection, adding more evidence that the virus poses a bigger threat than previously thought following the initial outbreak in Brazil in 2015.

In a study published Monday in the journal JAMA Neurology, a team of scientists show a variety of side effects in infants who contracted Zika in the womb. While only about 10 to 20 percent of babies who are exposed to the virus develop side effects, they can be severe when they happen.

Of the 11 babies studied, in whom the virus was confirmed in cord blood and amniotic fluid, three died within 48 hours of birth. Nine of them had microcephaly, while two of the babies had normal or above-average sized heads.

The researchers examined infants born in Brazil, the nation with one of the highest numbers of affected babies born in the past year and the first to report local active transmission in the Western Hemisphere.

The team recommends referring to these cases as "congenital Zika syndrome" due to the variety of birth defects associated with Zika that have been discovered over the past year. The public is primarily aware of microcephaly, which leads to abnormally small heads and brain damage, but research indicates there is a variety of disorders infants could develop.

"The general public is used to the term microcephaly for the babies congenitally infected by Zika. However, microcephaly is not the only thing that happens with fetal Zika infection," lead author Amilcar Tanuri told Time.

"This virus can disturb the normal development of the human brain by killing primary neural cells as well as delaying or modifying the movement of brain cells during development. If the lesions are very drastic the babies do not survive, and the ones that survive carry severe developmental or cognitive delays or deficits."

The study only involves a small number of cases, but adds to the growing body of scientific evidence surrounding Zika's connections to a host of disorders including Guillain-Barre syndrome. The findings also paint a comprehensive picture of how the virus appears to target developing brain cells.

The findings also illustrate the unique risk women who are pregnant or planning to become pregnant face as international agencies and health officials attempt to accelerate the development and distribution of reliable vaccines and treatments.

In addition to determining which disorders are linked to the Zika virus, the period of time the virus remains in a person's body is still largely unknown. However, another study published Monday presents evidence that Zika may remain in the saliva, sex organs and nervous systems of monkeys even after the body has successfully fought off the virus.

That study, published in the journal Nature Medicine, shows Zika could be transmittable well after the immune system has seemingly cleared the body of the virus. It also provides additional evidence that Zika can cause more neurological issues than previously thought, including in adults.

Led by James Whitney, a virologist at Harvard University, the team infected 36 macaques with two different strains of Zika, one from Puerto Rico and one from Thailand. After injecting the monkeys, they analyzed how Zika spread and found that the virus attached to immune cells that transported it to a nearby lymph node. The virus then multiplied and spread throughout the network of lymph nodes where immune cells replicate.

The team found that the monkeys had developed enough of an immune response to clear the virus from their bloodstream after five to eight days after infection. However, three weeks after the virus was gone from the blood, small amounts of Zika were still detectable in the saliva of about half of the monkeys.

Zika also remained in the testes, semen and prostate, as well as the uterus and cerebrospinal fluid. Upon looking at the brains of a few of the monkeys about one week after infection, the team found that the virus had infected the neurons of the cerebellum, which helps coordinate movement.

"There's a real urgency right now to learn about Zika virus, and we're still at an early enough stage that what we don't know is more than what we do know," David O'Connor, a pathologist at the University of Wisconsin who wasn't involved in the study, told The Verge.

Previous research has shown that Zika can remain in human saliva for about two weeks after infection, but the virus now appears to linger even longer and in multiple organs. This suggests people could be contagious longer than previously thought.

While the research raises several questions and adds to the potential risk Zika poses to infected individuals, the team did find that the monkeys in the study who became immune against one strain of the virus were also immune against the other strain. This finding could be important for the development of a vaccine.

"Every study that gets done is filling in pieces of this puzzle," O'Connor said.

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