(CNN) Iowa newlyweds are clinging to hope as their nearly 3-week-old daughter fights for her life after contracting a deadly virus believed to be from a simple kiss.

Nicole and Shane Sifrit welcomed baby Mariana on July 1. A week later -- two hours after the couple's wedding -- they say they noticed that the girl was not eating and would not wake up when they tried to get her to respond.

"Within two hours, she had quit breathing, and all her organs just started to fail," Nicole Sifrit told CNN affiliate WHO.

Herpes meningitis can be caused by bacteria, fungi or other types of germs, and it can be spread through sexual contact or from a woman to her baby during childbirth, according to

Mariana's parents both tested negative for the virus, they said, suggesting that it could have come from others who visited the child.

"They touch her, and then she touches her mouth with her hand," Sifrit explained. It's hard to pinpoint exactly how Mariana caught the virus, but she wants people to know that it's important that people are cautious when they let anyone handle their babies.

Nicole Sifrit says Mariana "isn't getting better, but she's not getting worse."

Dr. Tanya Altmann, a pediatrician at Calabasas Pediatrics in California, said that "viral meningitis is transmitted through close casual contact. However, she caught the virus and then developed meningitis. ... It is very common to catch the virus, but very rarely does it develop into meningitis.

"The first two months after a child is born are very critical, as a virus can rapidly spread and cause serious illness in newborns," she said. This is why parents are advised to be particularly careful during those first months.

Sifrit told CNN that Mariana was airlifted to the University of Iowa Children's Hospital in Iowa City on July 10 when her condition deteriorated. As of Sunday, "they are trying to keep the baby stable," and doctors are "fluctuating her dialysis to drain fluid off her body."

The mother is praying that her daughter's "liver starts repairing on its own and that the vessels around her heart start sealing and not leak oxygen so her body can heal."

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Doctors have warned that because of the damage the virus has caused, if Mariana survives, she will have long-term problems with her brain, liver and kidneys, according to Sifrit.

Mariana is expected to remain in the hospital for the next three to six months.