By Susan Scutti

CNN

(CNN) -- Mariana Sifrit, the infant girl who contracted viral meningitis caused by HSV-1 when she was less than a week old, died Tuesday morning, her mother posted on Facebook.

HSV-1 is the same herpes virus that causes cold sores, and only rarely does it lead to viral meningitis, which causes the tissue covering the brain and spinal cord to become enflamed, according to the US Centers for Disease Control and Prevention.

It is believed that baby Mariana contracted the deadly virus from a kiss. Mariana's parents, Nicole and Shane Sifrit, both tested negative for the virus, they told CNN affiliate WHO.

Just 18 days old when she died, Mariana had spent her last week at the University of Iowa Children's Hospital in Iowa City, suffering from severe medical complications.

"Our princess Mariana Reese Sifrit gained her angel wings at 8:41 am this morning in her daddy's arms and her mommy right beside her," her mother, Nicole Sifrit, posted on her Facebook page. "She is now no longer suffering and is with the Lord."

A week after Mariana's July 1 birth, her jubiliant parents married. Within two hours of the ceremony, though, the newlyweds noticed that their newborn was not eating and would not wake up, they told WHO.

"She had quit breathing, and all her organs just started to fail," Nicole Sifrit told WHO. Early symptoms of viral meningitis may include fever, light sensitivity, headache and a stiff neck, according to Johns Hopkins Medicine.

The newlyweds rushed Mariana to Blank Children's Hospital in Des Moines, Iowa, where they learned that she had contracted meningitis HSV-1, which can be carried by someone with the virus even if they do not have an open sore.

Her mother told WHO she could not pinpoint exactly how Mariana caught the virus.

"It is very common to catch the virus, but very rarely does it develop into meningitis," said Dr. Tanya Altmann, a pediatrician at Calabasas Pediatrics in California. "The first two months after a child is born are very critical, as a virus can rapidly spread and cause serious illness in newborns."

Babies younger than 1 month and people with weakened immune systems are more likely to develop severe illness when diagnosed with viral meningitis, according to the CDC, which advises parents to be particularly careful during the first months of a baby's life.

Sifrit told CNN that Mariana was airlifted to the University of Iowa Children's Hospital on July 10 when her condition deteriorated. As of Sunday, reports indicated that the baby's condition was stable, though her liver was damaged and she was undergoing dialysis. Her condition worsened thereafter.

"Thank you to everyone who has followed her journey and supported us through this," Sifrit wrote in her Facebook post. "In her 18 days of life she made a huge impact on the world and we hope with Mariana's Story we save numerous newborns life. R.I.P. sweet angel."

CNN's Andrea Diaz contributed to this story.