The parents of a child diagnosed with measles reportedly decided to send them to daycare in the Philadelphia area in December, leading to four more known infections.

At least eight people were diagnosed with measles after a child who recently spent time in another country contracted the virus and was sent to the Children’s Hospital of Philadelphia (CHOP), according to NBC News. The case was described by Philadelphia’s Department of Public Health as “imported,” but officials reportedly would not say where the child contracted the potentially deadly illness.

Three other people at CHOP contracted measles after the child was admitted, two of whom were already inpatients for unrelated reasons, the outlet noted. A parent and child were reportedly two of those infected, the latter of whom was allegedly not vaccinated against the disease.

Despite being given quarantine instructions, the parent reportedly decided to still take their child to daycare on Dec. 20 and 21, where four other individuals were infected.

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None of the individuals diagnosed were immune to measles, which apparently means they never received a measles-mumps-rubella (MMR) shot, according to the outlet. As an infected person can spread measles to around 90% of those they come into contact with, it’s unclear whether there will be legal issues related to the parent who thought it was okay to defy quarantine orders and perpetuate the spread of the disease.

Symptoms of measles can take up to two weeks to appear in an infected person, according to the Centers for Disease Control and Prevention (CDC). The disease spreads as a rash, with accompanying runny nose, cough and conjunctivitis (pink eye). (RELATED: Officials Believe They Found The Culprit Behind Deadly, Multi-State Listeria Outbreak)

Children under the age of five, pregnant women and adults aged 20 years or more are most at risk from complications from measles, according to the CDC. The most common cause of measles-related death in children is pneumonia contracted while suffering from an outbreak of measles.