The last time Costa Rica had a case of measles was in 2014, but that changed last week when a family from France brought their un-vaccinated kid along for the family vacation.

Health authorities have quarantined the five-year old boy as well as his parents, aged 30 and 35.  They arrived in the Central American country on holiday on February.  Sometime after that, they noticed a red rash on the kid and took him to see a local doctor.  The Costa Rica Star reports they told the doctor that there had been cases of measles reported at the boy's school.

The race is on to find anyone the family might have come into contact with and possibly infected.  That includes 311 people on board the flight from Paris.  Several workers at the hotel where the family stayed for one night have been vaccinated against the disease.

It's not clear why the French parents didn't have the five year old boy vaccinated.  But it comes at a time when the number of measles cases tripled in Europe over the past year (.pdf link), fueled mostly by an outbreak in Ukraine but in France with more than 2,900 cases.  This is being helped along by anti-vaxxers who wrongly believe the measles vaccine causes autism.  The UN World Health Organization says "vaccine hesitancy" is one of the top 10 global health threats this year.