As of Sep. 21, Japan has recorded 130 measles cases in 2016 to date, with the additional 21 cases reported last week, according to data from the Japanese National Institute of Infectious Diseases.

Japan Image/CIA

Japan has seen a spike in measles in the past five week, recording 111 cases since the end of August.

The number of cases in 2016 to date, triples the total cases reported in the same period last year.

Nearly two-thirds of the cases have been seen in adults ages 20-39.

105 of the 130 total cases are considered locally acquired measles cases, while 17 are imported and the status for another eight is unknown.

Earlier this month, we reported on a measles outbreak among dozens of employees of Kansai International Airport in Osaka Prefecture.

Related: How contagious is measles? Answer: Very

Measles is a highly contagious viral disease, which affects mostly children. It is transmitted via droplets from the nose, mouth or throat of infected persons. Initial symptoms, which usually appear 10–12 days after infection, include high fever, runny nose, bloodshot eyes, and tiny white spots on the inside of the mouth. Several days later, a rash develops, starting on the face and upper neck and gradually spreading downwards.

There is no specific treatment for measles and most people recover within 2–3 weeks. However, particularly in malnourished children and people with reduced immunity, measles can cause serious complications, including blindness, encephalitis, severe diarrhea, ear infection and pneumonia. Measles can be prevented by immunization.