Symptoms often show up days later.

Reported cases of herpes have reportedly increased in areas surrounding the Coachella Valley following the two weekends of this year’s annual music festival.

Dr. Lynn Marie Morski from online herpes treatment service HerpAlert told PEOPLE that they normally handle 12 cases a day in southern California, but during the first two days of the music festival earlier this month they received almost 250 inquires—about 10 times more than their average.

HerpAlert is an online service that allows users to send photos of their possible infection for clinical evaluation and prescription treatment.

In the last 13 days, coinciding with the dates of the music festival, Morski said that 1,105 consultation requests were sent to HerpAlert from the Indio, Palm Desert and Coachella Valley area around the music festival, along with the Los Angeles area, Orange County and San Diego County.

Morski noted that the symptoms of a new herpes case often show up days later, which could explain why the cases were spread out across Southern California, not limited to the Coachella Valley area, as festival-goers returned home after the weekend.

Coachella Valley area hospitals did not immediately respond to PEOPLE’s request for comment.

According to the World Health Organization, the herpes simplex virus comes in two types: one which is mainly transmitted from mouth-to-mouth contact and causes herpes around the mouth, and a second which is a sexually transmitted infection that causes herpes around the genitals.

Both infections are lifelong.

The WHO report, last updated in January 2017, estimates that 67% of people in the world under the age of 50 have the first type of herpes, while 11% have the second.

Symptoms of herpes include painful blisters, open sores or ulcers around the affected area.

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This Story Originally Appeared On People