Waves of needle pricks at musical events also have confounded authorities in France, Britain, Belgium and the Netherlands. Now it's seemingly Spain's turn.
The number of women in Spain reporting being jabbed with medical needles while at nightclubs or parties has risen to 60, according to the country's interior minister.
Fernando Grande-Marlaska told state broadcaster TVE that police are investigating whether "the inoculation of toxic substances" is intended to subdue victims and commit a crime, mainly of a sexual nature.
He added the probe will also seek to ascertain whether there is another motivation, such as creating insecurity, or intimidating women.
Waves of needle pricks at musical events also have confounded authorities in France, Britain, Belgium and the Netherlands. French police have tallied over 400 reports in recent months, and said the motive of the jabs was unclear. In many cases, it also wasn't clear if the victims were injected with a substance.
Spanish police have not confirmed any cases of sexual assault or robbery related to the mysterious jabs.
They said that 23 of the recently reported needle attacks were in northeast Spain's Catalonia region, which borders France.
Spanish police so far have found evidence of drugs in one victim, a 13-year-old girl in the northern city of Gijón who had the party drug ecstasy in her system. Local media reported that the girl was quickly taken to hospital by her parents, who were near her when she felt a prick with something sharp.
In an interview with TVE that aired Wednesday, Spain's justice minister Pilar Llop urged everyone who thinks they received a shot without their consent to go to the police since being stabbed with a needle “is a serious act of violence against women”.
Spanish health authorities said they were updating their protocols to improve the ability to detect any substances that were possibly injected into victims. The toxicological screening protocols call for blood or urine tests within 12 hours of a suspected attack, Llop said.
The guidelines advise victims to immediately call emergency services and go to a health centre as soon as possible.