This is the worst trend ever: Afghan police say yet another poisoning attack at a school -- the fourth this year and the second in a week -- has put 160 female students in the hospital as Taliban militants try to keep women from getting an education. But, as The BBC reports, not only has the Taliban denied the attacks (three of which hit girls' schools but the biggest of which affected a boys' school), a report this week says there's no evidence the students were actually poisoned.

In the latest incident in the northern province of Takhar, police said attackers poisoned classrooms with some kind of spray. Per CNN: "The girls, ages 10 to 20, complained of headaches, dizziness and vomiting before being taken to the hospital, according to Khalilullah Aseer, a police spokesman." The apparent attack follows one last week that put 120 schoolgirls and three teachers in the hospital, and an incident on May 15 in which some 400 boys became sick after apparently drinking poisoned well water. The trend started last month, when more than 100 schoolgirls went to the hospital after drinking well water thought to be poisoned.

The latest apparent attack comes just a day after Agence France-Presse's Lawrence Bartlett ran a report that found "neither the government nor NATO's military in Afghanistan have discovered proof of poisoning." Rather, one expert said that what looked like poisoning had "all the earmarks" of mass hysteria among a population traumatized by "three decades of war, poverty, family disputes and migration issues."