NEW YORK -- The number of vaping-related illnesses in the U.S. continues to rise, now reaching about 1,300 cases and at least 26 deaths.

Forty-nine states and one U.S. territory have reported illnesses. Only Alaska has not seen a case.

The Centers for Disease and Prevention on Thursday said 219 cases were reported in the past week. The count had risen by 275 each of the previous two weeks.

The outbreak appears to have started in March. Symptoms include severe shortness of breath, fatigue, and chest pain. Most who got sick said they vaped products containing THC, the marijuana ingredient that causes a high, but about 1 in 8 said they vaped only nicotine.

Until a cause is pinpointed, the CDC is advising Americans to refrain from using any vaping products.