Experts don’t agree on the likely path of the disease, with some fearing that it is becoming so widespread that it is on the verge of becoming an entrenched STD — like gonorrhea, herpes and HIV.

But no one’s really sure, and some say testing and vaccines can still stop the outbreak from taking root.

So far, more than 2,800 U.S. cases have been reported as part of an international outbreak that emerged two months ago. About 99% have been men who reported having sex with other men, health officials say.

Health officials are not sure how fast the virus has spread. They have only limited information about people who have been diagnosed, and they don’t know how many infected people might be spreading it unknowingly.