Across Los Angeles, there are dozens of billboards blaming the apps Tinder and Grindr for spreading sexually transmitted infections and encouraging people to get tested. Tinder would like the billboards to come down. The AIDS foundation behind the advertisements is standing its ground.

Certainly not all dating apps lead to casual sex, STIs and STDs, but the Internet has enabled more sexual anonymity; and in that environment, infection can spread. As my Post colleague Sarah Kaplan has reported: “The most conclusive evidence linking the Internet to STD rates is a much cited 2013 study that found that the introduction of Craigslist to 33 states across the country led to a 15 percent increase in HIV rates.”

The Centers for Disease Control and Prevention estimates that there are 20 million new cases of STIs every year in the United States. So once you’ve been tested, what’s the best way to disclose a positive diagnosis?

There are two mind-sets, says Jenelle Marie Davis, founder and executive director of the STD Project, who has had genital herpes since she was 16. You can either do it right out of the gate, Davis says, by noting in your dating profile that you’re HSV+ or using the number 437737, which spells out HERPES on a touch-tone phone.

By putting it out there immediately, “you don’t have to worry about having the conversation once people are emotionally invested,” she says, at which point rejection can sting a bit more.

Or you can wait a little while, she says, and bring it up before you engage in sexual activity and put the person at risk. Now 33, Davis runs a Web site and organization about STI awareness, so she doesn’t have to disclose her status to first dates; a quick Google search does that. But before she was “out” about her status, she preferred “to wait a little bit until I’ve established that trust.”

“No one goes to a first date and says: ‘I have foot fungus.’ Or: ‘My mom is in prison.’ Or: ‘I previously had a drug problem,’ ” Davis says. “If you say all the things about you that might be awkward or specific or weird, people would run.”

It’s taken a while for Davis to get comfortable disclosing that she has herpes. In her teens and early 20s, rather than take either of the two above approaches, she mostly had one-night stands and didn’t talk to the person again. When she got a bit older, if she was interested in someone, she still didn’t have the courage to disclose her diagnosis before getting intimate. Days after the fact she would ask the person, “Hey, do you have a minute?” and then go over to his house to talk about it.

“I’ve always said: Here’s the situation … so I have genital herpes. I was diagnosed when I was 16 years old,” she tells me. “I wasn’t overemotional about it. I gave them the factual information,” she says, then she’d leave and allow the person to think on it. She’d also make it clear that she would always respect the other person’s decision.

All three times she’s had this conversation, her partner has been accepting. Often, the response would be: “That’s it? That doesn’t make you a different person. … It doesn’t change how I feel about you.” (Davis is quick to point out that not everyone has such positive experiences with disclosure.)

What if you can’t bring yourself to have a conversation about it? There are anonymous tools, too. Davis cites Don’t Spread It and So They Can Know — Web sites that allow users to send anonymous e-mails or texts to partners about the potential transmission of STIs.

“Interestingly enough, now I’ve been told by men that it makes me hot and sexy” because she works to reduce stigma around STIs. “It’s almost overwhelming, in a good way,” she says, adding: “That says there’s a lot that has been changing” with regard to the stigma around STIs.

And that’s what makes the Los Angeles billboards so confusing to her. They imply that every person on a dating app not only has an STI but is an STI, she says, “as opposed to a person who may or may not have an infection, which means there should be an informed, conscientious and thoughtful discussion about whether they’ve been tested, or would like to be tested.”