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There has never been a documented case in which HIV was transmitted via saliva. But Willie Campbell, who is HIV positive, has been behind bars for nearly a decade and is serving a 35-year sentence for spitting at a Dallas police officer. According to the ruling, Campbell's saliva was a deadly weapon, and spitting at the officer was akin to using a firearm.

In 2008, Daniel Allen, who is also HIV positive, bit his neighbor during a fight and was subsequently arrested and charged — with bioterrorism. Allen faced a possible 28-year prison sentence before the charges were thrown out.

That same year, Patrice Ginn was sentenced to eight years behind bars on charges that she didn't tell her partner she had HIV. There was conflicting testimony at the trial about whether or not she told him; he brought the charges only after their relationship ended. Ginn's partner never actually contracted HIV.

These are just three examples of how old laws still on the books all over the United States — laws whose very premises are contradicted by science — are still getting HIV-positive people arrested and sent to prison. Many of the behaviors that are criminalized have almost no chance of transmitting the virus.

"We're not talking about cases from 10 or 20 years ago," said Catherine Hanssens, executive director of the Center for HIV Law and Policy. "People are being arrested and prosecuted right now."

At least 80 HIV-positive people have been prosecuted for having consensual sex, spitting on people, or biting people in the last two years alone, according to a report by the Center for HIV Law and Policy — and Hanssens says those are just the people of whom the center became aware. Thirty-four states have HIV criminalization laws, and even states without HIV-specific laws have been known to prosecute people with HIV.

Almost all of these laws were written shortly after HIV/AIDS was discovered in the 1980s. In some states, it's a felony for a person with HIV to share a sex toy, spit on someone, or put their finger in someone's ear, Hanssens says.

"These really came from the fear and stigma of the '80s, when we knew very little about HIV," said Jay Brown, director of research and public education at the Human Rights Campaign (HRC) .

According to watchdog groups, criminal charges associated with HIV haven't let up as the decades have passed, even though the retrovirus has become better understood and drugs to treat and prevent it have gotten better, says Sarah Warbelow, HRC's top lawyer. In the 1980s, contracting the virus was a relatively swift death sentence with no medications to speak of.

"Today, we're in a radically different environment," Warbelow said, explaining that decades in prison doesn't warrant the so-called crime of transmission, if transmission indeed takes place at all. "Individuals who are treating their HIV are living pretty close to normal life spans. It's no longer debilitating. But people still perceive HIV as it was when they first learned about it."

There are 1.2 million people in the United States living with HIV, according to the Centers for Disease Control and Prevention, though about 12.8 percent of them don't know they're HIV positive. People can take a daily cocktail of antiretroviral drugs that can make their viral loads — the amount of virus in their blood — undetectable and virtually impossible to transmit. People at risk for contracting HIV can also take an antiretroviral drug called Truvada as pre-exposure prophylaxis, or PrEP, to help avoid infection.

"We talk about HIV now as a chronic disease that needs chronic management and chronic attention much the same way we think about diseases we're more familiar with, like diabetes," said Dr Wendy Armstrong, professor of medicine at Emory University and vice chair of the national HIV Medical Association.

Still, people with HIV must take drugs daily and undergo routine blood work and other testing to be sure their viral loads are under control and they don't have any other health problems. Drug side effects can include diarrhea, headaches, and nerve problems in the short-term, as well as long-term blood sugar, cholesterol, and fat storage problems. Older patients may also have bone density issues and a buildup of cellular waste that can lead to liver failure.

This summer, the Kaiser Family Foundation conducted a survey in Georgia, which has the fifth-highest number of HIV/AIDS diagnoses in the country, and found that a large minority of people held several misconceptions about the way HIV is spread. Thirty-three percent of those surveyed said they thought HIV could be transmitted by kissing. Seventeen percent thought it could be spread by sharing a drinking glass, and 12 percent thought it could be transmitted by sitting on a toilet seat previously used by someone with HIV.

None of this is true.

In nine states, it is a felony for someone with HIV to have sexual contact without disclosing his or her HIV status, but most people don't know the law until they get charged, Hanssens says — and many charges are brought after a break-up of some kind. Only some states require plaintiffs to prove that the HIV-positive partner intended to transmit the virus.

"In a number of cases, it seems pretty clear that the complaining witness knew about the person's HIV," she said.

Armstrong says one of her patients who'd been raped was afraid to report it to police because she feared being arrested for failing to disclose to her rapist that she was HIV-positive.

"She was concerned if her HIV-positive status came out, in fact, she would be considered a perpetrator in that setting because of the criminalization laws," Armstrong said, acknowledging it's an extreme example, but one that illustrates the fear the laws can generate.

Infectious Diseases Society of America and the HIV Medicine Association, which are made up of physicians, health workers, and scientists, have come out against the laws, which they say discourage finding out one's HIV status and encourage those who know they're HIV positive to keep it a secret.

"Criminalization is not an effective strategy for reducing transmission of infectious diseases and in fact may paradoxically increase infectious disease transmission," they said in a March statement. "We, therefore, urge state policy makers to promote public health by revising statutes that criminalize transmission of diseases, such as HIV infection, viral hepatitis, and other communicable diseases."

While there is a movement to get the laws repealed, removing existing laws from the books is no easy task, says Boston University School of Law professor George Annas, who chairs the school's Department of Health Law, Bioethics, and Human Rights.

"Legislators just hate to repeal stuff because they're afraid to be blamed if something happens," he said, pointing out there's still a law prohibiting "fornication" in Massachusetts that no one wants to repeal.

HIV-positive activist Josh Robbins, who runs ImStillJosh.com, helped develop an iPhone app called Disclosur+ he says can be used as proof of disclosure in court. Before engaging in consensual sex, an HIV-positive person can bring up the app, which displays the phrase "I'm HIV positive," and the HIV-negative partner can tap to confirm that he or she understands. The app records a few seconds of soundless video to prove the disclosure and acknowledgment occurred.

Robbins says he finds existing HIV criminalization laws terrifying because cases involving disclosure often amount to court battles of he-said, she-said.

"You just have to think about in a jury situation, when I go to court and you are standing there accusing me and you're crying and pointing your finger at me, and I'm the HIV-positive person," he said. "I'm always going to get convicted no matter what. No one is going to believe me because of the stigma with HIV."

This story is part of a partnership between MedPage Today and VICE News.