NEW YORK - Maybe Andrew Speaker, flying abroad despite a dangerous strain of tuberculosis, took things too far. But many people push the limits by staying active when they're sick. Depending on circumstances, the choice can be seen as laudable, inconsiderate - or downright criminal.
At the office, coughing and sneezing workaholics might earn a thank you from a boss for their dedication, but dirty looks from co-workers worried about catching the bug. Athletes who compete while sick are sometimes praised for grit, but may risk infecting teammates.
And then there are people who know they are HIV-positive, yet press ahead with unprotected sexual encounters with partners who've been kept in the dark.
Speaker, now quarantined at a Denver hospital, knew he had a drug-resistant strain of TB before he flew to Europe for his wedding and honeymoon last month, but says he was advised before departure that he wasn't contagious.
Dr. John Chan, an infectious disease expert at Montefiore Medical Center in New York, says that in more routine TB cases it is often very difficult for doctors to determine how contagious a patient might be and when he or she could safely return to work.
"That's a very tough question to address, even when you treat the patient effectively," he said. "There's no one clear-cut answer."
Employers - whether an investment firm or a military base - try to walk a fine line when it comes to ailing workers. They don't want staff staying home for trivial reasons - a mild headache, say - nor do they want to create pressures that would prompt contagiously ill employees to bring germs into the office.
The investment firm Merrill Lynch confronted this issue last month when it announced new "attendance guidelines" reducing to three the number of sick days that employees can take without documented excuses. Company spokeswoman Selena Morris stressed that the move was aimed at abuses, adding, "I don't think in any way we were saying, 'Come to work sick.'"
In past decades, many employers oversaw some sort of "perfect attendance" policy rewarding workers who never missed a day over an extended period of time. Kim Stattner, an absence management expert with the consulting firm Hewitt Associates, said those policies are fading from the scene.
"They don't want to promote the kind of thinking that could encourage sick people to come to work," Stattner said. "If you're sick, that's why they give you the sick time. But it's not there to be abused."
In big-time sports, of course, the pressures are different. There is a time-honored tradition of athletes playing with the flu - or worse - especially in important games.
Now-retired quarterback Cade McNown, for example, lists as one of his career highlights a game he refers to as "The Breakfast." It involved "playing while sick, vomiting on the field, and coming back to throw for 202 more yards" while leading UCLA against Oregon in 1998.
When New York Ranger center Michael Nylander was playing with the flu early in this year's Stanley Cup playoffs, hockey fans praised his determination. "This is the time of year that only a severed limb would keep players out of the lineup," said a commentary about him on one fan Web site.
But even coaches need to be wary. Experts in sports medicine say the initial praise that a sick athlete may hear for coming to practice could switch to criticism if other team members soon show similar symptoms.
The ethics of being ill are of particular importance in regard to HIV-positive people. Though medical advances now enable many to lead long, productive lives - and to pose no public health threat - there is nonetheless a persistent problem created by a subgroup that engages in unprotected sex while keeping their status secret from their partners.
One study by Brown University researchers of 203 HIV-infected individuals - a mix of gays and heterosexuals - found that 40 percent did not disclose their status to sexual partners. The study also found that the non-disclosers were just as likely as the disclosers to engage in unprotected sex.
Many states have passed laws making it a crime to knowingly infect someone with HIV. One of the most infamous cases involved Nushawn Williams, an HIV-positive man who admitted trading drugs for sex with girls in upstate New York during the 1990s.
He knowingly infected at least 13 women with HIV and was sentenced to serve four to 12 years in state prison.
The bottom line, for health authorities and employers, is to persuade sick people to think of others as well as themselves.
"You want to be encouraging the right behavior, not the wrong behavior," Stattner said.