Penguins center Sidney Crosby is in isolation after being diagnosed with the mumps, becoming the latest victim of a bizarre outbreak that has struck at least a dozen NHL players this season.

The diagnosis was confirmed by a sophisticated test from the Centers for Disease Control, after a sample was sent Friday.

Crosby previously tested negative for the disease according to team physician Dr. Dharmesh Vyas, and was being treated for an infected salivary gland which complicated the diagnosis.

Extra testing and a subsequent two-game "precautionary" exile from playing this past weekend was prompted when the right side of Crosby's face swelled dramatically Friday after morning skate, for which he had been cleared medically.

"It was rapidly evolving. His condition worsened from the day before. And as soon as we noted that that's when we sent off additional samples," Vyas said.

Vyas said earlier blood tests indicated Crosby had very strong immunity to the disease from vaccination, and that he even had a booster vaccine before the Sochi Olympics.

"That's why it came about as a bit of a surprise to us," Vyas said. "Every indication was that he was well-protected against the disease. We made sure the whole team was checked. We immunized all of the players and staff who had low [immunity]. That was done approximately two weeks ago because of the outbreak of mumps in the NHL. We're trying to stay ahead of it."

No other players on the team have shown signs of the illness yet, but the team physician and general manager Jim Rutherford said they will continue to monitor everyone closely.

Players will get more sophisticated testing if they show symptoms of mumps, which are fever, chills, body aches, swelling and development of painful, tenderness along the jaw line.

Crosby is expected to miss at least a game tonight against the Tampa Bay Lightning, which would bring him to the end of a minimum five-day period of isolation recommended by the CDC.

Vyas did not rule out a longer absence.

"It's obvious we're concerned about it. It's a disease that's going throughout the league and you just don't know how far it can spread," Rutherford said. "So like Dr. Vyas said, we're watching this on a regular basis."

Complicating the diagnosis apparently was the fact that Crosby was being treated for an infected salivary gland on the right side of his neck.

Crosby had a CT scan after a game Nov. 29 at Carolina, when an opponent had squeezed his neck in an on-ice scrum, damaging and subsequently infecting, the gland on the right side of his neck.

Vyas said the incident had no direct connection to Crosby contracting the mumps, but admitted "it clearly confuses the picture" because it also caused swelling on that side of his face.

He also said the disease generally causes swelling on both sides of the face, not just one like Crosby had, and Crosby initially showed no symptoms of fever, chills or body aches.

Asked if the team made a mistake to allow Crosby to participate Friday in the morning skate, and potentially put teammates and others at risk, Rutherford said: "We can only go by the recommendations by the medical people. We're not going to overrule them on anything and quite frankly that decision was approved that he could be here. His condition worsened after the skate. That's when I got the call from Dr. Vyas, I think it was 5 o'clock in the afternoon. He said, you know, he could play in the game but there would be certainly some risk. At that point we said we're not going to do that. We're not going to do it, not only for our team, but for everybody around and the visiting team."

The best steps to contain the outbreak at Crosby, according to Vyas, is to sterilize the locker room frequently and use basic precautions such as washing hands frequently, not sharing water bottles "as much as we can for a professional hockey team" and continue to monitor players closely.

Mumps facts (Source: Mayo Clinic)

Cause: Mumps originates from the mumps virus, which spreads easily from person to person through infected saliva. If you're not immune, you can contract mumps by breathing in saliva droplets of an infected person who has just sneezed or coughed. You can also contract mumps from sharing utensils or cups with someone who has mumps.

Symptoms: Some people infected with the mumps virus have either no signs or symptoms or very mild ones. When signs and symptoms do develop, they usually appear about two to three weeks after exposure to the virus and may include swollen, painful salivary glands on one or both sides of your face (parotitis); fever; headache; weakness and fatigue; loss of appetite; and painful chewing and swallowing.

Vaccination: People are considered immune to mumps if they've previously had the infection or if you've been immunized against mumps. People should consult with their doctor to see if they need the vaccine or if they should forgo it; the necessity for vaccination depends on several factors, including age, gender, the state of your immune system and past vaccinations.

Recovery: A mumps infection must simply run its course. Most children and adults recover from an uncomplicated case of mumps within about two weeks. As a general rule, people are no longer considered contagious and may safely return to work or school one week after a diagnosis of mumps.

First Published December 14, 2014, 3:31pm