Hundreds of people who took Holy Communion at two Christmas Day services at Our Lady of Lourdes Church in Massapequa Park may have been exposed to the hepatitis A virus, Nassau County health officials said Monday.

Nassau County Department of Health announced what it's calling potential exposures to the virus during the 10:30 a.m. and noon Masses on Dec. 25, but would not say how many parishioners - if any - may have been infected. The health department declined to say who might have transmitted the pathogen, which is found in the fecal matter of the viral carrier.

"An individual tested positive for hepatitis A who is involved in the Communion process," said Nassau County health department spokeswoman Mary Ellen Laurain, referring to an unidentified person.

"We feel the transmission [level] is low," she added, saying only a few people were possibly exposed. "And to protect the public from potential illness, those who received Holy Communion on December 25 should receive prophylactic treatment."

Unlike its more virulent cousins - hepatitis B and C - hepatitis A is not as dangerous. "Hepatitis A can make you pretty sick," said Dr. Melissa Palmer, medical director of NYU Hepatology Associates in Plainview. "Most people will get flulike symptoms, diarrhea - on occasion some people will have jaundice. But unlike hepatitis B and C, it does not lead to chronic liver disease."

The health department is offering immune globulin injections or the hepatitis A vaccine to those who attended either of the Masses. Immune globulin contains antibodies that destroy the hepatitis A virus. The vaccine prevents infection.

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Roughly 7,500 parishioners belong to Our Lady of Lourdes, a Roman Catholic church, but it wasn't immediately known how many attended the two Christmas Masses or received Holy Communion that day.

"It was probably a full church," said Sean Dolan, a spokesman for the Diocese of Rockville Centre. He could not provide church capacity.

Calling the investigation ongoing, Dolan said he also could not identify who might have transmitted the virus. Generally speaking, priests are aided at crowded Masses by authorized eucharistic ministers, of which Our Lady of Lourdes has 30, he said.

"We don't want to jump to conclusions," he said. "Obviously, it's very concerning when there's potential exposure to any sort of virus."

Dolan said it's still too early in the diocese's review to speculate on any new hygiene practices. "We're hoping no one comes down with the virus, but we also urge prudence," he said.

Msgr. James Lisante, who is pastor of the parish, could not be reached Monday night. But an outgoing recording at the rectory referred questions to the Health Department. The diocese said on its website: "We pray that no one comes down with this virus."

Palmer said hepatitis A has a "fecal/oral route of transmission." Hepatitis A outbreaks are often associated with food handled by a carrier who has ineffectively washed his or her hands. Palmer said a Communion wafer is as likely a source of infection as would be any other food handled by a person with unclean hands. Treatment with immune globulin, she added, can effectively treat infection.

WHAT TO DO

Additional information is available by calling 516-227-9496 or visit the Nassau County Department of Health's website.

The immune globulin and vaccine also will be available at the church, 855 Carmans Road, in Massapequa Park, between 3 and 8 p.m. today and between 9 a.m. and 3 p.m. Wednesday.

ABOUT HEPATITIS A

Triggered by a virus that can cause a mild illness lasting a few weeks to a severe illness lasting several months.

Usually spread when a person ingests fecal matter - even in microscopic amounts - from contact with objects, food, or drinks contaminated by feces from an infected person.

Symptoms include a flulike illness, diarrhea, cramping and possibly jaundice. Once infected, a person is immune for life.

Infection can be effectively treated with the injection of immune globulin, an antibody that destroys the virus. A vaccine is available to prevent infection.

Even though it causes illness, the virus is not as dangerous as infection with hepatitis B or C, which cause a chronic disease and can lead to liver failure.

Sources: Dr. Melissa Palmer; Centers for Disease Control and Prevention; Nassau County Department of Health