Las Vegans who have spent the past 48 hours worrying about the possibility they've contracted hepatitis strains B or C or HIV, the virus that causes AIDS, received some small reassurances Friday from federal and state health officials.
"People need to be concerned but not overly afraid,'' said Dr. Scott Holmberg with the Centers for Disease Control and Prevention's Division of Viral Hepatitis. "The risk for any one person is very low.''
Holmberg said there are two things people should keep in mind when considering their risk of contracting one of the blood-borne viruses that people might have been exposed to as a result of medical practices at the Endoscopy Center of Southern Nevada, 700 Shadow Lane.
First, your risk increases if a patient who is infected was treated before you on the same day. In addition, not all nurse anesthetists at the facility were reusing their syringes, nor were all the reused syringes contaminating the vials.
"So one's risk," Holmberg said, "is proportional to a low probability times another low probability.
"People need to take the low risk seriously but not hysterically.''
The Southern Nevada Health District has sent letters to 40,000 patients who underwent procedures at the Endoscopy Center between March 2004 and Jan. 11, urging people to get tested for the hepatitis strains or HIV.
Holmberg noted that although there may be patients who end up testing positive for hepatitis C, it's no certainty they contracted it from the clinic.
Health district officials believe five people were infected with hepatitis C at the Shadow Lane center on Sept. 21 after nurse anesthetists reused syringes to administer medication.
One contracted the disease on July 25. Nurse anesthetists are certified registered nurses who administer anesthesia.
The five cases "pretty clearly are related, but for others, unless we see a clear clustering of time, it will be hard to impute transmission in the clinic setting,'' Holmberg said. "We've already linked four of the five through genetic analysis. That means the viruses they have are the same, so we are near certain they got it from there.
"We don't have the sample yet from the fifth person, but we are certain the transmission occurred there.''
If a few more people are diagnosed with hepatitis C in the near future and they had procedures done on July 25 or Sept. 21, Holmberg said, the odds will be overwhelming that their cases are related, regardless of whether health officials have completed their genetic analysis.
"Unless they were the first person to be seen,'' he said. "Then that person would be the index.''
Hepatitis C is a blood-borne disease that infects the liver. The infection can cause liver inflammation that is often asymptomatic.
It is spread by blood-to-blood contact with an infected person's blood.
Roughly 1.3 percent of U.S. residents, from 3 million to 4 million, are infected with hepatitis C, said Jennifer Ruth, a spokeswoman for the CDC. Only a tiny fraction of cases get reported locally to the health district.
Hepatitis B is serious disease caused by a virus that attacks the liver. It can lead to cirrhosis, liver cancer, liver failure and death.
Dr. Eugene Speck, director of infectious disease at the University of Nevada School of Medicine, also doesn't think there will be many cases of hepatitis or HIV as a result of this event.
"They had a syringe that was injected into someone. We're talking about a tiny amount of backflow of blood going into the syringe,'' he said. "That tiny amount goes into a vial. By then it is diluted. It is not a very concentrated amount of blood.''
"This is just my prediction," he said. "You also have to keep in mind, they've been doing this for four years and we haven't had many cases of hepatitis C in the valley.''
In general, it is 10 times more likely for a person to contract hepatitis B than HIV; and 100 times more likely for someone to contract hepatitis C than HIV.
Contact reporter Annette Wells at firstname.lastname@example.org or (702) 383-0283.