Officials from the Epidemic Intelligence Service arrived early Friday to investigate the recent outbreak of Group A Streptococcus at Evergreen Mountain View Health Care in Carson City.
The two investigators are from a special branch of the Centers for Disease Control and Prevention in Atlanta.
"We've had an unusual presentation in terms of respiratory illness, and this small cluster in such a relatively short time struck the Health Division and the CDC as unusual," said State Epidemiologist Randall Todd. "They offered to assist us."
The streptococcus organism was cultured from two of the four patients who died at the facility Dec. 9. Two were embalmed before test samples could be taken, but all allegedly died of an upper respiratory infection.
CDC officials were briefed on the incident at the State Health Division at 8 a.m. Friday, then went directly to the elder-care center, Todd said.
Group A streptococcus is a common bacterium, often found in the throat and on the skin. Normally, it causes relatively mild illnesses like strep throat or a skin infection called impetigo.
"More rarely, it can become invasive and cause blood infections," Todd said. "In some cases, it can cause respiratory illness and death."
Todd said the exact number of cases at Evergreen is still being determined. The organism was isolated from some patients after they were taken to Carson-Tahoe Hospital for treatment.
No other local nursing home facilities are being investigated, but CDC officials will also be meeting with Carson-Tahoe professionals because the patients were hospitalized, Todd said.
Tests for influenza on these patients are still pending and it is not known if influenza was a factor in the deaths. Those results are expected Tuesday, Todd said.
"Given the fact that streptococcus is a common bug, the question remains as to whether underlying or chronic conditions could have made this infection more invasive," he said. "Finding out will help us form the basis for better and more targeted prevention strategies for this facility and others."
Officials are looking at a number of variables including pre-existing conditions of the patients and their location in the facility. Todd said the studies shouldn't take long because Mountain View is relatively small, about 120 beds.
"We started the day before yesterday, culturing patients and staff to see if they carried the organism," Todd said. "When they've been cultured in the lab, we forward samples of the organisms to labs at the CDC for subtyping. The organism we might isolate from the staff or other patients may not be the same strain that caused the disease."
The epidemic intelligence service employs physicians and researchers for two-year assignments anywhere in the world.
"We've enjoyed help from the EIS on numerous occasions," Todd said. "They came here in the early '90s to investigate the first hanta virus cases and again in 1997 after the New Year's flood, when they conducted extensive testing to determine the distribution of environmenal toxins.
"This is a great opportunity for us to learn from them," he said.
Contact Susie Vasquez at svasquez@nevadaappeal.com or 881-1212.