Only one of the four nursing home residents who allegedly died of upper-respiratory infections at Carson City's Evergreen Mountain View Health Care on Dec. 9 tested positive for Type A Influenza, said State Epidemiologist Dr. Randall Todd.
The laboratory did not determine if the H3N2 strain, the one responsible for this year's flu epidemic, was involved. That determination isn't expected because the specimen was insufficient, Todd said.
A Clark County man was identified as Nevada's first reported flu-related death Tuesday as health officials continued to investigate whether influenza caused the death of the care center patient.
The Clark County resident was described only as in his 50s with health problems, and county health officials said the case was confirmed through a test conducted by a private laboratory.
The investigation is ongoing in the Evergreen care-center deaths, but at this point the only common denominator is a bacteria, Group A streptococcus.
The organism was isolated from several Evergreen patients transferred to Carson-Tahoe Hospital for treatment.
Six residents of Evergreen Mountain View Health Care died Dec. 9. Four of those were suspected to have had upper-respiratory illnesses. Two died of natural causes. Of those four with suspected upper-respiratory illnesses, two were tested for influenza, one of which tested positive.
The other two were embalmed before samples could be taken. Of the two tested, both tested positive for Group A streptococcus.
Streptococcus is most often associated with mild illnesses, like sore throats and skin infections.
Rarely, the bacteria becomes invasive and causes blood infections. In some cases, it can cause respiratory illness and death, Todd said.
Two of the five residents who died at Evergreen were embalmed before culture samples could be taken. Those cases will always be in question.
"We thought a viral illness may have preceded the Group A streptococcus infections, but we may never get that confirmation," Todd said.
"We heard about rapid testing done in the facility prior to the investigation and we're tracking down those results," he said. "But we have no other flu cultures pending in association with this outbreak."
Two members from the epidemic intelligence service, part of the Centers for Disease Control and Prevention in Atlanta, joined Nevada State Health Division for this investigation Friday.
The investigation is ongoing and to date, there are no conclusions.
"We're still working full throttle and we expect to be investigating for at least several more days," Todd said. "We don't have any answers yet, but that's typical, for this stage of the investigation.
"We start with a few questions and early on that lead to more questions," he said. "We're pleased the CDC is here to help with the investigation and in the end, we hope to have some answers and recommendations to help prevent this kind of outbreak in the future."
Contact Susie Vasquez at svasquez@nevadaappeal.com or 881-1212.