Riverside TB case poses no risk locally, official says

IMPERIAL COUNTY — A report of a case of active tuberculosis in a staff member at a Riverside County school does not portend an increased risk of the disease locally, said an Imperial County Health Department official.

An unidentified staff member at Westside Elementary School in Thermal, Calif., was recently diagnosed with active tuberculosis, according to a Riverside Public Health release published in the Imperial Valley Press Tuesday.

County health officials there sent letters to the parents or guardians of about 160 students who might have been exposed to the illness. The school also notified staff members who might have been exposed.

The case doesn’t pose a local threat locally, said Miguel Zamora, the Imperial County Health Department’s TB Controller. “We’re not at increased risk at all.”

Even amid the most virulent of TB cases, a person would have to be within close proximity (6 feet) to a patient for at least two to four hours to be at risk of infection, he said. And on the off chance one would develop symptoms, those wouldn’t appear for two or three months, at the soonest.

Most of the time, symptoms will never appear, Zamora said. About 95 percent of persons who test positive for TB are latent carriers.

Having latent tuberculosis means one has no symptoms and is not spreading the infection, but it doesn’t mean the carrier is entirely free of risk. About 5 percent to 10 percent of latent tuberculosis cases will turn active at some point during the patient’s life. These cases are frequently tied to certain high-risk factors such as homelessness, recreational drug use, diabetes and smoking, Zamora said.

In cases where a latent TB carrier is also positive for HIV, the chance of active infection skyrockets to 30 percent annually, he added.

Despite the Riverside tuberculosis case having little potential impact on the Valley, incidence of the disease here is relatively quite high. Zamora said national rates of tuberculosis infections are 2.9 cases per 100,000 persons. In Imperial County, the rate is 23.5 cases per 100,000 persons.

Zamora said there were 44 reported cases of TB in Imperial County in 2016 and 40 in 2017.