LOS ANGELES (CBSLA.com/AP) — With the number of whooping-cough cases in California now at an epidemic level, health officials are reporting a sharp increase in the number of infections in Los Angeles County.

KNX 1070’s Bob Brill reports a total of 345 confirmed and probable cases, but no deaths, have been logged so far this year in the county.

Infants are most susceptible to the infection, which is also known as pertussis, the Associated Press reported.

The county Department of Public Health says the number of cases this year has grown 17 percent from last year, when Los Angeles saw 296.

Last week, state officials said as of June 10 there were 3,458 reported cases statewide — more than in all of 2013. Of those who have contracted the disease, 84 percent are under 18 and three babies have died, including one in Riverside County.

Gil Chavez of the California Department of Public Health is encouraging pregnant women and newborns to get vaccinated for the disease.

“We basically are entering what is usually the most active and severe months for whooping cough,” Chavez said.

Once the summer months have passed, whooping cough activity statewide is projected to slow down, according to Chavez.

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