Whooping cough is on the rise again in California, with more cases being reported over the last five months than in all of 2013.

The Department of Public Health reports 2,600 cases of pertussis, with more than 800 in April alone.

That's the highest monthly count since an epidemic in 2010.

Whooping cough can be deadly, with infants too young to be fully vaccinated at the highest risk.

Health officials encourage vaccinations for pregnant women who are in their third trimester as the best way to protect newborns.

Two infants have already died this year, one in Riverside County and another in Placer County.