Doctors in the Central Valley say there has been an "explosion" in the increase of infants born with syphilis.
The babies sometimes lived only minutes or died within days or weeks, neonatologist Gurvir Khurana told KPCC. Khurana works at four Bakersfield hospitals.
The babies are born severely anemic, with their bodies covered in rashes and their lungs filled with fluid.
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They were all born to mothers with syphilis, KPCC reported. The mothers arrived at the hospital unaware they had the disease as they had no prenatal care.
"It's been an absolute explosion," Khurana told KPCC. "It's just spreading very, very quickly. Kern County has a huge public health problem on its hands."
The Central Valley, known as a vast agricultural and low-income part of California, said the spike in congenital syphilis has been occurring over the past few years.