PORTLAND — Experts say after years of decline, the number of confirmed cases of physical child abuse in Maine has climbed dramatically in recent years.

Confirmed cases of the physical abuse of children in Maine rose by 58 percent from 2011 to 2013.

Those who work with abused children said they’re not sure why the numbers are spiking, but they have several theories. They include a rise in drug abuse by parents, a still lackluster economy and more reporting of abuse driven by high-profile cases.

The increase in Maine cases was even greater for children younger than 5. Those cases climbed from 241 reported in 2011 to 424 last year, a 78 percent increase, according to state Department of Health and Human Services data.