BATON ROUGE, La. — The number of known coronavirus cases in Louisiana jumped by more than 500 Thursday, surpassing 2,300, with 86 deaths, the state Health Department said.A 17-year-old was among the latest deaths, the first fatality in the state of someone younger than 18.The higher infection numbers reflect the increase in testing. In Thursday’s figures, the number tested rose nearly 6600, to 18,000.Coronavirus has now been found in 53 of 64 parishes, although Gov. John Bel Edwards has said he believes it’s present in every parish, even as statewide mandates banning crowds and closing businesses continue.“We won’t see the impact of the distancing and the closing of schools and people staying home for a couple of weeks. ... We are not near the peak of this yet,” said Dr. Catherine O’Neal, an infectious disease expert and chief medical officer at Our Lady of the Lake Regional Medical Center in Baton Rouge.