coronavirus covid-19 illustration file photo cdc dark background

This illustration, created at the Centers for Disease Control and Prevention, reveals the structure of the novel coronavirus. The illness caused by this virus has been named COVID-19.

New coronavirus cases have jumped sharply in Pennsylvania in the past week, and increased testing doesn’t appear to be the only reason.

The 3,802 new cases recorded June 23-29 were up 24% from 3,065 the week before, while the number of tests increased by only 14%.

That means that the rate of positive tests has nudged back upward after weeks of decline, leading state officials to take a closer look at counties that might be experiencing increased community spread of the virus.

Of particular concern is Allegheny County, where the number of tests increased by 36% but the number of new cases tripled, from 134 in the prior week to 431 in the past seven days. In response, county officials are halting all on-site consumption of alcohol in bars and restaurants beginning Tuesday, calling the spike in new cases “alarming.”

“We cannot become complacent in practicing the measures we know can protect everyone from the spread of this very contagious virus,” Gov. Tom Wolf said Sunday in endorsing Allegheny County’s mitigation efforts.

In Lancaster County, the number of new cases increased slightly faster than the number of tests, pushing the weekly rate of positive tests up slightly, from 7.7% to 7.9%. Among the state’s larger counties, only Dauphin’s rate of positive tests was higher, at 8.9%.

Statewide, the rate of positive tests was at 4.5% in the past week, up from 4.1% the week before. The rate had been at 19% at the start of May and had been declining steadily each week.

The rate of positive tests increased in 34 of the state’s 67 counties, including Lackawanna, Dauphin, Centre, Cambria and Philadelphia.

The number of new cases statewide equaled 29.7 per 100,000 population in the past week, up from 23.9 the week before. Counties with the highest per capita rates of new cases in the past week were Lancaster, 71; Dauphin, 58; Philadelphia, 50; Lebanon, 49; and Allegheny, 35.

Testing increased sharply in Lancaster County, rising 49% from 3,292 June 16-22 to 4,889 in the past seven days. The number of new COVID-19 cases was up 53%, from 252 to 385.