Coronaviruses cases and COVID-19 deaths in three of New Jersey's largest counties — Bergen, Hudson and Essex — continue to climb as Gov. Phil Murphy and state officials express optimism that the state is turning a corner in this crisis.

Combined, the three North Jersey counties have the highest number of coronavirus cases in New Jersey, accounting for 40% of the state's total cases. And just under half of the state's total deaths from COVID-19, the disease caused by the virus, come from Bergen, Essex and Hudson.

The three counties account for less than one-third of New Jersey’s total population.

See the list:NJ coronavirus cases listed by town for Bergen, Passaic and Essex counties

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Bergen County officials have been sounding the alarm about coronavirus since before the state had its first confirmed case, with County Executive Jim Tedesco saying in the first days of the crisis that more people would die if he didn't take drastic measures like shuttering businesses and closing schools.

Health officials with Essex and Hudson counties were less gloomy when asked about their numbers. They said the spike in positive coronavirus cases should not frighten residents because they largely stem from the number of tests performed. Essex opened a mass tasting site in Newark that has tested more than 1,000 people and Hudson has three sites, with a fourth opening Wednesday. One of the Hudson sites has tested 3,500 people since it opened, a health official said.

“If we’re testing more, the numbers will go up," said Essex County Health Officer Maya Lordo.

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New Jersey's coronavirus outbreak started in Bergen County, which has consistently had by far the most number of positive cases of any other county. Its latest total is 10,426 cases, with 550 deaths. In recent weeks, cases in Essex and Hudson counties have risen close to Bergen's total. On Tuesday, New Jersey reported Hudson has 8,242 cases and 277 deaths, while Essex has 8,212 cases and 535 deaths.

The number of positive cases in each county has risen by about 400 daily since Friday.

Essex County Executive Joseph DiVincenzo and the county's sheriff, Armando Fontoura, both tested positive for coronavirus. A county spokesman said both men are recovering.

Carrie Nawrocki is director of the Hudson Regional Health Commission, which assists Hudson towns with public health emergencies. Nawrocki said with Hudson's proximity to New York City, the epicenter of the nation's coronavirus outbreak, it's not shocking that it would have so many positive cases.

“It’s not a surprise but it really reinforces the need for social distancing, wearing a mask while you’re outside and staying home when you’re sick,” she said.

Essex and Hudson counties are home to the state’s two biggest cities, Newark and Jersey City. They have the most coronavirus cases of any New Jersey municipality, Newark with 3,015 and Jersey City with 2,674. Both cities' mayors have used social media to reassure residents that there is light at the end of the tunnel.

"We're going to be OK. Newark is going to be OK because we've always been OK," Newark Mayor Ras Baraka said during a Facebook video posted Monday.

Terrence T. McDonald is a reporter for NorthJersey.com. For unlimited access to the most important news from your local community, please subscribe or activate your digital account today.

Email: mcdonaldt@northjersey.com Twitter: @terrencemcd