Martin and Brevard counties are among 17 in Florida "critically impacted" by the hepatitis A virus.

They're the main concern for Florida Department of Health officials and the reason the state's surgeon general declared a 'public health emergency' Thursday evening.

Florida Surgeon General Dr. Scott Rivkees said Friday he believes the declaration will make people take the matter more seriously. The number of people diagnosed with hepatitis A in Florida keeps increasing, he said.

A 'critically impacted' county has at least 10 cases per 100,000 people, said Emerson George, communications director for the state Department of Health.

The 15 other counties are: Citrus, Glades, Hernando, Hillsborough, Lake, Liberty, Manatee, Marion, Okeechobee, Orange, Pasco, Pinellas, Sumter, Taylor, and Volusia, according to the Florida Department of Health.

There are 2,034 hepatitis Acases statewide this year. Pasco County leads the state with 358 cases, followed by Pinellas with 328; Volusia with 179; Orange with 140 and Marion with 109, according to the state health department.

Brevard County has 64 cases and St. Lucie County has 30 cases. Martin County, with 32 virus cases, also has had four deaths attributed to it.

Friday, Indian River County joined them all in experiencing an 'outbreak' of the virus when health department officials in Vero Beach said a food service worker was diagnosed with the virus and is the county's fifth case.

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Why 'public health emergency'?

During a public health emergency, public and private places and businesses are asked to sanitize their bathrooms at least once per day with a solution of one and two-thirds cups of chlorine bleach per gallon of water or another cleaning product that specifically details it kills the virus.

"Our new recommendations really have guidance for sanitation of public facilities, which should help lessen the risk of hepatitis A remaining in services," Rivkees said. "Also, we all need to remember hand washing is a key to prevention."

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Rivkees' declaration signals to health care providers the importance of screening and vaccination for the virus throughout the state, health officials said.

The emergency can last 60 days unless the governor renews the declaration.

"By doing an emergency now, it really allows us to increase our vaccination activities and increase public awareness," Rivkees said.

State law dictates a public health emergency be declared by a state surgeon general if there's a threat, such as an infectious disease, that creates "substantial injury or harm to the public," according to the law.

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"This is one of those things that already was a topic of priority for the Department of Health in terms of controlling this virus, and seeing how the number of cases was continuing to rise, we thought a public health emergency was the next step to help get the message out to the public about how this virus is being spread," Rivkees said.

Along with Florida, Philadelphia also declared a public health emergency regarding hepatitis A Thursday.

What can you do to prevent Hep A?

Hepatitis A is a highly contagious disease that attacks the liver. The majority of the people who get the virus have flu-like symptoms – such as nausea and fevers – but recover within a week or two.

A person is considered part of the high-risk population for catching the virus if they are homeless, use intravenous drugs, have an underlying health condition, travel to countries where hepatitis A is common or if they are men who have sexual relations with other men.

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Rivkees said based on what the state has learned from other states dealing with the virus, 80% of the high-risk population has to be vaccinated for the number of cases in Florida to start to decline.

As of Friday afternoon, he said the state isn't near the 80%, but he believes it eventually will be.

Rivkees declined to say what percentage of the state's high-risk population is vaccinated.

"This is going to be a multi-month effort to get to that point," he said. "We have a ways to go."

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Recently, he said, officials at the Centers for Disease Control and Prevention told him they're impressed with how the state has worked to stop the spread of the virus.

"We have developed foot teams that will actually go into areas of homelessness where we can vaccinate individuals," he said. "Then they are going to jails where we can vaccinate individuals who may be at risk there."

The teams have primarily been used on the west coast of the state.

The best ways to prevent the virus, Rivkees said, is to wash your hands for 20 seconds in warm water after you use the restroom and before you eat, and get vaccinated.

As of Friday afternoon, Rivkees said the state has a plentiful supply of vaccines for the public.

Follow Sara Marino on Twitter: @saradmarino