The number of reported Zika cases in New Jersey has grown to exactly 100.

The New Jersey Department of Health reported the increase on Tuesday with additional cases added to the tally in Essex, Mercer and Somerset counties since last week. All of New Jersey's cases are travel-related, meaning the illness was contracted from outside the state by people who were traveling.

The number of cases reported in New Jersey doubled in just over a month since 49 cases were reported in July. No cases have been reported in Atlantic, Cape May and Salem counties.

Zika is a viral infection that is usually spread by the bite of an infected mosquito, according to the state health department. It can sometimes be spread by having sex with an infected partner as well. Most people infected with Zika won’t know they have the virus because they won’t show symptoms, but the most common symptoms include fever, rash, joint pain or conjunctivitis, the CDC said. The illness is usually mild and it’s rarely fatal.

It can cause serious birth defects, making it a particular risk for pregnant women.

When traveling, the New Jersey Department of Health recommends avoiding mosquito bites by using an EPA-registered insect repellent, wearing long sleeves and pants while outdoors and frequently changing water in flower pots, pet dishes and bird baths.

5 new Zika cases were reported in Florida on Tuesday including the first non-travel related case outside Miami. Florida Governor Scott Walker said there isn't enough evidence from the new case in Tampa Bay to declare a new zone of transmission.

Zika cases in New Jersey according to the NJ Department of Health (as of August 23)

  • Bergen: 21
  • Passaic: 18
  • Hudson: 11
  • Essex: 9
  • Middlesex: 7
  • Union: 6
  • Burlington: 5
  • Camden: 4
  • Morris: 4
  • Mercer: 4
  • Somerset: 3
  • Monmouth: 2
  • Hunterdon: 2
  • Cumberland: 1
  • Warren: 1
  • Ocean: 1
  • Gloucester: 1

The Associated Press contributed to this report.

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