Martin County health officials now say there are 18 confirmed cases of dengue fever, stemming from people living in Jensen Beach and the Rio community.

County officials, giving an update on Thursday, say they have never seen an outbreak of dengue fever like what they've experienced this summer. Residents who live in Rio or Jensen Beach might receive a knock on the door beginning Friday from health officials wanting to take blood samples.

Health officials say dengue fever is typically contracted by people in other countries. You can catch the disease by being bitten by a mosquito carrying dengue fever.

Residents are being urged to protect themselves from mosquitoes and to get rid of any standing water on their properties.

Meanwhile, the local OneBlood blood bank is temporarily halting donations, employees saying they will not take any more blood in Martin or St. Lucie Counties until the denque fever threat has minimized.