Two mosquito-borne diseases - dengue fever and chikungunya - are posing a serious threat to Florida and residents should take steps to control mosquito populations to try to limit the danger, a leading health expert said on Wednesday.

The Florida Department of Health, in its latest weekly report, said that through last week dengue fever had been confirmed in 24 people in Florida and chikungunya confirmed in 18 people. Both are viral diseases spread by mosquito bites.

All of the infected people in Florida have traveled to the Caribbean or South America and could have become infected there, according to Walter Tabachnick, director of the Florida Medical Entomological Laboratory in Vero Beach, which is part of the University of Florida.

Epidemiologists are worried that mosquitoes in Florida may have picked up the diseases by biting infected people, which could kick off an epidemic in the state, Tabachnick said.

"The threat is greater than I've seen in my lifetime," said Tabachnick, who has worked in the field for 30 years.

"Sooner or later, our mosquitoes will pick it up and transmit it to us. That is the imminent threat," he added.

Tabachnick urged the public to eliminate standing water including in buckets and rain barrels where mosquitoes can breed. "If there is public apathy and people don't clean up the yards, we're going to have a problem," Tabachnick said.

Dengue is potentially fatal, and both diseases cause serious and lingering symptoms. The most common symptoms of chikungunya infection are fever and joint pain, according to the U.S. Centers for Disease Control and Prevention.

Tabachnick said the last statewide epidemics in Florida of dengue occurred in the 1930s. Localized epidemics of dengue occurred in 2013 in a small neighborhood in Jensen Beach where 24 people were infected, and in 2009 and 2010 in Key West where 28 people were infected, according to state and federal reports.

The Caribbean Public Health Agency said this week that authorities in 18 Caribbean countries or territories had reported more than 100,000 confirmed or suspected cases of chikungunya.

In the Dominican Republic, where health officials reported more than 53,000 suspected cases, hospitals in hard-hit areas are treating hundreds of new patients per day.