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Think sharks, snakes or spiders are the deadliest critters? Skeeters want a word

Centers for Disease Control and Prevention
A mosquito that can transmit yellow fever is having a blood meal from a human.

The population of mosquitoes is growing along with Florida's population of people and brings diseases like dengue fever and malaria. Climate change is sending non-native, invasive mosquito species to North America – specifically Florida.

Mosquitoes have infected four people with malaria in Sarasota County over the past month, and half a coop of sentinel chickens near Orlando tested positive for eastern equine encephalitis several weeks ago.

The Florida Department of Health has issued a statewide mosquito-borne illness alert, especially since the summer rainy season in Florida equates with skyrocketing mosquito populations, and it’s just starting.

“Residents throughout the state should take precautions by applying bug spray, avoiding areas with high mosquito populations, and wearing long pants and shirts when possible — especially during sunrise and sunset when mosquitoes are most active,” Monday's advisory said.

The tiny mosquito is a big problem in Florida that is only getting worse. In addition to the death and illness that even one mosquito in one swarm can cause, the population of mosquitoes is growing along with the state’s population of people.

In a state where swamps are commonplace, the sheer number of mosquitoes can lead to apathy, which in turn can lead to a lack of awareness of the ways people can protect themselves against bites.

And climate change is sending non-native, invasive mosquito species to North America — specifically Florida — with increasing frequency.

A mosquito transmits diseases to humans through parasites, bacteria and viruses when it sticks its six-pronged proboscis into a person’s skin for a blood meal and leaves its infected saliva behind.

The number of mosquitoes that transmit diseases to humans is small compared to the total number of species. The majority pose little if any risk because they either don’t feed on humans or they lack the ability to transmit pathogens.

But enough do have that capability to make mosquitoes the world’s deadliest creature.

Mosquitoes love Florida

More people have died by mosquito than war.

The World Health Organization says mosquitoes kill 700,000 people annually. Malaria-spreading mosquitoes cause just more than half of those deaths — mostly toddlers and babies in poorer countries — and infect about 219 million people with the parasite.

The U.S. Centers for Disease Control and Prevention reports about 1,500 cases of malaria resulting in about five deaths in America each year.

Mosquitoes that spread the dengue virus infect at least 96 million people globally every year and kill 40,000.

Two people in Miami-Dade County were infected with dengue fever this year, and 88 more have been infected with the virus while outside of the U.S., with the symptoms starting here.

Last year, there were 68 cases of dengue fever from mosquito bites within Florida, 64 in Miami-Dade County, two in Broward County, and one case each in Volusia and Collier counties.

There are about 200 different species of mosquitoes in the country. Each prefers specific habitats, have unique behaviors and bite different types of animals.

Florida is ground zero for mosquitoes and the diseases they carry in the lower 48 states with more than 80 species ranging from the tropical and subtropical climates of the Keys and South Florida to the more moderate climates in the Panhandle.

The Culex lactator is an invasive mosquito that now inhabits Lee and Collier counties
Lawrence Reeves
The Culex lactator is an invasive mosquito that now inhabits Lee and Collier counties

“Like humans, mosquitoes live around the world but love to come to Florida,” said Sandra Fisher-Grainger, president of the Florida Mosquito Control Association. “Our highly trained scientists and experts are always working to reduce the risk of mosquito-borne illness, and every resident and visitor can help to limit the risk.”

Climate change and mosquitoes

Climate change is hiking global temperatures, changing wind patterns, causing droughts in some places and floods in others, and hastening the numbers of non-native mosquitoes arriving in Florida and other warm climates.

University of Florida agricultural researchers issued a recent report finding that global warming is posing a grave threat to the state’s $400 million strawberry industry, and suggested the fruit’s growers will have to move further north if they want to stay in the right temperature zone for their crops to flourish -- something certain disease-laden mosquitoes already figured out.

That’s what Kristie L. Ebi, a global health and environmental researcher at the University of Washington, predicted seven years ago in a paper titled “Dengue in a changing climate” published in the journal Environmental Research.

“Research indicates that the daily mean temperature and the variation in temperature are two of the most important drivers of the current distribution and incidence of dengue,” she wrote. “Precipitation extremes, whether associated with drought or excess rainfall, also affect mosquito abundance.

“As temperatures continue to rise and precipitation patterns change, opportunities are increasing for further geographical expansion.”

A mosquito known only by its scientific name, Culex lactator, is the latest to establish in the Sunshine State, according to a new study published in the Journal of Medical Entomology by faculty at the University of Florida Institute of Food and Agricultural Sciences.

The species made its way across the tropics into Florida, making a permanent home in Lee, Collier, and Miami-Dade counties. It is not yet known if the mosquito carries disease.

Scientists from the research center say they are concerned because of the rate of new mosquitoes arriving in Florida and the potential for them to transmit mosquito-borne diseases.

“That’s particularly true for species from the tropical forests, where mosquitoes are diverse and understudied,” said Lawrence Reeves, lead author of the study.

“Introductions of new mosquito species like this are concerning because many of our greatest mosquito-related challenges are the result of non-native mosquitoes,” he said. “And in a case like this, it’s difficult to anticipate what to expect when we know so little about a mosquito species.”

‘Fight the bite’

National Mosquito Control Awareness Week was last week amid the hope that what is colloquially known as a gallinipper, katynipper, gabber napper, galliwopper and granny-nipper will be taken seriously as a threat to human and animal life.

One of the main messages repeated throughout the week was not only can mosquitoes carry diseases that afflict humans, but they also can transmit several diseases and parasites that affect dogs and horses: heart worms, eastern equine encephalitis and West Nile virus.

“To fight the bite,” the week’s messaging repeated, wear long-sleeves, use insect repellent with DEET, stay indoors at dawn and dusk when mosquitoes are most active, and empty standing water from anything.

Even a bottle cap of rainwater can breed deadly mosquitoes.

“The risk of transmission to humans has increased,” the state Department of Health said. “To avoid being bitten by mosquitoes, take basic precautions to help limit exposure.”

Environmental reporting for WGCU is funded in part by VoLo Foundation, a nonprofit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health.

Copyright 2023 WGCU. To see more, visit WGCU.

Tom Bayles