What to know about dengue fever after Florida officials warn of cases: Five cases of locally acquired dengue fever have been reported this month in a region of the United States where locally acquired cases are uncommon. As a result, Florida health officials have issued a warning about the dangers of mosquito-borne illnesses.
After the cases were confirmed in Broward and Miami-Dade counties, health officials advised residents to take preventative measures against mosquito bites, such as draining standing water and wearing repellent.
According to the World Health Organisation, although approximately half of the global population is at risk for dengue, the majority of U.S. states report few or no locally acquired cases. The majority of cases in the United States are either imported by travellers to the continental United States or occur in U.S. territories. The World Health Organisation has warned that global warming could lead to a record number of global infections.
Cases of dengue, also known as breakbone fever, are typically mild or even asymptomatic, but severe cases can be fatal.
What to know about dengue fever after Florida officials warn of cases: What is dengue and how is it transmitted?
Dengue is a viral infection that is predominantly found in tropical and subtropical climates, as well as in urban and semi-urban areas. Female Aedes mosquitoes that have bitten an infected individual transmit the virus.
According to the Centres for Disease Control and Prevention, if symptoms occur, they typically commence a few days after infection.
There are four dengue viruses listed by the CDC, and since post-recovery immunity is type-specific, a person can contract dengue four times in their lifetime. A second infection with a virus serotype distinct from the initial infection increases the likelihood of severe illness. (A potential fifth dengue virus has been reported, but its existence has not been confirmed.)
Sharing a meal or a drink or utensils will not transmit the dengue virus. The only method to prevent infection is to avoid mosquito bites by wearing long sleeves and pants and utilising mosquito nets, window screens and insect repellents.
What to know about dengue fever after Florida officials warn of cases: What are the dengue infection symptoms?
Approximately one-fourth of those infected with dengue develop symptoms including fever, nausea, headaches, vomiting, and muscle and joint discomfort. According to the CDC, many mild symptoms are not unique to dengue and are frequently confounded with other illnesses.
Approximately one in twenty patients develop more severe symptoms, such as internal haemorrhage, shock, and organ failure. It is sometimes referred to as breakbone fever due to the intense muscle spasms and joint pain it can produce.
“It is uncommon for infected individuals to die, but it does occur,” Derek Cummings, an infectious disease epidemiologist at the University of Florida, wrote in an email. Approximately 40,000 dengue-related fatalities are reported annually, he added.
How prevalent is dengue in the United States and globally?
Dengue is prevalent in Puerto Rico and other U.S. territories, but it is uncommon in the continental United States, according to Cummings.
Between 2010 and 2020, the CDC recorded more than 33,000 locally acquired cases, the vast majority of which occurred in Puerto Rico and other U.S. territories. It is native to American Samoa, the U.S. Virgin Islands, and Guam, among other overseas territories.
In the past decade, epidemics have occurred in Florida, Texas, Arizona, and Hawaii, among others.
Cummings stated that travel-associated dengue is prevalent and has been increasing over the past few decades.
But the number of dengue cases in the United States, 513 so far this year, pales in comparison to some of the worst-affected regions of the globe. According to its National Centre for Epidemiology, Prevention and Control of Diseases, Peru has recorded more than 230,000 confirmed or probable cases of dengue so far this year, with approximately 400 deaths. In Bangladesh, the worst dengue fever outbreak on record has infected more than 92,000 and killed more than 400 people.
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What to know about dengue fever after Florida officials warn of cases: Exists a vaccine against dengue fever?
The U.S. Food and Drug Administration has only authorised one dengue vaccine, Dengvaxia, which is manufactured by the French pharmaceutical behemoth Sanofi Pasteur. It is only available to adolescents aged 9 to 16 who have previously been diagnosed with dengue. Vaccinated children with no prior dengue infection are at a greater risk of hospitalisation and severe disease.
Despite obstacles such as screening and ensuring that children complete the entire three-dose course of the vaccine, vaccination in Puerto Rico alone could prevent 3,000 hospitalisations over the next decade, according to a study published this year by researchers from the CDC in Puerto Rico. Dengue vaccinations in development could help a broader age range or people who have never had the disease.
Since Mexico was the first country to ratify Dengvaxia in 2015, more than 20 other nations have followed suit. In the European Union, the age range for vaccination is 6 to 45 years.
Two additional dengue vaccine candidates have been licenced in other nations or are undergoing evaluation.
What effect does climate change have on dengue cases?
This month, Raman Velayudhan, who directs the World Health Organization’s programme for the control of neglected tropical diseases, stated, “Dengue is a problem linked primarily to climate change” and that roughly half of the world’s population is at risk.
In the tropics, where dengue and other insect-borne illnesses are becoming more prevalent due to a rapidly changing climate that brings more instances of warm and wet weather and optimal breeding conditions for mosquito hosts, worsening outbreaks serve as warning signals.
“Climate change is expanding the range of suitable habitat for the Aedes species of mosquitoes that transmit dengue and increasing the transmission of dengue in areas where these mosquitoes are already present,” said Cummings, an epidemiologist from the University of Florida.
