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Over the past two decades, an increase in dengue cases has been reported worldwide, according to the World Health Organization (WHO). There's been ongoing transmission since the start of 2023, and health experts are now warning those who are travelling down south for the winter.
Dengue, also known as dengue fever, is a viral infection that is spread from an infected mosquito to a human, and is most common in warm, tropical climates.
WHO said this spike in dengue infections from 2000 to 2019 has resulted in close to a historic high of over five million cases and more than 5,000 dengue-related deaths in over 80 countries.
The Public Health Agency of Canada (PHAC) told Yahoo Canada in an email that dengue is not endemic in Canada and there are no locally-acquired cases of the viruses. However, an expert warned Canadians can still get infected if they're travelling to countries where dengue cases are present.
But what exactly are the risks of dengue and should Canadians worry? Here's what you need to know.
How and why does the virus spread?
Stephen Barr, a professor and researcher at Western University, explained to Yahoo Canada there's no human to human transmission of dengue, and a person can only get infected from a mosquito.
"When a human gets infected from the bite of a mosquito, another mosquito has to feed on that infected person and then the virus will basically replicate and incubate in that mosquito for about eight to 12 days, after which it can then become infectious and infect another human," Barr said.
According to Barr, the virus is on the rise in part due to global temperatures rising.
"In environments where the temperatures are favorable for mosquito breeding is where you have that increased risk of the virus surviving much longer," he said.
What are the symptoms of dengue?
According to the Government of Canada, infection with the dengue virus can cause severe flu-like symptoms.
In some cases, the website stated "it leads to dengue haemorrhagic fever, also known as severe dengue, which affects the body's vascular system (how blood moves through the body). This can lead to significant internal bleeding and organ failure."
It's a very serious disease... it's important you get medical attention.Dr. Stephen Barr
Barr said a person who gets infected can experience nausea, vomiting, rashes, aches and pain.
"It's very critical that if people suspect that they're infected with dengue, that they seek medical attention," Barr said.
He added people who end up experiencing severe pain will often end up taking over-the-counter painkillers such as ibuprofen, which can worsen the disease because of these drugs' ability to interfere with blood clotting.
"It's a very serious disease that if it's suspected, it's important you get medical attention so that you don't take the wrong painkiller for trying to overcome the symptoms," the expert advised.
Is there a cure for dengue?
There is no treatment for dengue, Barr said, and the therapy used to treat it is mostly pain management to help control symptoms.
There are also no approved vaccine or medications that protect against dengue fever.
"It's been very difficult coming up with an effective vaccine against dengue," Barr claimed. He added the only vaccine currently available is called Dengvaxia and is only given to a person who has been infected in order for it to work. It's also only recommended to those aged six to 45.
"If somebody who was not previously infected were to take the vaccine, they actually become at risk of getting a much more severe form of dengue," Barr said.
How can I stay safe from dengue when travelling?
The only effective way for a person to stay safe from dengue is to prevent themselves from getting bitten by a mosquito — which can be difficult.
Barr recommended that Canadians who are travelling to warm and tropical climates use insect repellent strong enough to keep mosquitos away, and to cover up any exposed skin.
According to the Government of Canada website, mosquitos that carry the dengue virus "can infect a person during the day or night although highest risk is during the day from sunrise to sunset."
People are recommended to wear:
Light-coloured, loose clothes made of tightly woven materials such as nylon or polyester
Long pants and tucked-in long-sleeved shirts
Closed-toe shoes or boots
A hat to keep mosquitoes at bay
"Typically at nighttime when people have their guards down, these mosquitoes can come and bite," Barr warned, adding mosquito nets around beds are also recommended.