TORONTO -- Jeanine Monteiro was back home from her vacation to Cuba for a week when she began to get intense headaches behind her eyes, followed shortly thereafter by strange hallucinations.

The unusual symptoms were the first signs of dengue fever, a potentially deadly disease that has exploded in prevalence in South America and the Caribbean with several tropical countries reporting outbreaks and national health emergencies.

But at the time, Monteiro, 42, thought she might just have the flu.

Within weeks, her symptoms spiralled out of control. She suffered joint pain and stiffness, and slowly lost her grip on reality. At one point, while in the car with her father after a doctor’s appointment, she struggled to read the pain medication she’d just been prescribed.

“My dad kept saying things to me and I remember saying, ‘Are you speaking English?’ And then I said, ‘What is this in my hand?’ And he said, ‘It’s your medication Jeanine. Don’t you remember?’” Monteiro told CTV News from her home in Cambridge, Ont.

“That’s the last memory I have.”

In the car, Monteiro suffered a seizure and was rushed to the emergency department. Doctors made a shocking discovery: she had suffered multiple organ failures and only had a quarter of her heart function left. She spent 11 days on life support as the medical team tried to figure out the source of her life-threatening condition.

“There was a couple days they weren’t sure I was going to make it,” Monteiro said.

The answer, it turned out, was a dengue-infected mosquito bite during her recent trip to Cuba. Montero was one of more than 560,000 people in North and South America to contract dengue fever in 2018. Those numbers skyrocketed in 2019 to 3.1 million cases – more than five times the previous year’s caseload.

The problem is widespread. Argentina is currently reporting a dengue fever outbreak, and emergencies have been declared in Honduras, Brazil, Jamaica and Paraguay. Recently, Paraguay’s president, Mario Abdo Benitez, contracted the virus and was ordered to rest.

But travellers such as Monteiro said they had no idea just how prevalent – and how dangerous – dengue fever could be until they contracted the illness themselves.

“That was my 18th time to Cuba, and I felt very safe going there,” Monteiro said.

Even after she recovered, dengue fever has had a lasting effect on Monteiro’s health. The illness triggered an autoimmune disease, scleroderma, that was lying dormant in her system. She also lives with kidney disease and is unable to work.

“It’s devastated my life,” she said. “Besides losing my career that I worked very hard to have, I was pretty healthy before all of this.”

Last month, Jodie Dicks, a 26-year-old woman from Toronto, contracted dengue fever while attending her friend’s destination wedding in Jamaica. Less than a week later, she suffered multiple heart attacks and died in her mother’s arms in a Florida medical centre.

Dicks’ death has drawn new attention to the disease, for which there is no vaccine available in Canada. CTV News spoke to three survivors who all said that Canadian travellers are not being given enough information about the virus.

When Monteiro learned of the young woman’s death, she said she immediately wanted to reach out to Dicks’ parents and offer her condolences.

“I think they’re feeling the same as me. They’re angry that there was no information about this. There was no preparation or warning,” she said.

“People need to know that this is happening. You might not hear about it often, it might be rare, but it’s happening, and it’s happening in all the most popular vacation spots.”

WHAT IS DENGUE FEVER?

Dengue fever is primarily spread by mosquitos. Symptoms include a sudden high fever, rash, nausea, swollen glands and pain in the bones, joints and eyes.

The federal government says travellers are at risk when travelling to countries where dengue fever is present. According to the World Health Organization, more than 40 per cent of the world’s population lives in areas where dengue can be transmitted.

Travel agents in Canada are encouraged, though not required, to warn travellers of such risks, according to the Association of Canadian Travel Agencies.

But what many people may not know about dengue fever is that the illness is potentially much more dangerous if a person contracts the virus more than once. That means frequent fliers to dengue-affected countries could be at greater risk.

“If you are infected once, you're actually at a set-up for a really bad outcome the second time when you are hit with a different strain,” said infectious diseases specialist Dr. Neil Rau.

Monteiro said that, due to the severity of her illness, there is a “big possibility” that she contracted dengue fever before. On an earlier trip to Jamaica she contracted flu-like symptoms on the third day of the trip and suffered lasting symptoms for weeks. After being prescribed antibiotics, she got better.

“It never occurred to me until I started reading and researching this disease and found out that it’s very possible that I was bitten once before,” she said. “A lightbulb kind of went off.”

It’s a situation Arletta Doroszuk is familiar with. The 50-year-old from Courtice, Ont. travelled to the Bahamas in 2011 and, after a few days of arriving home, suffered from a high fever and severe pain in her hands.

Doroszuk visited her doctor several times and, after the condition worsened, she was eventually tested for dengue fever. The tests came back positive.

Nine years after that trip, she hasn’t travelled south again. She’s afraid of what might happen if she contracts dengue a second time.

“I’m just afraid I might get (the virus again) and I will not be so lucky,” she said.

Her advice for travellers: pack bug repellent and research your travel destination to see if dengue fever is present.

Another woman, Carla Radke from Winnipeg, travelled to the Mexican community of Guayabitos north of Puerto Vallarta for a three-month vacation with her husband. She said her hotel sprayed for mosquitoes, but she still ended up suffering from pain behind her eyes and aching muscles -- both symptoms of the illness.

She was sick for nine days and, over the coming months, lost nearly 100 lbs. She was shocked when she found out she had dengue fever.

“I never thought of dengue. I only thought of Zika. To me, dengue is like an old thing...Zika was newer, and that was on my mind,” she said.

UNDERSTANDING THE RISK

Jodie Dicks’ mother, Christine Boissoin, and stepfather, Randy Boissoin, said they want to make sure that their daughter did not die “in vain.” They are now speaking out in hopes of educating other Canadians about the risks of dengue fever.

They say the government’s warnings are not easy to find, and that not enough travellers are aware of the problem.

“Jodie is not here with us now -- this isn’t a one-off. My Lord, people need the information,” Ryan Boissoin said.

“I would say just look at our story. We have a daughter who didn’t come home, and if you don’t think it isn’t a potential reality, you are sadly mistaken.”