Dengue wave hits Mexican coasts

Philomena Hanson, 70, was reading under a palapa by the pool on her annual vacation in Puerto Escondido, Mexico, when she noticed one side of her body had been eaten alive by mosquitos. She brushed it off and blamed the stagnant water in the pools being built next door. After all, she’d been escaping the Canadian winter in Mexico for over thirty years, and nothing bad had ever happened. Why would this year be any different?

She felt feverish within a couple of days, and she wasn’t the only one. At least three other people staying in the condos she was renting felt terrible as well: delirious with sore eyes and achy joints. This was December 2019, before COVID was on everybody’s radar. Eventually, the sickness passed. The property manager decided to spray insecticide in the area after the complaints of the mosquitoes and the sickness.

Fast forward to December 2022: Hanson and her family were enjoying their winter retreat until her son started feeling terrible. He got tested for COVID, only for it to come back negative. It was exactly what she had three years ago, Hanson thought, at the same place with the same symptoms.

Although Hanson never got tested, she was “99% confident” it was dengue.

Mexico’s dengue epidemic has been rising over the past year: there were more than 50,000 confirmed cases in 2023 compared with nearly 13,000 in 2022, according to reports from Mexico’s Secretariat of Health. Yucatán, the popular tourist destination, tops the list. Only 1 in 4 infected people have symptoms, so the government’s reports also include probable dengue cases, which stand at around 277,000 for 2023.

Dengue is a virus spread by mosquitoes in tropical areas and has a grim nickname, “breakbone fever,” because of the excruciating joint pain. Almost half of the world’s population (around 4 billion people) live in areas at risk for dengue, according to the CDC. The mosquitoes from the Aedes genus can spread any of the 4 types of the dengue virus. This means that even if people have been infected by the virus once, they can be infected again, says the CDC.

Yucatán, a common tourist spot known for its turquoise waters and ancient Mayan ruins, has the highest number of dengue cases in Mexico. The state had 518 cases in 2022. In 2023? More than 10,000, according to weekly reports from Mexico’s Secretariat of Health. The states of Veracruz and the state of Quintana Roo — home to tourist destinations Cancún, Cozumel and Isla Mujeres — are not far behind.

The government has tried to take a proactive approach in these states. For instance, in Yucatán, where Tulum has become a well-known party destination, the Tulum Health Department carried out fumigation campaigns in October 2023 before the rainy season. “No breeding sites, no mosquitoes, and no mosquitoes, no dengue,” they said in an effort to raise awareness about potential breeding waters for mosquitoes, like plastic soda containers or laundry buckets left on patios. In Quintana Roo, the state with most tourists and home to Cancún, the government invested 168 million Mexican pesos (around 10 million USD) for fumigation.

In comparison, Veracruz, the sixth most popular state for tourists, invested less than 2 million Mexican pesos (around 115,000 USD) in fumigation according to government contracts, despite also having over 10,000 cases of dengue.

But there’s more to it than insecticide, said Julián García Rejón, head of the arbovirology laboratory at the Autonomous University of Yucatán, where he studies these viruses.

“You have two options,” he said, “you either control the virus or you control the mosquitoes.” 

In Cancún, hotels are more than prepared for mosquitoes, carrying out these fumigations on their own without depending on the government, García said, “but it’s different in Yucatán, where tourism actually involves visiting the ruins, going to the cenotes and traipsing through the jungle.”

It’s easy to confuse dengue with COVID because of the fever and other overlapping symptoms. Despite the government’s recommendations to visit clinics in case of symptoms to get a more timely diagnosis for dengue, García said, the government is still mostly focused on fumigation.

They do implement prevention measures, said a representative for the Secretariat of Health in Yucatán, such as a surveillance system to monitor mosquito densities and campaigns to reduce potential mosquito breeding sites prior to the rainy season.

As for timely diagnosis? Yucatán also monitors patients with symptoms, categorizing them as probable until they’re confirmed, said the representative.

Timely diagnosis isn’t just an issue in Mexico. Late diagnosis has happened to tourists who’ve visited Mexico or other tropical countries and returned to the U.S. feeling sick. For Michelle Zung, 45, a Seattle-based advertising executive who traveled to Yucatán in September, it took a while to receive a proper diagnosis once she was back in the U.S.

Zung started feeling feverish with body aches towards the end of her trip and got back to Seattle still feeling sick. After a few days of testing negative for COVID, her sister, who’s a doctor, suggested she get tested for dengue. She couldn’t get an appointment with her doctor, so she went to urgent care and asked to get tested. She recalls that the doctor there said “I’ve been doing this for 30 years, and I’ve never seen a case of dengue.” 

The skeptical doctor was proven wrong by a positive test, Zung said. She got a call later from her county’s Public Health Department to confirm she caught dengue while traveling.

The number of cases for travelers who’ve come back with dengue is underestimated, says a dengue report from the CDC, “because many travelers with dengue do not seek medical care, are not tested for dengue when evaluated or do not receive a correct diagnosis.”

Doctors need more awareness about these types of diseases, said Joshua Wong, a researcher for the CDC who co-authored the report. Because it’s a disease that you don’t see very often, doctors don’t always think of dengue when the patients have a fever. It’s important for doctors to add it to their diagnosis, he said.

“I always say to doctors: think of dengue.”

But is dengue a strong enough reason to avoid visiting Mexico? Not really, Mexican researcher García said “Prevention is the most important thing. Wearing the right clothes and using the right insect repellent.”

Even for people who’ve caught dengue in Mexico, like Hanson, the “horrible experience” she went through couldn’t keep her from going back.

“I love Mexico and this is still a quintessential, beautiful community,” Hanson said. “The food, the people, everything’s a 10 out of 10. It’s paradise.”

As winter approached, Hanon prepared to leave for her three weeks in Puerto Escondido. She’d been eyeing the insect repellent on her kitchen counter that her husband had stocked up on the week before leaving — she threw it into her bag.