Dengue has been catching a lot of heat lately. In June, the Centers for Disease Control and Prevention (CDC) issued a health advisory about the increased risk of dengue virus among people who were recently in high-transmission areas in the Caribbean, Central America, Southeast Asia, and the Pacific Islands, among others. Months earlier, Puerto Rico declared a dengue epidemic.
New York is the state with the second-highest number of reported cases of dengue so far this year, after Florida, according to data from the CDC. With plenty of the summer travel season still to go, we wanted to learn more about how to keep safe amid the dengue alert.
We spoke with Dr. Sharon Nachman, chief of division of pediatric infectious disease at Stony Brook Children’s Hospital, about preventative measures, what to do if you develop symptoms, and why there’s been a rise in dengue diagnoses among New Yorkers and globally. The interview was condensed and lightly edited for clarity.
Epicenter NYC: Has there been an increase in patients you’ve seen treated for dengue-related concerns this year versus other years?
Dr. Sharon Nachman: Yes, New York State is clearly seeing more cases of dengue than we’ve had in the past.
In the past, if it was summer and you came to me and you had flu-like illness, I’d say, ‘oh, maybe it’s Covid, maybe it’s RSV, maybe it’s flu, you’ll get better.’ But now, if you’re coming to me, and we’ve been talking about dengue, and you say, ‘I came back from my travels a week, a week and a half ago,’ I would say, ‘we’re gonna test you for dengue.’
[We ask ourselves] is it because more people are traveling to those locations? Or is it that we’re more sensitized to it, and we’re diagnosing more patients? I think it’s both. Clearly after Covid has turned down, more people are traveling. It’s clear that there are more abundant cases of dengue in tropical areas. And thirdly, we are more sensitized to the issue, and we are testing more people.
Epicenter NYC: Why are we more sensitized to dengue?
Dr. Sharon Nachman: A lot of it has to do with the advisories. The first few patients got diagnosed, and everyone started talking about that. People that perhaps, in the past, would never have been testing their patients, were like, ‘Oh, this patient went away and got dengue — maybe you have dengue too. Let me test you for it.’
Our ability to get the tests — these are now standardized lab tests — is much easier. You can order it at Labcorp or Quest or something like that, and get the result back. It’s not that you have to send the blood to the state or the CDC; you can order this test.
There’s no one right answer. People are traveling, there are many more mosquitoes in those locations who are infected. And I think we’re also smarter about identifying the patients who have dengue.
Epicenter NYC: Has this rise in local dengue cases been happening earlier than it would have in previous years?
Dr. Sharon Nachman: It’s not a seasonal event at all. This is really about people traveling, and being smart about diagnosing them. It’s not like, ‘oh, it’s summer, you have dengue, but no one gets it in the winter.’ If you go to a lot of these countries in their winters, there’s still a fair amount of dengue, and there’s a fair amount of mosquitoes passing dengue. So will we see, in December, dengue cases in New York? Absolutely — clearly, we have no mosquitoes flying around in the snow. It’s all travelers-associated dengue.
Epicenter NYC: Has climate change been accelerating the spread of dengue?
Dr. Sharon Nachman: There’s a fair amount of data looking at the tracking of the mosquitoes that carry dengue over years or decades, and they show quite clearly that with the change in climate, mosquitoes’ reach is now further and further. So if you look 20 years ago, we saw just a little bit of dengue in places like Puerto Rico, but 20 years later, we see a full island coverage with dengue. There are mosquito maps worldwide that show the mosquitoes that carry the different pathogens, such as malaria and dengue, where they’re invading more and more. And yes, we do believe it is related to change in ecosystems and climate.
Epicenter NYC: When you say that in the past, you might have thought someone had Covid or another flu-like illness, when they actually had dengue — are the symptoms similar?
Dr. Sharon Nachman: They’re not similar in that there is no respiratory component to dengue. But when patients come to us with fever and muscle aches, we do jump on the ‘you have a virus’ [frame of mind].
Not every patient that had Covid came to you with a cough and sneezing on day one or two — they might get that later on. The dengue patients, on day one, come to you with a lot of the same symptoms that other viruses have, and that’s why you can’t distinguish one from the other. You say, ‘Oh, I’ll check one, I’ll check two, I’ll check three,’ and by the time you’ve checked 10 viruses, it’s number 11 virus.
Epicenter NYC: Who should be monitoring for dengue?
Dr. Sharon Nachman: For the person who has not traveled, dengue is off the table. We are not going to test them for dengue. There’s no evidence that we have any native Long Island, New York City mosquitoes that have the virus. We’re not seeing that at all. If you came home from work one day and felt crummy, we would not send you to test for dengue.
Viral symptoms look similar across many viruses. The most important part will be telling a physician ‘yes, I traveled’ and where you traveled. So if you perhaps travel to Iceland or Toronto, we would not test you for dengue. There isn’t really any dengue in Iceland or Toronto.
We are not quick though, to test for multiple viruses, because, for the most part, we can’t treat those. We have no antivirals for them. So for our summer viruses (the enteroviruses), no medication. We’ll tell you to go home. Drink a lot of water. Take your antipyretics, chicken soup, tea with honey, stay hydrated. And, more importantly, take it easy. That same advice goes for dengue as well. Go home. Take it easy. Don’t run around.
Epicenter NYC: What preventative measures do you recommend?
Dr. Sharon Nachman: Mosquitoes are all around the entire world; standing water breeds mosquitoes. So it doesn’t matter if the mosquito is a vector for dengue or West Nile Virus, which we have here on Long Island, or other viruses — the same conditions that allow mosquitoes to replicate are found all over the world.
Our job is really to cut down on standing water. Be smart about where we’re hanging out outside at dusk and dawn, and wear mosquito repellent. It’s not like we should worry about dengue, but not worry about other mosquitoes. It’s often the same mosquitoes that carry different pathogens in different parts of the world. So it’s not like, ‘oh, don’t go to Puerto Rico, because they have dengue, but go to Uganda and don’t worry about malaria there.’
The common sense approach often works. I tell patients not to stand around standing water at dusk. Dusk is when the mosquitoes feed the most. I also recommend thinking about using DEET as a strong mosquito repellent, both on their skin and spraying it on their clothing. A lot of the over-the-counter citronella candles and stuff like that don’t necessarily work. So while people invest in them, the data has not supported that they actually do a whole lot.
Epicenter NYC: Are there any vaccines or preventative medications?
Dr. Sharon Nachman: There is a dengue vaccine that is licensed in the U.S. But the problem with the dengue vaccine is that it cannot work before you’ve had your first event of dengue. It is a live attenuated vaccine, and it’s only meant to be used after your first documented event. So in order to get that vaccine, you have to have blood drawn showing you had a prior dengue event. Then you can be vaccinated and prevent your second dengue event — the first event is often not so terrible, but your second event of dengue is a much worse event. The vaccine was developed to be given to children over age nine through adults who had their first event of dengue.
The problem is, uptake has been incredibly poor. Having large swathes of children and adults prove they had the first event to dengue in order to get the vaccine hasn’t really worked. The manufacturer put out an alert saying that since no one really picked it up to take it, they’re not going to make any more production. So whatever vials are available out there are going to be used, and then they’re done.
Epicenter NYC: If you’re concerned you have dengue, what’s the first thing you should do?
Dr. Sharon Nachman: If you have signs and symptoms of a viral illness, you can reach out to your physician, and they will discuss it with you. It’s not just dengue that we worry about — in travel, you could pick up other illnesses. So staying at home playing Dr. Google is probably not the best.
It’s important to consider what kind of a patient you are. Do you have any comorbidities — like diabetes, high blood pressure, cardiac disease? Are your symptoms getting worse, is the fever not resolving? Those are the kind of things that would say, ‘aha, I need someone to take a look at me.’
Epicenter NYC: Besides monitoring their other conditions, in those cases, are there certain treatments you recommend?
Dr. Sharon Nachman: The antipyretics will make you feel better. We strongly want people to be well hydrated. We want them to take it easy. Last thing you want to do when you have an acute viral illness is walk 10 miles; you’re going to feel worse.
Epicenter NYC: Are there any long-lasting dengue impacts, the way we see with long Covid?
Dr. Sharon Nachman: No — there’s no long dengue. Those patients who get over their dengue, do so over a couple of weeks.
I hate mosquitoes bites. But these report on Dengue gave me some valuable information about how travel safe in summer time, thanks