When I sliced my toe on a rusty grate during last year’s Lunar New Year fireworks in Vietnam, I never thought it was the beginning of a long saga that would end with a dengue fever diagnosis.
When it happened, I immediately chose to ignore the bleeding toe and focus on New Year’s Eve fireworks instead. Breathing through the burning and the pain to watch fireworks seems like a mistake in retrospect, but nowhere near as impactful as the rest of them I made that year.
After the light show ended, I took a good look at my injury and saw that the grate had pierced my toenail and cut diagonally across the side of my toe, necessitating a tetanus shot and a lot of limping. Thankfully no stitches.
My Vietnamese friends were aghast. The local beliefs surrounding Tet, Vietnam’s Lunar New Year, include the fact that what happens around midnight on Tet eve dictates the tone and spirit of your coming year. This is why, as I noted in my long roundup from last Lunar New Year, the person who crosses the threshold into a person’s house at midnight must be compatible with the new year’s astrological sign.
My Vietnamese friends urged me to take care during this Year of the Snake, and predicted that it would be fraught with health issues. After all, it started badly, with an inauspicious blow to my general health (and my toe). Business-wise it could be a success, they insisted, but in terms of personal wellness they were worried.
I laughed it off. When I climbed Agung and Rinjani in Indonesia in 2009, I lost several toenails and much of the skin off the back of my heel. Plus, I’m also fairly clumsy. I’ve been known to walk into walls when not looking, to trip over sidewalks, to have an alarming amount of near-misses over the course of my life.
But my friends were unrelenting. This injury was different. This was a harbinger of a trend for the coming lunar year. I would, they asserted, anxiously await the day that the Year of the Snake was over.
They were right.
This piece discusses the symptoms for dengue fever that I ignored, as well as the different serotypes of dengue, their treatment, and their prevalence worldwide. With the pandemic in the mix, dengue news took a back seat in the news for a while. As you’ll read, vector viruses like dengue or Lyme are nonetheless spreading more rapidly than prior. This is due to climate change. It’s important to be informed about dengue before you travel to traditional hotspots like Southeast Asia or parts of South America, but it may also be important to take precautions in traditionally dengue-free areas in the near to mid-term future.
ORIGINALLY PUBLISHED: JANUARY 2014
LAST UPDATED: AUGUST 12, 2023
Table of Contents
How it began for me
When I created this site, I decided to do state of the union -style posts once a year, because I wanted the blog to be a place where people could learn about food—not read about my health complaints. So it is for this reason that when I started losing clumps of my hair in late February 2013, I never wrote about it.
A month later when I stopped being able to bend my hands or knees in the morning without considerable pain, or look at bright light, I didn’t mention that either. I kept up my usual schedule in Vietnam, exploring the Mekong and surrounding regions and walking around town for hours a day.
In May 2013, after flying to England to visit my family, I could barely walk down the street without feeling exhausted. Alarmingly, when my leg or arm was itchy and I scratched it, I’d develop lines of bruises, colouring the spot where nails had met skin.
As the summer went on, I sleepwalked through my existing obligations and plans—conferences, meetups, interviews and more. I found myself getting sicker and more listless. My immune system did not cooperate with anything I did; every cold or virus seemed to latch onto me stubbornly, and most of my days were obfuscated by a cloud of exhaustion.
The doctors I saw in North America or Europe were unhelpful, even infectious disease specialists. One suggested that I was just stressed. I had to tell him, “listen, as a former corporate lawyer, I know stress very well! This is not stress. Something is wrong with my body.” But I was dismissed, my symptoms were minimized, and I was told that I just “need to relax”.
In actuality, the pain and hair loss had started at a time when I was the least stressed in decades; I was in Vietnam, loving my exploration of the city and its soups. One doctor thought I had lupus, and to be fair many of the symptoms lined up, but tests for that condition gave no indication that I might have it.
As Maya Dusenbery says in her excellent book, Doing Harm, “the difference between a crazed neurotic and a seriously ill person is simply a test.” And not one doctor I saw thought to do a test for dengue, despite my being in Southeast Asia for years, where it is prevalent.
Not knowing what was going on with my body, my exhaustion and pain, and keeping it all quiet online meant that I struggled to explain why I couldn’t see friends or go to events. I spent August in San Francisco in a haze, my joints and fatigue worsening. I “looked” fine, but I was not at all fine.
I confided in my close friends, acquaintances, colleagues, and more, corresponding with many of them to brainstorm solutions. Before doctors ruled it out, I was connected to a woman had lupus, who shared coping strategies and foods to avoid.
And I was given the recommendation of a book that calmed my brain down considerably, Full Catastrophe Living, written for those dealing with the stress and exhaustion of chronic pain and fortuitously updated days before it was suggested to me.
By October, when I was heading to India with my mum, I felt like I was hanging on by a thread. We did have a terrific time in India, exploring the chaos and colour of Rajasthan in a few too-short weeks. But I did still get sick again and again, and much of the trip was clouded with pain. By the time I flew home to Canada, the airline stewardesses took one look at me as we boarded the plane and then cleared out the back row and insisted I sleep.
I was tired and confused and tired of being tired and confused.
And then, I figured it out.
Yep, it was a mosquito-borne virus, dengue fever
I kept going back to February when it all began. Earlier in the month I was supposed to go to the Mekong, but I woke up feeling so sick and tired that I couldn’t budge. I had a splitting headache and it felt like someone was pressing on my eyeballs; nothing relieved the pain.
I thought I had a bad flu and I postponed my visit. My “flu” cleared up a few days later for the most part, though the headache took longer to go away. A few days later, when I was visiting Vung Tau with my friends, I developed a strange rash all over my stomach.
It wasn’t itchy. It was just flat red dots, a maculopapular rash that appeared in constellations all over my torso and around my belly button. I remember my friends all gathered around me at the beach, awkwardly peering in at my stomach. (We probably confused the passersbys too).
We went with heat rash, and quickly forgot it existed. A few days later it was gone. What could have caused the rash and my flu-like symptoms and then all the tiredness, joint issues and pain?
Interestingly, that’s exactly why two of my friends were in Vietnam—they had gotten dengue in Bangkok and were in recovery on their visa run. Many months and fruitless doctor’s visits later, I Googled “dengue rash stomach” and saw exactly what was on my stomach in Vung Tau. And then I looked into what happens when you don’t take care of yourself when you have dengue. Those who have experience with it will know that the disease is not really treated per se; much like mono or glandular fever, treatment involves hospital visits, hydration, and rest. In dengue’s case, you are also supposed to monitor your white blood cells and platelets, both of which can be dangerously low when in the throes of its grasp.
I learned that when you ignore it as I did, it starts wreaking all sorts of other havoc on your immune system, on your joints and on your general state of being.
I went to a tropical diseases doctor when I was back in Vietnam and shared my thoughts. They confirmed that dengue is almost certainly what had happened, which jived with a February infection and my subsequent blood test results for antibodies, and earlier labs that showed a lower-than-normal white blood cell and platelet count.
Dengue fever is caused by a mosquito-borne virus that infects an estimated 390 million people every year. Each year it also kills about 25,000 people, leading the World Health Organization to describe it as one of the top 10 threats to global health.
“The disease is now endemic in more than 100 countries,” says the World Health Organization (WHO) in a January 2022 global dengue report, with cases having increased 30x in the last 50 years. While the viral fever is common in parts of Asia and Latin America, global warming has affected the reach of the mosquitoes that spread it. In September 2022, for example, France sounded the alarm about an outbreak of locally-transmitted dengue.
A June 2022 study also found that being infected with the virus causes you to produce a bacteria in the skin that makes you more attractive to mosquitoes. Not the kind of news anyone wants to read! Hopefully this team’s findings could help inform real-world public health strategies for controlling mosquito-borne flaviviruses like dengue and Zika, because by 2080, as many as 2.25 billion more people — or 60%t of the global population — will be at risk.
There is a race to try and find a solution, and at the bottom of this post I share a pilot project from June 2021 that provides some hope.
There are different types of dengue fever, called serotypes, that are active in different parts the of the world:
I was told often in Asia that recovery from one strain of dengue may offer lifelong immunity against that strain. However, that means that while the one strain you’ve had has immunity following infection, the preexisting antibodies from prior infection make the other strains more dangerous, and more likely that they could develop into dengue hemorrhagic fever (DHF).
See symptoms of that, below.
From Science “When Dengue Strikes Twice“:
Most of the more than 50 million people sickened by dengue virus each year develop dengue fever, a weeklong bout of joint and muscle pain. But many who suffer repeat infections have it worse. They come down with dengue hemorrhagic fever and suffer massive internal bleeding and liver damage. Oddly, the virus causing dengue fever comes in four strains, and immunity to one seems to make infection by a second strain more dangerous.
The reason? Following one infection, T-cells were primed to fight a different strain than the new one attacking them. Plus, those dengue-specific CD4 T-cells rapidly self-destruct following a new infection, which leads to tissue damage.
For years, scientists thought that resulting immune system misfire / cell suicide could be a primary cause for DHF, versus the more ‘simple’ dengue fever. However, a late 2019 study cleared CD4 T-cells of any wrongdoing. “We found no evidence to support the common dogma that these T cells are responsible for turning a mild infection to a severe one,” said Yuan Tian, PhD, one of the scientists on the study.
The hunt is on still for why DHF is so severe.
In 2020, Singapore reported a spike in the DenV-3 type of dengue, which their National Environment Agency noted may signal an outbreak in the near future. The DenV-1 and DenV-2 serotypes have been dominant in Singapore for the last three decades, so the country is on alert due to the rise of DenV-3 since population immunity is low and people are more susceptible to it.
Sure enough, in 2022, Singapore has announced a “dengue emergency” — prior to June 1, when dengue season usually peaks, it had 11,000 cases – far beyond the 5,258 it reported throughout 2021. Eradicating the mosquito-borne disease is likely an impossibility, though many scientists are racing to find solutions.
How dengue virus transmits between mosquitoes and humans. Via Al Jazeera
What are the symptoms of dengue fever? They range from asymptomatic, to deadly.
Dengue’s incubation period is between 4-10 days, so it’s difficult to backtrack to exactly what mosquito bit you. In my case, I have a very good idea. I was outside on a phone call and came inside so bitten up that I almost vomited. It was less than a week later that my symptoms started.
According to the CDC, the principal symptoms of dengue are high fever, feeling general malaise (like the flu), and at least two of the following:
- Severe headache
- Severe eye pain (behind eyes)
- Joint pain
- Muscle and/or bone pain
- Mild bleeding manifestation (e.g., nose or gum bleed, petechiae, or easy bruising)
- Low white cell count
Is there a cure for dengue fever?
There is presently no cure or “antidote” to getting dengue fever. All that one can do is manage the infection. There is no antiviral treatment approved for dengue fever, either, but research is underway for a highly potent dengue virus inhibitor (JNJ-A07) that scientists hope can help treat the growing levels of dengue fever worldwide.
What are the symptoms of severe dengue (dengue hemorrhagic fever (DHF)?
Dengue hemorrhagic fever (DHF, or as WHO calls it “severe dengue”) is, as I mentioned above, a more deadly form of dengue first recognized in the 1950s during dengue epidemics in the Philippines and Thailand. In Asia, epidemic DHF expanded from Southeast Asian countries west to India, Sri Lanka, the Maldives, and Pakistan and east to China. (Source) Today, DHF is in most of Asia, Southeast Asia, and Latin America, and is a leading cause of hospitalization and death in those regions.
Symptoms of DHF include the above list plus:
- Persistent vomiting
- Severe abdominal pain
- Rapid, shallow breathing
- Blood in the vomit
- Bleeding gums
- Vascular leak syndrome
- Skin hemorrhages such as petechiae, purpuric lesions, and ecchymoses.
The even more worrisome dengue shock syndrome is defined as dengue hemorrhagic fever plus:
- Weak rapid pulse
- Narrow pulse pressure (less than 20 mm Hg)
- Cold, clammy skin
It involves a mostly clinical diagnosis, and is associated with high mortality. (Source)
What to do if you get diagnosed with dengue fever?
Obviously do NOT do what I did and simply not get tested for it. No specific therapy has actually been shown to be effective in the treatment of any of the manifestations of dengue in a randomized controlled trial.
The mainstay of treatment is still careful fluid management (Source). So for treating a dengue infection:
- Get to a hospital and get tested.
- They will likely provide IV hydration and Tylenol.
- Do not use any aspirin or supplements that would thin the blood.
- Do not use NSAIDs either. This means no Advil/Ibuprofen.
- Lots of Nuun tablets and rehydration salts.
- Following the infection, I found going on a low-inflammation diet or auto-immune protocol diet very helpful. Please see my post about chronic pain for more.
- There is some evidence that mast cell stabilizers and targeting the immune system itself may be helpful, see this study.
- Avoid any medication that lowers platelet levels. These include Furosemide, NSAIDs (hence the above note about Advil), and some other medications. Best to ask your doctor to confirm.
Can you get dengue fever more than once?
Yes, you can get dengue more than once. As mentioned above, there are four serotypes (or strains) of the dengue virus: DENV-1, DENV-2, DENV-3 and DENV-4. It’s possible to get infected by each serotype, so a person can get dengue up to four times. Rarely, someone’s immune system does not produce sufficient antibodies for the strain they’ve had, and they can get the same strain again.
Compounding infections may cause something called antibody-dependent enhancement, where the next infection leads to more severe disease. This means that if someone got infected with dengue, it’s important to try and prevent another infection with a different serotype.
What are the long-term, lingering effects of contracting dengue?
While many friends have come out just fine after a dengue infection, lingering effects are very widely documented.
- Depression and anxiety after the infection wanes (source) – likely due to systemic inflammation. See also this study about anxiety/depression and severity of dengue symptoms.
- Epigenetic changes – much like other severe infections or viruses, geneticists have begun to look at whether your gene composition could affect the severity of the infection or whether it creates sufficient inflammation to “express” genes you may already have and create a genetic cascade.
- Autoimmune marker changes to titers for C3/C4, rheumatoid factor (RF), C-reactive protein (CRP), antinuclear antibodies (ANA), and immune complex (IC). Source.
- According to a survey published in 2020, patients with a history of dengue fever infection are at increased risk of developing leukemia compared with individuals without a history of dengue fever. The findings from this study were reported in Cancer Epidemiology, Biomarkers, & Prevention.
- Developing mast cell dysfunction following dengue fever is also a long-term possibility. Dengue induces increased mast cell activity, for example patients exhibit increased levels of urinary histamine, a major granule product of mast cells. And increased histamine was found to correlate with disease severity. But for some people, their immune systems get “stuck” in that state, post-virally. This is also what scientists think is happening with some Long-COVID / PAS-C patients. I’ve written a long (12,000+ word) page on tackling mast cell issues / increased allergic reactions, here.
- In rare cases, dengue fever can also affect the nervous system and lead to conditions such as myositis, Guillain-Barré syndrome, or hypokalemic paralysis.
Is there a cure for dengue fever?
Presently, no. Despite some 50–100 million infections per year, there are no current solutions. A 2021 paper does give some hope, however. A team of scientists from the University of California, Berkeley, and the University of Michigan has found an antibody that blocks the spread of dengue fever within the body. Their findings are found in an article in Science called “Structural basis for antibody inhibition of flavivirus NS1–triggered endothelial dysfunction“.
From a GEN news article:
The dengue virus uses a particular protein, called Non-Structural Protein 1 (NS1), to latch onto the protective cells around organs. It weakens the protective barrier, allowing the virus to infect the cell, and may cause the rupture of blood vessels. The research team’s antibody, called 2B7, physically blocks the NS1 protein, preventing it from attaching itself to cells and slowing the virus’s spread. Moreover, because it attacks the protein directly and not the virus particle itself, 2B7 is effective against all four dengue virus strains.
Will this turn into a pathway toward preventing infection in the body? We don’t yet know. I’ll be keeping an eye out for further developments, and update this post if we they arise.
Dengue fever makes mosquitoes bite more
Another interesting factor in dengue’s spread is that new studies have found dengue makes mosquitoes infected with it bite more than mosquitoes who are uninfected. This biting-the-host stuff is called “blood feeding behaviour”, and blood-feeding behavior is a key factor in how mosquitoes spread the disease.
Earlier studies on how dengue virus infection changes the way mosquitoes feed haven’t been that conclusive. But in 2022, researchers took a broader, multidisciplinary approach using a variety of tools like high-resolution video to try and analyze the differences in blood-feeding with mosquitoes who had dengue, and those that did not. A study in PNAS called, Dengue virus infection modifies mosquito blood-feeding behavior to increase transmission to the host, the research team sought to understand transmission to then look at the reasons why these changes happen. And, more promisingly, if they can identify a gene or protein that causes this, they may be able to mitigate against dengue from that angle!
“We found that the dengue virus increases mosquito attraction to the mammalian host and the number of mosquito bites,” says Ashley St. John, associate professor from Duke NUS’ Emerging Infectious Diseases (EID) Programme, and senior coauthor of the study. The higher attraction to the mammalian host increases the chances of the mosquito to bite, while more bites increase the number of transmission events because each bite results in the transmission of the virus.
So essentially: dengue-infected mosquitoes are extra dangerous because they not only carry a pathogen, but spread it more via extra “bites”.
The increase in bites isn’t due to a psychological drive to infect, but rather because the mosquitoes seem to be unable to find blood vessels to feed from as easily, so they bite multiple times to try and get one, thus releasing their dengue-filled saliva into the body more than those mosquitoes who are uninfected (and can find vessels more easily).
The video below shows high-res videos that were then analyzed by computer software, to understand the ways that blood-feeding differed between dengue-mosquitoes and non-dengue mosquitoes.
(Credit: Duke-NUS Medical School)
This is especially an issue a recent research article in Science concluded that mosquitos in Southeast Asia are starting to be resistant to insecticides that countries use to help control the spread of the disease.
Where are you at risk for dengue fever?
Per the Center for Disease Control, dengue is endemic throughout the tropics, subtropics, Latin America, the Caribbean, and Southeast Asia. Presently, it occurs in more than 100 countries worldwide. Risk now includes the United States, where sporadic local cases have popped up in Florida, Hawaii, and Texas along the border with Mexico.
Although the geographic distribution of dengue is similar to that of malaria, dengue is more of a risk in urban and residential areas than is malaria. As such, the WHO estimates that over 40% of the world’s population live in areas where dengue viruses can be transmitted.
Interestingly, a 2023 study posited that asymptomatic vectors are responsible for a far larger amount of dengue cases than previously realized. The study results found that 8% of areas where people gathered represented more than 50% of all the infections during an outbreak. Of those spaces, 74% infected cases were asymptomatic. These are people who have no symptoms, and continue to live their lives unknowingly infecting mosquitoes that bite them — mosquitos that then go and bite other people and infect them, too.
This study shows that while approaches have historically been reactive (treat people with symptoms; spray / net areas with known outbreaks), we need to also think about containing outbreaks proactively given the role of super spreaders who have no symptoms.
Per Gonzalo Vazquez-Prokopec, one of the study authors:
“Our findings show that any public health intervention that focuses on responding to symptomatic cases of dengue is going to fail to control an outbreak. Symptomatic cases represent only the tip of the iceberg.”
According to the Pan American Health Organization, during 2022, several countries in the South American region registered increases in the number of dengue, Zika, and chikungunya cases compared to those reported in 2021. During the first months of 2023, chikungunya and dengue fever outbreaks of high magnitude were recorded in South America. (source). Dengue has made the news considerably in 2023, especially in Peru where record breaking deaths and infections even led to the health minister’s resignation in June.
What about Chikungunya and Zika?
Dengue, Zika, and Chikunyunya are all carried by the pesky Aedes aegypti mosquito. As is yellow fever. And of all the mosquitoes out there, this one will happily breed in even the most shallow of water sources. It is unfortunately possible to obtain more than one mosquito-borne disease from the same mosquito.
Aedes aegypti is not the only species to carry the disease, but it is likely the most efficient: It happily takes up residence in human dwellings, biting many people in a row. If it feeds on a sick person, the disease incubates in its belly, then migrates to its salivary glands. It is injected at the next bite.
After six dengue-free decades, Brazil had its first outbreak in 1981. The situation has deteriorated: Last year, 1.6 million people in Brazil were diagnosed with dengue, more than ever before. Chikungunya and Zika have infected hundreds of thousands more.
– Zika Uncontained, Frontline
An American reader living in Manila for many years kindly sent me her story of both dengue and a similar disease called Chikungunya. In her words:
“My experience was horrendous. Very, very similar to what you went through. The reason I am emailing you is to let you know it’s very likely you had both dengue and Chikungunya. The mosquito that carries dengue can also carry Chikungunya. If you get bit by a mosquito carrying both, you can be infected by both dengue and Chikungunya at the same time. This is what happened to me.
While both diseases have similar symptoms, the main difference is dengue can be fatal, Chikungunya isn’t. However, and this is huge — Chikungunya gives you terrible joint and muscle pains. These pains can last up to TWO years! Eventually you will recover completely though. And it can also leave you exhausted. This is all somewhat new – in fact most of us had never heard of Chikungunya before. There was an outbreak in Manila, and there has also been an increasing number of people getting both dengue and Chikungunya at the same time. Most ridiculously, there is not enough information about this.”
So, something to keep in mind if you’re exhibiting symptoms of the kind I mentioned. The rash for Chikungunya is generally on the stomach area, per what I’ve read, and joint pains ongoing. The high fever and joint and muscle pain can last for several months.
The symptoms for both diseases are quite similar, per the CDC, and it has so far been found far outside its usual locations and as far as Texas, Spain (as of August 2015), Mexico, and more, including the Caribbean where it was first detected in the Americas.
The mechanisms of infection of human cells with the virus remain very poorly understood. In September 2019, researchers have identified a protein, four-and-a-half LIM domain protein 1 (FHL1), that is required for the virus to replicate within its target cells. The study shows that FHL1 is a key factor that enables a Chikungunya infection, and allows for a target to potentially develop therapies to treat or preemptively prevent the infection/
Given that the three illnesses offer up similar symptoms, I wanted to devote a part of this post to Zika as well. The virus didn’t just appear in 2016. In fact, it’s been around for a long time. First identified in monkeys in Africa (Uganda to be exact) in the late 1940s, it spread to humans around the early 1950s. The World Health Organization documents the first case at 1952.
In recent years, with a warming planet and an increase in travel, the disease spread. In 2007, cases were reported in the South Pacific’s Yap Island with a larger outbreak on French Polynesia and in Brazil in 2013.
Zika’s symptoms are reported as quite mild — far more so than my dengue symptoms noted in this piece. Per Vox’s Zika Primer,
Zika produces very mild symptoms — rash, headaches, pain in the bones, and fever — that usually show up between three and 12 days after a mosquito bite. These symptoms usually go away within a week, and one in four people don’t even develop any symptoms after being infected with the virus. This means people don’t usually go to the doctor for Zika, and many cases go unnoticed. There’s also no vaccine or treatment for the virus, so doctors just work on controlling and alleviating its symptoms.
Prior to 2013, the disease was not in the Western media, partly because of these mild symptoms and a fairly low mortality rate (compared to, say, malaria or dengue). However, given its now-establish effects on pregnant women and microcephaly in their fetuses, the disease has become a global concern and opened up debates about women’s rights and contraception in the often-conservative countries that Zika has thus far spread.
An end to my year of travels … with dengue fever
So, after many months of not saying anything I’m writing this post to reiterate what not to do when you get dengue. Or, put another way, when in dengue-prone areas and having symptoms of the flu, if you then see a rash on your person GET THEE TO A DOCTOR.
I wish I had gone to check it out, and could have then taken care of myself properly.
Global Update from 2023: Dengue on the rise worldwide. A new hope, though, from a Wolbachia-infected mosquito pilot project.
With a warming planet, mosquitoes have proliferated, and mosquito-borne illnesses have swept across the globe. Each year seems to be a been banner year for those illnesses, with more and more mainstream news coverage about dengue, Chikungunya and Zika. Said climate scientist Winston Chow from the College of Integrative Studies at Singapore Management University, “constant weather extremes create the perfect breeding conditions for mosquitoes”. With climate changes comes more viral emergencies, and with changing temperatures comes new patterns in global dengue transmissions:
At the time of updating, I have friends in Siem Reap, Cuba, Rio de Janeiro, and Delhi who have dengue at the same time and in very disparate places. One of the hardest symptoms following dengue is the depression and anxiety that follows. The WHO has also reported in 2023 about changes in dengue spread, and how the areas infected have expanded geographically.
The problem will get worse. Beyond the tropics and subtropics, the species has strongholds in Florida, Texas, California, and Arizona, and at least one population has managed to survive multiple winters in Washington, D.C. One recent study projected that by 2050, thanks to the climate crisis, the North American range of Aedes aegypti will extend to Chicago; in China, its range will go as far north as Shanghai.
Given how prevalent dengue has become, as well as the additional reporting about Chikungunya and Zika, I wanted to add a few more resources:
New hope: Wolbachia-infected mosquitoes
An interesting solution for the dengue problem: instead of only looking for a vaccine to help prevent the disease, what if the mosquitoes themselves could be defanged? There have been reports of genetically-modified mosquitoes released to test if it lowers the overall dengue cases. Another example of that is a pilot project in Yogakarta, Indonesia, where the mosquitoes are purposely infected with a bacteria commonly found in the insect world.
The bacteria, Wolbachia, was first discovered in 1924 and is found in mosquitoes–just not the Aedes aegypti
From a June 10, 2021 piece by Ed Yong:
They’ve loaded the mosquitoes with a bacterium called Wolbachia, which prevents them from being infected by dengue viruses. Wolbachia spreads very quickly: If a small number of carrier mosquitoes are released into a neighborhood, almost all of the local insects should be dengue-free within a few months. It’s as if Utarini’s team vaccinated a few individuals against a disease, and soon after the whole population had herd immunity.
The team found that just 2.3 percent of feverish people who lived in the Wolbachia release zones had dengue, compared with 9.4 percent in the control areas. Wolbachia also seemed to work against all four dengue serotypes, and reduced the number of dengue hospitalizations by 86 percent.
While the Wolbachia strategy is not immediate, it blocks dengue infections in a few different ways that lead the mosquitoes to be less likely to carry dengue and thus transmit it to people.
In Indonesia, following this trial, scientists are breeding these Wolbachia-infected mosquitoes to try and tackle the dengue fever problem in the country. The theory is that by breeding the “good” mosquitoes, they will not transmit the virus when biting humans.
Hopeful experiment! I’ll be updating once there is more data from other regions.
Mosquito transmission of disease and lack of vaccine:
- A November 1, 2019 episode of Bloomberg’s Moonshot investigates how scientists are attempting to modify the Aedes aegypti mosquito, the primary vector for infecting humans with dengue. After injecting the insects with a bacteria called Wolbachia, which blocks transmission of the disease to humans, the non-profit research team released them out into the world. “My hope,” Scott O’Neill, the founder of The World Mosquito Project, says, “would be that we could eliminate dengue at some point.”
- Interesting article from the Smithsonian Magazine, about how the isolation of a single protein could help develop a vaccine for dengue. This is a different vaccine than the Sanofi one that is in development and testing stages, since it targets a protein that, if this piece is correct, could help protect against all of the dengue strains.
- A 2019 piece in the New York Times, “The Mosquitoes are Coming for Us” goes into history as well. “The mosquito and her diseases have accompanied traders, travelers, soldiers and settlers (and their captive African slaves) around the world and have been far more lethal than any manufactured weapons or inventions.”
- A 2019 article about how mosquitoes “slaughtered our ancestors and derailed history” in the New Yorker. “Along with smallpox and influenza, mosquito-borne diseases led, by Winegard’s estimate, to the deaths of ninety-five million indigenous inhabitants of the Americas, from a pre-contact population of about a hundred million.“
- There is currently no widespread / accepted vaccine. Previously, the Sanofi vaccine, Dengvaxia, rolled out to very problematic results. In December 2022, though, a dengue vaccine developed by Japanese drugmaker Takeda Pharmaceutical Co was authorised for use in the European Union. The vaccine, branded QDENGA, is authorized for use in those aged 4 and older to prevent any of the four serotypes of dengue. Takeda’s vaccine is based on a Dengue 2 virus, with DNA from the other three serotypes added in so it protects against all serotypes. Data from Takeda’s main trial showed that the vaccine induces immune responses (varied ones, depending on the person’s immune system) against all four dengue types.
COVID-19 and Dengue Fever
At the time of this update in June 2023, Covid-19 is still a high global concern, despite some suggestions that it is “over”. (It is definitely not over: per wastewater data, weekly US Covid-19 transmission during the past year has been 28.9% higher than during the Delta wave.)
The pandemic has further weighed on countries where dengue fever is already an endemic population threat, primarily in tropical and subtropical regions of the world. Both Covid-19 and dengue share some symptoms, and this has led to diagnostic challenges in quite a few countries. Moreover, cross-reactivity of the body’s immune response to each of these infections is something on scientists’ radar, since the concern is that pre-existing DENV antibodies might affect the body’s ability to clear COVID-19.
A September 18, 2020 study review called “Covid-19 and dengue: Double punches for dengue-endemic countries in Asia,” examines the current state of the data here. An excerpt:
Clinical symptoms of Covid-19 include cough, muscle aches, fatigue, skin rash, and petechiae, making it challenging to differentiate Covid-19 from other endemic viral infections in the region, such as dengue, and thus potentially leading to misdiagnosis. In addition, a study in Singapore reported the possibility of serological cross-reactivity between SARS-CoV-2 and DENV, raising the question of overlapping immunological cascades between Covid-9, dengue, and other arboviruses.
In March 2022, a study review summarized treatment for dengue and covid-19 co-infection, alongside an overview of the existing literature on the topic. “Regardless of whatever infection the first symptom points to,” says the article, “confirmation diagnosis of both COVID-19 and dengue should be mandatory, particularly in dengue-endemic regions, to prevent health deterioration in individuals treated for a single infection.”
Dengue led to Mast Cell Activation Syndrome (MCAS) for me
The fatigue, the hair loss, the joint pain, and the depression and anxiety are all quite devastating but from my non-scientific poll of many friends who have gotten it, vary from person to person.
For me, with an existing autoimmune condition (celiac), the infection was really difficult. For others, they had a few months of problems but are fine now. I never got “back to normal”.
It has been several years, and the infection plus my stubborn unwillingness to stop traveling and rest longer-term led to an inflammatory immune condition called mast cell activation syndrome, which is similar in symptoms to long covid descriptions. I even had what people are calling “covid toe” for years.
I now have many new reactions to foods, smells, even the sun. I go into anaphylaxis on the regular. Vascular changes abound, and I have become intolerant to hot or very cold weather, to the point where my circulation is affected and I lose feeling in my extremities as they swell.
At the time I initially wrote this piece in 2014, I thought I’d get back to normal. Instead, my immune system got wonkier and wonkier, I got a lumbar puncture to rule out certain conditions, and ended up with a spinal CSF Leak that is still ongoing in 2022.
The immune issues? It’s a condition called mast cell activation syndrome, something we are also seeing post-virally with Covid-19. Some patients following a C19 infection are “stuck” in this hyperinflammatory state. I wrote a very long resources page for this condition given that it is more and more prevalent. You can check it out here.
I did return to Southeast Asia, and then moved to Oaxaca, in Mexico, before my life fully went off the rails health-wise.
So if you get sick with some of these symptoms, I urge you to please get tested for dengue fever, and take more time to rest than you might want.