Dengue fever is unknown to many outside of the tropics. For those at risk of dengue, it is often known as “break-bone” fever due to the debilitating joint and muscle pain. Typically dengue fever is limited to the tropics and subtropics. However, due to climate change, and specifically warmer winters, the range of dengue fever is rapidly increasing.
Dengue used to be a seasonal disease but thanks to warmer winters, it is becoming a year-round threat. Last year there were around 5 million cases of dengue fever reported. That’s the number of people who showed symptoms and became ill. This year there have been close to 10 million cases reported, mostly in South America. Puerto Rico declared a public health emergency due to the massive increase in infections. Even as far north as Germany, Europe is seeing dengue becoming endemic.
This ain’t no flu
Like malaria, Dengue fever is transmitted by mosquitos. Unlike malaria, the typical mosquito vector, A. aegypti, is a grazer like sheep. An infected mosquito can spread the disease quickly over a crowd, since it’s biting multiple people. They are the double-dippers of the mosquito world.
Symptoms of dengue appear from 3-14 days after infection. Meanwhile, people can be infectious (passing to a mosquito to then another primate) from 2-10 days after infection. Only about 20% of people show symptoms, but that means the other 80% can still get you infected. The unluckly 20% get a high fever (40 C/104 F) for 2-7 days along with debilitating joint pain. The really unlucky 5% of these (or 1% of the total population) get a few days of severe dengue that involves blood leakage leading to massive internal bleeding.
From anecdotal accounts I’ve read, symptoms can linger for a month. For already-strained health systems, this is bad news. We’ve already seen the consequences of overwhelmed health systems. Disease prevention is a key strategy to protect the healthcare system from failing. It also happens to be a lot more pleasant than suffering dengue fever!
Another complicating factor of dengue is that there are five distinct strains. Each is slightly different. While vaccines exist, not everyone is allowed to take it because it can increase the risk of severe dengue in certain cases. The complex messaging required around dengue will most certainly lead to more antivax and anti-science hysteria that will put more people at risk.
I previously wrote about wildlife not having access to A/C. A heatwave in Vietnam has killed hundreds of thousands of fish in the Song May reservoir. One of the confounding factors is that the reservoir management discharged water in an attempt to save crops from drought. That meant fish had less depth to protect themselves from the searing heat.
How to limit the impact of Dengue
Two things are desperately needed to get ahead of the rapid spread of Dengue. Just like heat risk forecasts, we need infectious disease risk forecasts. Timely forecasts require health surveillance data, which needs to be far more accessible than it is now. I wrote previously how in the USA, the CDC can only publish monthly data. Individual states hold the keys to higher frequency data. We need legislation that pushes the healthcare industry to be more transparent with data in a timely manner.
Second, hyperlocal monitoring is needed to accurately identify community risk of dengue. As with heat risk forecasts, high-level messaging is ineffective. People need tangible messaging that resonates with their individual lifestyles. This is why we are building mosquito abundance models that work on our sensor data. The goal is that anyone who owns a sensor device can get a daily suite of personalized climate risk guidance.
To be even more equitable, we need municipalities to get on board so all members of the community can be protected. We need you to reach out to your local municipality and ask for real-time mosquito surveillance.
The time to act is now.
Hotter Times is published by Zato Novo. We are building the Climate Adaptation Data Platform, an open source sensor and data infrastructure to accelerate climate action and digital development projects. Quickly build applications for food security and public health that rely on hyperlocal weather forecasts. Get in touch with Brian at rowe@zatonovo.com to learn more.