4 Methods Scientists Use to Anticipate Outbreaks of Infectious Disease


Outbreaks of infectious disease are, by their very nature, difficult to predict. Microbes evolve rapidly, making it challenging to determine what will be the “next big one.”  To further complicate matters, our knowledge of microbes is incredibly limited. In the past decade, we’ve started to understand how much our microbiome—the collection of all of the microbes in and on our body—plays a role in health and disease. We’ve also found that we’re only scratching the surface when it comes to knowing about the microbes in the world around us, with an estimated 300,000 animal viruses lurking in the wild, undiscovered.

However, we do have some ways to figure out what may be coming next, from pathogens both known and new. Here are four approaches scientists use to try to anticipate where, how, and when outbreaks of infectious disease might occur. 


With hundreds of thousands of viruses—not to mention an untold number of bacteria, viruses, and parasites—how do we figure out which ones could spread in the human population and cause us harm? It’s a big issue to tackle, and there are a number of approaches. Ideally, we want to find these pathogens before they start making people sick, so we can be aware of them should they “spill over” from their reservoir into the human population. Those reservoirs are usually other animal species, which account for 60 to 75 percent of all new infectious diseases, but may also include other environmental sources (such as soil or water).

Finding these means carrying out labor-intensive sampling in humans and animals around the world. Virologist Nathan Wolfe is one such “pathogen hunter,” traveling the globe to collect blood samples from people and animals that might contain new viruses. This has already led to the discovery of viruses related to HIV in African hunters. Another “virus hunter,” Ian Lipkin of Columbia University, has been involved in the discovery of 500 new viruses over the past quarter-century.

While we can find these new microbes before they cause disease in humans, we’ve also used the pathogen discovery approach to determine the cause of unidentified microbes that are making people sick. We’ve recently discovered the Heartland virus as a cause of disease in humans in the Midwest and South, and studies in wildlife identified the tick-borne virus in deer, coyotes, moose and raccoons in 13 states, suggesting it may be more common in humans as well but undiagnosed. The Bourbon virus was also recently found in a man from Kansas, who later died of the infection. 


Surveillance is very expensive. While ideally we’d see the types of studies described above carried out everywhere all the time, logistically this is impossible. So researchers have worked to identify hotspots—areas where new microbes are more likely to move into the human population. These type of studies have often pointed to impoverished areas that often lack coordinated surveillance as some of these hotspots—parts of Africa, Latin America, and Asia. With hotspots identified, we can, in theory, better target expensive surveillance into areas where we will get the most bang for the buck, and catch more diseases even though we’re using a smaller, more focused, net.

A recent paper modifies the hotspot idea. Researchers at the University of Georgia outlined a framework for predicting the emergence of infectious diseases by bringing together human, wildlife, and environmental data. Lead researcher Patrick Stephens noted in a press release, “"To understand what's going on with diseases overall, you need to integrate understanding of human, animal and environmental health. You can't look at diseases of humans in complete isolation of diseases of wildlife, and you can't look at diseases of wildlife in complete isolation of what's going on with the environment, because a lot of times those diseases are related to environmental degradation.”


Sometimes, we know what microbe to expect—we just don’t know where it will show up, or what version it will be. Influenza, for example, is a virus that’s constantly evolving and emerging. We saw the H1N1 “swine flu” pandemic of 2009, and saw pandemics that derived from avian influenza viruses in 1968, 1957, and most famously 1918. We know we’ll see another influenza pandemic sometime—but we don’t know when, or where it will start, or whether it will originate in birds or pigs or some other animal altogether.

To try to catch these microbes before they become a problem, we look at high-risk populations of people or animals. For example, studies have tested workers and animals in wet markets in Asia where live animals are sold and butchered—and where viruses such as SARS and several types of avian influenzas have been found in humans. We can look for people who are currently sick with these infections, or look for evidence of previous infections via antibodies in people's blood. Or we can monitor places where they’ve shown up previously, like Ebola has multiple times in Uganda.

The problem with these type of surveillance is that if we’re too focused in one area or on one microbe, we can miss an emergence elsewhere. That was the case in 2009 when the H1N1 influenza pandemic originated in Mexican pigs while we were watching the “bird” influenza virus H5N1 in Asia. It happened again in 2013 when Ebola took us by surprise in West Africa because we were expecting any outbreaks to appear in Central Africa.


The good news is that any data we have on existing infections can be crunched by computers in order to try and predict where and when new outbreaks might occur. These models can incorporate information about geography, climate, and dozens of other variables in order to forecast when and where infections might appear. This has been used recently to predict the spread of the Zika virus, and previously for malaria, Rift Valley fever, and many others. The downside is that this technique works best for well-studied microbes, though work is ongoing to create more general models.

Perhaps one day in the future, we’ll be able to accurately predict and prevent “the next big one.” For now, we’re still vulnerable to the global ravages of the tiniest life forms on Earth. 

What’s the Difference Between Type 1 and Type 2 Diabetes?

The odds are pretty good that you know someone with diabetes. Affecting more than 30 million Americans, it's an incredibly common—and commonly misunderstood—condition.

The word diabetes comes from the Greek for "siphon"—a reference to the frequent and copious urination the condition can cause. The term was coined in the first century by ancient physician Aretaeus the Cappadocian, who vividly (and inaccurately) described the theory that "great masses of flesh are liquefied into urine."

Today we know a bit more about this illness, what causes it, and the forms it can take.

Diabetes is ultimately a hormone problem. The hormone in question is insulin, which helps the body convert glucose (sugar) into energy. Your pancreas releases a little dose of insulin into your bloodstream when you eat. The insulin tells certain cells to gobble up the glucose you've just added. The cells take in the sugar and put it to work.

Or at least that's how it's supposed to go. If you've got diabetes, the situation looks a little different.

Like rheumatoid arthritis or celiac disease, type 1 diabetes is the result of a person being attacked by their own immune system. In rheumatoid arthritis, the issue manifests in the joints; in celiac disease, it occurs in the gut; and in type 1 diabetes, it's the insulin-producing cells in the pancreas that are targeted by the immune system.

Little fluctuations in blood sugar that would breeze right through a healthy system can wreak havoc in the body of someone with type 1. People with type 1 must keep a very close eye on their glucose levels and take supplemental insulin, in shots or through a pen, port, pump, or inhaler, as blood sugar that goes too low or too high can cause serious complications and even death.

Type 2 diabetes is caused by an obstacle at the other end of the road. Someone with type 2 diabetes typically may have enough insulin to function, at least to start; the problem is that their body can't process it. Unused glucose builds up in the bloodstream and the body begins to need more and more insulin to see any effect.

Type 2 used to be known as adult-onset diabetes and type 1 as juvenile diabetes, but both kids and adults can and do develop both types. And while being overweight or obese does increase a person's risk of developing diabetes, thin people get it too. To complicate matters even further, researchers in Finland and Sweden recently identified five subgroups of diabetes, each with its own unique characteristics and risks for complications. Knowing which subgroup people fall into may improve treatment in the future.

And while we're myth-busting: The idea that diabetes is the product of eating too much sugar is a gross oversimplification. How you eat affects your body, of course, and a low-carb diet can help keep blood sugar in check, but diabetes can be caused by a lot of different factors, including genetics, medications, and other health conditions. (If you're on insulin, talk to a doctor before starting a low-carb diet, as low blood glucose levels can result if not done carefully.)

There's no common cure for diabetes—at least not yet. An artificial pancreas and other treatments for the immune system and pancreas cells are all in the works. In the meantime, both types can usually be managed with medication, diet changes, exercise, and a lot of doctor visits.

The Colorful Kit Helping Diabetic Kids Manage Their Injections With Temporary Tattoos

No kid looks forward to getting their shots, but for children living with type 1 diabetes, insulin injections are a part of everyday life. When Renata Souza Luque, a graduate from the Parsons School of Design in New York, saw how much of a toll the routine was taking on her 7-year-old cousin Thomas, she designed a product to make the process a little easier for kids like him. The result, Thomy, is a tool kit that aims to make insulin injections less intimidating to young diabetics, as Dezeen reports.

The brightly colored, easy-to-carry kit is designed for ages 4 and up, with an insulin pen specifically made to fit in a child’s hand. In addition to being easier for kids to hold and use, the Thomy pen is designed to be more fun than your average insulin injector. It has a thermochromic release valve, so that when it touches the patient’s skin, it begins to change color. The color-morphing doesn’t serve any medical purpose, but it provides kids with a distraction as they’re receiving the injection.

A purple insulin pen in an orange case
Renata Souza Luque

The kit also includes playful temporary tattoos to help kids figure out where their injections should go. Diabetics need to change the site of their injections regularly to prevent lumps of fat from developing under the skin, and for patients injecting themselves multiple times a day, keeping track of specific spots can be difficult. Kids can apply one of Thomy's temporary tattoos over their injection sites as a map for their shots. Each time they need an injection, they wipe off one of the tattoo's colored dots with alcohol and insert the needle in its place. When all the dots are gone, it's time to move on to a new area of the skin.

A child wipes at a temporary tattoo on his abdomen with a cloth.
Renata Souza Luque

Souza Luque originally created Thomy for her senior capstone project, and last year it was named a national finalist at the James Dyson Awards. Most recently, she presented the concept at the Design Indaba conference in Cape Town in late February.

[h/t Dezeen]


More from mental floss studios