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. 

97 Percent of Us Are Washing Our Hands All Wrong

Most of us know the importance of washing our hands, but we're still pretty clueless when it comes to washing them the right way. As CNN reports, we fall short of washing our hands effectively 97 percent of the time.

That number comes from a new study conducted by the U.S. Department of Agriculture that looked at 383 participants in a test-kitchen environment. When they were told to wash their hands, the vast majority of subjects walked away from the sink after less than 20 seconds—the minimum hand-washing time recommended by the Center for Disease Control and Prevention. Many of them also failed to dry their hands with a clean towel.

The researchers had participants cooking and handling raw meats. Because they didn't wash their hands properly, volunteers were spreading potentially dangerous germs to spice jars 48 percent of the time, contaminating refrigerator handles 11 percent of the time, and doing the same to salads 5 percent of the time.

People who don't wash their hands the correct way risk spreading harmful microbes to everything they touch, making themselves and those they live with more susceptible to certain infections like gastrointestinal illness and respiratory infections. Luckily, the proper hand-washing protocol isn't that complicated: The biggest change most of us need to make is investing more time.

According to the CDC, you need to rub your hands with soapy water for at least 20 seconds to get rid of harmful bacteria. A helpful trick is to sing "Happy Birthday" twice as you wash—once you're finished, you should have passed the 20-second mark. And if your bathroom or kitchen doesn't have a clean towel to dry your hands with, let them air-dry. 

[h/t CNN]

This Mysterious Condition Makes People Think Bugs Are Crawling Under Their Skin

After seeing a spider or beetle scurry past you, it’s normal to get a creepy-crawly feeling, even if you know there’s nothing on you. For many people, though, the persistent sensation of phantom insects or parasites crawling underneath their skin—known as formication—is very real, Newsweek reports.

The condition is called delusional infestation, and although cases have been documented around the world, there hasn’t been enough research to determine if it’s a skin condition or psychological disorder. However, two new studies are attempting to shed light on the mysterious ailment that can cause symptoms such as itching, fatigue, joint pain, rashes or lesions, and difficulty concentrating. Some people have reported picking “fibers” out of their skin.

Researchers from the Mayo Clinic and Denmark’s Aarhus University Hospital believe tens of thousands of Americans could have this condition, making it more common than previously thought. Their study, published in the journal JAMA Dermatology, found that people with the condition are often “resistant to medical evidence [showing that there is no infestation] and reluctant to pursue psychiatric evaluation.” Some patients, convinced that they have something crawling underneath their skin, self-harm with tweezers, bleach, or razor blades.

The researchers stopped short of calling it a psychological condition, but they did conclude that schizophrenia, dementia, other psychiatric conditions, and drug use can trigger delusional infestation in some cases, Science News reports.

Another new study, published in the journal Annals of the Academy of Medicine of Singapore [PDF], also seemed to favor a psychological explanation for the condition. The researchers noted that Chinese patients with the condition were treated with antipsychotics, and 10 of the 11 patients with isolated cases of delusional infestation (who had no other underlying disorders) improved with medication.

However, other researchers have drawn different conclusions, arguing that the condition is the skin's response to “tick-borne pathogens” typically associated with Lyme disease. The condition has gone by several names over the years, including Morgellons disease—a term coined in 2004 by a medical researcher and mother who says she found “fibers” on her young son’s skin after he kept scratching at the "bugs" he claimed were there. Regardless of the origin, what's clear is that the condition has very real consequences for those who suffer from it, and more research is needed to find suitable treatments.

[h/t Newsweek]


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