NSF Grant Funds Research to Better Predict Infectious Disease Outbreaks

The National Science Foundation has awarded $2.35 million to Penn State researchers who have been tasked with further exploring disease transmission among animals in hopes that their research will help inform ways to better predict infectious disease outbreaks among humans.

The research will focus on exploration of the virome, or collection of viruses, that “live” in white-footed mice (Peromyscus leucopus), which transmit hantavirus, and black-legged ticks (lxodes scapularis), which transmit Powassan virus.

In a recent press release, Kurt Vandegrift, PhD, research associate in the department of Biology at Penn State and the grant’s principal investigator, discussed the reasoning behind a study involving two animals that are common inhabitants throughout the Eastern and Midwestern United States.

He explained, “The rodents that live in our homes and garages are the primary reservoirs for several of the emerging infectious viruses that we’ve seen in humans so far, including babesiosis, Lyme disease, and Rocky Mountain spotted fever. And we are frequently discovering new viruses in these rodents, and in the ticks that feed upon these rodents and then upon us.”

He also shared that his team has found that both of the aforementioned animals “harbor many undescribed microbes, including close relatives of human pathogens such as hepatitis C viruses and hantaviruses.” Dr. Vandegrift feels that with this study, his team may be able to identify “new infectious viruses” that are present in the animals “before they spill over into humans.”

According to Dr. Vandegrift, these diseases “threaten global health and security,” but not much is known when it comes to when or where these diseases will strike. When it comes to emerging infectious diseases, what the Centers for Disease Control and Prevention define as “infectious diseases whose incidence in humans has increased in the past 2 decades or threatens to increase in the near future,” researchers are always searching for ways to be better prepared.

Dr. Vandegrift and his team have been monitoring thousands of white-footed mice each year, spanning 15 years, in order to gain a better understanding of their viromes. Once they catch the mice, the scientists collect data regarding body length, mass, and reproductive status. In addition, the scientists note the number of ticks or parasites present on the mice in addition to identifying them. Then, the scientists collect blood and fecal samples, “mark the animal with a transponder, and release it for eventual recapture.”

According to Dr. Vandegrift, the scientists could capture the same mouse up to 36 different times. By doing this, they are provided with “a sort of ‘movie’ showing how parasites move through individual mice within populations, and from both mouse to tick and tick to mouse.”

In addition, his team is also paying attention to the viromes of ticks “during their various life stages,” paying particularly close attention to any notable differences or similarities between the ticks who have fed on mice and those who haven’t, according to the press release.

The scientists are also looking into how “human-caused disturbances” or variations in mouse/tick abundance impact the viromes of the animals or influence the “pathogen transmission patterns.”

Dr. Vandegrift explained, “Anthropogenic disturbance, particularly forest fragmentation and degradation, can affect abundances of mice and ticks. Similarly, long-term studies show that mouse abundance can be predicted many months in advance based on acorn production, and that human contact rates with the pathogens harbored by mice and ticks are generally more frequent during acorn-driven mouse outbreaks. As a result, we seek to determine whether virome composition and transmission dynamics differ between habitat types and between years of high and low mouse abundance.”

When it comes to gathering all of their data and using it to make predictions regarding future outbreaks, the scientists are using a kind of artificial intelligence where “computers learn without being explicitly programmed,” also referred to as “machine learning.”

“Despite the staggering diversity of viruses and their prominence in causing many of the most virulent human emerging infectious diseases, very little is known about viral communities. We hope that our research will shed light on these important communities and how they spread through animal hosts, including humans,” Dr. Vandegrift concluded.