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Moving beyond descriptive epidemiology

Wednesday, June 12, 2019

Alvarez teaching a spatial analysis course at the Minnesota Department of Health 

CAHFS organizes spatial analysis training course for external partners 

The University of Minnesota College of Veterinary Medicine (CVM) has a long history of collaborating with the Minnesota Department of Health (MDH) and the Minnesota Board of Animal Health (BAH) to implement solutions to the state’s most pressing public health problems. The partnership also results in real-world applications for University of Minnesota research on timely topics, such as deciphering how bacteria develop antimicrobial resistance.

As the public health arm of the CVM, the Center for Animal Health and Food Safety (CAHFS) drives outreach initiatives that identify specific research topics that would best help MDH address current threats to the state’s food safety. When MDH officials expressed an interest in delving into how the U of M approaches this research, CAHFS organized a training course for MDH and BAH employees. In April, instructors from the U of M created a course that presented applications of spatial analysis, a discipline that can help track how a disease spreads and pinpoint measures that should be taken to mitigate it most effectively.

When epidemiologists conduct a spatial analysis, they study the different determinants that drive the spread and distribution of an infectious disease within a certain space, such as an animal production facility or a region.

“Often we are not able to identify all the factors related to the space, but we can certainly look into the distribution of these health events,” says Julio Alvarez, DVM, PhD, who was among the course instructors who illustrated the full extent of U of M resources that can be utilized in future collaborations with MDH. “We can study the spatial patterns and then test whether or not those patterns are statistically significant.” Alvarez is an adjunct professor at CVM who primarily works at the Veterinary Health Surveillance Center at the Complutense University of Madrid, where his research takes a quantitative approach to studying the epidemiology of infectious diseases in the human-animal-environmental interface.

Julio Alvarez Alvarez

Diseases do not spread at random—they are the result of contributing factors that facilitate distribution. By identifying these risk factors through spatial analysis, researchers like Alvarez can develop targeted control measures.

“We are moving beyond descriptive epidemiology, which essentially involves stating what you’re seeing,” Alvarez says. “When you apply quantitative analysis, you may be able to ultimately also predict what will happen so strategies can be changed accordingly.” Alvarez and other U of M instructors presented case studies of spatial analysis that focused on infectious and zoonotic diseases as well as invasive species, such as milfoil, which pose a specific threat to Minnesota.

“We have a lot of case studies that we can present and show, ‘this is the health problem, this is what we know, and this is how this spatial analytic tool helps me understand what I don’t know,’” says Alvarez. He’s also uniquely positioned to bring public health examples from other parts of the world that can be applied to local issues. Alvarez is currently working with Spanish authorities on the analysis of data on salmonella in animals and humans to understand the epidemiology of salmonellosis as performed in a recent collaboration between the U of M and MDH.

“By comparing what we see in two different parts of the world and determining what’s the same and what is different, we can better determine which factors are driving these differences and why,” says Alvarez.

Malia Ireland, DVM, MPH, DACVPM, an epidemiologist with the MDH zoonotic diseases unit, has been working with the U of M on better understanding blastomycosis, a fungal infection that affects both humans and animals. “It's a disease with very distinct geographical patterns and we want to use those patterns to learn about the ecological niche that the fungus prefers,” says Ireland.

With the help of U of M researchers, Ireland has been able to analyze the location of people and animals infected with blastomyces, the organism responsible for blastomycosis, to divulge clues about what kind of ecosystem the fungus prefers. Ireland was among nearly 20 participants from MDH who joined the course, which included epidemiologists who work with zoonotic, foodborne, waterborne, and vector-borne diseases, and those focused on sexually transmitted diseases and HIV as well as tuberculosis monitoring.

“It was a great opportunity for us to brainstorm ways we can partner with the U of M to use the information that MDH has already collected on reportable diseases,” says Ireland. “We have a greater understanding of how we can use geographical location and spatial analysis to better protect the health of Minnesotans.”

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