Professor Examines COVID-19, Other Disease Transmission in Vulnerable Populations.

Professor Studies COVID-19, Other Disease Transmission in Vulnerable Populations

From animal influenza viruses to antibiotic-resistant bacterial infections, Jessica Leibler has dedicated her research career to understanding the environmental transmission of pathogens through food systems and the environmental exposures that disadvantaged populations experience.

As an assistant professor of environmental health and an environmental epidemiologist, Leibler has studied the impact of infectious disease transmission on many of the populations that are disproportionately affected by the COVID-19 pandemic, including food agricultural workers, people experiencing homelessness, and people who inject drugs.

She is currently working on two studies funded by the National Institutes of Health and Google to gain a deeper understanding of the social and environmental determinants that lead to the disproportionate transmission and impact of COVID-19 among vulnerable populations in Massachusetts.

In collaboration with members of the Center for Research on Environmental and Social Stressors in Housing Across the Life Course (CRESSH), including Jonathan Levy, chair and professor of environmental health; Patricia Fabian, associate professor of environmental health; and Kevin Lane, assistant professor of environmental health, Leibler is aiming to address the gaps in research on the variation of root causes of racial disparities among different geographical communities. In Massachusetts, one of the hardest-hit states during the pandemic, COVID-19 has not only disproportionately impacted African American and Hispanic populations, but has spread at a higher rate in majority-minority cities, such as Chelsea and Brockton.

“For these projects, we’re working with datasets that identify economic, demographic, housing, and occupational vulnerabilities that communities might have, and then looking to see if there are risk factors that we can align with the rates of COVID on the town level,” says Leibler. The Massachusetts Department of Public Health is providing the team access to individual-level COVID-19 datasets with address-level geocodes and daily temporal resolution. Fabian and Lane have also developed a geospatial database to conduct analyses of environmental exposure disparities and the environmental stressors that contribute to them.

“It’s really exciting to work closely with DPH to inform their efforts and planning on COVID as we move forward into winter,” Leibler says.

Among her other research on novel viruses, Leibler is collaborating with researchers at Colorado State University and Duke University to examine the transmission of the influenza D virus (IDV) among cattle and cattle workers in the US. Previous studies have detected exposure rates of this emerging disease at higher than 80 percent among cattle, and 90 percent among cattle workers in certain regions, but little is known about the virus’ health impacts. Leibler will examine the risk factors and health effects of IDV among cattle workers, their household members, and the community.

Leibler’s longtime research on zoonotic diseases has exposed the many environmental vulnerabilities that food agricultural workers face in the US. She has analyzed the regulatory gaps in backyard poultry ownership that have contributed to Salmonella outbreaks, and has also studied biocontainment issues at food animal production facilities, including poor ventilation and waste management, that increase the threat of an avian influenza outbreak and other pathogens.

“Meatpacking workers and slaughterhouse workers are a very vulnerable population in the US and around the world,” says Leibler. “They work very close together in confined spaces that can increase the risk of human-to-human disease. As essential workers, she notes, they have continued to work throughout the pandemic, “but it was fairly late into the emergence of COVID that the industry implemented some controls to protect these workers.”

Many agricultural workers are undocumented immigrants with limited access to adequate healthcare, which poses additional health risks.

“These workers produce our food and play a hugely important role in sustaining our country, our families, and our communities, but in many ways, they are an invisible population,” Leibler says. “They face risks across multiple demands—from zoonotic diseases and human disease transmissions to high rates of injury, and economic and immigration stress.”

Leibler has also conducted extensive research on the transmission of MRSA (Methicillin-resistant Staphylococcus aureus) among people experiencing homelessness and people who inject drugs. The highly drug-resistant bacteria can cause a range of symptoms, from skin infections to sepsis, and it is one of the leading causes of hospitalizations among both of these populations.

Since joining SPH six years ago, Leibler says she has really enjoyed the collaborative experience of working with peers across so many disciplines, particularly on current COVID-19 research. She also enjoys teaching the Quantitative Methods course in the MPH core program.

“Students bring so much enthusiasm and energy, and so many interesting ideas that I never would have thought of on my own,” says Leibler. “I love working with students right when they enter the core program because they are so idealistic and so passionate.”