Researchers studying how human food scraps contribute to diseases in ecosystems
Monica Ponder, a professor in the Department of Food Science and Technology, traveled to Botswana to study how bacterial diseases transmitted by food, including food scraps, can spread diarrheal diseases.
Virginia Tech researchers are studying the impact of bacteria from human food scraps that travel through ecosystems in both Botswana and the United States. These bacteria are often associated with fruits, vegetables, and raw or undercooked meats and can spread through the ecosystem from scraps being fed to companion animals or livestock.
These food scraps also get consumed by wildlife, providing another avenue for transmission and method for disease to establish itself in a wildlife population before spreading further.
This causes human diseases to spread among wildlife, both locally and regionally. Monica Ponder, a professor of food science and technology in the College of Agriculture and Life Sciences, is studying how these bacterial diarrheal-associated diseases spread through ecosystems as well as the antibiotic resistance of bacteria that may infect animals and people.
“The research project in Botswana gave me a different kind of ecosystem with very different animals compared to my work in the United States,” said Ponder, also an affiliated faculty member of the Fralin Life Sciences Institute.
The National Science Foundation funded the research project with $1.2 million in funding over two years particularly because of the focus on understanding how antibiotic resistance moves through the systems in the two countries with varied public antibiotic access and differences in land use.
When Ponder first arrived at Virginia Tech, she shared an adjoining lab with Kathleen Alexander, a professor in the Department of Fisheries and Wildlife in the College of Natural Resources and Environment, who has worked in Botswana for around 30 years in various capacities.
Because the labs were so close, the duo looked for ways to collaborate. Thirteen years ago, they began their partnership examining how E. coli, a bacteria found in the gut of most mammals, spreads through the ecosystems. The Alexander Lab has been studying the spread of infectious diseases in wildlife populations in Botswana for more than 15 years.
They have partnered to explore the role of water to transmit diarrheal disease-causing bacteria. Botswana differs from the United States in health care access, particularly with antibiotic access being over-the-counter in significant parts of the country due to more limited access to doctors. If someone has a stomach ache, they can go to a pharmacy and pick up an antibiotic. This can, however, increase antibiotic resistance among the population.
“We hypothesized antibiotic-resistant E.coli would be far more prevalent within the urban environment, and that does seem to be true,” Ponder said. “In the United States, we believe that antibiotic resistance is spread through clinical use of antibiotics to treat diseases but also due to antibiotics used for food animal production. The study region of Kasane in Botswana doesn’t have large-scale food animal production, so gathering data about antibiotic resistance in these two extremely different environments has been immensely valuable.”
Recently, they turned their attention to the role of food and food waste, as Ponder is a food microbiologist, in the spread of an understudied diarrheal disease agent, Campylobacter, associated with an estimated one million infections in the United States and Sub-Saharan Africa.
Campylobacter may also be a leading cause of diarrheal illness in Botswana, and recent collaborations of the Alexander and Ponder labs have shown that wildlife may also harbor Campylobacter. Wildlife often venture into the landfill sites and scavenge for food, rummaging through the garbage before returning to the wilderness.
“We saw the Marabou stork at the landfill facilities in Botswana and watched them take their fill of the garbage before flying off into the nearby national parks where they may be spreading human-associated bacteria to other animals in the park,” Ponder said.
Another one of the animals Ponder and Alexander observed were baboons. These animals would eat the rinds of different fruits for a short while before dropping them and moving on to something else. Only patience was required to pick up the remnants.
“We are testing the discarded food waste both for disease-causing bacteria but also antibiotic resistance profiles. We collected poop from the baboons that are in that facility to see if they were exposed to human-associated bacteria and analyze their gut microbial ecology,” Ponder said.
The pair fought with dung beetles to collect poop samples – quickly snagging the coveted dung before the beetles could land on it and begin their slow march.
“So far, we’ve been able to isolate several different potentially pathogenic bacteria from food scraps and also from animal feces within the system. It’s not surprising. We see that foods can spread diarrheal disease in the United States as well,” Ponder said.
The same approach could be used to track and compare other bacteria in ecosystems to potentially determine if they are coming from the same sources, Ponder said.