Many have wondered if living in a predominantly man-made urban environment makes us less vulnerable to autoimmune disease than living in close connection with nature. Is the human body truly better off since the advent of cleaning products, air filtration systems, and having a room of one’s own?
Despite these questions, little attention has been paid to the microbes that live in buildings. Currently, there are few studies on how different forms of construction – from pre-modern to contemporary - affect the human microbiome. Associate Professor Atila Novoselac recently returned from a month-long trek to the Amazon Basin to help assess the transfer between built environment microbes and skin microbiota in different human habitats.
As part of the project, he collected samples in the indigenous village of Checherta. The isolated and humid conditions of the rainforest presented many challenges, but the team quickly learned to adapt.
This past summer, project investigators of “Microbes in Homes Across Cultures” came knocking on Novoselac’s door, seeking his expertise in pollutant transport and human exposure within an enclosed space. The team needed his help to collect samples by recording indoor environmental parameters in a variety of human dwellings ranging from a village in the jungle to a major metropolitan area. The project, funded by the Alfred P. Sloan Foundation and led by microbiologist Maria Gloria Dominguez Bello, also includes a medical scientist, a parasitologist and an architect. Their overall objective is to study the building microbes of homes within a wide spectrum of acculturation and to compare household microbes with animal/human inhabitants.
Novoselac’s research at CAEE contributes to indoor environmental control, human exposure studies, aerosol science, and building energy efficiency communities. In the area of environmental quality, his work quantifies how source properties and ventilation affect occupant exposure. Based on the results of his work, human exposure researchers evaluate the risk associated with the spread of infectious diseases or exposure to different harmful airborne aerosols. Environmental control systems designers also use the results to select appropriate ventilation systems for different indoor environments. In the area of energy, his research on heat transfer in buildings has been directly implemented into the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) design procedures and the Department of Energy (DOE) EnergyPlus software, which is a widely used energy simulation tool for building performance analyses.
On site in Peru and Brazil, the team determined bacterial and fungal taxonomic and metagenomic composition of surfaces and objects, houses, and the skin (hands, feet, oral, fecal) of human and animal occupants. These samples were collected in four communities in a gradient from remote villages with Indigenous populations (Checherta) to rural settings (Puerto Almendras) and mid-size towns (Iquitos) to modern cites (Manaus).
In all settings, Novoselac recorded environmental parameters such as outdoor air ventilation rate, humidity, temperature (air and surfaces), ultraviolet light that reaches surfaces, clothing temperature and moisture content, material moisture capacity, surface pH, air CO2, CO, PM2.5, and ultrafine particle concentration. He quickly learned that collecting data in the Amazonian rainforest and rural villages presents many challenges. Fixing equipment in the field and taking measurements of natural materials rather than manufactured construction materials forced him to adapt quickly and creatively.
“Many of the homes in the rainforest were remote and took several days to reach. We were in planes that landed on make-shift runways and also traveled by boat,” says Novoselac. “In the small villages, I found myself characterizing materials such as half rotten wood filled with termites – very different than working with high-end building materials. The humidity greatly affected our instruments as well.”
In the more urban settings, building and human parameters were measured in shanty town structures without running water and electricity, homes built in the 1940s with no air conditioning, and homes of the extremely affluent.
Now that the team is back home, the next step is interpreting the data – over 1,500 microbiological samples were collected in the field and a large database of environmental parameters that characterize the condition in which these microbial organisms develop. In the following months, the team members will sequence the samples to obtain bacterial taxa and genes and correlate results to measured environmental parameters created.
The expected outcome of this project is to determine the extent to which the built environment shapes the human skin biome. The project investigators hope to establish links that will help with a better understanding of modern autoimmune diseases and set the basis for remediation by restoring an ancestral microbiome. They also hope to address broad questions of how microbes and hosts interact.
“Many feel that the human body has become crippled by our desire to live in a sterile environment – excessive use of cleaning products and isolation from outdoors,” says Novoselac. “This study should help with testing this hypothesis.”
Novoselac plans to share his experience with the Greater Austin Chapter of Engineers Without Borders. He will also return to Brazil to train researchers at the Federal University of Amazonas for related studies.
