It’s no exaggeration to say that bacteria are everywhere, but one place is especially bad. Work done by Dr. Sarah Kwan of The Peccia Environmental Biotechnology Laboratory at Yale University found an overwhelming number of microbes in schools — or, more specifically, on school desks. Though germs in schools are to be expected, the study found that even after a deep cleaning, the germs on school desks came back in full force within just a few days.
The results can be found in the Journal of Applied Microbiology.
Shocking Findings
Dr. Kwan and her team of researchers took 10 desk surface samples from three schools, grades seven through 12. They took one pre-cleaning sample from each desk and five additional samples post-cleaning. The post-cleaning samples were taken at 30 minutes and one, three, seven and 21 days. What they found is pretty appalling.
The first sample, taken at just 30-minutes post-cleaning, revealed that the scrubbing only reduced the number of fungi, bacteria, and human cells by just 50 percent. Between days two and five, the microbial concentrations on each desk surface were at the same levels as they were post-cleaning.
Those aren’t the only shocking findings, however.
“The bacteria and fungi found on the school desks I looked at overwhelmingly came from the students that sat at the desks,” Dr. Kwan tells Parentology, “mainly from their skin, but also from their oral cavities, and in nearly all cases a significant amount from fecal matter.”

These findings were consistent both pre-cleaning and at each sample interval post-cleaning.
The conclusion? The dominant source for fungi and bacteria is not an environmental factor, but rather humans.
What the Findings Mean for Students
Though the thought of sending one’s child to school with bacteria-infested desks might disturb some parents, Kwan encourages parents not to worry. Too much.
“Co-existence with microbes is a part of everyday life,” she explains. “On the whole, the microbes our children come into contact with at school should not cause people to lose sleep … as they are not all harmful.”
Jack J. Springer, MD, Assistant Professor of Emergency Medicine at Zucker School of Medicine at Hofstra/Northwell, echoes this sentiment.
“We are immersed in a world of bacteria,” he tells Parentology, “… and our coexistence with bacteria is a normal and necessary part of human life. Bacteria grow on almost all [surfaces] … including classroom desks.”

Moreover, Springer explains, bacteria reproduce via a process called binary fission, which is similar to the process of mitosis but vastly different in purpose. Cell division in the human body occurs to replace old, worn-out cells, while in the case of bacterium, the process occurs as a means of adding more to the bacteria population. This might explain the Yale researchers’ findings.
Though completely natural and normal, the rapid rate at which germs spread on students’ desks can pose a threat to certain students.
“[Some] microbes can also be detrimental to our health,” Kwan warns. “For instance, many fungal genera contain species that are known allergens, which can aggravate asthma symptoms and/or cause other respiratory issues.”
Moreover, students with compromised immune systems might fall ill more frequently and more severely when they come into contact with a desk that hasn’t been recently cleaned. Also, if there is some kind of outbreak in school — which is highly possible today thanks to the anti-vaccine movement — infrequently cleaned desks could pose a major health threat.
Both Kwan and Springer agree that schools and students should take active measures to protect themselves from illness.
“In the schools I studied, they cleaned their desks once a semester,” Kwan laments. “My work showed that microbial levels returned to pre-cleaning concentration in 2-5 days. Perhaps daily cleaning would be more appropriate?”
In addition to schools increasing the frequency with which they clean desks, students and faculty members can take care to wash their hands and always cough and sneeze into their elbows or into tissues.
“It’s impossible to sanitize the classroom, your home or the world,” Springer says. However, we’re sure society can agree, it’s worth a try.
Germs on School Desks — Sources
Journal of Applied Microbiology
Dr. Sarah Kwan
Jack J. Springer, MD