Editor’s note: This is the second in a series of articles looking at the impacts of and questions around poultry farms in Seward County. The Seward County Board of Commissioners on Aug. 4 began a six-month moratorium on consideration of any new livestock operations. There is one conditional use permit application pending review by the commissioners on Aug. 26.
Seward County residents are familiar with the U.S. Environmental Protection Agency’s Maximum Contaminant Level for nitrate in drinking water at 10 milligrams of nitrate per liter and other substances for which water is tested regularly.
Noise, dust and chemical exposure are often measured in work and community environments.
But getting a handle on how much of the naturally occurring histoplasma fungi is too much can be problematic.
There is no established standard or benchmark that says how much exposure is safe.
University of Nebraska Medical Center Professor Matthew Nonnenmann is an industrial hygienist in the UNMC College of Public Health who has specialized in measuring human exposure to hazardous agents like fungi, noise, dust and chemicals.
While he does not focus specifically on histoplasma, he has worked with agricultural production, including poultry and swine operations in the southern United States and here.
His views and findings have been cited by advocates in the poultry industry at recent public hearings in Seward County. He said he has been invited to attend the Seward County Commissioners’ public hearing on Aug. 26 related to a conditional use zoning permit for a poultry operation.
The hearing will likely be the last of its kind until next year because of the commissioners’ temporary moratorium on new livestock feeding permits while they assess policy and procedures. Since the first of the year, the county has approved three other chicken farms, bringing the current approved number of farms to 11.
Nonnenmann said he does not see a major community health hazard in histoplasma, but factors like distance and moisture could influence individual settings.
Starlings, bats or other birds may spread histoplasma in barns or other areas where their droppings are found. It can also be found in dirt.
Nonnenmann describes histoplasma as opportunistic, showing up wherever people are working.
“We are breathing fungi every day,” he said.
The U.S. Centers for Disease Control and Prevention website outlines several activities in which people may be exposed to histoplasma, including cleaning home chicken coops, exploring caves, working on or tearing down old buildings, landscaping, gardening, farming and construction work.
People with compromised immune systems are especially prone to developing histoplasmosis from exposure to histoplasma. That group includes those taking corticosteroids or TNF-inhibitors, organ transplant recipients, people with an HIV/AIDS diagnosis, adults over 55 and infants.
Histoplasmosis is a lung infection or pneumonia with symptoms that can range from mild to life-threatening. It is similar to bacterial or viral pneumonias in its presentation, with fever, chills, headache, cough, fatigue, chest pain and body aches.
It is often misdiagnosed or diagnosed late due to those similarities but requires treatment with an anti-fungal medication. That makes early testing important, according to the CDC website.
Nonnenmann said people get sick when they are exposed to enough fungi to overwhelm their innate immunity to it.
“It’s challenging to predict,” Nonnenmann said. “Folks who know they are immune compromised have to be cautious. They need to be more diligent in so many areas – flying in airplanes, being in big crowds. They are just more vulnerable.”
While many people are exposed to histoplasma and do not become ill, the CDC recommends those at risk wear N-95 masks, which were commonly recommended during the COVID epidemic.
According to the American Medical Association’s website, an N-95 mask can filter out 95% of airborne particles if worn properly.
Nonnenmann said he does not see a need for widespread concern.
“My general opinion is that I don’t think the community would be particularly at risk for more histoplasmosis,” he said. “But, again in my opinion, it is really more the people who are immune compromised that need to be more careful.”
So how much histoplasma is too much?
“We don’t really have a good answer for it,” Nonnenmann said. “That is what makes this scenario hard.”
One of the measures used is testing and comparing indoor and outdoor air quality.
Some of the precautions he has seen in the ag industry are not reusing animal bedding, requiring reasonable distances between poultry barns and neighbors, keeping the chicken litter dry, and generally being good neighbors who communicate with each other.
Nonnenmann said in the late 1990s, chicken farms, primarily in the south, started using protective gear and developing new technology to work with animal barns.
Backyard flocks may have more risk for histoplasma growth, Nonnenmann said, only because they may not change out litter as frequently or keep it as dry as big barn operations can.
While the CDC and others advocate for spraying possible areas that may have histoplasma with a liquid substance to keep dust down, Nonnenmann said his concern with that is that the moisture could spur wet fungi to grow.
Nonnenmann said researchers are now looking at ultraviolet lighting to see if it could be used to inactivate unwanted organisms in the air – similar to the work done with ultraviolet light applications during the COVID epidemic.
They hope for some “unexpected solutions” from the research, for example, learning whether ultraviolet lighting’s use in a hospital waiting room could limit the spread of viruses.
Next week: When histoplasmosis is diagnosed
