Two men from upstate New York have died from a type of pneumonia after using bat poop to grow cannabis.
The men, who were based in Rochester, developed fatal cases of histoplasmosis: a lung infection that is caused by breathing in spores of the harmful Histoplasma fungus.
The pair, who were not named, had been using the droppings to fertilize cannabis plants. It was not immediately clear when they died.
“Exposure to bat guano among cannabis growers appears to be a recent trend that can lead to histoplasmosis cases and outbreaks,” University of Rochester researchers said in a recent report. Bat poop is also known as guano.
The findings were published in the journal Open Forum Infectious Diseases.
One man, 59, had emphysema — a disorder affecting parts of the lungs — as well as arthritis, and had been admitted to the Strong Memorial Hospital for respiratory failure. He had lost weight for six weeks before he was seen and had a sore throat and difficulty swallowing.
When he was admitted, he was weak and infected with bacteria. He was treated for pneumonia and the presence of bacteria in the blood, but still needed to be put on a ventilator machine.
A biopsy, a procedure removing tissue or cells from his body, showed fungi that were consistent with histoplasma.
He had reported the use of bat guano from an online store before he went into respiratory failure.
The other man, 64, had a condition in which narrow arteries reduced blood flow to his arms and legs. He had bypass surgery, and was hospitalized for low levels of sodium and other nutrients in the blood. He had lost 35 pounds over several months and had a “chronic cough.”
“Remarkably, the patient reported a heavy bat infestation of his attic with a thick layer of guano that he inspected on multiple occasions intending to use it as fertilizer for his cannabis plants. He denied other potential exposures to Histoplasma,” the authors said.
He was admitted with a fever and there were cysts on his pancreas.
After being treated for suspected histoplasmosis, he was discharged. But, after a month, he was readmitted with abdominal pain. The man died of complications related to bowel ischemia: a rare condition that occurs when blood flow to the intestines is reduced or stopped.
The authors said that it is crucial to raise awareness of this issue to reinforce personal preventive measures and establish timely diagnosis. Histoplasmosis is often misdiagnosed or diagnosed late. Infection can be mild to severe and result in meningitis: inflammation around the brain and spinal cord.
Furthermore, recent literature suggests infections are more widespread across the US than previously described, the report said. Factors like climate change and bat migration have influenced where cases crop up, although the majority of cases are sporadic. Each year around 1 to 2 per 100,000 people in the U.S. are infected with histoplasmosis. Symptoms include fever, muscle aches, and chest pain.
Bats are one of the few species infected with the fungus, but bird droppings could also contribute to infection.
They warned that, given recent legalization of cannabis and the promotion of bat poop as fertilizer, it is important to raise public awareness about its potential risk.
“Commercial biofertilizers containing bat guano should be tested for [the fungs] before reaching the market,” they stressed. “If testing is not feasible, risk mitigation strategies should be implemented.”