Two men have died in New York after trying to grow cannabis in bat excrement.

Rochester, New York-based men have died after contracting a rare fungal infection in their lungs from bat guano they intended to use as fertilizer to grow marijuana, according to a new journal article. Open forum Infectious diseases.

After inhaling the spores of the so-called Histoplasma capsulatumwhich was hidden in bat droppings, the men developed a pneumonia called histoplasmosis. One man, aged 59, bought bat guano online, while another, aged 64, found the droppings in his own attic after a “severe bat infestation”.

“Exposure to bat guano among cannabis growers appears to be a recent trend that may lead to cases and outbreaks of histoplasmosis,” the researchers wrote in the paper.

Histoplasma capsulatum is a type of fungus that causes histoplasmosis, a fungal infection mainly affecting the lungs.

“Initially, the infection was described as endemic to the Ohio and Mississippi river valleys, but it is now regularly occurring in the central and eastern United States, with cases being reported across the country,” the researchers wrote.

Histoplasma capsulatum is often found in soil enriched with bird or bat droppings, especially in caves, chicken coops and old buildings. Infection occurs by inhalation of airborne spores from disturbed contaminated soil – the fungus is not transmitted from person to person.

“Bats are one of the few infected species Histoplasma capsulatum. Bird and bat droppings provide an ideal medium for the growth of Histoplasma and serve as a source of mold in the environment. In particular, the use of bat guano or bird droppings as fertilizer can contribute to infection Histoplasma capsulatum.”

Only about 1 percent of people exposed to the fungus actually develop histoplasmosis, and the condition can vary in severity, sometimes even spreading to other organs. According to the US Centers for Disease Control and Prevention (CDC), about 5 percent of people who contract the infection die, and only 1 to 2 people in 100,000 are infected each year in the US.

Both men mentioned in the study experienced symptoms including fevers, chronic cough, weight loss and respiratory failure. Despite treatment with antifungals in the hospital, both men unfortunately died as a result of the infection.

People with lung disease or a weakened immune system before inhaling the fungus are more susceptible to severe symptoms. Both men were heavy smokers of both tobacco and cannabis, and one had a lung disease called emphysema.

The men’s deaths represent a troubling trend in the use of bat guano as a cannabis fertilizer, the researchers note.

“Many media articles promote bat guano as a ‘natural superfood’ for cannabis plants due to its richness in nitrogen, phosphorus, potassium and organic compounds,” they wrote.

Doctors said public health communication about the risks of using bat droppings for this purpose needs to be improved.

“Given the recent legalization and expected increase in domestic cannabis cultivation, along with the promotion of bat guano for this purpose, it is important to raise public awareness of the potential risk of using bat guano as a fertilizer and to emphasize the need for protective measures. , such as wearing masks when handling,” the researchers wrote.

“A broad spectrum of the population may be at risk of disease from this exposure, with the highest risk among immunocompromised individuals, particularly those with advanced HIV infection, patients treated with TNF inhibitors, and organ transplant patients. Physicians need to inquire about bat guano exposure in cannabis growers to they discussed preventive measures and made early diagnoses.”

Reference

Sudnik, P., Passarelli, P., Branche, A., Giampoli, EJ, & Louie, T. (2024). Histoplasmosis associated with bat guano exposure in cannabis growers: two cases. Open forum Infectious diseases. https://doi.org/10.1093/ofid/ofae711