Notes from the field: Histoplasmosis!
I was very excited this week to receive my Centers for Disease Control and Prevention update. This week in the Morbidity Mortality Weekly Report: “Histoplasmosis outbreak among day camp attendees–Nebraska, June 2012.” My excitement was mainly due to the fact that it was about a fungal disease, and one that I actually know someone who had an infection due to the organism.
Histoplasma capsulatum is one of the 4 primarily pathogenic fungi discussed in Bauman; these species of fungi are generally only found in the presence of disease in humans, and do not share a commensal relationship. Fortunately, most disease in humans tends to rather mild and readily treatable, however complications can occur particularly in immunocompromised individuals. Most fungal infections in humans are not contagious from person-to-person, so outbreaks in a community are generally the result of a mass environmental exposure. Histoplasmosis is considered an endemic disease throughout the Midwest and Eastern United States, particularly in the Mississippi and Ohio River valleys. Major risk factors for developing histoplasmosis include coming into contact with bird or bat droppings. Symptoms include fever, headache, and respiratory presentation, however complications can involve multiple body systems.
The current outbreak detailed in MMWR describes a group of camp counselors from Omaha, Nebraska who became sick with fever and acute respiratory illness in mid-June 2012. Positive cases were diagnosed either by serum or urine test anytime after arrival at the camp. Thirty-two counselors were positive for Histoplasma and showed varying levels of symptoms. No hospitalizations or deaths occurred. Screening of camp attendees indicated that just over 11% of campers in close proximity to the sick counselors also had detectable levels of Histoplasma with case defined disease. Infection of campers and counselors likely occurred at two campsites that had noticeable bat guano at a campground shelter, and presumably the pre-camp cleanup carried out by the counselors contributed to the aerosolization of fungal spores that diminished in numbers the further you got from the contaminated campsite.
Following this outbreak, the city Parks and Recreation Department relocated the day camps to another park. The Department of Health’s recommendation was threefold: 1) to prevent bat roosting in these areas, 2) to better identify potentially contaminated areas, and 3) to further develop ways for decontaminating biohazardous sites while maintaining the safety of the public. My colleague in graduate school who was diagnosed with histoplasmosis never knew how it was acquired, and by and large was completely asymptomatic. The only reason that the infection turned up was due to a health screening x-ray for a new job, which showed a spot on the lung. Turned out that histoplasmosis was a far, far better diagnosis than lung cancer.
BONUS: Because we typically run out of time at the end of the semester, fungi can get short shrift in BIO230. To remedy this and have a quiz grade raised to a “5”, list in the comment thread:
1) a fungal pathogen, 2) how it can be acquired, and 3) how it might be treated
Note: all submissions must be new and original in the thread, so read what others have put down, and no one put down Histoplasma capsulatum!
BONUS all done: Fall break is imminent!