By JOSE SERRANO, MPH
| LDH Public Health Epidemiologist Specialist; POOJA GANDHI, MPH, CHES | CDC
Mycotic Diseases Branch Health Communication Specialist; and KAITLIN BENEDICT,
MPH | CDC Mycotic Diseases Branch Epidemiologist
“Fungal diseases have
taken a backseat to bacterial and viral infections, to the point where mycotics
are left out of many doctors’ diagnoses. Awareness efforts, such as multiple
statewide surveillance projects and outbreak findings, show the growing concern
of invasive fungal diseases in the general population.”
— Jose Serrano, MPH, epidemiologist
specialist and lead investigator of this outbreak from the Louisiana Department
of Health
In November 2018, what seemed like a normal camping trip led
to a group of campers in Louisiana getting sick with what was later discovered
to be histoplasmosis, an infection caused by Histoplasma capsulatum, a fungus
that lives in soil.
The Louisiana Department of Health got a call about two
patients — a teenage girl who was thought to have viral pneumonia, and a
middle-aged man with an unknown respiratory illness — who were hospitalized
with symptoms that weren’t improving after being treated with antibacterials.
After their doctors consulted with an infectious disease specialist, the two
patients were eventually tested, diagnosed with and treated for
histoplasmosis. Both people have recovered from the illness.
Both of them had traveled to a campsite in a rural area in
southern Louisiana in the three weeks prior to falling ill. LDH contacted
campsite officials to get a list of fellow campers who might have also gotten
sick and began an investigation, with support from the Centers for Disease Control
and Prevention’s Mycotic Diseases Branch, to figure out if others were infected
and how these campers became sick in the first place.
Investigating the
outbreak
LDH’s interviews with the campers revealed that about half
of the people on this camping trip were sick. They asked the CDC to test the
campers’ urine samples, which confirmed histoplasmosis.
“The rapid and robust public health response to this
outbreak highlights the importance of partnership and enhanced collaboration
between CDC and state health departments,” said Nancy Chow, PhD, a molecular
epidemiologist with the Mycotic Diseases Branch.
The fungus lives in the environment, particularly in soil
that contains large amounts of bird or bat poop. But, none of the sick people remembered any bird
or bat poop at the campsite. Or, at least that’s what LDH initially believed.
The team searched the entire campsite looking for clues about where these
campers could have become exposed to the fungus.
After more investigation, LDH learned that the campers
participated in many different activities, including hiking, collecting
firewood, digging soil and geocaching. Geocaching is a digital scavenger
hunt-like game played through a smartphone app. The app directed the campers to
different objects and locations throughout the campsite, which soon became key
to the investigation, getting public health officials one step closer to the
source of the outbreak.
 |
| This hollowed-out tree was found to be the source of Histoplasma at a Louisiana campsite. |
The Mycotic Diseases Branch laboratory tested soil samples
from areas surrounding a few of the geocaching sites and found that one of the
samples tested positive for Histoplasma. The sample was from a hollowed-out
tree that reportedly had bats living inside, based on photos. This site was one
of the geocaching sites many of the campers had visited, making all the more
sense that it was the source of infection.
After uncovering the site of this fungus, LDH worked to identify any potential high-risk areas to prevent others from becoming exposed, and told campers to avoid activities involving soil disturbance. Additionally, a summary risk reduction document was provided to camp officials for all future campsite visitors.
After uncovering the site of this fungus, LDH worked to identify any potential high-risk areas to prevent others from becoming exposed, and told campers to avoid activities involving soil disturbance. Additionally, a summary risk reduction document was provided to camp officials for all future campsite visitors.
Preventing future
outbreaks
The investigation team recommended that future campers consider the following to help prevent people from getting histoplasmosis:
The investigation team recommended that future campers consider the following to help prevent people from getting histoplasmosis:
- Avoid soil disruption activities (including geocaching) and contact with hollow trees.
- Teach campers about the risks for histoplasmosis and other fungal diseases, especially those who are weakened immune systems and at high risk.
- Spread more awareness about histoplasmosis throughout Louisiana.
“Fungal disease outbreaks are relatively rare — this
investigation confirmed that histoplasmosis is endemic to Louisiana, and that
disruption of soil is still a significant health risk for both sick and healthy
individuals,” said Jose Serrano, MPH, an LDH epidemiologist specialist and lead
investigator of this outbreak.
“Once this outbreak was confirmed, every single
epidemiologist dropped what he or she were doing to lend a helping hand in the
investigation. Our strength comes from our teamwork, and no investigation is
ever handled alone,” he said.
Learn more about histoplasmosis here.
