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Mystery Outbreak Investigation 2014 - Leptospirosis licerasiae

 CAMP GONSALVES, OKINAWA, Japan - Marines and sailors use ropes to pull themselves across a stream during the jungle endurance course June 20 at Camp Gonsalves, Marine Corps Base Camp Smedley D. Butler, Marine Corps Installations Pacific. As part of the course, the service members are expected to navigate their way through water obstacles and pass through tunnels while holding onto a rope, allowing them to safely and effectively complete their training. The Marines and sailors are with 1st Battalion, 8th Marine Regiment, which is currently assigned to 4th Marines, 3rd Marine Division, III Marine Expeditionary Force, under the unit deployment program. (U.S. Marine Corps photo by Lance Cpl. Diamond N. Peden/Released)
By Vivian Mason

As a Navy preventive medicine officer, Cmdr. (Dr.) Tammy Servies is used to investigating disease outbreaks.  But a mysterious outbreak in September 2014, where more than 30 Marines simultaneously fell ill, was one for the books.

Servies, a Uniformed Services University of the Health Sciences (USU) class of 2003 graduate, was in Japan teaching a class on preventive medicine to independent duty corpsmen at the Naval Hospital Okinawa.  She was stationed in Hawaii at Navy Environmental and Preventive Medicine Unit 6 (NEPMU-6), but was TDY on the island for a few days for the course.

A man in military gear is nearly submersed in dirty water with only his face, hands, and gun, above the water
Cpl. Kevin E. Kusler floats through stagnant muddy water as he avoids concertina wire during the jungle endurance course June 20 at the Jungle Warfare Training Center on Camp Gonsalves, Marine Corps Base Camp Smedley D. Butler, Marine Corps Installations Pacific. During the course, Marines and sailors must pass through numerous obstacles without physically touching the wires. Should they touch one of the wires they are required to restart that portion of the course. Kusler is a Bradenton, Florida, native and machine gunner with 1st Battalion, 8th Marine Regiment, which is currently assigned to 4th Marines, 3rd Marine Division, III Marine Expeditionary Force, under the unit deployment program. (U.S. Marine Corps photo by Lance Cpl. Diamond N. Peden/Released)

Navy Cmdr. (Dr.) Joy Dierks, USU class of 2004, was stationed in Okinawa as the preventive medicine officer for the III Marine Expeditionary Force.  As she reported to work that September morning, she was greeted by the sick Marines, who had come to the island from all over the world to participate in a Jungle Warfare Training course.  Some of the Marines were so ill they had to be admitted to the Naval Hospital.  Some went to the intensive care unit and two ended up in surgery, with their gallbladders removed.  Elective surgeries in the hospital were cancelled to meet the demand for the operating room.

It was Dierks’ job to investigate what was going on.

Dierks went into full investigative mode. What was the common thread among the Marines? They   all had troubling flu-like symptoms: fever, chills, head and muscle aches, diarrhea, nausea, vomiting, and other signs. She suspected leptospirosis, a bacterial disease affecting humans and animals, because it was known to be in the fresh water sources in area.  Leptospirosis can be very serious, causing kidney damage, liver failure, meningitis, and even death.  The Marines had been training in open water sources.

People in military gear stand in a forest
Investigative team seeking sources of leptospirosis at the 
Jungle WarfareTraining Center, Okinawa, Japan. 
(Image credit: CDR Tammy Servies)
Equipped with a very small staff, Dierks enlisted the aid of Servies to help with the outbreak investigation, along with her USU classmate, Navy Cmdr. (Dr.) Tai Do, who was working as a preventive medicine officer at Naval Hospital Okinawa and was responsible for the data analysis.  Dierks also consulted a team of Navy, Army, and Air Force professionals, including environmental health officers, public health technicians, microbiologists, and veterinarians, as well as local Japanese public health personnel.

The team discovered that the Marines’ exposure had occurred 10–14 days earlier at the Jungle Warfare Training Center at Camp Gonsalves.  Dierks and Servies traveled to the site of suspected exposure to look around and see what the risks were.

At Camp Gonsalves, they inspected the conditions on the base, including living and dining facilities and the endurance course. The endurance course consisted of a number of obstacles, many of which involved significant water exposure. The training includes sending Marines through muddy culverts, pools, and pits that often requires them being submerged or clawing the muddy banks to get through.  The investigative team, donned in protective gear, evaluated the conditions of the course and took water samples, attempting to identify areas of highest risk.

Two women in military uniform with mud up to their knees pose for a photo
LCDR Tammy Servies (left) and LCDR Joy Dierks after 
conducting truefield epidemiology during a 
leptospirosis outbreak in Okinawa, Japan.
(Image credit: Personal collection of CDR Tammy Servies)
“We also needed to question everyone about what happened, and we came up with a questionnaire based loosely on what the state of Hawaii did because they have a lot of leptospirosis cases. We also developed additional questions that were very specific to our situation,” explained Servies. “We knew that the Marines were supposed to have taken doxycycline, but we didn’t know for sure if they had actually taken it,” she continued. “So, we asked questions about that. We let the Marines know that there would be no repercussions if they answered truthfully. Then, we sent out some preventive medicine technicians to interview everyone.”  Doxycycline is the prescribed treatment for leptospirosis, according to the Centers for Disease Control and Prevention. The Marines going through the Jungle Warfare training were given prophylactic doses of the drug, which is used to treat bacterial infections, before and after the training.

Water, soil and other samples taken by Dierks and her team were negative for leptospirosis, and the number of casualties was rising. The count was up to more than 65 and climbing.  Even a military working dog had contracted the illness and had to be euthanized.

If the Marines were taking their medication, how did this become the largest outbreak recorded in military service members?

When the results of the questionnaire had been analyzed by Do, they learned that some of the Marines admitted that they had not taken the drug, and according to Servies, “It seemed that doxycycline was hit or miss as to whether or not it actually worked. Perhaps it worked for some forms of leptospirosis and not other forms. We weren’t really sure because more research was needed.”

Two men in military gear. One is pulling the other out of a dirty river onto a muddy bank.
Cpl. James E. King, top, pulls Lance Cpl. Laquan K. Wilkerson out of a water obstacle during the jungle endurance course June 20 at the Jungle Warfare Training Center on Camp Gonsalves, Marine Corps Base Camp Smedley D. Butler, Marine Corps Installations Pacific. During this portion of the course, participants use their weapons to push up concertina wire, low crawl through narrow trenches, and submerge under water while following a length of rope until an instructor pulls them up. King is a New York, New York, native and warehouse clerk, and Wilkerson is a Gaithersburg, Maryland, native and field wireman. Both are with 1st Battalion, 8th Marine Regiment, which is currently assigned to 4th Marines, 3rd Marine Division, III Marine Expeditionary Force, under the unit deployment program. (U.S. Marine Corps photo by Lance Cpl. Diamond N. Peden/Released)

Additional testing revealed Leptospirosis licerasiae as the cause, a species new to Japan.  The outbreak was likely related to heavy rainfall that year with a higher than normal mongoose population in the area.  When infected mongoose and other rodents urinate into the water, the disease can be transmitted to humans.

In the end, nearly 90 Marines contracted the illness, and all fully recovered.

Servies believes an additional study should be performed to compare the effectiveness of daily versus weekly dosages of doxycycline to avoid outbreaks like this in the future.

This was the largest recorded outbreak of leptospirosis in the military.  With a little USU teamwork, Servies, Do, and Dierks were able to effectively manage the outbreak and solve the mystery.