Corps officials have closed off a portion of the jungle warfare training center in Okinawa, Japan, thought to be contaminated with a bacteria that has left dozens of Marines sick.
Over the past two months, about 90 Marines are suspected to have contracted a rare illness called leptospirosis, which can turn serious if left untreated. So far, more than half of those cases were confirmed to be caused by the bacterial infection, which can cause chills, nausea, fever, vomiting, headaches and other flu-like symptoms.
Normally, military medical teams on Okinawa see a few cases of the disease each year, said Lt. Cmdr. Joy Dierks, the surgeon and preventive medicine officer for III Marine Expeditionary Force. But when a slew of Marines were reporting similar symptoms, she said they began to suspect there was a common thread.
"Whenever there is a large group of people who have the same things it is a sign," Dierks said.
The Marines getting sick were all found to have attended the Jungle Warfare Training Center at Camp Gonsalves.
The illness varied from Marine-to-Marine. Some were sent to an intensive care unit and three had their gallbladders removed, she said. The need for time in the operating room was so high that Naval Hospital Okinawa canceled elective surgeries in order to free the facilities for sick leptospirosis patients.
Others with less severe symptoms are cured with antibiotics, and doxycycline or azithromycin — often called a "Z-Pak" — are prescribed. It typically takes about a week to recover, Dierks said. The Centers for Disease Control and Prevention also list penicillin as an effective treatment, according to its website.
The CDC includes military on a list of people most at risk of contracting the bacteria that causes the disease. The agency also warns that without treatment, the illness can cause kidney damage, meningitis, liver failure, breathing problems. It can also be fatal.
Dierks said one military working dog was euthanized after it fell ill with leptospirosis.
For now, the training area remains off limits, she said.
Origins of the outbreak
Dogs, wild pigs, mongooses and other animals are believed to be behind a series of leptospirosis cases on Okinawa. Animals infected with the leptospira bacteria are thought to have urinated in a waterway that Marines use for jungle warfare training, getting the service members sick as well.
"Basically they pee in the pool, as we say," Dierks said.
In this case, the pool is a pond at the Jungle Warfare Training Center. It's used as a mucky obstacle in a training course and when Marines go through the soupy mess the bacteria inadvertently enters cuts, their mouth and their nostrils, causing them to contract the bacteria and fall ill.
It's not known why there have been so many cases this year, but military healthcare providers, Army veterinarians and Okinawa government health officials are trying to figure it out. Dierks said she expects the number of new cases to end later this year as temperatures cool.
This problem hasn't only affected Camp Gonsalves and the Jungle Warfare Training Center. Okinawan health officials have also seen a rash of cases amongst locals who use a nearby swimming hole as well, she said.
Symptoms typically appear between two days and four weeks after a person is exposed to a contaminated water source, according to the CDC. Dierks said that it often takes longer for patients who took preventative antibiotics to develop symptoms if their prophylactic medicine regimen fails to work.
Marines who were scheduled to use the watery obstacle were given antibiotics in an attempt to stop them from contracting the disease. For now, however, the obstacle isn't being used for training and it's off limits for Junglefest 2014, a public tour of the training facility, Dierks said.
While they took the outbreak seriously, it's not a new disease. Leptospira can be found around the world and has caused outbreaks before, including one on Okinawa in 1987. Still, the 27-year gap has left them a bit stumped.
"There's nothing new looking at it historically here, there just haven't been a lot of cases," Dierks said. "So why all of a sudden now?"
Okinawan health officials suspect the weather might have something to do with this year's uptick and are consulting with meteorologists to get weather and rainfall data so they can figure out if there were unique conditions that helped the bacteria thrive.
They've also enacted a series of new initiatives designed to prevent future outbreaks. Efforts include:
■ Field treatment. Since the bacteria can be found all over the world, military medical personnel are trying to find the best way to prevent people from falling ill during a real operation, and, if they do become sick, the best way to treat them in a field setting. Dierks said their biggest effort is to prevent illnesses on the battlefield.
■ Animal care. Military working dogs are being inoculated with a leptospira vaccine specifically for versions of the bacteria found in Japan.
■ Staying clean. Marines are encouraged to change their soaked uniforms and quickly clean them. During training, they're sprayed with a fire hose. But Dierks said they're looking into whether a gentler wash might reduce the likelihood that contaminated water is blasted into the mouth.
Proper hand hygiene helps prevent the spread of many illnesses, but doesn't do much to prevent human-to-human transmission of leptospira bacteria. The bug can't survive long on dry surfaces so poor hand-washing habits don't have much impact on transmission.
■ Prevention. They're evaluating the best antibiotic regimen to administer before exposure to potentially contaminated water. They're trying to find the best way to prevent the illness.
■ Possible immunity. They're evaluating how people develop antibodies to leptospira. Medical studies show that 20 percent of people in Cambodia don't fall ill from the germ, and they're looking to see if some Marines, particularly ones that have been through the jungle warfare center course previously, or instructors who spend months there, have developed an immunity.
