The Lewis and Clark County Health Department released a summary this week detailing its investigation into the virus and bacteria that left 14 hunters sick with two different ailments at a hunting camp in late October.

"This turned out to be a routine disease investigation," said Mike Henderson of the county health department. "And we're pleased with the way our emergency preparedness structure is."

According to the report, the Elkhorn Mountain camp was used by 29 individuals over 21 days in late October and early November.

Four hunters were apparently ill before reaching the camp and 11 more became sick after arriving. All 29 hunters drank water from the same spring, the investigation found.

"The camp had 30 inches of snow at the beginning of the season," the report said. "During the last week, the snow had melted."

The agency received its first report on Nov. 7 in which an infectious disease specialist suspected the presence of leptospirosis in one of the sickened hunters.

There are fewer than 100 cases of the disease reported in humans annually across the country.

Leptospirosis is generally contracted through the urinary shedding of infected animals. It enters the body through abraded skin or mucous membranes.

The bacteria can also live in soil, mud and vegetation when temperatures remain above 71 degrees.

"This would lead to a conclusion that the spring water was too cold to harbor leptospirosis," the report found. "That would leave rodents and elk as potential sources of this disease."

The investigation narrowed the window of the initial infection to Oct. 22 and 23 -- a two-day period where three hunters shared the same tent.

One of the hunters shot an elk and two others helped him field dress the animal and haul it back to camp -- an act that likely infected one of the men with the bacteria.

By early November, one member of the camp was already being hospitalized. Two others, who shared the same water source, were sick as well, though it appeared they suffered from different symptoms.

"During the investigation, it appeared there were two different disease patters," the report found. "One was a gastrointestinal illness and the other a more serious disease with symptoms of high fever, severe headache and myalgia (body aches)."

The health department issued its first media alert on Nov. 9. One party member, who was still sick at that time, submitted further tests to the state health lab on Nov. 13, which detected the presence of the second disease, norovirus.

"A Health Alert Network message was sent to local doctors and schools to inform them that norovirus had again been found in our community," the report notes. "Our emergency preparedness worked well to provide a method of disseminating information to our community partners and the media for disease prevention measures."

The investigation found that at least one member of the camp had apparently been sick with norovirus for three days before arriving at camp, leading health officials to conclude that the virus was present in the community and carried to the camp.

Conditions in the camp likely helped the virus spread once the source arrived. Sharing a latrine, warming a toilet seat inside the tent and sharing a hand-wash basin may have contributed to the virus's spread.

"This was an example of how easily this particular virus can spread," Henderson said. "Norovirus is highly contagious."

"We've seen outbreaks of norovirus within the last year, added Laurel Riek, and environmental health specialist with the county health department. "But this was unusual in that we had two diseases going on at the same time within the same group of people."

Reporter Martin Kidston can be reached at 447-4086, or at mkidston@helenair.com.