KETCHIKAN (AP) -- The bugs plaguing Ketchikan stomachs in recent weeks have been confirmed as Noroviruses.
The federal Centers for Disease Control identified the virus from stool samples sent from Ketchikan in mid-December.
Norovirus is the official name for Norwalk-like viruses. The CDC's findings confirms earlier speculation by public health officials, who said a Norwalk-like virus was the probable cause of recent outbreaks of vomiting, diarrhea and related symptoms in Ketchikan.
The first outbreak, which spiked with nearly 200 cases during the first two weeks in December, was traced to a handful of cases in early November. Health officials say the rate of new cases had slowed considerably since mid-December.
What appeared to have been a fresh outbreak hit students and staff at Holy Name Catholic School on Thursday and Friday.
Dr. Joe McLaughlin of the state Section of Epidemiology said Tuesday that six of the eight specimens sent to CDC in mid-December tested positive for Norovirus.
''There were a total of three different strains of Norovirus identified,'' McLaughlin said.
One strain, detected in three of the Ketchikan samples, was an exact match to a strain involved in six outbreaks elsewhere, said McLaughlin.
Three of those outbreaks were on cruise ships. The other three were in North Carolina and Michigan.
''This sequence is definitely making its rounds around the U.S.,'' he said.
Another Norovirus strain identified in the Ketchikan samples had one base difference from the above-mentioned strain, said McLaughlin, meaning that the strains are quite similar and the virus could have changed as it passed from person to person.
The third strain identified by the CDC had three base differences from the main strain.
''This variance is distinctly different than the others,'' he said. ''So what we've probably seen in Ketchikan is that there are probably two distinct strains of Norovirus involved in this outbreak.''
McLaughlin cautioned that the outbreak is not over in Ketchikan, and Norovirus-related outbreaks are cropping up in just about every region in Alaska.
''So people need to be vigilant, especially if they have family members who've been affected,'' he said.
Noroviruses are spread person-to-person, typically by eating food or drinking water contaminated by the feces of an infected person, according to health officials. The state Section of Epidemiology recommends frequent and thorough hand-washing, proper food-handling, and cleaning affected household surfaces with a dilute chlorine bleach solution.
It also recommends that individuals who have experienced symptoms not return to school or a place of employment until 72 hours after the symptoms have subsided.
On the net:
State Section of Epidemiology: http://www.akepi.org
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