Norovirus is being blamed for a severe bout of gastrointestinal illness suffered by about 80 people after they swam at Thetis Lake in recent days.
Medical lab results from some of the dozens of swimmers who became sick confirmed late Tuesday that the highly infectious viral infection they contracted is norovirus, said Dee Hoyano, medical health officer for Island Health.
“I think it confirms it was human transmission,” Hoyano said. Most of those who fell ill were children, teens and young adults enjoying the beach Friday through Sunday.
Lab results from CRD water samples received Tuesday confirmed there is no elevated bacterial counts in the lake. Regular testing of lake water over the last four weeks yielded the same result.
The illness doesn’t appear to have been transmitted by an animal or bacteria in the water. “Norovirus is not passed on from animals so it mostly likely points to the fact it was some sort of contamination from someone who was ill at the beach,” Hoyano said.
The most common exposure for all the people who fell ill was lake water, Hoyano said.
Symptoms of norovirus include nausea, vomiting, diarrhea and stomach cramps. For the frail elderly and people with weakened immune systems, the virus can be a contributing factor to more serious illnesses.
Millions of particles may be spewed when a person vomits or has an attack of diarrhea or coughs, and it only takes contact with a few such particles to transmit the illness.
While norovirus germs can live for days on hard surfaces such as those found in a bathroom — water taps, countertops and toilets, for example — some of those who reported falling ill never used the washrooms at the beach, according to Island Health.
Island Health surveyed the people who became sick — where they were at various times while at the beach and with whom they were in contact.
If the virus was in the water, from an ill swimmer, it would likely dissipate but how quickly that would happen depends on factors including the water flow, the number of people in the water and the temperature, said Island Health.
Gaylia Lassner took 10 children to Thetis Lake Saturday afternoon to celebrate her son Remy’s 10th birthday. There were about 200 people there, Lassner said.
The children were in the water from 4 p.m. until 5:30 p.m. Afterwards, all of themfell sick with a gastrointestinal illness starting at about 11 p.m. Sunday and continuing through Monday.
Most of those afflicted continue to recover quickly, which is typical for norovirus cases.
The beach, a popular draw for swimmers, has not been closed but CRD staff have been extra vigilant in cleaning and conducted thorough sterilizing cleanings Monday and Tuesday.
Island Health issued a bulletin Monday urging people not to swim if they are ill, not to consume the lake water, and to clean their hands thoroughly before eating and drinking and to shower at home after swimming.
Rehydration is important for those suffering from gastroenteritis, said the bulletin. Anyone seeking medical attention can call 811 for advice.
Island Health spokeswoman Sarah Plank said, as a precaution, additional water samples for bacteria were taken at Thetis Lake on Monday and will continue to be taken over the next few weeks. However, Island Health can’t test for a virus in the lake water. The confirmation of norovirus came from tests conducted on people who became ill.
