BC Closes Bird Flu Investigation After No Further Cases Found

A British Columbia teenager who got sick with bird flu two weeks ago did not infect any people or animals they were in contact with while infectious, according to provincial health officer Dr. Bonnie Henry.

The B.C. teenager was admitted to BC Children's Hospital on Nov. 8 and remains in critical condition, although they have made some progress over the last few days and their care team is “hopeful that they will recover,” Henry said at a press conference Tuesday.

Because there have been no new cases and there are no new leads, the public health investigation will be closed for now, Henry said.

If there are new cases or new leads or the teenager recovers enough to speak with investigators, the case will be reopened, Henry said, adding it’s possible the teenager will not be able to remember enough to be helpful.

The teenager, who Henry said is not being identified to protect their and their family’s identity, remains in airborne isolation in hospital, and health-care workers and family members who are in contact with them wear personal protective equipment. They are being closely monitored but for now remain healthy.

The youth had no underlying health conditions and, prior to infection, was a “healthy teenager,” Henry said.

This is the first case of bird flu in Canada where a human appears to have gotten sick from a local exposure, Henry said. The only other case of H5N1 in Canada was in Alberta in 2014, when a woman got sick while flying home from Beijing and died in hospital seven days later.

Henry said the public health investigation wasn’t able to determine where the teenager caught the virus, but was able to find that the strain of bird flu they are sick with is most similar to a strain that was found in two cackling geese that died in the Lower Mainland and were tested in October.

Bird flu happens naturally in wild ducks and geese, but an infection doesn't usually make them very sick, Henry said.

When the virus passes to children or poultry, however, it can be devastating. Henry said in cases in Asia there can be a 50 per cent fatality rate when kids are infected, and infections are also extremely lethal to chickens.

There have been around 900 confirmed cases of H5N1 in humans since it first appeared in Hong Kong in 1997, Henry said. Most of these cases have been in children in Southeast and South Asia, and most have been traced back to exposure to an infected animal.

The strain of H5N1 the B.C. teenager is infected with is not the same as the strain that is infecting poultry farms in B.C. or dairy farms in the United States, Henry said.

The Canadian Food Inspection Agency has been testing Canadian dairy cows and milk and has not found any H5N1 infections, Henry said.

In the United States there have been 55 human cases of H5N1 across seven states, which Henry said were mostly adult dairy workers who had “mild” infections. One child is confirmed to have contracted H5N1 in California, she added.

So far there have been 54 poultry farms in B.C. that have had bird flu outbreaks. The safety precautions in place seem to be working, Henry said, because no poultry farm workers have been infected.

Henry said it’s not known why kids get hit hardest. One hypothesis is that adults who have been vaccinated or infected with H1 flu strains, for example during the 2009 H1N1 pandemic, have some immunity against the virus.

The current flu vaccine available in B.C. protects against human influenza strains H3N2 and H1N1, which may also offer some immunity against the bird flu strain, Henry said.

The H5N1 virus is aerosolized and can infect humans when the virus enters their nose, throat, eyes or lungs. Exposure deep in the lungs can lead to more severe illness, Henry said.

The B.C. teenager’s illness first presented as an eye infection and then a rapidly worsening lung infection, Henry said. She added that researchers are looking into whether a mutation happened to the virus while they were sick, causing more severe illness.

It’s important to keep up to date on all vaccinations, Henry said, because that reduces the risk that a person could become infected with two strains of influenza at the same time. If a person were infected with two strains of influenza, that would increase the risk that the viruses exchange genetic information or create a more dangerous version of the flu.

“We are aware of the pandemic potential of H5N1,” Henry said, adding that the biggest risk would be if the virus changed so it could more easily transmit from person to person.

“So far this H5N1 virus does not seem to transmit between people very well,” Henry added.

British Columbians can reduce their risk of coming into contact with bird flu by avoiding unnecessary contact with ducks, geese or poultry, for example at petting zoos, Henry said.

She also recommended keeping dogs on leashes, not letting them eat or roll in goose poo and keeping them out of places such as ponds, which could be contaminated with bird flu from droppings.

Dogs and cats can be infected with bird flu, Henry said. If a pet rolls in goose poo, you can wash them with soap and water, and it's always good to wash your hands after feeding or petting an animal, she added.

If a pet gets sick, take them to the vet to be assessed and keep the pet away from your children, Henry said.