Breaking down the growing US bird flu situation

California officials have declared a state of emergency over the spread of bird flu, where an outbreak of disease in dairy cattle has caused rare diseases in the US population.

That raises new questions about the virus, which has spread for years to wild birds, commercial poultry and many other mammals.

The virus, also known as Type A H5N1, was first detected in US dairy cows in March. Since then, bird flu has been confirmed in at least 866 flocks in 16 states.

More than 60 people in eight states have been infected with the virus, with minor illnesses, according to the US Centers for Disease Control and Prevention (CDC). One person in Louisiana has been hospitalized with the first known case of the virus, US health officials said this week.

Here’s what you need to know.

Why did California declare a state of emergency?

Gov. Gavin Newsom said he declared a state of emergency to better position government workers and assets to respond to the outbreak.

California has been looking for bird flu in large milk tanks during processing. And they found the virus in at least 650 herds, representing about three-quarters of all affected US dairy herds.

The virus was recently found on dairy farms in Southern California after being found in the Central Valley since August.

“This announcement is a deliberate action to ensure that federal agencies have the resources and conditions they need to respond quickly to this outbreak,” Newsom said in a statement.

What is the danger to the general public?

Officials with the CDC reiterated this week that the virus poses little risk to the general public.

What is important is that there are no reports of human-to-human transmission and there are no signs that the virus has changed to spread easily between humans.

In general, flu experts agree with that assessment, saying it’s too soon to tell which way the outbreak might take.

“The unsatisfying answer would be: I don’t think we know yet,” said Richard Webby, an influenza expert at St. Jude Children’s Research Hospital in Michigan.

But virologists are careful because flu viruses are constantly mutating and small genetic changes can change the outlook.

Are the cases becoming more serious?

This week, health officials confirmed the first known case of severe illness in the US All previous US cases – about 60 – have been mild.

A patient from Louisiana, who is over 65 years old and has health problems, is in critical condition. Few details have been released, but officials say the man developed severe respiratory symptoms after being exposed to a flock of sick birds.

That makes it the first confirmed US infection tied to backyard birds, the CDC said.

Experiments have shown that the strains that cause human illness are those found in wild birds, but not in cattle. Last month, Canadian health officials reported that a BC teenager had been hospitalized with a severe case of bird flu, a virus found in wild birds.

Previous infections in the US were almost exclusively among farm workers who were directly exposed to infected dairy cows or chickens. In two cases — with an adult in Missouri and a child in California — health officials are still unclear about how they caught it.

Dr. Amesh Adaljia, a senior scientist at the Johns Hopkins Center for Health Security and an infectious disease physician in Baltimore, said H5N1 does not pose a threat to the general public at this time, but that does not mean it should be completely ignored. given exposure to farm workers.

“We only had one serious case in the United States and we understand why most cases are soft, that’s a big challenge,” Adaljia said in an interview with CBC News.

The BC case was the strain most closely related to what was spread to geese, while the Louisiana version was most closely related to what was spread to chickens, Adaljia said.

How can people protect themselves?

People who come into contact with dairy cattle, commercial poultry or backyard birds are at increased risk and should use safety precautions including respiratory and eye protection and gloves, the CDC and other experts say.

“If birds start to appear sick or die, they should be very careful about how they treat those animals,” said Michael Osterholm, a public epidemiologist at the University of Minnesota.

The CDC paid for the flu shot to protect farm workers from seasonal flu — and the risk that workers could be infected with two types of flu at the same time, which could allow the bird flu virus to mutate and become more dangerous. The US government also said that farm workers who are in close contact with infected animals should be tested and given antibiotics even if they do not show symptoms.

Dr. Jesse Papenburg, a pediatric infectious disease specialist at the Montreal Children’s Hospital, said Canadians should be aware of the increased risk of human exposure and infection through contact with poultry and wild birds, other animals or their habitats.

“Be more aware of the conditions around flu-like illnesses, especially as Canada enters flu season along with the US,” Adalja said.

How does bird flu spread again?

In addition to direct contact with farm animals and wild birds, the H5N1 virus can be spread through raw milk. Pasteurized milk is safe to drink, because heat treatment kills bacteria, according to the US Food and Drug Administration.

But the highest levels of the virus have been found in unpasteurized milk. And two brands of raw milk sold in stores in California were recalled in recent weeks after the virus was found in farms and products.

In Los Angeles, county officials reported that two indoor cats that were fed boiled milk died from bird flu infections. Officials are investigating additional reports of sick cats.

Health officials are urging people to avoid drinking raw milk, which can spread more germs than bird flu.

The US Department of Agriculture has increased testing of raw milk nationwide to help detect and contain outbreaks. A federal order issued this month requires testing, which began this week in 13 states.