Louisiana health authorities announced Monday that a resident has died after being hospitalized with avian influenza, the first U.S. death from the H5N1 virus.
“The patient is over 65 years old and reportedly has underlying medical conditions,” the Louisiana Department of Health said in a statement. Health officials still believe the public health risk from the virus to the public is low.
The patient tested positive after exposure to wild birds and private backyard poultry infected with the virus, according to the health department. No other people in Louisiana have been diagnosed with the virus.
The H5N1 virus has been linked to at least seven deaths in other countries in recent years. Last year, another U.S. hospital patient in Missouri tested positive for the virus, but officials said the patient was not hospitalized with the virus. Instead, the patient is being treated in the hospital for other existing conditions.
The U.S. Centers for Disease Control and Prevention determined last month that the Louisiana patient was infected by genetic sequencing of the D1.1 avian influenza virus.
Sequencing revealed that the patient's virus did have some rare and potentially concerning mutations. The CDC investigation concluded that these genetic changes in the virus may occur after human infection and are not found in animals that may be infected with them.
“While it is concerning and a reminder that H5N1 viruses may change during the clinical course of human infection, it would be of greater concern if these changes were detected in animal hosts or during early stages of infection,” the CDC said. .
The D1.1 strain is the same virus that sickened a 13-year-old girl who was hospitalized in Canada late last year.
Health authorities in the Canadian province of British Columbia said last year they had been unable to identify the source of the infection, but did find that the virus sequence closely matched a wild bird that flew through the province in October.
The D1.1 strain of H5N1 avian influenza is different from the B3.13 genotype, which caused unprecedented outbreaks at dairy farms across the United States last year
Including the cases in Louisiana, the CDC counts 66 human cases of the H5 avian influenza virus reported in the United States since last year.
How is bird flu spread?
Most human cases are workers infected with the B3.13 strain after working with infected cattle. None of the human cases were hospitalized or died from the virus.
The CDC said there is “no evidence of sustained human-to-human transmission of the H5N1 virus.” The agency said there had been some outbreaks overseas in the past and it suspected the H5N1 virus had “limited” spread among small groups.
Wild birds or poultry in every state have now tested positive for at least one strain of the H5N1 virus. Hawaii becomes 50th state to report sighting of infected birds last year. Hundreds of cattle herds in at least 16 states have also tested positive for the H5N1 virus.
“While the current public health risk to the public remains low, people who work with or engage in recreational activities with birds, poultry or dairy cows are at higher risk of exposure to them. The best way to protect yourself and your family from H5N1 infection is to avoid infection source of exposure,” the Louisiana Department of Health said.
What are the symptoms of bird flu?
In recent outbreaks, bird flu has caused a variety of symptoms, including common flu symptoms such as coughing and vomiting. Many people also suffer from conjunctivitis or pinkeye as their only symptoms, which experts suspect is caused by contaminated milk from cows infected with bird flu being splashed into their eyes.
Symptoms in most U.S. cases resolve on average four days after first becoming ill. Most people are also treated with the antiviral drug oseltamivir (also known as Tamiflu), which may help speed up their recovery.
The hospitalized child in Canada initially developed conjunctivitis and fever, followed by cough, vomiting and diarrhea. She later was intubated due to respiratory failure.
