First Human Bird Flu Death Confirmed in United States

The first human patient in the United States with a confirmed case of avian influenza has died, according to a press release from the Louisiana Department of Health. The individual was older than 65 years and had underlying medical conditions and remains the only known human case in the state.

The patient contracted highly pathogenic avian influenza, also known as H5N1, through exposure to wild birds and a noncommercial backyard flock, according to the release. The Louisiana Department of Health has found no additional H5H1 cases in the state and no evidence of person-to-person transmission.

The Centers for Disease Control and Prevention (CDC) conducted genetic sequencing of specimens of the virus collected from the Louisiana patient. They compared the sequences with sequences from dairy cows, wild birds, and poultry in various areas of the United States that were infected with the H5N1 virus.

The Louisiana patient was infected with the D1.1 genotype of the H5N1 virus. Although D1.1 is related to other D1.1 viruses found in recent human cases in Washington State and British Columbia, Canada, it is distinct from the widely spreading B3.13 genotype that has caused H5N1 outbreaks in dairy cows, poultry, and other animals and has been linked to sporadic human cases in the United States, according to the CDC.

Despite evidence of some changes in the virus between the Louisiana patient and samples from poultry on the patient’s property, “these changes would be more concerning if found in animal hosts or in early stages of infection,” according to the CDC. The CDC and the Louisiana Department of Health are conducting additional sequencing to facilitate further analysis.

In the meantime, the risk to the general public for H5N1 remains low, but individuals who work with or have recreational exposure to birds, poultry, or cows remain at increased risk.

The CDC and the Louisiana Department of Health advise individuals to reduce the risk for H5N1 exposure by avoiding direct contact with wild birds or other animals infected or possibly infected with the virus, avoiding any contact with dead animals, and keeping pets away from sick or dead animals and their feces. Additional safety measures include avoiding uncooked food products such as unpasteurized raw milk or cheese from animals with suspected or confirmed infections and reporting sick or dead birds or animals to the US Department of Agriculture by calling 1-866-536-7593 or the Louisiana Department of Agriculture and Forestry Diagnostic Lab by calling 318-927-3441.

The CDC advises clinicians to consider H5N1 in patients presenting with conjunctivitis or signs of acute respiratory illness and a history of high-risk exposure, including handling sick or dead animals, notably birds and livestock, within 10 days before the onset of symptoms. Other risk factors include consuming uncooked or undercooked food, direct contact with areas contaminated with feces, direct contact with unpasteurized milk or other dairy products or with parts of potentially infected animals, and prolonged exposure to infected animals in a confined space.

Clinical symptoms also may include gastrointestinal complaints such as diarrhea, as well as fatigue, arthralgia, and headache. Patients with more severe H5N1 may experience shortness of breath, altered mental state, and seizures, and serious complications of the virus include pneumonia, acute respiratory distress syndrome, multiorgan failure, and sepsis, according to the CDC.

Clinicians who suspect H5N1 cases should contact their local public health departments. The CDC offers additional advice on evaluating and managing patients with novel influenza A viruses.