Louisiana, Dec 20, (V7N) - The Centers for Disease Control and Prevention (CDC) has confirmed the first severe human case of avian influenza in the United States, caused by the H5N1 strain of the virus. The patient, a resident of Louisiana, was hospitalized after being exposed to sick and dead birds from a backyard flock. This marks the first case in the U.S. where human infection was linked directly to exposure from a backyard poultry flock.

The CDC’s statement highlights that the investigation into the source of the infection is ongoing, but authorities have confirmed that the patient came into direct contact with infected birds. The confirmation of this case follows the earlier identification of a child in California diagnosed with the virus in 2024. The total number of confirmed human bird flu cases in the U.S. now stands at 61.

Understanding Avian Influenza (Bird Flu)

Avian influenza, or bird flu, is caused by a type of influenza virus that primarily infects bird species but can also infect mammals, including humans. The disease is caused by several strains of influenza, but the H5N1 strain is among the most well-known and concerning because of its ability to cause severe illness in humans.

Bird flu can be categorized into low-pathogenic avian influenza (LPAI) and high-pathogenic avian influenza (HPAI), with H5N1 being a particularly dangerous strain because of its potential to cause severe disease and death in both birds and humans.

Recent Developments: H5N1 Strain in the U.S.

The H5N1 strain, which has been circulating globally for several years, has raised significant concerns due to its occasional transmission from birds to humans. Although human-to-human transmission of the virus remains rare, the ongoing spread of avian influenza in animal populations increases the risk of spillover events, especially for individuals working closely with poultry, waterfowl, or other affected animals.

In the U.S., H5N1 has been spreading rapidly among bird populations, with approximately 123 million poultry being affected across all 50 states since 2022. The virus has also impacted over 700 herds of dairy cows since March 2024, highlighting the broader implications for livestock industries.

Infection Source and Risk Factors

The recent case in Louisiana underscores the importance of avoiding exposure to infected birds. The patient in Louisiana had direct contact with sick and dead birds, which is the primary mode of transmission of the virus to humans. Infections can occur when a person touches surfaces or objects contaminated with bird flu virus and then touches their eyes, nose, or mouth. Another route of transmission is through handling infected birds, which can introduce the virus into the human body via mucous membranes.

Symptoms of Bird Flu in Humans

The symptoms of avian influenza in humans can vary in severity, from mild to severe illness, and in some cases, it can lead to fatal outcomes. Some of the more common symptoms of bird flu include:

  • Fever
  • Fatigue and weakness
  • Cough
  • Sore throat
  • Muscle aches
  • Headaches
  • Pink eye (conjunctivitis)
  • Nausea, vomiting, and diarrhea
  • Shortness of breath or difficulty breathing

In severe cases, bird flu can cause pneumonia, requiring hospitalization, and can lead to respiratory failure and death. The virus can be particularly dangerous for individuals with underlying health conditions, as well as those with compromised immune systems.

Transmission and Spread of Bird Flu

Bird flu spreads primarily through direct contact with infected birds or their droppings. Humans can contract the virus by handling contaminated poultry, eggs, or animal products. The virus can also spread by touching contaminated surfaces, which is why frequent hand washing and avoiding touching the face are crucial preventive measures.

Although the primary mode of transmission is animal-to-human, there have been very limited cases of human-to-human transmission in other parts of the world. However, these occurrences remain rare and are mostly seen in close-knit settings, such as healthcare environments where individuals are in frequent close contact with infected patients.

Additionally, avian influenza can be spread through the consumption of undercooked poultry or eggs, which is why cooking poultry and eggs thoroughly is an essential preventive step.

Who is Most at Risk?

People who are most at risk of contracting avian influenza are those working in environments where they have close contact with infected birds. These individuals include:

  • Poultry workers: Those involved in the production, processing, or handling of poultry are at the highest risk of exposure.
  • Farmers and agricultural workers: Workers who raise poultry or keep backyard flocks of birds.
  • Veterinarians and wildlife specialists: Professionals who work with birds, both domesticated and wild, are at higher risk due to frequent exposure to infected animals.
  • Zoo workers: Individuals in zoos or wildlife reserves where birds are kept may also be at risk, as seen in recent cases of zoo animals contracting the virus.

Despite these elevated risks, human-to-human transmission remains rare. The CDC has continued to emphasize that while avian influenza is a concern for specific populations, the general public remains at low risk.

Preventive Measures and Recommendations

To reduce the risk of contracting bird flu, the CDC and health experts recommend several safety measures:

  1. Avoid exposure to sick or dead birds: People should stay away from live or dead wild birds, poultry, and other animals that may be infected.
  2. Use personal protective equipment (PPE): Workers who are exposed to animals, including those in agricultural settings, should wear proper protective gear, such as gloves, masks, and face shields.
  3. Wash hands frequently: After handling animals, animal products, or contaminated surfaces, individuals should wash their hands thoroughly with soap and water.
  4. Cook poultry and eggs thoroughly: Ensuring that poultry products are cooked to a safe internal temperature (165°F or 74°C) helps prevent infection from consuming contaminated food.
  5. Monitor poultry and livestock health: Those who keep backyard flocks or raise poultry should observe strict biosecurity measures to reduce the risk of infection in their animals.

Animal Infections and Impact on Wildlife

The spread of avian influenza has not only impacted domestic poultry but has also affected wildlife populations. In Arizona, several zoo animals, including a cheetah, a mountain lion, and various bird species, were infected after exposure to bird flu. The deaths of these animals underscore the broader ecological impacts of the virus.

Poultry industries, zoos, and wildlife sanctuaries are on high alert to prevent further outbreaks and transmission, as the virus continues to affect a wide range of species.

Conclusion

As the H5N1 bird flu strain spreads across animal populations in the U.S., public health authorities are closely monitoring the situation. The confirmed case in Louisiana serves as a reminder of the potential risks associated with exposure to infected animals, particularly for individuals working with poultry, livestock, or wildlife. While human infections remain rare, ongoing vigilance and adherence to safety measures are critical to preventing further cases and safeguarding public health.

END/SMA/NYC/AJ/