Health Alert: First Case of Novel Influenza A (H5N1) in Texas

The Texas Department of State Health Services (DSHS) is reporting the first human case of novel avian influenza A(H5N1) in Texas. The patient became ill following contact with dairy cows presumed to be infected with avian influenza. The patient’s primary symptom was conjunctivitis. This is the second case of avian influenza A(H5N1) identified in a person in the United States and is believed to be associated with the recent detections of avian influenza A(H5N1) in dairy cows announced by the Texas Animal Health Commission. DSHS along with local, regional, state, and federal partners, is investigating this ongoing situation. Avian influenza A(H5N1) viruses have only rarely been transmitted from person to person. As such, the risk to the general public is believed to be low; however, people with close contact with affected animals suspected of having avian influenza A(H5N1) have a higher risk of infection.

DSHS is issuing this health alert to provide awareness to healthcare providers and ask them to be vigilant for people with signs and symptoms of avian influenza A(H5N1). Suspicion for avian influenza A(H5N1) should be heightened for people who have had contact with animals suspected of having avian influenza A(H5N1).

Background

In March 2024, samples were collected and tested for influenza from several animals in Texas and Kansas. These animals, including wild birds, cats, and dairy cows, were tested because they exhibited signs of illness. Some of the animals tested positive for influenza. Further testing of these samples indicated the presence of avian influenza A(H5N1). This is the first time avian influenza A(H5N1) has been detected in cattle in the United States. DSHS, including regional staff have been working with other state and federal health agencies to investigate suspect cases of avian influenza A(H5N1) in both humans and animals.

The USDA and state animal health agencies routinely conduct surveillance for avian influenza A viruses in poultry in the United States and have previously detected the same strain of influenza A(H5N1) in backyard poultry flocks in Texas. Highly Pathogenic Avian Influenza Detected in Moore County Birds (texas.gov); HPAI Confirmations in Commercial and Backyard Flocks (usda.gov)

Recommendations for Clinicians

Providers should consider the possibility of avian influenza A(H5N1) virus infection in people who have symptoms of influenza and relevant exposure history. This includes people who have had close contact with a person with suspected or confirmed avian influenza A(H5N1) infection, affected animals, or unpasteurized milk from dairy farms with suspected avian influenza A(H5N1). A close contact is defined as a person who is within 6 feet of a confirmed or probable avian influenza A(H5N1) case for a prolonged period of time, or who had direct contact with infectious secretions while the case was likely to be infectious (beginning 1 day prior to illness onset and continuing until the resolution of illness).

Signs and symptoms of avian influenza A(H5N1) infection may include:

• Fever (temperature of 100°F [37.8°C] or greater) or feeling feverish or chills
• Cough
• Sore throat
• Runny or stuffy nose
• Headaches
• Fatigue
• Eye redness (conjunctivitis)
• Difficulty breathing/shortness of breath
• Diarrhea
• Nausea
• Vomiting
• Seizures

Although not commonly associated with seasonal influenza, conjunctivitis has been observed in avian influenza A virus infections. Because of this, healthcare providers including optometrists and ophthalmologists, should be aware of the potential of individuals presenting with conjunctivitis who have had exposure to affected animals.

Illness in humans with avian influenza A(H5N1) virus have ranged from mild to severe. Reports of severe avian influenza A(H5N1) illness in humans have included fulminant pneumonia leading to respiratory failure, acute respiratory distress syndrome, septic shock, and death.

If providers encounter a patient with symptoms compatible with avian influenza A(H5N1) infection and exposure to affected animals is suspected, they should immediately consult their local health department.

Recommendations for Public Health

Novel influenza A including avian influenza A(H5N1) is a notifiable disease condition in Texas and must be reported immediately.

Local and regional health departments should investigate all suspected, probable, or confirmed avian influenza cases and perform public health follow-up on close contacts. A close contact is defined as a person who is within about 6 feet of a confirmed or probable avian influenza case for a prolonged period of time, or who had direct contact with infectious secretions while the case was likely to be infectious (beginning 1 day prior to illness onset and continuing until the resolution of illness).

Recommendations for the Public

Although this is an evolving situation, the risk to the general public is low. People can protect themselves against flu by washing their hands often, covering their coughs and sneezes, not picking up dead birds and animals, and staying home if sick.

Routine antiviral treatment, such as Tamiflu (oral oseltamivir), is known to be effective against flu. If you suspect you have influenza, discuss treatment options with your healthcare provider.

Milk and milk products provide numerous health benefits. However, raw unpasteurized milk can make people sick. Pasteurization is the process of heating milk to a high enough temperature for enough time to kill harmful germs in the milk, including all kinds of flu viruses. Milk sold in stores is required to be pasteurized and is safe to drink.