Third Human H5N1 Bird Flu Case in US Is First To Experience Respiratory Symptoms

The US has recorded the first H5N1-infected person to have respiratory symptoms in what is considered to be the third human case in a current outbreak among dairy farms.

Unexpected Symptoms

On May 30, the Centers for Disease Control and Prevention (CDC) reported a third human case of bird flu, which has been linked to the outbreaks in cows on US dairy farms. However, this one came with respiratory symptoms, like a cough.

Health authorities first became aware of the spread of bird flu among US dairy cows in March. Since then, the viral disease has been found among cattle on farms in nine states.

Before the outbreak in cows, only one person in the US has been infected with bird flu. Since the outbreak began, three people have also been infected through exposure to sick cows.

The first person infected by a sick cow was from Texas, while the second was from Michigan. Both of them are dairy farm workers who only developed eye infections from the virus.

The third case linked to cow exposure was also in Michigan but from a different farm. The patient was given treatment and is now isolated at home while waiting for the symptoms to resolve.

The patient reported symptoms in the upper respiratory tract, such as cough without fever and eye discomfort with watery discharge. According to the CDC, this is the first reported human case of H5N1 in the US, which includes more typical symptoms of acute respiratory illnesses linked to influenza virus infection.

Finding another case of H5N1 infection in humans is not surprising, the CDC says. This is due to the extent of the spread of virus in dairy cows.

H5N1 is also known for causing respiratory symptoms, but observing these in patients is still concerning. Generally, symptoms such as sneezing and coughing can make it easier for a virus to spread from one person to another.

Detecting the Spread of H5N1

In the past, H5N1 has sporadically infected humans but has never spread widely from one person to another. However, these rare human infections can be deadly. There is also a concern that the H5N1 virus picks up the mutations needed to easily spread through the human population.

In humans, bird flu viruses can cause mild symptoms - like cough, pink eye, sore throat, runny nose, and body aches - as well as severe ones, like difficulty breathing, pneumonia, and body aches. Severe cases can be fatal, although antiviral drugs available for seasonal flu can aid in treating the viral disease.

Every time the virus is transferred to people, it gains a chance to pick up mutations that enable it to spread sustainably between humans. In the worst scenario, a chain of events like this can trigger a pandemic.

With this possibility in mind, the CDC continues to monitor for unusual flu activity across the US. So far, the agency has not detected any sign of unusual influenza activity in humans, such as an increase in emergency room visits for flu and an increase in laboratory detection of human flu cases.

Check out more news and information on H5N1 in Science Times.