Health
How is H5N2 bird flu transmitted and what differences does it have from the common flu?
Avian flu has been causing outbreaks in poultry and dairy cows, affecting some people, raising concerns about how it is transmitted to humans.
In June of this year, the World Health Organization (WHO) confirmed the death of a person who had contracted the bird flu strain A (H5N2), the first laboratory-confirmed human case of influenza A (H5N2) virus infection reported worldwide.
However, although the 59-year-old man from Mexico was infected with that strain of bird flu, the WHO later clarified that his death was multifactorial and not attributable to the H5N2 virus, since the Infected person had other pathologies, such as chronic kidney disease, type 2 diabetes and systemic arterial hypertension.
According to reports from health agencies, in April, the patient arrived at the hospital after suffering symptoms for weeks and died the same day he was examined at the health center. After that, tests were carried out in which he tested positive for the H5N2 virus.
Other subtypes of bird flu, such as H5N1, have been diagnosed in people in several countries over the past two decades, including several people in recent months in the United States. And just this week, California declared a state of emergency over it. Here is how the pathogen is transmitted.
What is bird flu?
According to the Centers for Disease Control and Prevention (CDC), there are four types of influenza (flu) viruses: A, B, C, and D.
In the case of influenza type A, it is classified into multiple subtypes or strains according to two proteins on the surface of the virus. These subtypes are composed of a letter H and a number, a letter N and a number, or both pairs.
In the case of avian flu, it is an illness caused by infection with the type A avian influenza (flu) virus. According to the CDC, these avian influenza viruses are found naturally among wild waterfowl around the world and can infect domestic poultry, other birds and other animal species.
Not all strains infect people. The influenza A virus subtypes currently detected in people are the H1N1 and H3N2 strains.
How is bird flu transmitted?
Although infection in a human is rare, avian influenza viruses can be transmitted from infected birds to humans in several ways, according to the CDC: Directly from infected birds or from environments contaminated with avian influenza A viruses or through an intermediate host organism, such as another animal.
According to the CDC, infections in humans can occur when “enough of the virus enters a person’s eyes, nose, or mouth, or when the person breathes it in.” People who have prolonged unprotected contact with infected birds or places contaminated by their mucous membranes, saliva or feces could be at greater risk of infection.
Bird flu symptoms
Reported symptoms of avian influenza virus infections in humans have ranged from asymptomatic to mild cases, such as redness of the eyes (conjunctivitis) or mild upper respiratory tract symptoms similar to of influenza, even severe cases, such as pneumonia requiring hospitalization.
In severe cases, symptoms include fever (temperature of 100ºF [37.8ºC] or higher), cough, sore throat, runny nose, muscle or body aches, headache, fatigue, and shortness of breath or difficulty breathing. Less common signs and symptoms include diarrhea, nausea, vomiting, or seizures.
For more details about bird flu, go to the official website of the Centers for Disease Control and Prevention (CDC), where you will find information in English and Spanish.
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