The H5N1 strain of avian influenza - or bird flu - was recently discovered in herds of diary cows across the United States, leading to the infection of a farm employee. Mohamed Satti, PhD, MSc, assistant professor in the College of Human Medicine's Master of Public Health program, explains what this means for the general public and discusses the virus's potential pandemic potential.
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The public health community is concerned after the announcement of the confirmed human case in Texas. The H5N1 Avian flu A transmission is mainly a result of a close contact with an infected animal. That is why in such type of infections the public health efforts are directed towards controlling the spread of the infection in animals. The worry comes from the fact that it can be very pathogenic in some people. Person to person transmission is possible through wet droplets when infected people cough, sneeze, or talk.
As the name indicates, the infection starts in birds and spread quickly among them before jumping to infect mammals. Precaution should be taken to control the spread of the infection in animals to prevent a possible pandemic. In 1997 the bird flu infected 18 individuals in China and Hong Kong, killing six of them. The death rate can reach 50% among humans.
The virus has a huge economic impact. This is a result of the high mortality caused by the virus in birds. A few years ago, the virus resulted in the death of 15 million domestic birds and 193 million were culled to control the spread of the infection. This gives an idea about the economic damage that can be caused by this virus. Until now there is no evidence that the virus can spread from mammals to mammals. That is why the control efforts are mainly directed towards birds. The virus can mutate and that can result in an easier spread among mammals.
This virus was linked to the pandemic that happened in 1918 when it infected a third of the world population. That high transmission was attributed to the spread of the infection among World War 1 troops due to their suppressed immune response resulting from the war stress. There were three more pandemics after that in 1956, 1968 and 2009 (different strains).
The current strain H5N1 rarely infects human through contact with infected animals. Human to human infection is possible. There is a vaccine for birds but H5N1 affect wide range of different types of birds. This makes birds vaccination a challenge.
The infection among humans can be avoided through the following measures:
- People should not prepare or eat uncooked or undercooked food or related uncooked food products, such as unpasteurized (raw) milk, or products made from raw milk such as cheeses, from animals with confirmed or suspected HPAI A(H5N1)-virus infection (avian influenza or bird flu).
- Avoid contact with infected animals and their dead carcasses.
- Make sure to take all the precautions that we have used to during the COVID-19 pandemic until we know more about the mechanisms of the transmission of N5H1 and if there are new strains emerging. However, the exact measures that we should follow will be announced based on the way the transmission progresses and the outcomes of the animals control measure.
Mohamed Z. Satti, an assistant professor in the Master of Public Health (MPH) program, is an expert in infectious diseases, particularly those caused by parasites. After receiving his undergraduate degree and his M.Sc. from the University of Khartoum, Sudan, he completed his Ph.D. degree at Copenhagen University, Denmark. He conducted research and taught in Sudan, the Cayman Islands, Denmark, Switzerland, Saudi Arabia and at Cambridge University in England before joining the MSU faculty in 2011.
April 16, 2024
