H5N1: another Pandemic or a Passing Storm?

Since 2023, cases of bird flu (H5N1) in more than 200 different types of mammals have been recorded. Recently, such reports have been increasing throughout the world, especially in the United States, Europe, and Asia, of humans and mammals such as cattle, wild foxes, and house pets (dogs and cats) contracting bird flu viral infections. This is causing a great concern and worry among all public health officers, veterinarians, physicians, and governments.

Why is this a concern? First of all, the bird flu virus, called H5N1, only infects poultry but not mammals (example dogs, cats, cattle, sheep, and goats) and humans. Hence, seeing these infections in humans and mammals is a great concern as it means that the virus has gained additional abilities to not only infect poultry but also humans. Secondly, the bird flu virus is very deadly, causing death in about 50% of those it infects. Therefore, should this virus start spreading from humans to humans, we can be sure that it will be more deadly than covid as it will end up killing almost half of all who are infected.

Bird flu is presently spreading through cattle and poultry farms in many countries around the world. It has been also found in wild and domestic animals around these farms, including in wild birds.

H5N1 outbreak was first reported in Hong Kong in 1997 when it affected many poultry farms there. During this outbreak the first human infections were also reported in Hong Kong. H5N1 spread from Hong Kong to the whole world, affecting poultry in almost all countries at different periods. Between 2013 and 2019, another bird flu outbreak in mainland China, caused by H7N9, also occurred among poultry birds there and infected about 1500 people, killing hundreds. Since 2014, reports of sporadic human infections from H5N6 and other avian influenza have been reported from China exclusively.

Indeed, in the United States, this bird flu strain is not only causing havoc among poultry farms, but is also spreading through several dairy farms, affecting both the output of eggs and milk. In Texas, Idaho, and New Mexico, several farmers are reporting that the virus is infecting their cattle and cats around the farm have also caught the virus. A farm worker who was milking the cattle also caught the virus and was hospitalized. In that farm worker, the virus attached the eyes and when the virus’ DNA was analyzed, it was found to be almost the same as that from the cattle but with some mutations. Wild birds caught around the farms were also found to harbour the flu virus, raising concerns that the virus is being transmitted from these birds from state to state and farm to farm. There are also concern that the virus can spread from cow to cow and humans to humans.

A dairy worker in Texas and several other people in South America, Europe, and Asia who were exposed to animals infected with bird flu have also been infected with the virus. The virus was also found in milk and meat from infected animals.

The CDC just released a health alert to all clinicians, state health departments, and the general public about this virus. As a result of this spreading infection, poultry prices have gone up in the USA. The US Department of Food and Agriculture just found the virus in milk collected from infected cows.

The WHO released a public statement about a man in Vietnam who contracted the virus and died shortly after. This man had no underlying medical conditions, was exposed to poultry on the 3rd week of February and died on 23rd March. The virus has already affected and killed several people in Asia, especially in Cambodia where one person out of five infected people died. All these five were exposed to poultry. Many of you may remember the swine flu pandemic that swept through the world between 2009-2010 and killed an estimated 284,400 people worldwide. The swine flu is also a type of flu found in pigs but can now affect humans: it is an influenza virus. The bird flu is also an influenza virus that affects humans who have close contact with poultry birds. Already, variations of the virus are being seen in Asia: there are concerns that these variations might lead to more deadly viruses that can attack and spread through humans.

From Hong Kong and mainland China, these bird flu viruses, just like the corona virus, spread throughout the whole world. New variations (mutations) of these viruses are being identified in ducks in Aisa, raising concerns of more pathogenic and virulent mutants that can infect humans emerging.

Mammals can be infected with H5N1 bird flu viruses when they eat infected birds, poultry, or other animals and/or if they are exposed to environments contaminated with virus. Spread of H5N1 bird flu viruses from mammal to mammal is thought to be rare, but possible. Given that the virus is now in cattle, it is obvious that it will also be in milk and beef, through which it can easily spread to humans if not well cooked or handled. Whereas COVID only killed 0.1% of people who were affected (it killed 20% at the start of the pandemic), data from the WHO shows that so far 52% (463 deaths out of 888 reported infections) of those infected with the Avian flu (H5N1) since 2003 have died. The presence of these viruses in cattle is making everyone worried as this is the first time this is happening, meaning that the virus is starting to mutate and find new hosts. Furthermore, having infected cattle, it can easily mutate to infect and spread through humans.

Notably, the fact that some humans have been affected and died already shows that this virus has crossed the species barrier and might start spreading soon through humans. The number of human infections from different parts of the world is very disturbing. It is only a matter of when, not if. It therefore beggars the question: is this a new pandemic in the offing or it is just a passing storm? The near future shall answer this question.