The Potential of H5N1 to be a Global Pandemic and How to Prevent It

Sahasra Karamsetty, 5/17/24

Infectious diseases have historically posed significant threats to global public health, with pandemics reshaping societies and economies. Among these threats, the H5N1 virus stands out due to its high pathogenicity and potential to cause a global pandemic. This article delves into the origins, characteristics, and potential consequences of an H5N1 pandemic, exploring the current state of preparedness and mitigation efforts.

H5N1 was first identified in geese in China in 1996 and subsequently spread to other parts of Asia, Europe, and Africa. The H5N1 virus is a subtype of the influenza A virus, which causes influenza (flu) predominantly in birds. It is enzootic (maintained in the population) in many bird populations, and also panzootic (affecting animals of many species over a wide area). Avian Influenza is classified into two subcategories -low pathogenicity avian influenza (LPAI) A viruses, and highly pathogenic avian influenza (HPAI) A viruses. causes either no signs of disease or mild disease in chickens/poultry (such as ruffled feathers and a drop in egg production). Most avian influenza A viruses are low pathogenic and cause few signs of disease in infected wild birds. In poultry, some low-pathogenic viruses can mutate into highly pathogenic avian influenza viruses. Highly pathogenic avian influenza viruses cause severe disease and high mortality in infected poultry. Only some avian influenza A(H5) and A(H7) viruses are classified as HPAI A viruses, while most A(H5) and A(H7) viruses circulating among birds are LPAI A viruses. HPAI virus infections can cause disease that affects multiple internal organs with mortality up to 90% to 100% in chickens, often within 48 hours. 

Whenever avian influenza viruses are circulating in birds, there is a risk for sporadic infections in mammals and humans due to exposure to infected animals (including livestock), or contaminated environments and thus, further human cases are not unexpected. Humans and other mammals can only become infected after prolonged close contact with infected birds. In mammals including humans, A/H5N1 influenza (whether LPAI or HPAI) is rare.H5N1 possesses several characteristics that make it a formidable threat to human health. Its high pathogenicity is underscored by a mortality rate exceeding 50% in human cases, making it one of the deadliest strains of influenza. While human-to-human transmission has been limited, genetic mutations could enhance its ability to spread efficiently among humans, potentially triggering a global pandemic.

The World Health Organization (WHO) was notified about a laboratory-confirmed case of human infection with an influenza A(H5N1) virus on 1 April 2024 by the United States of America IHR National Focal Point (NFP). The patient developed symptoms on 27 March and had a history of exposure to dairy cattle (cows) presumed to be infected with influenza A (H5N1) virus. This is the second confirmed human case of influenza A(H5N1) detected in the country. Avian influenza virus infections in humans may cause diseases ranging from mild upper respiratory tract infections to more severe diseases and can be fatal. This is the first human infection caused by avian influenza A(H5N1) virus in 2024 in the United States and the second confirmed detection in humans in the country. This also appears to be the first human infection with A(H5N1) acquired from contact with an infected mammal although human infections with other influenza subtypes have been acquired from mammals.

The threat of a global pandemic caused by H5N1 is not merely theoretical but is based on historical precedent and scientific evidence. The influenza virus is notorious for its ability to cause pandemics, as evidenced by the Spanish flu of 1918, the Asian flu of 1957, the Hong Kong flu of 1968, and more recently, the H1N1 pandemic of 2009.

Current knowledge concerning virus excretion patterns and periods of potential infectivity during human infections with H5N1 viruses is limited. In its present form, the H5N1 virus is poorly transmissible from avians to humans and from humans to humans. However, because of the uncertainty about the modes of human-to-human transmission, the high lethality of human disease, and the possibility that the virus may change to a strain capable of more efficient human-to-human transmission, enhanced infection control measures seem to be warranted.

So, just like how prevention is better than cure for any other disease, we can prevent H5N1 virus from affecting us by avoiding one simple yet a very integral part of our dietary habits. Yes, milk which you drink every day might be the reason for your death. There have been recent findings that the virus is transmitted through milk through the death of a cat who licked spilled milk at a farm in Texas, when further investigation was done on the body fluids of the cows concerning the transmission of the virus, it was found that the virus was only found in milk and not other fluids such as mucosa and saliva. By eliminating dairy from our diet, we support a reduction in the number of large-scale farms that often house multiple types of animals, thereby minimizing the risk of cross-species transmission of viruses.

Beyond directly addressing the conditions that foster H5N1, a vegan lifestyle also offers significant environmental benefits that indirectly help control the spread of zoonotic diseases. Animal agriculture is a leading cause of deforestation, habitat destruction, and biodiversity loss. These environmental changes disrupt ecosystems and can lead to increased contact between humans and wildlife, creating more opportunities for viruses to jump species. By going vegan, we contribute to a more sustainable and balanced ecosystem, reducing the instances of such zoonotic spillovers.

A vegan diet is often associated with better overall health and stronger immune systems. Populations with robust health are better equipped to withstand infectious diseases and are less likely to suffer severe consequences if they contract viruses like H5N1. Furthermore, plant-based diets reduce the risk of antibiotic resistance, a significant problem in animal farming, where overuse of antibiotics in livestock can lead to resistant strains of bacteria and viruses, including those that affect humans.

In conclusion, the potential for the H5N1 virus to spark a global pandemic is a genuine concern rooted in historical precedent and scientific evidence. Ultimately, prevention remains the best strategy in combating infectious diseases. By making conscious dietary choices and advocating for sustainable practices, we can play a crucial role in safeguarding public health and preventing the emergence of global pandemics like COVID-19.

References 

https://www.cdc.gov/flu/avianflu/influenza-a-virus-subtypes.htm

https://www.who.int/emergencies/disease-outbreak-news/item/2024-DON512

https://pubmed.ncbi.nlm.nih.gov/17428885/