H10N5 and H3N2 Outbreak 2024: The First-Ever Co-Infection With Influenza A Viruses Has Been Culpable for the Contemporary Public Health Crisis

Dear Editor,

Avian influenza causes infection in all species of birds, including domestic and poultry birds. ¹ Human infections are attributed to 5 subtypes of avian influenza viruses (H3, H5, H6, H7, and H9). The subtypes of avian influenza that infect humans most frequently are viruses H5, H7, and H9. ² H10N5 is the most recent subtype of avian influenza identified in humans. Reportedly, a patient from the Chinese province of Anhui perished as a result of a concurrent infection caused by H3N2 and H10N5 influenza genotypes. ³

H3N2, a notable subtype of the virus responsible for the 1968 pandemic, has been the principal contributor to seasonal influenza-related morbidity and mortality for the last half-century, resulting in over twofold the number of hospitalizations. ⁴ Between 2017 and 2018, the Centers for Disease Control and Prevention (CDC) estimate that 41 million individuals experienced influenza symptoms associated with the H3N2 subtype. ⁵

Based on the historical documentation of H3N2 infections, an inquiry emerges as to whether the co-infection of influenza H10N5 and H3N2 could significantly jeopardize global public health. Furthermore, third world countries are particularly vulnerable to co-infection with the virus; could public awareness serve as a means to mitigate this risk?

Recently, China reported the initial documented instance of avian H10N5 infecting humans; this fatal case was determined to be the consequence of co-infection with the H3N2 subtype of influenza virus. The predominant cause of seasonal influenza epidemics affecting entire populations is H3N2. ⁶

Cross-species transmission of avian influenza is a plausible hypothesis, as the acute infectious viral disease primarily impacts the respiratory and digestive systems and is typically transmitted through direct or indirect contact with infected birds, including chickens. ³ Human beings can contract bird flu viruses through inhalation, nasal passage, ocular contact, or inhalation. This can transpire when an individual inhales airborne particulate matter or dust that is replete with viruses, or when they come into contact with contaminated surfaces and subsequently come into contact with their lips, eyes, or nostrils. ⁷ Prior to her death from co-infection with H10N5 and H3N2, the woman in question had acquired poultry-related contact through the procurement of a duck. A laboratory analysis revealed that 7 samples of the duck meat, which had been stored in her refrigerator, contained H10N5. ⁸ This co-infection is characterized by fever, shivers, and sore pharynx. It can, however, result in catastrophic complications such as respiratory failure, septic shock, and multiple organ failure if individuals are not adequately immunized. ⁹

Globally, the H3N2 subtype infection is the most prevalent, and co-infection with H10N5 may increase the mortality rate. The primary source of suspicion regarding the co-infection of H10N5 and H3N2 in human species is that it originated from a poultry farm, where direct or indirect contact with an infected mallard transmitted the pathogen.

Approximately 23 billion poultry farms exist on a global scale. ¹⁰ It is a highly desirable vocation in both rural and urban regions, particularly in developing countries at the lower end of the spectrum. However, in comparison to high-income countries, low and middle-income countries (LMICs) face a greater vulnerability to misidentifying the infection in avian species, which can result in severe public health repercussions. Direct contact with a surface or environment that harbors the virus, nevertheless, escalates the likelihood of contracting this cross-species infection. In the majority of nations across the globe, aviculture serves as both an occupation and a vocation. The infection may be transmitted by domestic animals that are infected. A cross-border migration of infected wildlife may increase the likelihood that humans will contract this co-infection. Additionally, menagerie birds may present a risk of this human co-infection. ¹ The transportation and reception of preserved and unverified poultry meat carries the inherent danger of human co-infection with avian influenza strains H10N5 and H3N2. Unaware individuals may be susceptible to infection if they fail to maintain proper personal hygiene practices, such as donning sanitizers and wearing masks, subsequent to contact with domestic birds or poultry farms, and so forth. Based on the discourse, it is possible to deduce that this co-infection may pose a worldwide risk to public health.

A primary treatment for the human co-infection caused by Avian influenza H10N5 and H3N2 could consist of antiviral medications. As the woman who died from this co-infection was reportedly not vaccinated against influenza, it is crucial to increase public awareness regarding the vaccine in order to reduce the infection rate. In order to reduce the likelihood of co-infection with H10N5 and H3N2, it is critical that individuals maintain a high level of awareness by refraining from pursuing wild birds, conducting regular personal hygiene checks on domestic and poultry birds, and more. When blood, bodily secretions, or excrement cannot be avoided, individuals, particularly poultry workers, should use a double-walled plastic container or don gloves. When washing hands with detergent and water, remove any mittens that may have been on, as with COVID-19. In the absence of detergent and water, utilize a hand sanitizer that comprises a minimum of 70% alcohol.^11,12 Vaccinating and identifying infected animals is necessary to prevent the disease from spreading to humans.

The novel co-infection of H10N5 and H3N2 presents an additional potential hazard to public health, given that exposure to this virus has the capacity to result in fatalities. A significant apprehension associated with this infection is the virus’s inherent reservoir in avian species, which is impracticable to completely eradicate and will persist in heightening the threat to public health. Additionally, there is cause for concern due to the fact that the co-infection has only recently been introduced to the human population and no immunity has yet developed against it. This could rapidly escalate into a severe global pandemic. It is advisable to conduct research in order to enhance comprehension of the diseases at hand and develop effective vaccination therapies to prevent the co-occurrence of H10N5 and H3N2 influenza viruses. Additionally, LMICs may be the most severely affected, as they are most vulnerable to the consequences of improper co-infection identification and personal hygiene practices.