Avian influenza, commonly known as bird flu, is a highly contagious viral disease affecting birds. There are many different strains of the avian influenza virus, some of which can occasionally infect humans as well. While human cases of avian flu used to be rare, there has been an uptick in infections in recent years, raising concerns about the possibility of a future pandemic. So is avian flu still active and posing a threat in 2023? Let’s take a closer look.
Current Status of Avian Flu
Yes, avian flu is still active and circulating among wild birds and poultry flocks globally. According to the World Health Organization (WHO), there have been recent outbreaks of highly pathogenic or potentially highly pathogenic strains of the virus reported in birds across Europe, Asia, Africa, and the Middle East in 2022 and 2023 so far.
Some of the countries/regions reporting bird flu outbreaks this year include:
- China
- Vietnam
- Cambodia
- Japan
- South Korea
- Taiwan
- India
- Israel
- Saudi Arabia
- Germany
- Netherlands
- United Kingdom
- France
- Spain
These outbreaks have resulted in the death and culling of tens of millions of domesticated birds like chickens, ducks, and turkeys to control the spread. Wild bird populations have also been affected. The virus remains endemic in certain parts of the world.
Human Cases of Avian Influenza
Sporadic human infections and deaths associated with avian flu continue to be reported as well, though not yet sustained human-to-human transmission. Since 2003 when the aggressive H5N1 strain first jumped to humans, there have been over 850 confirmed human cases of this strain in 21 countries, with a mortality rate of 53%, according to the WHO.
Most human H5N1 cases have occurred in Egypt, Indonesia, Vietnam, and Cambodia. But infections have also cropped up occasionally in China, Thailand, and other Asian countries where the virus is circulating in poultry. More recently, the H5N6 and H9N2 strains have caused human illness too.
Year | Number of Human Cases | Number of Deaths |
---|---|---|
2003 | 1 | 1 |
2004 | 46 | 32 |
2005 | 98 | 43 |
2006 | 115 | 79 |
2007 | 86 | 45 |
2008 | 44 | 33 |
2009 | 73 | 32 |
2010 | 48 | 21 |
2011 | 33 | 17 |
2012 | 56 | 21 |
2013 | 44 | 27 |
2014 | 4 | 0 |
2015 | 121 | 47 |
2016 | 46 | 16 |
2017 | 602 | 349 |
2018 | 312 | 228 |
2019 | 69 | 23 |
2020 | 27 | 11 |
2021 | 24 | 12 |
2022 | 2 | 1 |
The vast majority of human cases involved direct contact with infected poultry or contaminated environments. But a few rare cases of human-to-human spread have occurred as well, sparking fears that the virus could mutate to spread more easily between people and trigger a pandemic.
Pandemic Potential
The WHO considers avian influenza viruses like H5N1 to pose the greatest pandemic risk. If these viruses gain mutations that allow sustained transmission between humans, it could lead to a global outbreak. While H5N1 so far lacks efficient human-to-human spread, it meets several criteria for causing a human pandemic:
- It causes severe illness in humans with high death rates
- It is prevalent in wild and domestic bird populations globally
- It continues to evolve, with new viral variants emerging
The prevalence of H5N1 in poultry coupled with its wide circulation in nature makes eradication unlikely. Spillover events from birds to humans are expected to persist. This prolongs opportunities for the virus to acquire mutations that could enhance transmission between people.
Certain genetic changes in receptor binding properties observed in recent H5N1 strains suggest the virus may be becoming increasingly adapted to infecting mammals. However, other changes would likely also be needed before the virus can spread easily from person-to-person.
Prevention Efforts
Extensive efforts are underway to reduce avian flu outbreaks in poultry and prevent transmission to humans, including:
- Culling of infected bird flocks
- Increased biosecurity on farms
- Restrictions on live bird markets and trade
- Active surveillance of wild bird populations
- Development of new poultry vaccines
- Public health monitoring for human cases
- Use of personal protective equipment by workers exposed to birds
But consistent control has been challenging. The virus mutates readily and seems able to reinfect areas previously hit. As long as H5N1 persists in any reservoir, experts warn sporadic human spillover infections are likely to continue even with mitigation measures.
Conclusion
In summary, avian influenza remains an active threat globally both for poultry populations and humans. Outbreaks in birds and occasional spillover human cases are ongoing. The situation continues to pose a public health risk given the pandemic potential of viruses like H5N1 if they evolve heightened human transmissibility. Improved surveillance and biosecurity are crucial to detect and contain outbreaks when they occur. More research is also needed to understand the mutations that could lead to a pandemic strain as well as develop new vaccines and treatments. While a human pandemic is not imminent, the possibility can’t be ruled out as long as avian flu persists.