While India and other countries are still fighting against the corona virus, China has bombarded the situation with yet another addition to the list of viruses. On Tuesday, 2nd June 2021, China’s National Health Commission (NHC) informed the world about the first case of a human infected with the H10N3 strain of bird flu. The 41 year old man who was a resident of the city of Zhenjiang, was hospitalised on April 28 after developing fever and other symptoms. Further notifying on the concern, the commission mentioned that the patient was clinically diagnosed with H10N3 on May 28. The commission however, has not given details of how the man was infected. Stating further, NHC said that his condition is now stable and he is ready to be discharged. Investigation of his close contacts found no other cases. Adding to the excerpt, it mentioned that no other cases of human infection with H10N3 have been reported globally as of now. Although, researchers do not claim this virus to be a member of deadly viruses, it still poses a risk of being mutated, as has been evident in the case of COVID-19.
What is Avian influenza?
Avian influenza refers to infection of birds with avian influenza Type A viruses. These viruses occur naturally among wild aquatic birds and can infect domestic poultry and other birds and animal species. While wild aquatic birds are prone to be infected with avian influenza A viruses, they usually do not get sick. However, avian influenza A viruses are very contagious among birds and some of these viruses can sicken and even kill certain domesticated bird species including chickens, ducks, and turkeys. The major organs of infection are generally their intestines and respiratory tract. While the H10N3 has been stated to be a relatively weaker strain with no previous source to support it being one of the deadly viruses, it nevertheless alerts us about the increasing cases of influenza.
H10N3 in animals:
The record suggests only 160 cases of the virus to be reported in the 40 years before 2018. Most of them were reported in waterfowl or wild birds. Existing studies show that H10 influenza viruses are present in a wide range of domestic and wild avian species, as well as in mammals, showing considerable potential for adaptation. The influenza strain has been isolated across a diverse geographic distribution, including in species such as domestic poultry (chickens), waterfowls, and terrestrial birds. In animals, the virus displays a complex pathology, supported by complex mutations. These mutations contribute to pathobiology patterns in chickens, ducks and mice indicative of a possible threat to humans, although H10N3 is usually a less severe strain and is unlikely to cause a significant outbreak.
Why should we be concerned for the spread of Avian influenza?
Infection of poultry with LPAI (low pathogenic avian influenza) viruses may cause no major illness and only cause mild signs (such as ruffled feathers and a drop in egg production) and may remain undetected. However, infection of poultry with HPAI (high pathogenic avian influenza) viruses can cause severe disease with high mortality. Both HPAI and LPAI viruses, are reported to spread rapidly through flocks of poultry. HPAI virus infection in poultry (such as with HPAI H5 or HPAI H7 viruses) can cause disease that affects multiple internal organs with mortality up to 90% to 100%, often within 48 hours.
Avian influenza outbreaks, therefore are of concern in domesticated birds for several reasons:
- The potential for low pathogenic H5 and H7 viruses to evolve into highly pathogenic viruses
- The potential for rapid spread and significant illness and death among poultry during outbreaks of highly pathogenic avian influenza
- The possibility that avian influenza A viruses could be transmitted to humans
It has now been quite evident that many different strains of avian influenza are present in China. Of these, some sporadically infect people, primarily targeting those working with poultry. There have been no significant numbers of human infections with bird flu since the H7N9 strain that killed around 300 people during 2016-2017.
When the outbreak of deadly viruses strain of H5 or H7 avian influenza occur in poultry, depopulation (or culling) of infected flocks is carried out. In addition, surveillance of nearby flocks or those linked to the infected flock(s) is performed with quarantine of exposed flocks, if disease is detected.