Avian Influenza (AI), also known as avian flu or bird flu, is a highly contagious or infectious disease of birds caused by the influenza A virus. The primary hosts for most avian influenza viruses are birds, which means that a variety of the influenza subtypes can be found in birds such as waterfowls and shore birds (Spackman, 2008). Domestic poultry is also vulnerable to the virus, and this has seen its rapid cause of epidemics in flocks in various parts of the world. Moreover, humans are at risk of contracting influenza A virus through direct contact with infected animals or contaminated environments although there is a minimal transmission of the same between people. Over the years, avian influenza has captured the attention of the global community with numerous outbreaks of the same in poultry having adverse impacts on livelihoods as well as international trade in several nations (Avian Flu Working Group, 2006). Despite the unpredictability of avian influenza pandemics, their recurrence can have adverse health, economic, and social consequences worldwide, underscoring the relevance or need to focus on the same. An agreed or most widely quoted date for the beginning of recorded history of avian influenza was in 1878, a time when AI was differentiated from other death-causing diseases among birds. From 1959 to 1995, a total of 15 incidences of the emergence of AI in poultry was recorded although losses accompanying the same were minimal. The period between 1996 and 2008 saw the occurrence of AI at least 11 times with 4 of these involving millions of birds worldwide. The growth in global poultry population by 76 percent in developing countries and 23 percent in developed countries in the 1990s saw an increase in the prevalence of avian influenza. In recent years, AI outbreaks have become common because of the frequent movement of flocks from intensive poultry production. Reports indicate that since 2003, over 700 cases of AI among humans have been reported to the WHO with most of these from 15 countries in Asia, Africa, Europe, the Pacific, and the Middle East. From early 2013 to early 2017, 916 lab-confirmed incidences of AI among human were reported to the WHO. In China, towards the end of 2016, there were reports of 35 deaths and two potential cases of human-to-human transmission of AI.
Anatomy and Physiology of Condition
AI is more prevalent in birds than humans, and therefore, birds’ anatomical structures appear to be affected more by this condition. Reports indicate that the avian influenza virus affects nostrils, mouth, and eyes of infected birds as the virus is found in secretions from the mentioned structures. Some strains of the virus are also found in the intestinal tract of shore and water birds, and therefore bird droppings also contain the virus. One of the physiological processes in birds disrupted by avian influenza is egg production (Causey & Edwards, 2008). In humans, the virus has serious effects on the throat, and therefore, it is a cause of breathing problems among people.
Signs and Symptoms
Although avian influenza is common in birds, there can be minimal or no signs or symptoms of the same in birds. However, mild signs of avian influenza in birds may include ruffled feathers and a significant drop in egg production. Reports indicate that birds such as ducks can be infected with AI without any signs of illness. In humans, signs and symptoms vary depending on whether the AI is low pathogenic or highly pathogenic. Reported signs and symptoms of low pathogenic avian influenza (LPAI) in humans range from conjunctivitis to influenza-like illnesses such as fever, sore throat, cough, muscle aches, as well as pneumonia, which require hospitalization. Signs and symptoms of high pathogenic avian influenza (HPAI) in humans is associated with a broad range of illness including conjunctivitis only and influenza-like illness, severe respiratory complications such as shortness of breath, difficulty in breathing, acute respiratory distress, respiratory failure, and pneumonia. Other signs of HPAI in humans are multi-organ diseases that may be accompanied by nausea, diarrhea, abdominal pain, and neurologic changes such as seizures and altered mental status (Suarez, 2000).
Diagnosis of avian influenza in humans can be by observing signs and symptoms although laboratory testing remains the most effective method of diagnosis. Primarily, diagnosis takes place through the collection of a swab from the throat or nose of the sick person during the first few days of illness. The specimen is then to a lab where a search for the avian influenza is done using molecular test by trying to grow the virus. Diagnosis for critically ill patients occurs through the collection and testing of lower respiratory tract specimens. At times, diagnosis of avian influenza involves looking for evidence of the body’s immune response to the virus infection by detecting specific antibodies produced by the body in response to the virus although this is not a common method because two blood specimens are required (Chaudhary & Pahwa, 2013).
Treatment and Management
A common and recommended way of treating avian influenza is the use of antiviral drugs such as oseltamivir, peramivir, or zanamivir. Analyses of avian influenza viruses suggest that most of these viruses are susceptible to oseltamivir, peramivir, and zanamivir. Oseltamivir should be prescribed as soon as the virus is suspected to maximize therapeutic benefits. However, in recent years, success rates of these interventions are on the decline as some evidence of antiviral resistance has been reported. Seasonal influenza vaccination can also help reduce the risk of co-infection with human and avian influenza viruses (Chaudhary & Pahwa, 2013).
The success or failure of the interventions mentioned above is dependent on factors such as socioeconomic status and access to health care. People from low socio-economic classes cannot afford the mentioned interventions, and therefore deaths resulting from avian influenza are common in poverty stricken communities. Besides, the lack of access to healthcare is a major contributing factor to the failure of the interventions in various parts of the world.
Avian Flu Working Group. (2006). The global economic and financial impact of an avian flu pandemic and the role of the IMF. In The global economic and financial impact of an avian flu pandemic and the role of the IMF. Avian Flu Working Group.
Causey, D., & Edwards, S. V. (2008). Ecology of avian influenza virus in birds. Journal of Infectious Diseases, 197(Supplement 1), S29-S33.
Chaudhary, S., & Pahwa, V. K. (2013). Avian Influenza. Journal of Universal College of Medical Sciences, 1(03), 1.
Spackman, E. (Ed.). (2008). Avian influenza virus (Vol. 436). Springer Science & Business Media.
Suarez, D. L. (2000). Evolution of avian influenza viruses. Veterinary microbiology, 74(1), 15-27.