Recently, World Health Organization (WHO) has confirmed the first-ever human death caused by the H5N2 strain of avian influenza.
Avian influenza is a zoonotic disease, meaning it can spread from animals to humans.
Types of transmission |
About |
Bird-to-Bird |
Direct contact, contaminated water, or surfaces |
Human infections |
It usually occur through direct or close contact with infected birds or contaminated environments. |
Human-to-human transmission |
It is a potential concern as the virus acquires the ability to spread efficiently among people. |
People become infected with H5 viruses through direct contact with birds and poultry, not other humans.
Points of Difference |
H5N1 |
H5N2 |
Origin |
The goose/Guangdong-lineage of H5N1 avian influenza viruses first emerged in 1996 and has been causing outbreaks in birds since then. |
H5 viruses have been circulating among poultry and wild birds in Mexico since the mid-1990s. Australia reported the first human infection with A(H5N1), with no evidence of transmission. |
Meaning |
H5N1 is one of several influenza viruses that causes a highly infectious respiratory disease in birds called avian influenza (or "bird flu"). |
H5 N2 is a subtype of the species Influenzavirus A (avian influenza virus or bird flu virus). |
Spread |
Infections in mammals, including humans, have also been documented. (Almost all cases of H5N1 virus infection in people have been associated with close contact with infected live or dead birds). |
The subtype infects a wide variety of birds, including chickens, ducks, turkeys, falcons, and ostriches. Unlike other avian influenza strains that have caused outbreaks in humans such H1 and H3 viruses — H5 viruses rarely infect humans. |
Human to Human transfer |
The virus is yet to show any signs of transfer between humans. |
A human infection due to novel influenza A virus subtype even has potential for high public health impact. |
Vaccine |
Currently, human infections of H5N1 are limited and vaccines are not recommended. (In China, inactivated H5N2 has been effectively used as a poultry vaccine for H5N1). There is also an mRNA vaccine targeting a specific subtype of the H5N1 virus. |
There are no specific vaccines for preventing influenza A(H5) virus infection in humans. |
Symptoms |
The clinical signs of the disease are identified as a decrease in food consumption and a simultaneous decrease in rumination, a reduction in milk production, dehydration, fever, clear nasal discharge, tacky or loose faeces, lethargy and thicker, concentrated, colostrum-like milk. |
Symptoms include fever, shortness of breath, diarrhea, nausea, and general discomfort. |
1. Down to Earth | Avian flu H5N1 spreads to 40 cattle in Minnesota, US.
2. Down to Earth | WHO confirms first death from bird flu strain H5N2 in Mexico.