Avian Influenza – 5 Common Myths Exploded

Bird flu or avian influenza is the latest health scare in Asia. It is widely believed that the avian influenza would soon attain epidemic proportions. Are these fears genuine? Read on and find out the truth behind the common myths doing rounds about the avian flu.

Myth 1

Bird flu is a kind of human influenza.
Fact Avian influenza is a contagious disease of animals caused by viruses that normally infect only birds and sometimes pigs. Avian influenza viruses are highly species-specific and have rarely crossed the species barrier to infect humans.

Myth 2

All kinds of influenzas in birds infect humans.
Fact Influenza viruses are grouped into three types – designated A, B, and C. Influenza A and B viruses are of concern for human health. Only influenza A viruses can cause pandemics.

Influenza A viruses have 16 H subtypes and 9 N subtypes. The H subtypes are epidemiologically most important as they govern the ability of the virus to bind to and enter cells where multiplication of the virus then occurs. The N subtypes govern the release of newly formed virus from the cells.

Only viruses of the H5 and H7 subtypes are known to cause the highly pathogenic form of the disease. However, not all viruses of the H5 and H7 subtypes are highly pathogenic and not all will cause severe disease in poultry.

On present understanding, H5 and H7 viruses are introduced to poultry flocks in their low pathogenic form. When allowed to circulate in poultry populations, the viruses can mutate into the highly pathogenic form, usually within a few months.

Though more than 100 human cases have occurred in the current outbreak, this is a small number compared with the huge number of birds affected and the numerous associated opportunities for human exposure.

Myth 3

All migratory birds are carriers of avian influenza. Fact, The role of migratory birds in the spread of avian influenza is not very sure. Wild waterfowl are considered the natural reservoir of all influenza A viruses. They are known to carry viruses of the H5 and H7 subtypes but usually in low pathogenic form. Considerable circumstantial evidence suggests that migratory birds can introduce low pathogenic H5 and H7 viruses to poultry flocks – which then mutate to the highly pathogenic form.

Recent events suggest that some and not all migratory birds may be directly spreading the H5N1 virus in its highly pathogenic form.

Myth 4

Poultry products can transmit avian influenza to humans.Fact Avian influenza is not transmitted through cooked food. To date, no evidence indicates that anyone has become infected following the consumption of properly cooked poultry or poultry products – even when these foods were contaminated with the H5N1 virus.

Myth 5

The entire world is grappling with the deadly bird flu. Fact Avian flu is mostly confined to the Asian countries. The primary countries that have reported confirmed cases of the disease in poultry includes the Republic of Korea, Vietnam, Japan, Thailand, Cambodia, Lao People’s Democratic Republic, Indonesia, China, Malaysia, Kazakhstan, Mongolia. Of late certain European countries like Turkey and Romania have also reported confirmed cases of avian flu in poultry.

Of these, only Cambodia, Indonesia, Thailand, Vietnam and Turkey have confirmed human cases afflicted by avian influenza.