The world’s population including consumers, poultry producers, and the public sector look to international agencies for guidance on the control and prevention of diseases which can impact the livability of flocks, marketability of products, and the health of entire continents. Highly pathogenic avian influenza (HPAI) caused by clades of H5N1 virus is now endemic in West Africa, Southeast Asia, and countries in the Middle East and Eurasia. In addition, sporadic outbreaks have occurred seasonally in both Western and Eastern Europe since 2003.
The zoonotic potential of this virus has resulted in a reappraisal of the interaction among subsistence and intensive poultry production and human populations. Fatalities from HPAI have been recorded in Indonesia, Thailand, Egypt, China, Vietnam, and Cambodia and possibly have occurred in other nations. Despite the fact that the virus has been circulating in poultry in affected areas since the late 1990s, the number of diagnosed human clinical infections has been thankfully limited to the low hundreds. This incredibly infinitesimal incidence rate should be viewed against the billions of person-day contacts with infected birds on small farms, live bird markets and large-scale commercial units in affected areas. With the emergence of the infection in Southeast Asia during 2002, epidemiologists affiliated to the World Health Organization (WHO) and academia initiated a series of dire predictions concerning the possibility of mutation to become pathogenic to humans. Citing the 1918 influenza pandemic and applying models with somewhat speculative assumptions, world leaders were subjected to a barrage of crisis scenarios concerning pandemics involving millions of fatalities. Poultry and egg consumption dropped precipitously in any country following an initial diagnosis of HPAI although public acceptance and complacency seem to gradually restore demand.
The urgency expressed by the WHO and national public health agencies resulted in vast sums of money being granted for research on the virus, stockpiling antiviral drugs, and developing vaccines. It appears that HPAI has spawned an entire infrastructure absorbing funds largely supplied by industrialized donor nations.
It has taken Dr. Bernard Vallat, Director of the World Organization for Animal Health (OIE) to question the doomsday scenario. He has stated publicly that the risk of an influenza pandemic caused by avian origin H5N1 is minimal. He based this statement on his interpretation of research demonstrating “extreme stability” of the virus with the implication that the risk of mutation and a pandemic has been overstated. This reasonable conclusion from an informed official heading an agency of the FAO elicited a chorus of strident opposition and criticism. Strong deprecations of Dr Vallat’s comments have been issued by scientists who are at best concerned over the risks and consequences of mutation and at worst may be biased by their need for continued funding.
Obviously there is a risk of mutation of H5N1, but recent history and molecular characterization of viral isolates, and the duration of the disease in poultry populations, suggest that risks may have been overstated. Preparing for an influenza epidemic or even a pandemic is a worthwhile exercise. Developing innovative and effective vaccines and antiviral agents has been stimulated by the threat of mutation. Surveillance of poultry and migratory bird populations and humans for influenza is justified. History indicates that an influenza pandemic may occur at some future time just as we will experience devastating earthquakes, volcanic eruptions and meteorite collisions with the Earth.
It is apparent that HPAI is now the equivalent of velogenic Newcastle disease in this century. This contagious infection can be suppressed in poultry by diligent vaccination but cannot be eradicated in countries with live bird marketing, subsistence farming and suboptimal biosecurity and veterinary infrastructure.
What we are entitled to receive is an unbiased assessment of the risks of HPAI extending from poultry to humans. If it is low then we should reallocate funds to control other diseases such as malaria, tuberculosis and AIDS which are taking a toll every day. If a pandemic is not imminent the level of publicity should be moderated. If a pandemic is imminent we need to be vaccinated. Either way we need clarity.