Avian Influenza Virus – A Threat that Cannot be Ignored
By Robert C. Wesley, Jr., MD
The H5N1 avian influenza virus, now endemic in the bird populations of Africa, Asia, and Europe, has claimed the lives of over 60% of 350 people infected worldwide since 2003. Developments over the last year suggest a growing risk of human global pandemic.
While the virus is currently difficult for humans to contract, usually requiring close contact with infected birds, clusters of fatal human cases have emerged among singular families in Pakistan, Indonesia, and Vietnam, suggesting possible transmission via human to human (H2H) contamination.
The virus has not sufficiently mutated to permit facilitated H2H transmission; communal outbreaks beyond the affected families have not occurred. This could change. The virus is clearly mutating. There are now nearly 10 families of H5N1 virus with subtypes spread over Asia, Africa and Europe.
The greatest known risk would be simultaneous infection of a human host with both the regular seasonal influenza virus and the H5N1 virus, acquired by poultry contact. The two viruses could then share genetic material, transmitting to the H5N1 virus the ease of transmission of the regular seasonal virus. An additional vector might be simultaneous infection in pigs, living in close proximity to humans in endemic areas. Porcine genes have already been identified in some strains of influenza virus.
Current public awareness and preparedness is not commensurate with the growing threat to global health.
The Flu Pandemic of 1918-19 killed millions in America and tens of millions worldwide, mostly in the prime of life, under the age of 40. The highest mortality rate is for ages 10 to 19. The case mortality rate in some regions, such as Indonesia, has exceeded an astounding 80%. Although there is the potential for under-identification and under-reporting of milder cases in Indonesia, a recent NEJM article suggested that this is not the case. Thus, it is conceivable that a global pandemic could kill several hundred million people, a human catastrophe of unimaginable proportions.
With globalization of travel, a pandemic might eclipse the globe in a matter of weeks. Warning time will be dependent upon accurately pinpointing the epicenter of H2H transmission, a daunting task in many regions of the world afflicted by war, famine, poverty, and dysfunctional public health. The most vulnerable region is Africa. Under such conditions, containment appears unlikely.
The onset and severity of a pandemic cannot be predicted. It could be tomorrow; it could be 5 years from now or longer. That it will occur is a near statistical certainty. In the last 100 years, there have been 3 global influenza pandemics, (1957 and 1968 both mild and 1919 severe). We are currently overdue. As a species, we are not prepared. The sooner we start to prepare, the better off we will be.
As physicians, we have a professional and moral obligation to protect society in the broadest sense. However, we will not be able to perform this function if we have not taken adequate steps first to protect our families and those dearest to us. The general principal is to start as individuals and broaden out to ever-increasing concentric circles of involvement until the entire world is prepared.
The first step is self-education. We recommend the government sponsored web site with direct links to CDC, www.pandemicflu.com. For information regarding preparedness for specific sectors of society, go to the right hand column of www.fluwikie.com. For up-to-date monitoring of global conditions, go to www.birdflubreakingnews.com. Aside from news content, use some discretion regarding blogger commentary.
If a severe pandemic should occur, a strict quarantine may be imposed. Provisions for up to 3 months and specific steps to treat mild cases at home may be required. Specific items to avoid public exposure, such as N95 respirator masks, should be acquired now as they will be in sparse supply once a pandemic occurs.
Beyond steps for self-protection, we must prepare each of our own care delivering institutions to respond adequately. We recommend the concept of a “dry run”; i.e. for a proscribed rehearsal period, treating current and future seasonal influenza as if it were pandemic flu and then assessing the adequacy of response.
Universal vaccination for seasonal influenza is an absolute priority. Aside from limiting potential vectors for the spread of pandemic influenza, seasonal flu kills over 35,000 Americans each year. Moreover, derived immunity from prior seasonal flu exposures and/or vaccinations may confer some limited protection from pandemic flu as suggested in a recently released Italian study.
Finally, aside from self-protection and institutional preparation, we, as PSR, must prepare the public at large. We must do so in a well-thought out and responsible manner and, in doing so, mitigate fear and instill public confidence.
Robert C. Wesley, Jr., MD
Dr. Wesley is a practicing cardiologist in Las Vegas, a former Co-President of PSR-LA, and former member of the national board of PSR. He has been charged by his 17-member cardiology group to devise a disaster plan for the practice.