Bird Flu H5N1 Threat and the Community Health Nurse's Role

Introduction

Leading infectious disease experts have warned about the health and economic consequences of an outbreak of pandemic influenza from a deadly strain of bird flu, H5N1, which has already destroyed poultry flocks across Southeast Asia (Russell 2005). This virus has the potential to trigger another flu pandemic far more virulent than those of prior years — one to which the human population has no natural resistance. Experts have simultaneously warned about the world's lack of preparation to meet such a disaster.

Director Anthony Fauci of the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, noted that federal spending on influenza preparedness rose to $419 million from $40 million over the preceding five years, but added that he was dissatisfied with the United States' current level of readiness. An experimental H5N1 vaccine was under testing, but the manufacturing system — the same system that produces millions of ordinary flu injections each year — remained prone to failure. The federal government held enough reserves of the Tamiflu antiviral, which shows promise against bird flu, for only 2.3 million Americans, or less than 1% of the population.

Director Michael Osterholm of a university's Center for Infectious Disease Research and Policy warned that an H5N1 pandemic strain could be more devastating than the 1918 pandemic, and he urged the world's leading economic powers to confront the problem directly. He estimated that a flu strain as lethal as the one of 1918 could kill 180 to 360 million of the world's population of 6.5 billion. He further emphasized that industrialized nations accustomed to the prompt delivery of health care still do not have enough medical supplies to care for the sick, nor even detailed plans for handling the dead.

Epidemiological Profile of Influenza

Influenza, a virus with a genome arranged in eight separate segments, has an increased potential to form recombinants and may contribute to the rapid development of new flu strains (Keen 1995). Avian and human strains of the virus may recombine in pigs in the Far East to produce virulent human strains. The Influenza A virus, an avian virus, appears to have relatively recently made the jump to infecting mammals. Every 10 to 15 years, a major new pandemic strain emerges in humans with a completely new hemagglutinin (HA) and neuraminidase (NA) configuration, capable of triggering a major epidemic worldwide.

The constant antigenic change of the flu virus over the years demands the development of new vaccines on a regular basis. Furthermore, new flu strains spread quickly among children in schools and in crowded places. Influenza epidemics lead to economically significant levels of absenteeism (Keen 1995).

Influenza, commonly known as flu or grippe, is a highly infectious respiratory disease belonging to the Orthomyxoviridae family (Smith 2005). It spreads rapidly via airborne droplets produced by infected persons. When the virus is inhaled, it attacks cells in the upper respiratory tract and produces the typical flu symptoms: fatigue, fever and chills, a hacking cough, and body aches. The infected person also becomes susceptible to potentially life-threatening secondary infections. The incubation period is short — one to three days — allowing the rapid spread that leads to epidemics.

Impact and Risk Factors

Flu is more debilitating than the common cold and strikes more suddenly (Smith 2005). The annual death toll linked to influenza and its complications averages 20,000 in the United States alone. The 1918–1919 Spanish flu pandemic killed 20 to 40 million people worldwide, half a million of whom died in America. There have been regular influenza outbreaks throughout history, the most serious of which are pandemics that affect millions worldwide and persist for several months. Other notable pandemics occurred in 1957 as the Asian flu and in 1968 as the Hong Kong flu. Epidemics occur every two to three years and typically affect 5–10% of the global population.

Influenza occurs throughout the world. Its basic antigen types are A, B, and C. Types B and C are known to affect only humans, while Type A may infect both humans and animals. Influenza reaches a peak from December to March in temperate climates. Between 1976 and 2002, peak influenza activity in the United States was recorded in January and February. In tropical areas, influenza circulates throughout the year.

Documents show increased morbidity in high-risk adults who require hospitalization two to five times more often during major epidemics. People aged 65 or older, individuals of any age with chronic medical conditions, and very young children are most likely to develop complications from influenza. These complications include pneumonia, bronchitis, and sinus and ear infections (Centers for Disease Control and Prevention 2004). Flu can also worsen pre-existing chronic health conditions, such as asthma and congestive heart failure.

Other persons at elevated risk include residents of nursing homes and chronic-care facilities, those with chronic heart or lung conditions, individuals with chronic metabolic diseases such as diabetes and renal dysfunction, young people on long-term aspirin therapy, pregnant women in their second or third trimester, immunocompromised individuals, those in close contact with any of the above groups, and travelers to foreign countries.