Abstract
The world has experienced three H1N1 Influenza virus pandemics since last century. The effects of these pandemics on human beings have varied in magnitude. The 1918 pandemic was the most devastating compared to later ones. The catastrophic potential of these pandemics has drawn a lot of attention in the quest of understanding their viral agents and Influenza infections they cause. The highly contagious flu infections they cause have been studied in various aspects using various scientific techniques. Due to the highly unstable and unpredictable nature of the viral agents , a lot of efforts have been concentrated on understanding the pattern of infections and illnesses of these viruses on the general human population. As most scientific investigations have shown, understanding the social and behavioral aspects of pandemic viruses such as H1N1 is crucial in formulating control and prevention strategies for future outbreaks.
Definitions and Description
H1N1 refers to a strain of non-seasonal Influenza Type A virus which was first detected in Mexico in April 2009. Upon its medical discovery, the viral infection quickly spread to other continents in the world warranting its classification by the WHO as a pandemic. Initially referred to as “Swine flu” among a host of other names by various countries ,the WHO proposed name, Pandemic Influenza A /H1N1 2009 was later adopted to differentiate it from the 1918 H1N1 strain that killed millions of people.
H1N1 bears structure akin to most viruses. It is spherical with a diameter of 80-120 nm (Dandagi & Byahathi, 2011). It is composed of RNA enveloped by a lipid. The enveloping lipid is characterized by surface proteins namely Hemagglutinins (HA) and Neuraminidase (NA) that are responsible for virulence properties (Mpolya et al., 2009). The Influenza virus causes highly contagious diseases in pigs that are rarely transmitted to human beings. Besides pigs other hosts include human beings, birds (Chicken and ducks), pigs and horses (Mpolya et al.,2009). The Influenza virus is classified as A, B and C. Human beings are mostly susceptible to the “A” strain that causes seasonal flu common in winter and autumn.
The development of the 2009 H1N1 subtype of Influenza A is attributed to reassortment of different genes of influenza viruses found in swine, avian species and human hosts (Dandagi & Byahathi, 2011).It genome has been pointed out to be a combination from four Influenza viruses namely: N. America Swine Influenza, Asia/Europe swine Influenza, human Influenza and avian Influenza (non-H5) (Narain, Kumar & Bhatia 2009, e1). The reassortment is believed to occur by antigenic drift whereby mutations in the surface proteins produce a novel subtype (Mpolya et al., 2009 ).
Transmission of H1N1 influenza occurs through inhalation of infected respiratory droplets of after sneezing and coughing and from formites on infected surfaces (Mpolya et al., 2009, p.29).This means close contact is an important facilitating factor of the infection
Owing to previous Influenza pandemics most government in the developed world were well prepared to closely monitor the 2009 H1NI pandemic. The surveillance was in terms of monitoring the communicability of the virus which was measured by attack rates, the virulence or severity measured by case fatality rates and governmental response which was measured by the surge capacity of the health or medical services (Narain, Kumar & Bhatia 2009, e1).Most governments set up monitoring centers that collaborated and exchanged data with other nations. Unlike previous pandemics, a lot of scholarly effort was noticeably with many publications on the H1N1 coming out. The private media was also used to channel out awareness messages to the public.
Most scientific studies have examined the social and behavioral epidemiological aspects of H1N1 Influenza from various parameters of the affected population such as the age group, climatic area, socioeconomic impact, associated risk factors, seroprevalence, hospitalization rates, time course of the pandemic, case fatality rate (CFR), behavioral response, and international management efforts. The objectives of such studies have been to explain the causal relations and the significance of each determinant and possible prediction of future similar pandemics. Many epidemiological models and analytic tools from diverse disciplines have been employed to this end. The results based on these factors have been critical in drafting and executing mitigation responses.
Epidemiology profile
Distribution and burden of the disease
By the time the WHO declared H1N1 pandemic over in 10 August 2010, almost all countries had confirmed cases of pandemic H1N1 2009 virus (WHO committee on Clinical Aspects of pandemic H1N1, 2010). According to the WHO committee on clinical aspects of pandemic H1N1, from the start of the H1N1 flu pandemic up to mid February 2010, an estimated 59 million Influenza –like illnesses (ILI), 265,000 hospitalization and 12500 deaths were reported in the United States alone. Data from this committee also shows that Overall fatality rate was less than 0.5% and In the US and UK the case fatality rate for symptomatic illness was estimated to be 0.048% and 0.026% respectively.
In the Western Pacific Region, the WHO reports that from April 2009 to July 2010, over 250,000 cases and 1800 fatalities were due to the Pandemic H1N1 2009 virus (McCallum & Partridge, 2010). By NEJMra1000449age groups, 8.6%, 41.9%, 48.3% and 1.2% of cases were in the <5 yrs, 5-14 yrs, 15-64 yrs and 64+ years group respectively while the overall crude fatality ration was 0.5% (McCallum & Partridge,2010). An assessment carried out from May 1 to Aug 24, 2009 by Department of Health and Human Services of the United States on the 2009 H1N1 Influenza outbreak in some southern hemisphere countries (Argentina, Australia, Chile, New Zealand and Uruguay) also revealed H1N1 to be predominant in school-aged children and adults under 65 years of age. The assessment also revealed that pregnant women and individuals with underlying chronic diseases were at an increased risk of severe forms of the H1N1 2009 flu.
Economic costs
The economic effects of the pandemic H1N1 2009 virus varied from country to country. This was as a result of measures taken by authorities to contain the spread of the pandemic within their locality. Some countries experienced significant workers absenteeism especially when close proximity of persons in public and work places were restricted. This might have negatively affected morale and thence productivity. Tourism also suffered in some countries after travel bans were effected perhaps influenced by the novel flu pandemic that was underway. According to a 2009 assessment report by the US Department of Health and Human Services (HHS), Low tourist arrivals were reported in Australia and Argentina during the peak periods of the epidemic. In Chile, Uruguay and Japan, many schools were closed during the height of the pandemic. Many retail businesses in the affected countries may also have suffered as locals shunned public and overcrowded place they perceived as dangerous. Most governments were also forced to divert funds to combat the pandemic through provision of medical facilities, medical personnel, and awareness and surveillance initiatives.
Intervention practices and their effects
Broadly, intervention for pandemic H1N1 may be pharmaceutical or non-pharmaceutical based. Non pharmaceutical intervention (NPI) may involve isolation and social distances whereby caregivers of the H1N1 victims and their patients are isolated until they do not show any symptoms related to the flu. Social distancing may also involve closure of school and prohibiting mass assembly in public places as was the case in the United States and Japan where large number of schools were closed in the wake of the H1N1 2009 pandemic. Public and health care workers education has also been identified as a crucial part of any campaign against an influenza virus pandemic (Balinska and Rizzo, 2009)
Perhaps the most stressed intervention practice stressed by health authorities is that people should observe high standards of personal hygiene accompanied by a behavioral change. In creating awareness of the pandemic the populace is always reminded to thoroughly wash hands with soap and running water after sneezing. They are also advised to cover their mouth and nose with a tissue to be disposed immediately in a waste container. Face masks are also encouraged when in public. Touching of the nose, mouth and eyes is also discouraged as formites in the places are perfect entry routes for the flu viruses. Healthy people are also discouraged from getting in contact with persons with influenza illness as they will be exposed to droplets from sneezing and coughing of the victims. Those with Influenza like illness are also advised to stay away from public places and healthy persons. This is because the virus is still transmissible even in recovering victims and this may extend to even week from the onset of the illness (Mpolya et al., 2009). Some countries have also been known to issue travel advisory to affected countries. People are generally advised to seek medical care when they develop Influenza-like symptoms that among others include fever, cough, sore throat, runny nose, nasal obstruction, fatigue, joint or muscle pain, headache and nausea (Mpolya et al., 2009 ).
Pharmacological intervention of pandemic H1N1 virus has involved vaccination and use of antiviral drugs. However novel influenza viruses are known to have developed resistance to some of these drugs. A case in point is the drug Oseltamivir/Tamilfu and Adamantanes drugs such as Amantadine and Rimantadine which the pandemic H1N1 viruses have become resistant to (Mpolya et al., 2009 ). Vaccination offers the best prevention against influenza although most vaccines have considerable development time. In this respect Balinska and Rizzo (2009) have found out that NPIs offer the most significant mitigation results in the absence of a vaccine during an influenza pandemic. The 2009 H1N1 pandemic was tackled at international level. This involved coordinated researches and collaboration by all affected nations with the view of exchanging crucial epidemiological, clinical and genomic data for developing population-specific vaccines and formulating management policies (Mpolya et al., 2009).
Social-ecological, behavioral risks and resiliency factors
The social-ecological aspect of the H1N1 can be viewed from a standpoint of how the environment influences the development of H1N1 viruses. Maliszewski and Wei (2011) hypothesized and confirmed that public transportation usage, agricultural land proportions and population proximity are significant parameters for the social ecological profile of H1N1 viruses. According to their study, public transportation networks place masses at close proximity to the pathogenic viruses increasing the chances of contracting it. Owing to their zoonotic nature most influenza viruses, they suggest that close association of animal farming communities with their animals may easily expose human being to infections in the case of a novel influenza virus capable of human infection. In their study they found a positive correlation between influenza illness hospitalization and the proportion of agricultural land in the sample community. With regard to geographical proximity of populations, they found, although marginally significant, a positive correlation between communities at close proximity and hospitalization rates of pandemic H1N1 2009. This was a rare study of its kind but altogether shows that more effort be channeled into studying social ecological factors of pandemics for purposes of future preparedness.
Public awareness has been applied in many countries in times of Influenza campaigns. Although health authorities always react swiftly by increasing awareness of an infection during pandemics some behaviors increase risk of contracting the infection. A study in Malaysia at the height of the H1N1 2009 pandemic concluded that observing precautionary behavior by the masses under a pandemic attack is an important step in curbing further spread of the pandemic and enhancing psychological appreciation for future outbreaks (Sam & Wong 2011, 23).
At a personal level, the behavioral aspect of influenza A H1N1 can be categorized in terms of fear of contracting the illness, risk avoidance and health protective behavior (Wong & Sam 2011, 24). For Influenza H1N1,risky behavior include: not wearing face masks in public, going to crowded places, using public transport, visiting victims’ hospitals, travelling to infested places have been cited to greatly increase the chances of contracting infection. Most importantly, coughing and sneezing without covering the mouth and nose greatly exposes danger to those in the surroundings. This is due to the fact that the droplets from coughing are believed to be the major carrier of the viruses. Other factors are not washing of hands upon sneezing and/or coughing and adopting a poor lifestyle (poor diet and little/no physical exercise).
The global spread of the Influenza H1N1 virus in a matter of days points to its resilience nature. Unlike the seasonal flu a novel influenza virus is not affected by seasons or other environmental dynamics. The most noticeable feature of most influenza pandemics is that they occur in two waves before subsiding. The 1918 H1N1 pandemic was devastating in its second wave leaving millions of deaths in its trail. Their however is little literature with regard to this behavior. The novelty and perhaps resilience of influenza virus has been explained in terms of reassortment of the virus genes from various sources via antigenic shift whereby significant changes take place in the surface proteins namely: HA and NA proteins resulting in more virulent subtypes (Mpolya et al 2010 ,26). The 2009 H1N1 pandemic affected mostly young people and most elderly persons over 65 yrs of age were spared. This has been attributed to previous exposure to influenza viruses that conferred to them protective immunity. The short incubation period of the pandemic H1N1 2009 virus may explain its short lived illness.This may be explained as perhaps the infected body producing heavy immunity that effectively overwhelms the virus at shedding period.
Models for studying causal relationships of the epidemiology of Influenza H1N1 viruses
In causal relationships, the cause and the effect of a phenomenon are studied for any relationship between them. In epidemiological studies the cause may refer to exposure while the effect may constitute a disease. In such studies the main objective is to determine and analyze the determinants of a disease which is a key to setting up prevention and control measures (“Epidemiological modeling and risk analysis”, Chap 9). The determinants may include lifestyle, characteristics, incubation period, host factors (age, sex, breed, race, immune status) and environmental determinants such as climate, season, housing, nutrition and management (“Epidemiological modeling and risk analysis”, Chap 9). After drawing up a list of the possible determines/variable they are then subjected to thorough testing using various analytic tools such as the widely used multivariate analytic techniques of regression analysis. There are many attempts to explain causal relationship, which by and large, is still a much debated topic in many disciplines. In this section a number of classical and modern ones will be briefly discussed.
Some of the causality models of epidemiology include: the host-agent-environmental model, person place and time model, exposure-outcome mode, cause effect model, observational-experimental model and mathematical and statistical model. In this paper ,due to brevity requirement, only the host-agent-environmental model and the cause-effect model of infectious diseases will be discussed.
The cause-effect model is based on the premise of the interaction of an agent and disease. According to this model, a disease cannot develop in the absence of exposure to an agent (Vineis & Kriebel, 2006 ). In this model there can be a clearly defined one agent-one disease such as in small pox. This is referred to as the Pasteur and Koch Postulate. This is a rare occurrence. Conversely, a clearly defined cause /agent (e.g. bacteria, parasite or virus) may result in a myriad of symptoms such that the end disease is not clearly defined. This is common with some chronic diseases. The cause/agent has also been explained in terms of the Rothman’s pie hypothesis whereby the cause is said to be made up of a number of components, each with unique significance that are necessary to initiate and produce a disease (Vineis & Kriebel, 2006,p.1).
The epidemiological triangle is a modern tool used together with other biological disciplines; mainly biostatistics to investigate causal relationship of a disease.It is an important tool in formulating prevention and control strategies of infectious diseases. It based on the interaction of the host, agent and environment of a disease. The epidemiological triangle can be used to draw a model of causative interactions of the H1N1 Influenza virus (see fig.1). The basis for establishing casual inference for the two models is based on the Bradford Hill criterion. The parameters for this criterion are strength of association, of association, consistency, specificity, temporal relationship, Biological gradient, plausibility, coherence, experiment and analogy.
Conclusion and Recommendation
There is always a likelihood of an eruption of an influenza pandemic owing to the unstable nature of influenza viruses. New genetic makeup from a combination of different strains can present a novel strain whose effects can be catastrophic both socially and economically as has been experienced from the H1N1 subtype. Data from the influenza epidemics of 1918, 1958/68, 1976 and more recently 2009 indicate that Influenza viruses have high transmissibility and have the potential to cover a large geographical expanse in a short period of time. This means that time is critical factor in combating a new influenza outbreak. In this regard, governments should always have appropriate response strategies to handle any sudden outbreaks.
This can be achieved by perfecting Predictive models of epidemiology. As was the case during the 2009 H1N1 Influenza pandemic, the role of international collaboration cannot be downplayed. Developed nations need extend resources (personnel, finances, facilities, technology etc) to less developed/developing nation so as to strengthen their capacity to combat such pandemics. Otherwise, their localized efforts are bound to greatly fail. As most research have shown, public awareness and behavioral change at a personal level change have significant mitigating effects during the initial periods of an influenza outbreak when vaccines are unavailable. Therefore, public education strategies should put more emphasis on social measures such as personal hygiene and behavioral change. This form of awareness should persist even after the end of a pandemic. This can be achieved by incorporating pandemic education in mainstream education curriculum.
Understanding every aspect of a pandemic such as H1NI is crucial for future preparedness. Epidemiological studies and research should focus on the crucial areas such as host, environment and agent factors for purposes of setting up appropriate countermeasures.
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