TITLE: THE IMPACT OF BIOTECHNOLOGICAL ADVANCES ON WORLD HEALTH IN THE NEXT CENTURY
In the words of WHO, "Health can be defined as a state of complete physical, mental, and social well-being and not merely the absence of disease, or infirmity. In the present world, this definition applies to men, women, and children and also to both the developed and developing countries. At the turn of the 19th century, the world started experiencing a rapid increase in population growth with decrease in mortality due to technological advances, economic progress, political stability (less war) and medical breakthroughs. Life expectancy was on the increase and within a short time, the world population grew from 2.8 billion in 1955 to 5 billion by the mid-1980s and to 5.8billion in 1996; it was expected to reach 6 billion by the end of the 20th century, having taken 40 years to double (United Nations, 1998). Despite these advances and improvement in lifestyle mostly for those in the developed countries; people in the developing countries did not enjoy most of these benefits as 80 percent of the global burden of diseases are borne by them (developing countries), this is expressed by the disability adjusted lifestyle estimate (DALYs)(Bastian.H,2000).
Globally, 132 million children are born each year. From this statistics, 52 million deaths occur each year, and 20% of them are children under the age of 5, about one third of these deaths are due to infectious and parasitic diseases (World health organisation, 1998). Infectious diseases are predominantly the major cause of death globally, especially in the developing world. Other causes of death globally include but is not limited to AIDS (this is also an infectious disease, but I choose to place it on a different scale as mortality is high) which is a leading cause of death globally. Cancer, heart disease, malaria and avian flu or other pandemics like SARS epidemic that had a negative impact of a global scale economically and socially (Benatar, R.S. et al., 2009). Malnutrition is also one of the leading causes of poor health and or death, about 800 million people suffer from malnutrition globally (WHO, 2008). Health policies, political stability and world economic status are also factors that affect global health.
The relief that has come from biotechnology in recent years has been felt on a global scale in healthcare and quality of life, as mortality rate has decreased in comparison to the 19th century or early 20th century and there is an improvement in the quality of life of people who are affected by some forms of incapacitating diseases. Biotechnology is a field that encompasses both genetic engineering and molecular biology; it has been used in recent years to bring solutions to problems that have been around for centuries, with advances in biotechnology there was a successful eradication of small pox (Saborg.C, et al, 2009). The prevalence of poliomyelitis has also been reduced and brought under control through immunisation with vaccines, but with these improvements there is also the emergence of new diseases and fear of resurgence of old ones that have been previously eradicated (what if smallpox reemerges in a new form?).
With advances in biotechnology there will be hope for the future of world health as new treatments and cure for otherwise fatal diseases will be developed, improvement in already existing treatments i.e. xenotransplantation; malnutrition will be reduced with improvement of food crop yield through utilization of plant-microbe association to yield plant biomass or the production of GM (genetically modified crops), and a new type of therapy will be developed for multi-drug resistant diseases.
2. INFECTIOUS DISEASES
2.1 TYPES OF INFECTIOUS DISEASES
Infectious diseases are basically diseases that are caused by the presence of pathogenic microorganisms; Infectious diseases are either emerging or re-emerging. Emerging infectious diseases represent a major challenge to human health worldwide as they are novel and not much is known about them. The WHO estimates that at least one new emerging pathogen appears each year (WHO, 2007), and the infections are becoming harder to treat. There is a high chance that the world will face a new threat similar to AIDS, SARS or Ebola within a decade (Avila.M, et al, 2008).
The risk of evolving new infectious pathogens has been intensifying due to urbanization, demographic changes, air travel, inappropriate use of antibiotics, and climate change (Avila.M, et al, 2008).This re-emerging disease causing pathogens include those that were thought to have been eradicated and that have only recently started reemerging. These pathogens infect people from both developed and developing countries, the pathogens are not discriminatory in pathogenicity; as they can infect anyone from a CEO in the developed world to an undernourished child in the poorest village of the developing world. The fact that an infectious disease has emerged or reemerged indicates naivety in the infected population, or altered virulence potential or an increase in antibiotic/antiviral resistance in the pathogen population (Seib et al., 2009). The rapid development of vaccines and therapeutics that target these pathogens is therefore essential to limit their speed (Seib et al., 2009).
In 1976, the Ebola virus was first recognized in the Congo by its ability to cause aggressive lethal hemorrhagic fever in humans and non-human primates. Since this time, there have been numerous outbreaks in Africa, with mortality rates from 50 to 90% (Mohamadzadeh et al, 2007). Ebola (an emerging infectious disease) is known as a quick-progressing disease which has complicated the study and characterization of the disease. Currently there is no effective treatment against Ebola in humans (Nabel et al., 2004).
Most uninformed people may assume that emerging pathogens are first detected mainly in developing countries, but Legionnaires' disease which is a severe illness, was first reported in 1982 in Pennsylvania among American Legion members who fell ill with an acute respiratory illness (Fraser, D.E.et al, 2005).Actually, many new pathogens are detected in the United States or Western Europe (Avila et al., 2008). The causative agent of Legionnaires' disease, Legionella pneumophila, had been infecting only amoeba in its natural environment for thousands if not millions of years, before modern technology provided air conditioners that could transmit Legionella via aerosols into the alveolus of the lung (Avila et al., 2008). The natural sources of the bacteria are ponds and creeks, but modern-day reservoirs include cooling towers and water fountains (Fraser et al., 2005).
An example of a reemerging infectious disease is tuberculosis; it is caused by Mycobacterium tuberculosis complex (MTBC), and it is transmitted from humans to humans (Avila et al., 2008). In the developed world, TB incidence declined steadily during the second half of the 20th century and so funds for research and control of TB decreased substantially during that time as it was thought to have been brought under some form of control (Kaufmann et al., 2007.) When TB started to re-emerge in the early 1990s, fuelled by the growing pandemic of HIV/AIDS (this leads to susceptibility to TB, as host immune system is compromised),scientists were caught off-guard; billions of dollars funds of emergency were then needed to control TB outbreak (Frieden et al.,1995).
Thanks to recent increase in research funding for TB (Kaufman et al., 2007), substantial progress has been made in the understanding of the basic biology and epidemiology of the disease (Comas et al., 2009). While TB incidence appears to have stabilized in many countries, the total number of reported cases is still increasing as a function of global human population growth (WHO, 2009). Of particular concern are the ongoing epidemics of multidrug-resistant TB(WHO, 2008), as well as the synergies between TB and the ongoing epidemics of HIV/AIDS and other comorbidities such as diabetes (Comas et al., 2009).
Rapid and accurate diagnosis of infectious diseases helps public health officials manage disease outbreaks and enables health care providers to prescribe the correct treatment at the right time (NIAID, 2006). Many different pathogens, notably those that cause emerging infectious diseases, have no distinctive symptoms. This makes diagnosis quite difficult, particularly in the early stages of infection when interventional strategies are most advantageous (NIAID, 2006).
There are varying methods used in diagnosis of varying infectious diseases, and some are quite expensive. Some are based on visible signs, while others will be diagnosed by taking specimen (blood, body fluid like saliva or even a part of the body) from an individual or group of people.
In diseases caused by viruses, there are a number of ways of making a laboratory diagnosis and these can be divided into viral antigen or nucleic acid detection and serological methods. The latter involve mostly detecting the host's immune response to that virus but in some circumstances, namely HBV and HIV infection, can also involve antigen detection. Viral antigen detection includes the use of electron microscopy and virus isolation in cell culture. In addition, direct or indirect immunofluorescence is used to diagnose viral respiratory tract infections in nasopharyngeal aspirate samples. Recent advances have seen these methods being supplanted by nucleic acid detection methods (Zuckerman, 2009).
An international group of researchers have recently developed a new technology for pinpointing pathogens. Called the "GreeneChip," this device consists of a glass slide onto which are attached nearly 30,000 pieces of genetic material taken from thousands of different viruses, bacteria, fungi and parasites (NIAID, 2006). When human fluid and tissue samples are applied to the chip, these probes will stick to any closely related genetic material in the samples. This allows the rapid and specific identification of any pathogens thereineven those related to but genetically distinct from the ones represented on the chip. This biotechnological advance may improve the capacity for emerging infectious diseases surveillance and outbreak response (NIAID, 2006). The drawback to this method might be the inability to identify recent emerging pathogens and giving false negative or false positive results. The cost for diagnosis might be another limiting factor.
Recent advances in biotechnology, has significantly shifted the concept of vaccine and therapeutics development from microbiological to sequence based approaches. Genomics, transcriptomics, metabolomics, structural genomics, proteomics, and immunomics are being exploited to perfect the identification of targets, to design new vaccines and drugs and to predict their effects in patients (Seib et al., 2009). Human genomics and related studies are providing insights into aspects of host biology that are important in infectious diseases. The continuous advances in biotechnology will play a critical role in the future to enable timely development of vaccines and therapeutics to control emerging and reemerging infectious diseases (Seib et al., 2009).
Genomics-based approaches used in the control of EIDs (Emerging Infectious Diseases) from the outbreak of a disease to the development of a vaccine or drug.
(A) The causative agent of a disease may first be identified from patient samples by using metagenomics.
(B) Vaccine and therapeutic targets can be identified from the pathogen genome using a variety of screening approaches that focus on the genome, transcriptome, proteome, immunome or structural genome.
(C) The human genome can be screened to avoid homologies or similarities with pathogen vaccine and therapeutic targets, or to identify new targets.
(D) Once candidate vaccine and therapeutic targets have been identified they must be shown to provide protection against disease and to be safe for use in patients.
(E) The clinically tested vaccine or therapeutic can then be licensed for use. The clinical responses of a vaccine and/or therapeutic can be analyzed using human genome based studies (dotted arrows). The pathogen genome can also be used to analyze mutants that are able to evade the immune system in vaccinated subjects or organisms that develop antibiotic resistance (Source: Seib et al., 2009).
Despite significant progress in the development and distribution of vaccines, a great deal remains to be accomplished. There is an urgent need in both developing and developed countries for safe and effective vaccines that are affordable and easy to deliver (Oakes, et al., 2009). The World Health Organization continues to support the research of new technology and vaccine delivery systems to help in meeting these needs (Jodar et al., 2001 cited in Oakes et al., 2009).
Unfortunately, the requirement for refrigeration during storage and transportation adds greatly to the manufacturing cost of a vaccine and places a burden on those in developing countries where the need for immunization and the prevention of disease is the greatest (Rigano et al., 2005 cited in Oakes et al., 2009). Over the last two decades recombinant DNA technology has made it possible to express heterologous antigens in numerous systems, including plants, thereby increasing the likelihood that high cost and other issues associated with vaccines may be mitigated with novel vaccine platforms that could aid with goals for global immunization (Giudice et al., 2006 cited in Oakes et al., 2009).
3. NON INFECTIOUS DISEASES
Malnutrition is estimated to contribute to more than one third of all child deaths, although it is rarely listed as the direct cause (WHO, 2008). Malnutrition is prevalent in third world nations as poverty is widespread; there is no access to water, food and in most cases there is drought, war or a corrupt government that has failed to provide for its citizen. That is not to say malnutrition does not affect people in developed countries, it does.
Malnutrition means "badly nourished" but it is more than a measure of what we eat, or fail to eat. Clinically, malnutrition is characterized by inadequate intake of protein, energy, and micronutrients and by frequent infections or disease (WHO, 2008). Thus a deficiency in any of the nutrients is malnutrition.
In the words of Dr G.H.Brundtland, "Nutrition is a key element in any strategy to reduce the global burden of disease; Hunger, malnutrition, obesity and unsafe food all cause disease, and better nutrition will translate into large improvements in health among all of us, irrespective of our wealth and home country"(WHO, 2008). Nutrition is not currently an important driver of most plant breeding efforts, and there are only a few well known efforts to breed crops that are adapted to the needs of optimal human nutrition. Biotechnological tools are available to greatly enhance the nutritional value of our staple crops. However this can only be achieved if nutritional traits are introduced in tandem with important agronomic yield drivers, such as resistance to emerging pests or diseases, to drought and salinity, to herbicides, parasitic plants, frost or heat (Sand et al., 2009).
The use of GM crops is one advance in biotechnology that can be used to tackle malnutrition. Vitamin A deficiency is a leading cause of preventable blindness in children and the deficiency increases the risk of death from severe infection and diseases (Linster, C.L. et al, 2008). To tackle this kind of deficiency, Golden Rice was developed by inserting two genes into rice that turn on - carotene production in the endosperm (Sand et al., 2009), this increases the content of vitamin A in the rice. The use of plant-microbe interaction (another biotechnological advance) to improve plant biomass yield is another way to tackle malnutrition, especially in drought or low crop yield areas.
All cancers arise as a result of changes that have occurred in the DNA sequence of the genomes of cancer cells. Over the past quarter of a century much has been learnt about these mutations and the abnormal genes that operate in human cancers. The World however, is moving into an era in which it will be possible to obtain the complete DNA sequence of large numbers of cancer genomes (Stratton et al., 2009).
Approximately 100,000 somatic mutations from cancer genomes have been reported in the quarter of a century since the first somatic mutation was found in HRAS. Over the next few years several hundred million more will be revealed by large-scale, complete sequencing of cancer genomes. These data will provide us with a fine-grained picture of the evolutionary processes that underlie our commonest genetic disease, providing new insights into the origins and new directions for the treatment of cancer (Stratton et al., 2009).
The mortality rate from both infectious and non infectious diseases (Avila, 2000) would have been higher, if not for the biotechnological advances currently in place; but there is still a need and great prospect for improvement in terms of development of new vaccines, manufacture of drugs, novel pathogen detection methods for diagnosis of diseases and increase in yield of crops with high nutritional value.
In conclusion biotechnological advances will have a positive effect on world health in the next century as there will be a remarkable improvement on current biotechnological techniques.
Avila, M., Said, N., & Ojcius, D. M. (2000). The book reopened on infectious diseases. Microbes and Infection: Vol.10 , pp. 942-947.
C.Sands, D., Morris, C. E., A.Dratz, E., & Pilgeram, A. (2009). Elevating optimal human nutrition to a central goal of plant breeding and production of plant-based foods. Plant Science; Vol. 177 , pp. 377 - 389.
Comas, I., & Gagneux, S. (2009). PLoS Pathogens. Retrieved 0ctober 30, 2009, from plospathogens website: http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000600
E.L.Giudice, & Campbell, J. (2006). Needle - free vaccine delivery. Advanced Drug Delivery Reviews; Vol. 58 , pp. 68 - 89.
Fraser, D. (2005). The challenges were legion. Lancet Infectious Diseases; Vol. 5 , pp. 237 -241.
Frieden, T., Fujiwara, P., Washako, R., & Hamburg, M. (1995). Tuberculosis in New York City- TURNING THE TIDE. The New England Journal of Medicine; Vol. 333 , pp. 229 - 233.
Gushulak, B., & MacPherson, D. (2000). Population mobility and infectious diseases: the diminishing impact of classical infectious diseases and new approaches for the 21st century. Clinical Infectious Diseases; Vol. 31 , pp. 776-780.
Jodar, L., Duclos, P., J, B. M., Griffiths, E., M, T. A., & Clements, J. (2001). Ensuring vaccine safety in immunization programmes: a WHO perspective. Vaccine; Vol.19 , pp. 1594 -1605.
Kaufmann, S., & Parida, S. (2007). Changing Funding patterns in tuberculosis. Nature Medicine; Vol.13 , pp. 299 - 303.
L.Jodar, P.Duclos, Griffiths, J., Aguado, M., & Clements, C. (2001). Ensuring vaccine safety in immunization programmes: a WHO perspective. Vaccine; Vol. 19 , pp. 1594 - 1605.
L.Lamberts, & Delcour, J. (2008). Carotenoids in raw and parboiled brown and milled rice. Journal of Agriculture and Food Chemistry; Vol. 56 , pp. 11914 - 11919.
Linster, C., & S.G.Clarke. (2008). L- Ascorbate biosynthesis in higher plants: the role of VTC2. Trends in Plant Science; Vol. 13 , pp. 567 - 573.
M.Mohamadzadeh, Chen, L., & Schmaljohn, A. (2007). How Ebola and Marburg viruses battle the immune system. Nature Reviews Immunology; Vol. 7 , pp. 556 - 567.
Mark, Z. (2009). Pathogenic Viruses: Clinical Detection. Retrieved October 29, 2009, from Encyclopedia of Life Sciences website: http://mrw.interscience.wiley.com/emrw/9780470015902/els/article/a0001093/current/pdf
Nabel, G. J., Sullivan, N., & Yang, Z. Y. (2004). Cellular and molecular mechanisms of Ebola pathogenicity and approaches to vaccine development. In H. D. Klenk, Ebola and Marburg Viruses: Molecular and Cellular Biology. Wiltshire: The Cromwell Press.
NIAID. (2006). New "GreeneChip" Identifies Multiple Pathogens Rapidly and Accurately. Retrieved November 1st, 2009, from National Institute of Allergy and Infectious Diseases: http://www3.niaid.nih.gov/news/newsreleases/2006/greenechip.htm
Oakes, J. L., & Piller, K. J. (2009). Stability of a soybean seed- derived vaccine antigen following long-term storage, processing and transport in the absence of a cold chain. Journal of the Science of Food Agriculture; Vol. 89. No. 13 , pp. 2191 - 2199.
Rigano, M. M., & Walmsley, A. M. (2005). Expression systems and developments in plant - made vaccines. Immunology Cell Biology; Vol. 83 , pp. 68 - 89.
Rigano, M., & Walmsley, A. (2005). Expression Systems and developments in plant - made vaccines. Immunology and Cell Biology; Vol. 83 , pp. 68- 89.
Seib, K., Dougan, G., & R.Rappuoli. (2009). PLoS Genetics. Retrieved October 30, 2009, from plosgenetics website: http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1000612
Soborg, C., Molbak, K., Doherty, T. .., Ulleryd, P., Brooks, T., Coenen, C., et al. (2009). Vaccines in a hurry. Vaccine; Vol. 27 , pp. 3295- 3298.
Sommer, A. (2008). Vitamin A deficiency and clinical disease: an historical overview. Clinical Nutrition; Vol. 138 , pp. 1835 - 1839.
Stratton, M. R., Campbell, P. J., & Futreal, P. A. (2009). The cancer genome. Nature; Vol. 458 , pp. 719-724.
WHO. (1999). Ageing - exploding the myths. Ageing and Health Programme (AHE) , PP. 1 -21.
WHO. (2009). Anti-tuberculosis drug resistance in the world report; No. 4. Geneva: World Health Organisation (WHO).
WHO. (2009). Global tuberculosis control - surveillance, planning, financing. Geneva: World Health Organisation (WHO).
WHO. (2007). International Spread of Disease Threatens Public Health Security. Geneva: World Health Organisation (WHO).
WHO. (2000). Turning the tide of malnutrition: responding to the challenge of the 21st century. Geneva: World Health Organisation (WHO).
WHO. (2007). WHO Report on Global surveillance of Epidemic-prone Infectious Diseaes Plague, Epidemic and Pandemic Alert and Response (EPR). Geneva: World Health Organisation (WHO).
WHO. (2008). World Health Statistics. Geneva: World Health Organisation (WHO).
Young, D., Perkins, M., K.Duncan, & Barry, C. (2008). Confronting the scientific obstacles to global control of tuberculosis. Journal of Clinical Investigation; Vol. 118 , pp. 1255 - 1265.