.. ltifactorial nature of viral evolution makes it difficult to predict such events. According to Doolittle, retrovirus evolution is sporadic, with retroviruses evolving at different rates in different situations. For instance, the human endogenous retroviral element is shared with chimpanzees, indicating no change in over 8 million years, whereas strains of HIV have diverged in mere decades. Endogenous retroviruses carried in the germline evolve slowly compared with infective retroviruses.
Generation of new viral pathogens is rare, and often possible only because of high mutation rates that permit many neutral mutations to accumulate before selective pressure forces a change. The seeming unpredictability of these events ensure that recognition of new pathogens must await their emergence. CONCLUSION The proposed American fiscal budget for 1995 allows allocations for the CDC which remain basically the same as those for past years and the $11.5 billion budget for the National Institutes of Health includes only a modest increase for non-AIDS infectious and immunological diseases research (Cassell 1994). In view of the magnitude of the problem, this budget is unacceptable. Currently, infectious diseases remain the leading cause of death worldwide.
In the United States infectious diseases directly account for 3 and indirectly account for 5 of the 10 leading causes of death, AIDS is the ninth leading cause. Infectious diseases account for 25% of all visits to physicians in the United States. In total, the annual cost of AIDS and other infectious diseases reached $120 billion in 1992, about 15% of the nation’s total health-care expenditure. The expanding pool of immunodeficient patients due to the AIDS epidemic, cancer treatment, transplant recipients, and hemodialysis has caused an explosion of opportunistic infections due to a number of fungal, parasitic, viral and bacterial agents. According to the Gail H. Cassel, president of the American Society of Microbiology, the public health system is not prepared to meet the challenges of new and re-emerging infections.
Perhaps the most obvious defect is inadequate disease surveillance and reporting. In America, only one-quarter of the states have a professional position dedicated to surveillance of food-borne and waterborne diseases. In 1992, only $55000 was spent on federal, state and local levels tracking drug-resistant bacterial and viral infections. In addition, the public health laboratories are eroding. Overall, CDC’s budget for infectious diseases unrelated to AIDS has declined approximately 20% in the last decade.
This is the case in the developed world of the United States, and we in developing South Africa are certainly no better off in terms of disease surveillance and concomitant protection. It should be clear that a mixture of basic and applied research related to infectious disease is needed. Coupled with this, better diagnostic techniques, prevention strategies and risk factor analysis is needed. Finally, enhanced communication among health care professionals and the public is integral in coming to terms and dealing with this issue. The American National Institute of Allergy and Infectious Diseases (NIAID) plans to develop a research and training infrastructure to elucidate the mechanisms of molecular evolution and drug resistance and to learn more about actual disease transmission through molecular and environmental studies and to continue their emphasis on vaccine development. For example, NIAID-funded research has already led to the creation of a new Haemophilus influenzae type B vaccine which is expected to save nearly $400 million in health-care costs each year.
Similarly, the NIH spent less than $27 million dollars to find the connection between Helicobacter pylori and chronic peptic ulcers, yet using antibacterial therapy for the disease will save $760 million dollars in health care costs annually. Given the diverse nature of threats from infectious diseases, it is not adequate merely to face each crisis as it emerges, as this may provide a strategy which proves to be too little and too late. Instead, a more holistic approach is required. This must include a global perspective as well as the need to address the issue of infectious disease within the context of shared environmental responsibility. Improved health care derived from socioeconomic betterment is crucial, as are long term policies involving systems thinking as opposed to the limiting nature of long term over-specialization.
Bibliography Cassel G.H. 1994. New and Emerging Infections in the Face of a Funding Crisis. ASM News 60, 5: 251-4 Culliton B.J. 1990. Emerging Viruses, Emerging Threat. Science 247: 279- 280 Diglisic G., Xiao S-Y., Gligic A., Obradovic M., Stojanovic R., Velimirovic D., Lukac V., Rossi C.A.
and J.W. DeLuc. 1994. Isolation of a Puumala-like Virus from Mus musculus Captured in Yugoslavia and Its Association with Severe Hemorrhagic Fever with Renal Syndrome. J. Inf.
Dis. 169: 204-7 Domingo E. and J.J. Holland. 1988. High error rates, population equilibrium and evolution of RNA replication systems.
In: RNA genetics. Vol. 3. (eds. Domingo E., Holland J.J. and P.
Ahlquist). Boca Raton, FL: CRC Press. Doolittle R.F., Feng D.F., Johnson M.S. and M.A. McClure. 1989.
Origins and evolutionary relationships of retroviruses. Q. Rev. Biol. 64: 1-30 Dowdle W. 1994.
Dowdle Reflects on CDC, Changing Demands of Disease Surveillance. ASM News. 60, 5:237-8 Hahn C.S., Lustig S., Strauss E.G. and J.H. Strauss.
1988. Western equine encephalitis virus is a recombinant virus. Proc. Natl. Acad. Sci.
USA. 85: 5997-6001 Hughes J.M. and J. R. La Montagne.
1994. The Challenges Posed by Emerging Infectious Diseases. ASM News 60, 5: 248-50 Hunter S. 1991. Tropical Medicine. 7th edn.
W.B. Saunders Company Kida H., Shortridge K.F. and R.G. Webster. 1988.
Origin of the hemagglutinin gene of H3N2 influenza viruses from pigs in China. Virology. 162: 160-166 Kilbourne E.D., Easterday B.C. and S. McGregor. 1988.
Evolution to predominance of swine influenza virus hemagglutinin mutants of predictable phenotype during single infections of the natural host. Proc. Natl. Acad. Sci.
USA. 85: 8098-8101 Lederburg J. 1994. Emerging Infections: Private Concerns and Public Responses. ASM News.
60, 5: 233 Manson-Bahr D.E.C. and D.R. Bell. 1989. Manson’s Tropical Diseases. 19th edn.
Bailliere Tindall. May R.M. and R.M. Anderson. 1987. Transmission dynamics of HIV infection.
Nature. 326: 137-142 Morse S.S. (ed.). 1993. Emerging Viruses. Oxford University Press.
Morse S.S. and A. Schluederberg. 1990. Emerging Viruses: The Evolution of Viruses and Viral Diseases.
J. Inf. Dis. 162: 1-7 Murphy F.A. 1994. Infectious Diseases.
Adv.Vir. Res. 43: 2-52 Parvin J.D., Moscona A., Pan W.T., Leider J.M. and P. Palese. 1986.
Measurement of the mutation rates of animal viruses: influenza A virus and poliovirus type 1. J. Virol. 62: 3084-3091 Peters C.J. 1994. Molecular Techniques Identify a New Strain of Hantavirus. ASM News.
60, 5: 242-3 Steinhauer D. and J.J. Holland. 1987. Rapid evoltuion of RNA viruses. Annu Rev.
Microbiol. 41: 409-433 Treanor J. and B. Murphy. Genes involved in the restriction of replication of avian influenza A viruses in primates.
In: Applied virology research: virus variation and epidemiology. Vol. 2. New York: Plenum Press (eds. Kurstak E., Marusyk R.G., Murphy F.A. and M.H.V.