GLobal Neuro health by Clark1968

Journal of the Neurological Sciences 165 (1999) 101–105

Review article

Neurology without borders: Neurological disease in a shrinking world Donna C. Bergen* Department of Neurological Sciences, Rush Presbyterian St. Luke’ s Medical Center, 1725 West Harrison Street, Chicago, IL 60612, USA Received 6 January 1999; received in revised form 5 April 1999; accepted 5 April 1999

Abstract The last half of the twentieth century has seen social, political, economic, and environmental changes which have altered patterns of health care in all parts of the world. International influences are becoming stronger each year, and the practice of medicine in any single country is becoming more and more influenced by events and practices in others. Environmental degradation may involve widespread dissemination of neurological toxins. Newly emerging or drug-resistant infections include those involving the nervous system. Effective neurological practice is more dependent than ever on knowledge of international health. Neurologists can act as effective advocates for appropriate treatment, allocation of resources, and prevention of neurological diseases.  1999 Elsevier Science B.V. All rights reserved. Keywords: International health; International neurology; Environmental medicine; Emerging infections; Global warming; International travel

1. Introduction Globalisation of the world economy and trade, the growing volume and inclusiveness of world trade (including trade in illegal substances and armaments), and increasing migrations of populations, will have an increasing impact on health in the next century [1]. The health of individuals in all countries is increasingly influenced by international economic and physical inter-relationships. A survey of these interdependences and their effects on health are the subject of this paper.

2. International travel and migration Both increasing individual travel and mass movements of populations have characterized the latter part of the 20th century. Commercial air travel moves 500 million people across national borders each year, and 70 million people

*Tel.: 11-312-563-2030; fax: 11-312-563-2024. E-mail address: donnab@neuro.rpslmc.edu (D.C. Bergen)

work outside their home countries [2]. An estimated 50 million people have migrated because of war or other social displacement [3]. The recreational or business traveler may serve as the victim or the vector of disorders not endemic to his / her country of origin. In 1992, for example, the occurrence of central nervous system schistosomiasis in two Peace Corps volunteers after recreational water exposure in Lake Malawi (Africa) prompted a serological survey of 955 resident expatriates and visitors to Malawi [4]. Thirty-two percent of those who swam in popular resorts on Lake Malawi were seropositive for schistosomiasis. About 11 000 tourists visit the lake each year. Each year, millions of people from non-endemic countries visit countries where malaria is prevalent. Some contract the disease. Political and economic upheavals cause population shifts and the collapse of health care structures with serious international health implications. For example, notification rates for syphilis in the former Soviet Union and Eastern Europe have increased throughout the 1990s. But not only these countries are affected: a study of foreign-born prostitutes in Italy revealed active syphilis in 28% of those

102

D.C. Bergen / Journal of the Neurological Sciences 165 (1999) 101 – 105

from the former Soviet Union [5]. Most of the cohort had been prostitutes for less than a year. Similarly, other local public health issues can be addressed only if global patterns of disease are considered. Since the introduction of immunization to prevent early childhood measles, acute measles encephalitis and subacute sclerosing panencephalitis have become rarities in developing countries. But local eradication is impossible in the face of immigration from still-endemic areas. Based on serological typing, virtually all measles seen in the US since 1993 is thought to be from importation of virus [6]. The success of national measles elimination programs in Latin America has sharply reduced the number of imported cases in the US [6]. Similarly, although incident cases of tuberculosis (TB) have been declining in the US, increasing immigration from endemic areas has meant higher incidence rates of tuberculosis in foreign-born residents of the US, who now account for 37% of new TB cases [7]. The admixture of populations in some cases is striking. It has been claimed, for example, that one out of four people now living in Toronto comes from a developing country or has parents who did [8].

3. New infections The human immunodeficiency virus (HIV) pandemic has left no doubt that infectious disease is a global concern. The HIV positive population now tops 30 million, with the highest prevalence in Africa and Southeast Asia [9]. Population movements, social dislocations, the international sex industry and drug trade, and other factors ensure continuing global spread of the disease. Recent brief but vicious epidemics of ebola viral hemorrhagic fever, Marburg viral infection, and Lassa fever highlight the vulnerability of immunologically ‘naive’ populations to disease caused by alterations in patterns of human social contacts or environments, cross-species ‘escape’ of pathogenic organisms from their natural animal reservoirs, or viral mutations [2]. Modern travel makes wide broadcasting and amplifications of such disease outbreaks not only possible but likely. The eradication of smallpox through global efforts spurred and organized by the World Health Organisation exemplifies the international approach which increasingly typifies effective infection control. Recent WHO targets are diseases primarily or secondarily involving the nervous system. Thanks to an international immunization program, the last case of wild-type poliomyelitis seen in the Western Hemisphere occurred in 1991, and by 1995 only 6179 cases were reported worldwide [10]. Eradication of leprosy and hemophilus influenza, and control of tuberculosis remain current goals.

4. Drug resistant infections A recent worldwide survey by WHO leaves no doubt that drug-resistant tuberculosis is a global problem, and is itself a powerful argument that the only rational approach to defining and solving certain serious health problems is international [11]. Whether developing countries or industrialized ones, all 35 countries surveyed reported drug resistant tuberculosis, with a median of 9.9% of patients showing resistance to at least one drug. With immigrants, refugees, and travelers carrying the disease across borders, an international approach to tuberculosis control is essential. Recent decades have seen increasing use of routine antibiotics in farm animals, as well as rampant, inappropriate prescribing of antibiotics to humans. Powerful new antibiotics are increasingly available worldwide, and are often aggressively marketed even in areas where other aspects of medical care are relatively primitive. Such drugs are commonly used to treat viral infections, or when older, less costly or specific antibiotics are equally effective. These practices, in addition to short, sub-therapeutic treatment courses, ensure the increasing selection of multiply drug-resistant bacterial strains. These changes in our bacterial milieu are not local affairs. Penicillin-resistant Staphylococcus aureus and Neisseria gonorrhoeae, and chloroquine-resistant Plasmodium falciparum (the most common cause of cerebral malaria) are ‘ubiquitous’ [8]. In 1988 the spread of a clone of multiresistant Streptococcus pneumoniae first detected in Spain was subsequently tracked to the United States, Mexico, Portugal, Korea, and South Africa [8]. Thus the prescribing practices of physicians in one country can affect the health of people in many countries.

5. The global marketplace and infection Flourishing global trade makes infection control an international matter. The shopping cart from an ordinary American supermarket, for example, may contain fruit from Israel, Mexico, or Guatemala; vegetables from Chile or Spain; sausage from Hungary, and sweets from Poland. Thirty-eight percent of fruit consumed in the United States is now imported [12]. The appearance of atypical Creutzfeldt-Jacob disease in humans in Britain in 1996 vividly demonstrated the vulnerability of users of the global marketplace to the spread of infectious disease [13]. The temporal relationship between this spongiform encephalopathy and an epidemic of bovine spongiform encephalopathy (BSE) in British cattle, similar glycosylation patterns of PrPres in the human and bovine diseases, and susceptibility studies in mice all suggest that the two diseases have a common origin; human ingestion of diseased beef is a possible link

D.C. Bergen / Journal of the Neurological Sciences 165 (1999) 101 – 105

[14]. Cattle contribute to the production of some heparins, insulin, gelatin, lactose, lactulose and serum for vaccines. Because of the very low infectivity of tissues used in these substances, a BSE pandemic is thought to be extremely unlikely, but ‘with the current state of knowledge, the risks in some cases are as unquantifiable as those of having eaten beef in the mid-1980’s [15]. Recognising the increasingly global nature of infectious disease occurrence and expansion, a European equivalent of the United States Centers for Disease Control and Prevention met for the first time in September 1998 [16]. The European Centre for Infectious Diseases, made up of experts from Europe, the United States, Brazil, and India, will study and plan responses to infectious disease using a global perspective.

6. Environmental degradation The worldwide atmospheric effects of the eruption of Mount Pinatubo in the Philippines, the recent country-wide forest fires in Indonesia, and the near melt-down of the Chernobyl nuclear plant left no doubt that environmental disasters can have international effects [17]. Spurred by the United Nations Environment Program (UNEP), an Intergovernmental Negotiating Committee on Persistent Organic Pollutants will meet for the first time this year. The goal of the committee, composed of representatives from 100 countries, will be to write a global convention aimed at reducing these pollutants. It will focus on 12 long-lived organochlorines which can be and are shared globally through atmospheric spread or movement through the food chain. Some of these are neurotoxins, and pose an environmental risk even to citizens of countries which have banned their local production and use [18]. Local precautions may not be sufficient protection in a densely populated world where precious resources cross national borders. This is most clearly seen in water use, where overfishing in one hemisphere may threaten longstanding dietary habits in the other. Dams, levees, or fluvial diversions in one country may threaten the water supply of another nation downstream.

7. Global climate change Despite ever more feeble denials from governments and politicians unwilling to take unpalatable and costly corrective action, global warming has begun, and possible effects on health are beginning to emerge. The international agreement on reducing ‘greenhouse gases’, reached in Kyoto earlier this year, demonstrates the dawning realisation that the prosperity, and possibly the survival, of any single nation is dependent to a large extent upon the

103

behavior of all nations [19]. Global warming may cause geographical shifts of vector borne diseases. Malaria is of particular concern to neurologists because of cerebral involvement often associated with falciparous malaria. Malaria already causes 1.5 to 2.7 million deaths worldwide each year [20]. Recent northward movements of malaria or its mosquito vectors has already been reported on several continents in conjunction with retreating glaciers and ascent of alpine plants [21]. The eventual ‘malaria belt’ may shift northward well into the southwestern United States and parts of Europe [22]. Malaria was endemic in many parts of Europe earlier this century, and its ability to reappear in circumstances of war, breakdown in health care structures, reduction in vector control procedures, and population migrations is typified by its resurgence in Armenia in 1997 [23]. Climatic influences on the vector organisms for trypanosomiasis (sleeping sickness), certain viral encephalitides, and schistosomiasis would alter the populations at most risk. A 3–5 degree temperature increase has been predicted to cause a significant northern shift in western equine and St Louis encephalitis, and transmission rates may also increase [24,25]. Protein calorie malnutrition, already a major cause of worldwide mental retardation, may increase with altered food productivity secondary to changes in climate and associated pests and diseases [22]. Further threats to mental health and spread of infectious diseases will be posed by social, economic and demographic dislocations which are difficult to predict or quantify. Potential effects on public health of population dislocations due to lowland flooding, water shortages in arid areas, and economic and political upheavals are beginning to be taken seriously by planning groups worldwide. The United Nations-sponsored Intergovernmental Panel on Climate Change included a report on possible health impacts in its second report issued in 1996 [26]. In the United Kingdom, the Climate Change Impacts Review Group of the Department of Environment highlighted potential health effects in Britain [27].

8. International trade in illicit or dangerous goods The global economy includes trade in both legal and illicit substances which have major impact on health. As cigarette smoking becomes less attractive to informed customers in the richer countries, tobacco companies are focusing on markets in developing countries. The former Soviet Union, Eastern Europe, and China are among the countries targeted by joint ventures and aggressive marketing campaigns. Smoking in the young is growing, recently up to 42% of Muscovite boys and 24% of girls 15 to 17 [28]. Chinese men, who make up 10% of the adults in the world, smoke 30% of the cigarettes consumed globally

104

D.C. Bergen / Journal of the Neurological Sciences 165 (1999) 101 – 105

[29]. By the year 2050, tobacco related deaths in China may reach 12 million per year [30]. In addition, the global heroin and cocaine market has grown 10-fold since 1977 [31]. International trade in armaments and the development and spread of nuclear arms, neurotoxic chemical weapons, landmines, blinding lasers, and other armaments not only pose direct threats to human health, but also divert resources away from desperately needed healthcare. It has been estimated that the cost of the order of 40 Mirage fighter planes from one developing country, for example, would pay for safe water for all of its 55 million citizens without it, family planning services for the 20 million couples who lack it, essential drugs for the 13 million without access to health care, and basic education for the 12 million children not attending primary school [32]. Among the ‘goods’ traded internationally in the modern world are cultural and economic practices which alter the lifestyle of whole nations. Some of these changes, such as the availability of modern healthcare and better education, have improved the lives of many. But some changes in diet and lifestyles which are imported from industrialized countries into developing countries, not only from direct contact but from cultural influences purveyed by international cinema and television, may have a profound negative impact on the pattern of disease prevalent in a community. Sharp increases in mortality and morbidity from diseases related to smoking, unhealthy diets, and environmental pollution, are expected to occur over the next 20 years. These include coronary vascular disease, chronic obstructive pulmonary disease, and cancers, particularly in developing countries [33].

continuing medical education (CME) is increasingly adopted by healthcare systems throughout the world, and CME is increasingly available online. Influential medical journals such as the Journal of the American Medical Association and the British Medical Journal publish local editions in developing countries. Recently, as part of its educational mission the International League Against Epilepsy has authorized an Indian edition of Epilepsia. This less expensive, locally produced edition, appearing quarterly, includes some full-length articles from the parent journal, a full list of contents, and news of local neurology meetings and activities [34].

10. Harmonisation of regulations While growth of the international pharmaceutical industry has brought powerful economic pressures to bear on health care systems globally, it has also fostered helpful attempts to expedite and rationalize regulatory approval of new therapeutic drugs and devices. The European Union (EU), for example, has agreed on common standards of proof of efficacy and safety for all the countries of the EU, reducing the time and expense of new drug development. Similarly, the International Commission on Harmonisation, made up of delegates from Europe, the United States, and Japan, has written a code of conduct for clinical trials based on internationally recognized ethical standards. This code is available for clinical investigators in all countries who are doing research involving humans [35].

11. Response of neurologists 9. Benefits of globalisation International movement and exchange of medical and scientific personnel play a large role in the world health care system, with both negative and positive effects. The ‘brain drain’ of well-educated, skilled health care workers is a serious problem for many developing countries and for the emerging market economies. On the other hand, the intellectual and professional contributions of research and health care providers from these countries are vital elements in the health care systems of many developed countries, and many of those trained there bring home skills and knowledge vitally needed by their countries of origin. The personal and electronic sharing of medical information pervades medical practice. Few large clinical or research conferences are without attendees from many countries, and more and more medical information is available globally through the internet. In addition to facilitating direct communication among researchers, the internet gives easy access to specialist consultations, online journals, and medical indexes. The concept of routine

The medical community is becoming more and more aware of these developments in international health. A 1997 report by the United States Institute of Medicine called upon Congress to appoint an interagency task force on global health to coordinate efforts in international health, and to pay its debts to the United Nations and the World Health Organisation [36]. The Lancet recently published a prominent series of articles devoted to international health [1,37,38]. Because neuropsychiatric disease is responsible for 14% of productive years of life lost due to ill health globally, and with international influences becoming more powerful each year, neurologists must stay informed about international neurology as well as local health problems [33]. The World Federation of Neurology is active in strengthening meaningful international contacts between neurologists, focusing attention on important or neglected neurological disorders, and encouraging neurologists to increase their involvement in educating non-neurologists. Out-spoken, well-informed neurologists can be powerful advocates for health-promoting choices in environmental management, economic choices, and public health policy.

D.C. Bergen / Journal of the Neurological Sciences 165 (1999) 101 – 105

References [1] Walt G. Globalisation of international health. Lancet 1998;351:434– 7. [2] Johnson RT. Emerging viral infections. Arch Neurol 1996;53:18– 22. [3] Wilson ME. Travel and the emergence of infectious diseases. Emerg Infect Dis 1995;1:39–46. [4] Cetron MS, Chitsulo L, Sullivan JJ, Pilcher J, Wilson M, Noh J, Tsand VC, Hightower AW, Addiss DG. Schistosomiasis in Lake Malawi. Lancet 1996;348:1274–5. [5] Smacchia C, Parolin A, DiPerri G, Vento S, Concia E. Syphilis in prostitutes from Eastern Europe. Lancet 1998;351:572. [6] Vitek CR, Redd SC, Redd SB, Hadler SC. Trends in importation of measles to the United States, 1985–1994. J Am Med Assoc 1997;277:1952–6. [7] Luber PLF, McKenna MT, Binkin JN, Onorato IM, Castro KG. Long-term risk of tuberculosis among foreign-born persons in the United States. J Am Med Assoc 1997;278:304–7. [8] Goldsmith MS. Health woes grow in shrinking world. J Am Med Assoc 1998;279:569–71. [9] World Health Report 1998. Life in the 21st century, a vision for all. Geneva: WHO, 1998;45:93. [10] Progress toward poliomyelitis eradication — India. Morb Mortal Weekly 1996;45:370–3. [11] Pablos-Mendez A, Raviglione MC, Laszlo A, Binkin N, Rieder HL, Bustreo F, Cohn DL, Lambregts-VanWeezenbeek CSB, Kim SJ, Chaulet P, Nunn P. for the World Health Organization–International Union Against Tuberculosis and Lung Disease Working Group on Anti-Tuberculosis Drug Resistance Surveillance. Global surveillance for antituberculosis-drug resistance, 1994–1997. N Engl J Med 1998;338:1641–91. [12] Bennet J. President wants FDA to regulate foreign produce. New York Times 1997:1, 3 October. [13] Will RG, Ironside JW, Zeidler M, Cousens SN, Estibeiro K, Alperovitch A et al. A new variant of Creutzfeldt-Jacob disease in the UK. Lancet 1996;347:921–5. [14] Johnson RT, Gibbs Jr CJ. Creutzfeldt-Jakob disease and related transmissible spongiform encephalopathies. N Engl J Med 1998;339:1994–2004. [15] Wickham EA. Potential transmission of BSE via medicinal products. Br Med J 1996;312:988–9. [16] Bradbury J. European infectious diseases centre takes shape. Lancet 1998;352:969. [17] Baverstock K. Chernobyl and public health. Br Med J 1998;316:952–3. [18] Jacobson JL, Jacobson SW. Intellectual impairments in children exposed to polychlorinated biphenyls in utero. N Engl J Med 1996;335:783–9. [19] Kyoto agreement on greenhouse gases receives mixed response. Br Med J 1998;316:7.

105

[20] World Health Report 1997. Conquering suffering, enriching humanity. Geneva: WHO, 1997:15. [21] Burgos JJ. Global climate change in the distribution of some pathogenic complexes. Entomologia y vectores 1994;1:69–82. [22] McMichael A, Haines A. Global climate change: the potential effects on health. Br Med J 1997;315:805–9. [23] Epidemic malaria transmission — Armenia, 1997. J Am Med Assoc 1998;280:689. [24] Reeves WD, Hardy JL, Reisen WK, Milby MM. The potential effect of global warming on mosquito-borne arboviruses. J Med Entomol 1994;31:323–32. [25] Reisen WK, Meyer RP, Presser SB, Hardy JL. Effects of temperature on the transmission of Western Equine encephalomyelitis and St Louis encephalitis viruses by Culex tarsalis (Diptera: Culicidae). J Med Entomol 1993;30:151–60. [26] Houghton T, Meira Filho LG, Callander BA, Harris N, Kattenberg A, Maskell K, editors, Climate change, 1995 — the science of climate change: contribution of Working Group I to the second assessment report of the Intergovernmental Panel on Climate Change, New York: Cambridge University Press, 1996. [27] Climate Change Impacts Review Group. The potential effects of climate change in the United Kingdom. Second report. London: HMSO, 1996. [28] Hurt RD. Smoking in Russia: what do Stalin and Western tobacco companies have in common? Mayo Clin Proc 1995;70:1007–11. [29] Peto R. Tobacco — the growing epidemic in China. J Am Med Assoc 1996;265:1683–4. [30] Warner KE. Tobacco taxation as health policy in the third world. Am J Public Health 1990;80:529–31. [31] Frenk J, Sepulveda S, Gomez-Dantes O, McGuinness MJ, Knaul F. The new world order and international health. Br Med J 1997;314:1404–7. [32] Sidel VW. The international arms trade and its impact on health. Br Med J 1995;311:1677–80. [33] Murray CJL, Lopez AD. In: The global burden of disease, Boston: Harvard University Press, 1996, pp. 352–60. [34] Pedley TA, Kale R. Epilepsy information for developing countries: the role of Epilepsia Digest. Epilepsia 1998;39:455–7. [35] International Committee on Harmonisation Secretariat. ICH Harmonised Tripartite Guideline for Good Clinical Practice. Brookwood, Surrey: Brookwood Medical Publications, 1996. [36] Self-interest case for US global health cooperation. Lancet 1997;349:1037. [37] Howson CP, Fineberg HV, Bloom BR. The pursuit of global health: the relevance of engagement for developed countries. Lancet 1998;351:586–90. [38] Jamison DT, Frenk J, Knaul F. International collective action in health: objectives, functions, and rationale. Lancet 1998;351:514–7.