Growing disease problems

Infectious diseases are on the rise and now kill 17 million people a year, particularly young people in the developing world.  Rising levels of drug resistance are making them more difficult to treat (WHO, 1996a).  The concern over new viruses, started with HIV causing AIDS, has been reinforced as other emergent viral diseases have been reported, including Ebola, Hantavirus and Rift Valley Fever.  Growing drug resistance, new virulent strains, continuing poverty, the breakdown of public health measures, and increased human contact are leading to renewed outbreaks of other epidemic diseases (WRI/UNEP/UNDP/WB, 1996).  Travel and urbanization are increasing human vulnerability to epidemics of both old and emerging diseases (Maurice, 1993; Day, 1996).  There is also concern that climate change may have significant effects on health (WHO, 1996b).

Tuberculosis is now the world's single largest cause of death from a single agent, with one third of the population latently infected and 3.1 million deaths in 1995, up 13 percent from the previous year (WHO, 1996a).  At the rate TB is spreading, it could claim over 100 million lives over the next 50 years. The association of TB with the AIDS epidemic is one of the main reasons for the increase (Kochi, 1996).

There are presently about 300-500 million clinical cases of malaria a year, 90 percent in Africa, and malaria deaths rose 5 percent in 1995, killing 2.1 million people, mostly children (WHO, 1996a).  Global warming could cause another 50-80 million cases as disease-bearing mosquitoes move into new areas (Martin and Lefebvre, 1995; Pearce, 1995a; IPCC, 1995).

Food poisoning and food-borne diseases are also rising rapidly, even in the most developed countries.  The incidence in Europe tripled over the last decade, and in the US there may be 24-82 million cases and 10,000 needless deaths from food poisoning annually.  Increased environmental contamination, wider exchange of pathogens, and large-scale food processing and preparation are some causes implicated (Maurice, 1994).

Recent increases in solar ultraviolet (UV-B) radiation at ground level, related to stratospheric ozone depletion, are expected to augment adverse health effects such as skin cancer, eye cataracts and suppression of immune response.

While life expectancy has generally been increasing for decades, there has been a sharp reversal in recent years in some countries of Central and Eastern Europe and sub-Saharan Africa.  In Russia, life expectancy among men decreased from 65 years in 1987 to 57 in 1994.  Causes may include the stresses of economic transition, deteriorating health care, and possibly the toxic burden of decades of environmental contamination.  In Africa, the AIDS epidemic is expected to reduce average life expectancy by almost 8 years (WRI/UNEP/UNDP/WB, 1996).

Heavy use of antibiotics in people and animals, encouraged by commercial pressures, risks causing significant antibiotic contamination of the natural environment and consequent development of
resistance in communities of non-disease organisms.  Such contamination of microbial communities in septic tanks, sewers, soil, receiving waters and other environmental compartments could create a widespread pool of antibiotic-resistant microbes from which resistance could be transferred back into human and animal disease organisms.  The risk from widespread use of antibiotics as growth promoters in livestock is being widely debated (Coghlan, 1996; Bonner, 1997).  Antibiotic and other drug resistance is already a major issue in medicine, with significant health and economic impacts, as shown by the resurgence of tuberculosis and malaria, and multiple resistance is easily developed (LeBlanc et al. 1997)  What has not been appreciated is the potential of drugs as environmental pollutants to create new pools of resistance which, given the new evidence of genetic transfers across species, could accelerate the development of resistance in many disease organisms.  If new forms of resistance start to come not only from human treatments and hospital settings, but by inter-species transfers from the environment, the growing ineffectiveness of present forms of treatment and a revival of major epidemics is a distinct possibility.

Industrialized countries have the highest antibiotic use, and so could be the first to see the development of environmental pools of resistance.  However, with global travel and widespread commerce, drug resistance can be expected to spread steadily to all parts of the world.  Developing countries might thus suffer the worst consequences because of the poor state of their health services and their inability to pay for alternatives to cheap antibiotics.  Pharmaceutical companies should see that it is in their own interest to minimize drug use and pollution of the environment, since avoiding the spread of resistance will keep their medicines effective longer.

Research is urgently needed into the environmental impacts on natural microbial communities of heavy antibiotic and other drug use in medicine and agriculture/aquaculture.  The scenario is plausible, but the risks cannot be estimated because of insufficient understanding.  As a precautionary approach, the use of drugs/antibiotics should be reduced to the minimum necessary.  In addition, drugs could be developed that break down quickly in the environment; doctors could be assisted, perhaps by expert systems, to chose medicines and to adopt treatment regimes that minimize the risk of creating or spreading resistance; waste treatment facilities that destroy drugs before they contaminate the environment should be installed in hospitals and other settings where drug use is high; and national and international legislation could be considered to prevent or limit the spread of drug resistance.

Hormone disrupters - updated to 9 July 1999

While the environmental effects of persistent organic pollutants (POPs) such as halogenated hydrocarbon pesticides (DDT, dieldrin, etc.), furans, dioxins and PCBs have long been known (see POPs), there has been a growing body of recent evidence that some of them may mimic or inhibit hormones and interfere with natural regulatory processes even in extremely low doses.

Their effect on wildlife is well documented and includes the feminisation of male foetuses, reproductive dysfunctions, behavioural changes and developmental problems. Marine mammal and amphibian populations around the world have declined, possibly due to a lack in fertile males, or males full stop. Studies of alligators in Florida and of polar bears on the Svalbard archipelago found unusual numbers born with a set of partially developed male and female sexual organs, abnormally small genitals in males and a shift in sex ratios (see Declining sex ratios below). And in the Great Lakes, herring gull nests were found with double the normal number of eggs, which were unfertilised and tended by pairs of female birds, because the males had lost interest in mating and rearing young. (Colborn et al., 1996)

Their effects on humans seem to parallel those found in wildlife  and may include ovarian, breast, testicular and prostate cancers, reduced sperm counts in men (Auger et al, 1995; Kelce et al, 1995), depressed immunity, a rise in early puberty, and impaired foetal development leading possibly to smaller babies, reduced intelligence, hyperactivity and violence (Colborn et al, 1996; Mathews, 1996; Meadows, 1996; Repetto and Baliga, 1996).

Oestrogen-mimickers are found in a broad range of products, from pesticides to solvents and detergents, industrial chemicals or unintended byproducts of industrial processes. Once released into the environment, people are exposed to them in foods such as milk, soya beans, fish and animal fats, and in drinking water. There are pressures to ban the most dangerous chemicals.

Declining sex ratios - updated to 1 April 1998

There has been a statistically significant decline in the ratio of male to female births in several
industrialized countries, including Denmark, the Netherlands, Canada, and the United States, that cannot be attributed to known factors. Parallel declines have also been reported in Sweden, Germany, Norway and Finland.  Birth defects of the male reproductive tract and diseases such as testicular cancer have also increased in some industrialized countries, possibly associated with exposure to certain environmental compounds. The downward trends in sex ratio may not have a benign cause. Occupational and community exposures to pesticides and dioxin have been linked with declines in sex ratio in a number of studies. The reduction in the proportion of males born may be a sentinel health indicator that some, as yet, unrecognized environmental health hazards are affecting both sex ratio and the other unexplained defects in male reproduction (Davis, Gottlieb and Stampnitzky, 1998).

Chemical interactions

Almost nothing is understood about interactions between the many different chemicals to which we are exposed which could aggravate their effects.  A recent illustration of the potential dangers is the evidence that the Gulf War syndrome affecting many soldiers who served in that conflict might be due to some combination of chemicals such as a drug that protects against nerve gas and an insect repellent.  Research has demonstrated nerve damage by such combinations in laboratory animals (Institute of Medicine, 1995).

Air pollution and health

New studies have documented the importance for health of controlling air pollution.  In the United States, air pollution may be responsible for 50,000 deaths annually, more than 2% of all deaths (Thurston, 1995), and similar health risks have been reported from France (Le Tertre et al., 1994), the United Kingdom (Anderson, 1994; Bown, 1994) and elsewhere (Journal of Epidemiology and Community Health, 1996).  The self-inflicted air pollution from tobacco smoking now kills 3 million people a year world-wide, and this could rise to 10 million annually in four decades if present trends continue (Nakajima, 1995).

Noise pollution - updated 6 August 1999

Noise is an increasingly omnipresent, yet underestimated, form of pollution. Long periods of  exposure to relatively low levels of noise can have adverse effects on human health, such as raised blood pressure, hypertension, disrupted sleep and cognitive development in children (Kiernan, 1997b), diminished working memory span, and psychiatric disorders (Bond, 1996).
An estimated 80 million people suffer unacceptable levels of continuous outdoor transport noise within the EU (New Scientist, 1998). In Amsterdam, 29% of the city's inhabitants complain of noisy neighbours, 28% are regularly disturbed by the jarring sounds of traffic, and 26% suffer the dissonance that comes from living under the airport flight paths. In Great Britain survey results showed that for 7% of homes in Britain, noise levels outside the building were more than 68 dB (Bond, 1996). Even in the American national parks, it is estimated that noise-free intervals rarely exceed several minutes (Geary, 1996).

The World Health Organisation's guidelines recommend a nighttime average level of noise suitable for undisturbed sleep of from 35 to 30 dB, and include a peak nighttime maximum of 45 decibels. However, an OECD survey of traffic noise estimates that 16% of people in Europe suffer more than 40 dB in their bedrooms at night (Bond, 1996). In the United States, a conservation initiative has been established with the goal of creating sites where human-caused noise pollution will not be tolerated (Geary, 1996). Furthermore, every city in the European Union with more than 250,000 inhabitants will be required to draw up 'noise maps' of their streets by 2002 (New Scientist, 1998).  In the Netherlands, it is illegal to build houses in areas where 24-hour average noise levels exceed 50dB. And in Great Britain, the Noise Act gives local authorities powers to confiscate noisy equipment and to fine people who create excessive noise at night. Several countries are also investing in porous asphalt, which can cut traffic noise by up to 5dB.

Electromagnetic radiation - updated 6 August 1999

The debate over the effects of continued exposure to electromagnetic radiation remains unresolved after 30 years. The reports cited below suggest possible emerging problems, but the evidence remains inconclusive due to the inability of epidemiological studies to detect small effects and a lack of consistency in results in different laboratories on the same experiment.

It has been suggested that exposure to weak electromagnetic fields (EMFs) can disturb the production of the hormone melatonin by the pineal gland in the brain, eventually leading to an increase in the risk of breast cancer and degenerative diseases such as coronary artery disease, Parkinson's and Alzheimer's. Likewise, epidemiological and laboratory reports suggest that children exposed to EMFs from power lines are at greater risk of developing leukaemia, and that adults exposed to EMFs at work run a higher risk of leukaemia and brain cancer (Edwards, 1995a). There are more recent concerns that cellphone users are more likely to suffer from brain tumours (Day & Kleiner, 1999). Nevertheless, such reports lack adequate foundation and have yet to be confirmed.

Many physicists argue that there is no plausible mechanism by which low levels of non-ionising radiation could affect living tissue, as magnetic fields are thought to be harmless, and electric fields are thought to flow around, rather than through the human body. Epidemiologists, however, point to the dozens of studies that have found anywhere from a twofold to a tenfold increase in the risk of cancer among people routinely exposed to EMFs (Knight, 1997). It has been suggested that, while radon gas and powerful electromagnetic fields have separately been linked to cancer, these two environmental hazards can combine with extremely dangerous effects, and this link with radon may provide an answer (O'Brien, 1996).

There is other evidence that electromagnetic fields may have biological effects, including an increase in the rate of cell division. In the case of plants, it has been found that trees growing close to a giant 90 kilometre communications antenna in a Michigan forest have grown unusually quickly since the Navy moved into the forest in 1986. Forestry researchers attribute the extra growth to the electromagnetic field around the antenna. The health of the trees did not appear to be damaged (Kiernan, 1995). Furthermore, larvae exposed to an overnight dose of microwaves wriggled less and grew 5% faster than larvae that were not exposed, suggesting that the microwaves were speeding up cell division (Concar, 1999).

Anderson, Ross. 1994. Report for UK Department of Health, quoted in Bown, William. "Deaths linked to London smog." New Scientist, 25 June 1994, p. 4.

Auger, Jacques, J.M. Kunstmann, F. Czyglik and P. Jouannet. 1995. "Decline in semen quality among fertile men in Paris during the past 20 years." New England Journal of Medicine 332(5):281-285. 2 February 1995.

Bond, Michael. 1996. "Plagued by noise", New Scientist, 16 November 1996, p. 14-15.

Bonner, John. 1997. "Hooked on drugs." New Scientist, 18 January 1997, p. 24-27. (also letters commenting on this article in New Scientist, 22 February 1997, p.  51.)

Bown, William. 1994. "Dying from too much dust." New Scientist, 12 March 1994, p. 12-13.

Coghlan, Andy. 1996. "Animal antibiotics 'threaten hospital epidemics'." New Scientist, 27 July 1996, p. 7.

Colborn, Theo, Dianne Dumanoski, and John Peterson Myers.  1996.  Our Stolen Future.  Dutton, New York.

Concar, David. 1999. "Get your head around this". New Scientist 10 April 1999, p 20.

Davis, Devra L.,  Michelle B. Gottlieb, and Julie R. Stampnitzky. 1998. "Reduced Ratio of Male to Female Births in Several Industrial Countries: A Sentinel Health Indicator?". Journal of the American Medical Association, 1 April 1998.

Day, Michael. 1996. "Scourge of infections kills Third World's young", New Scientist, 25 May 1996, p.6.

Day, Michael, and Kurt  Kleiner. 1999. "Mixed Messages". New Scientist, 29 May 1999, p5.

Edwards, Rob. 1995a. "Leak links power lines to cancer". New Scientist, 7 October 1995, p 4.

Geary, James. 1996. "Saving the sounds of silence", New Scientist, 13 April 1996, p. 45.

Institute of Medicine (US). 1995. Committee to review the health consequences of service during the Persian Gulf War: Medical Follow-up Agency, Institute of Medicine. Health consequences of service during the Persian Gulf War: Initial Findings and Recommendations for Immediate Action. National Academy Press, Washington, D.C..

IPCC. 1995.  Climate Change 1995.  WMO/UNEP Intergovernmental Panel on Climate Change, Second Assessment Report.  Cambridge University Press, Cambridge.

Journal of Epidemiology and Community Health, 1996. Special issue, April 1996. Cited in "Death in the city" (15 European cities). New Scientist, 13 April 1996, p. 10.

Kelce, William R., C.R. Stone, S.C. Laws, L.E. Gray, J.A. Kemppainen and E.M. Wilson. 1995. Persistent DDT metabolite P,P'-DDE is a potent androgen receptor antagonist." Nature 375:581-585. 15 June 1995.

Kiernan, Vincent. 1995. "Forest grows tall on radio waves". New Scientist, 14 January 1995, p5.

Kiernan, Vincent. 1997b. "Noise pollution robs kids of language skills". New Scientist, 10 May 1997, p. 5.

Knight, Jonathan. 1997. "Power crazy".  New Scientist, 9 August 1997, p16.

Kochi, Arata. 1996. Kochi, Arata, director of WHO global TB programme, quoted in Spinney, Laura. "Global emergency as TB toll mounts".  New Scientist, 30 March 1996, p. 8.

LeBlanc, Donald et al. 1997. Antimicrobial Agents and Chemotherapy 41:1598.

Le Tertre, Alain et al. 1994. Regional Health Observatory for Paris, report, October 1994, cited in Patel, Tara. "Killer smog stalks the boulevards". New Scientist, 15 October 1994, p. 8.

Martin, Philippe H., and Myriam G. Lefebvre. 1995. "Malaria and climate - sensitivity of malaria potential transmission to climate." Ambio 24(4):200-207. June 1995.

Mathews, Jessica. 1996.  "Overlooking the 'POPs' Problem."  Washington Post, 11 March 1996.

Maurice, John. 1993. "Fever in the urban jungle". New Scientist, 16 October 1993, p. 25-29.

Maurice, John. 1994. "The rise and rise of food poisoning". New Scientist, 17 December 1994, p. 28-33.

Meadows, Donella H.  1996.  "Humans, an Endangered Species?"  International Herald Tribune, 24/25 February 1996.

Nakajima, Hiroshi. 1995. WHO appeal, 31 May 1995. Quoted in Evans, Robert. "U.N. blasts tobacco firms over smoking deaths." Reuter, 30 May 1995.

New Scientist. 1998. "Quiet please", New Scientist, 19 September 1998, p. 23.

O'Brien, Claire. 1996. "Are pylons and radon a lethal cocktail?" New Scientist, 17 February 1996, p 4.

Pearce, Fred. 1995a. "Global alert over malaria". New Scientist, 13 May 1995, p. 4-5.

Repetto, Robert, and Sanjay Baliga. 1996. Pesticides and the Immune System: The Public Health Risks. World Resources Institute, Washington, D.C.

Thurston, George. 1995. Paper presented at international conference of American Thoracic Society and American Lung Association, May 1995, cited in Reuter news release, 22 May 1995.

WHO. 1996a.  World Health Report 1996.  WHO, Geneva.

WHO. 1996b.  Climate Change and Health.  WHO, Geneva.

World Resources Institute/United Nations Environment Programme/United Nations Development Programme/World Bank. 1996. World Resources 1996-97.  Oxford University Press, New York and Oxford.