– also called conservation medicine, ecological medicine, or medical geology-
A In simple terms, environmental medicine deals with the interaction between human and animal health and the environment. It concerns the adverse reactions that people have on contact with or exposure to an environmental excitant . Ecological health is its primary concern, especially emerging infectious diseases and pathogens from insects, plants and vertebrate animals.
B Practitioners of environmental medicine work in teams involving many other specialists. As well as doctors, clinicians and medical researchers, there may be marine and climate biologists, toxicologists, veterinarians, geospatial and landscape analysts, even political scientists and economists. This is a very broad approach to the rather simple concept that there are causes for all illnesses, and that what we eat and drink or encounter in our surroundings has a direct impact on our health.
C Central to environmental medicine is the total load theory developed by the clinical ecologist Theron Randolph, who postulated that illness occurs when the body’s ability to detoxify environmental excitants has reached its capacity. His wide-ranging perception of what makes up those stimuli includes chemical, physical, biological and psychosocial factors. If a person with numerous and/or chronic exposures to environmental chemicals suffers a psychological upset, for example, this could overburden his immune system and result in actual physical illness. In other words, disease is the product of multiple factors.
D Another Randolph concept is that of individual susceptibility or the variability in the response of individuals to toxic agents. Individuals may be susceptible to any number of excitants but those exposed to the same risk factors do not necessarily develop the same disease, due in large part to genetic predisposition; however, age, gender, nutrition, emotional or physical stress, as well as the particular infectious agents or chemicals and intensity of exposure, all contribute.
E Adaptation is defined as the ability of an organism to adjust to gradually changing circumstances of its existence, to survive and be successful in a particular environment. Dr Randolph suggested that our bodies, designed for the Stone Age, have not quite caught up with the modern age and consequently, many people suffer diseases from maladaptation, or an inability to deal with some of the new substances that are now part of our environment. He asserted that this could cause exhaustion, irritability, depression, confusion and behavioural problems in children. Numerous traditional medical practitioners, however, are very sceptical of these assertions.
F Looking at the environment and health together is a way of making distant and nebulous notions, such as global warming, more immediate and important. Even a slight rise in temperature, which the world is already experiencing, has immediate effects. Mosquitoes can expand their range and feed on different migratory birds than usual, resulting in these birds transferring a disease into other countries. Suburban sprawl is seen as more than a socioeconomic problem for it brings an immediate imbalance to the rural ecosystem, increasing population density so people come into closer contact with disease-carrying rodents or other animals. Deforestation also displaces feral animals that may then infect domesticated animals, which enter the food chain and transmit the disease to people. These kinds of connections are fundamental to environmental medicine and the threat of zoonotic disease looms larger.
G Zoonoses, diseases of animals transmissible to humans, are a huge concern. Different types of pathogens, including bacteria, viruses, fungi and parasites, cause zoonoses. Every year, millions of people worldwide get sick because of foodborne bacteria such as salmonella and campylobacter, which cause fever, diarrhoea and abdominal pain. Tens of thousands of people die from the rabies virus after being bitten by rabid animals like dogs and bats. Viral zoonoses like avian influenza (bird flu), swine flu (H1N1 virus) and Ebola are on the increase with more frequent, often uncontainable, outbreaks. Some animals (particularly domestic pets) pass on fungal infections to humans. Parasitic infection usually occurs when people come into contact with food or water contaminated by animals that are infected with parasites like cryptosporidium, trichinella, or worms.
H As the human population of the planet increases, encroaching further on animal domains and causing ecological change, inter-professional cooperation is crucial to meet the challenges of dealing with the effects of climate change, emergent cross-species pathogens, rising toxicity in air, water and soil, and uncontrolled development and urbanisation. This can only happen if additional government funds are channelled into the study and practice of environmental medicine.
Reading Passage 2 has eight paragraphs, A–H.
Which paragraph contains the following information?
Write the correct letter, A–H, in boxes 14–19 on your answer sheet.
14 an explanation of how population expansion exposes humans to disease
15 the idea that each person can react differently to the same risk factors
16 types of disease-causing agents that move between species
17 examples of professionals working in the sphere of environmental medicine
18 a definition of environmental medicine
19 how ill health results from an accumulation of environmental stressors
Complete the sentences below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
Write your answers in boxes 20–26 on your answer sheet.
20 According to Dr Randolph, people get sick because of ……………….. – in other words, a failure to adjust to the modern environment.
21 Vague, far-off concepts like global warming are made more urgent when ……………….. are studied together.
22 Rising temperatures result in more widespread distribution of disease because some insects are able to ……………….. .
23 Large-scale removal of trees forces wildlife from their habitat and brings them into contact with ……………….. .
24 Uncontrollable ……………….. of zoonotic viruses are becoming more numerous.
25 Collaboration between many disciplines is needed to confront the problems of urban development, pollution, ……………….. and new pathogens.
26 Environmental medicine should receive more ……………….. to help it meet future demands.
21 environment and health/health and environment
22 expand their range
23 domesticated animals
25 climate change
26 (government) funds