Introduction to environmental health and hygiene

• Hygiene is the conditions or practices that maintain health and prevent disease, especially through cleanliness.
• Hygiene is a main prophylactic branch of medicine. It studies the causes and effects that violate the normal physiological life of humans and seeks ways to eliminate or weaken them.
• Environmental health draws on five basic disciplines: environmental epidemiology, toxicology, exposure science, environmental engineering and environmental law.
• Hygiene has six main branches: general hygiene, community hygiene, nutritional hygiene, occupational medicine, childhood and adolescent hygiene, and ionising radiation hygiene.
• Medical ecology is the science that defines the aspects of the environment with a direct bearing on human health.
• Humans adapt to the environment genetically, physiologically and socially.
• Humans damage biological systems by degrading the environment, and pollutants can be carried through the environment biologically or physically.

This topic introduces the field of environmental health, which concerns how the environment affects human health. It is one of the main areas that hygiene covers, and it sits alongside the other disciplines in this course.

Health and hygiene

Health is the science, practice and study of human wellbeing, of keeping people healthy and preventing illnesses and human injuries.

Hygiene is the conditions or practices that are conducive to maintaining health and preventing disease, especially through cleanliness.

Hygiene is also the medical knowledge that studies the causes and effects that violate the normal physiological life of humans, and seeks the means for their elimination or weakening. This is the point at which hygiene becomes a branch of medicine, covered in section 2.

The five basic disciplines of environmental health

The five disciplines that contribute to environmental health are:

• Environmental epidemiology
• Toxicology
• Exposure science
• Environmental engineering
• Environmental law

Hygiene is one of the main prophylactic branches of medicine. Prophylaxis means preventing disease rather than treating it after it has appeared.

Aim of hygiene

Hygiene studies how causes and effects disturb normal physiological life, and it looks for means to deal with them. The work follows three steps, and its aim is set out in the diagram.

The aim is to maintain health and prevent disease. Conditions and practices that support health are the subject of the field.

The six main branches of hygiene

Hygiene is divided into six main branches. Each covers its own subjects.

Medical ecology is an emerging science. It defines those aspects of the environment that have a direct bearing on human health.

Human adaptation and the environment

Medical ecology looks at how people adapt to their surroundings. The adaptation can be:

• Genetic, carried in inherited characteristics
• Physiological, in the way the body functions
• Social, in the way people live and organise themselves

Humans and the environment

Humans contribute to the destruction of biological systems through the degradation of the environment. Pollutants can be transported through the environment, either biologically or physically. For this reason medical ecology pays attention to the environment as a whole, not only to the places where people live.

The terms in this topic are summarised below.