everything

• stroke • Ischaemic heart disease • Unintentional injuries • Cancers • Chronic respiratory diseases • Diarrhoeal diseases • Respiratory infections • Neonatal conditions • Malaria • Intentional injuries

People are exposed to risk factors in their homes, work places and communities through: 1. Air pollution 2. Inadequate water sanitation 3. chemicals 4. radiation 5. community noise 6. occupational risk 7. agricultural practices 8. built environment 9. climate change

Children under 5 and adults between 50-75 are most affected by the environment

Physical well-being is: - an absence of disease of symptoms of the disease - a lack of risk factors that lead to disease - good physical health Mental well-being is: - a lack of mental illnesses - a capacity to deal effectively with the normal stresses and strains of life

A disorder of structure or function in an organism that produces specific symptoms or that affects a specific location and is not simply a direct result of physical injury.

• Pathogens • Genetics • Environmental factors • Idiopathic

Infectious: A disease caused by an organism or infective agent (pathogen) Non-infectious: A disease that is not caused by a pathogen, and with exception of inherited diseases, cannot be passed from one person to another

A disease-causing agent Cellular pathogens: - Bacteria - Fungi - Single-celled protozoa - Multicellular ectoparasites and endoparasites Non-cellular pathogens: - Viruses - Prions

Inherited diseases: 1. Cystic fibrosis 2. Huntington’s 3. Turner syndrome 4. Sickle cell anemia 5. Hemochromatosis 6. Muscular dystrophy 7. Hemophilia Increased risk factor for disease 1. Many cancers 2. Obesity 3. Diabetes 4. Heart disease

• Pathogens • Mould and fungi • Blood and bodily fluids • Sewage • Stinging insects • Plants • Animal and bird droppings

• Toxins • Pesticides • Cleaning substances • Petroleum products • Heavy metals (mercury, lead) • Particulate matter in the air

• Electricity • Noise • Heat or cold • Fire • Air pressure

• Destroying cells and tissues with enzymes. • Producing toxins that are harmful to the host. • Causing the initiation of a debilitating immune system response

Transmitted from one host to another when the skin of the two hosts come into contact. Reproduction of the pathogen in the skin often causes formation of fluid filled lesions containing millions of copies of the pathogen. These lesions are itchy, and scratching allows the spread of the pathogen. Examples: * Chickenpox * Impetigo * Cold sores

Body fluid are liquids that come from inside the body, including sweat, tears, vomit, nasal secretions, blood, saliva and urine. Pathogens that are transmitted in this way need to be able to survive outside of the body for substantial periods of time. Examples: * Glandular fever * HIV * HPV

Pathogen enters the body via the gastrointestinal tract via food. Pathogen may spread to the food via faeces from an infected person, or meats may be infected by bacteria from the animal’s intestinal tract. Examples: * Food poisoning – Salmonella, E. coli etc. * Rotavirus

Pathogen is spread via bodies of water. In many developing countries, sewage is can enter the waterways, which can lead to faecal-oral transmission of diseases. Examples: * Schistosoma * Typhoid * Cholera * Hepatitis A

Pathogen is spread via the air. Coughing or sneezing can release millions of microbes into the air in droplets of mucus or saliva. Some diseases promote this by causing excess nasal secretions. Examples: * Legionnaire’s disease * Measles * Mumps * Common cold and influenza * SARS * COVID-19

• Antibiotics • Antiseptics and disinfectants. • Antivirals, fungicides.

Disease transmission is not constant and will vary depending on the type of disease, the population and the time. Endemic diseases – a disease that occurs at a relatively constant rate in the population Epidemic diseases – a disease that is uncommon, occurs when there is a spike in cases in the population above what is considered to be normal

• Infectivity – How easily the pathogen can jump from host to host • Virulence – the capacity of the pathogen to cause severe disease in the host • How long the pathogen can persist in an asymptomatic host

• Available infrastructure • Climate • Density of the population • Proportion of the population immune to infection • Movement of individuals in the population

• Pandemic – global outbreak of a disease • Epidemic – widespread occurrence of an infectious disease in a community or in a restricted geographic area at a particular time • An epidemic can develop into a pandemic, but not vice versa

• Caused by the bacterium Yersinia pestis • Infects rodents • Transmitted between rodents and to humans by fleas