KA 3: The transmission and control of infectious diseases (a) Transmission and Control (b) Epidemiological Studies

By the end of this section you will be able to ….. KA 3a: The transmission and control of infectious diseases By the end of this section you will be able to ….. Name 5 types of pathogen Name a disease caused by each type of pathogen Name 6 methods infectious diseases can be transmitted from person to person Name 5 methods that can be used to control the transmission of infectious diseases Describe both the individual and community responsibility of controlling transmission of infectious diseases Infectious diseases caused by pathogens, transmitted by direct physical contact, water, food, body fluids, inhaled air or vector organisms and controlled by quarantine, antisepsis, individual responsibility (good hygiene, care in sexual health and appropriate storage/handling of food), community responsibility (quality water supply, safe food webs and appropriate waste disposal systems) and vector control. Due to its role in maintaining health and combating infectious diseases on a global level, the immune system is at the centre of much of the research in public health. Infectious diseases are caused by pathogens such as viruses, bacteria, fungi, protozoa and multicellular parasites (b) Epidemiological studies of infectious diseases. Description of spread to include sporadic (occasional occurrence), endemic (regular cases occurring in an area), epidemic (unusually high number of cases in an area) or pandemic (a global epidemic). Control measures to include preventing transmission, drug therapy, immunisation or a combination of these. Epidemiologists study the outbreak and pattern of infectious diseases to determine the factors which affect the spread of infectious disease. Based on epidemiological studies control measures can be considered.

What is an infectious disease? An infectious disease is one that is capable of being transmitted (spread) from one person to another.

Causes of Infectious Diseases Pathogens! Infectious diseases are caused by many types of pathogen. Examples of pathogens include: Bacteria Viruses Fungi Protozoa Multicellular Parasites

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Human diseases caused by this type of pathogen Description Human diseases caused by this type of pathogen BACTERIA Single celled organisms without a nucleus tuberculosis, diphtheria, typhoid, cholera, tetanus, dysentery and pneumonia VIRUSES Non-living particles that can only reproduce within a living cell Common cold, herpes, measles, AIDS, chicken pox, small pox FUNGI Simple organisms including mushrooms and yeasts that grow as single cells or thread like filaments Ringworm, athletes foot, candidiasis, histoplasmosis PROTOZOA Single celled organisms with a nucleus Malaria, giardiasis, chagas disease, sleeping sickness, leishmaniasis MULTI- CELLULAR PARASITES Living organism, that can live inside intestinal tract or blood stream Round worm infections, tape worm infections

Think / pair / share What is meant by transmission? Choose one disease from each row in your table and describe how it could have been transmitted

Smallpox

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Malaria

Rabies

Transmission of infectious diseases The spread of microbes and infection is also known as… TRANSMISSION! Transmission by inhaled air Coughing Sneezing Breathing Transmission by food Eating undercooked food Transmission by water Drinking dirty or contaminated water

Transmission of infectious diseases Transmission by vector organisms A bite from an infected animal Transmission by direct physical contact Touch Transmission by body fluids Sexual contact Blood transfusion

Transmission of Infectious Diseases The spread of pathogens and infection is also known as TRANSMISSION! Transmission can occur by: Inhaled air Food Water Vector organisms (carry and transmit a pathogen into another organism) Direct physical contact Body fluids

How can we control the transmission of infectious diseases? Direct physical contact Water Food Body fluids Inhaled air Vector organisms Appropriate storage and handling of food Quarantine Good hygiene Care in sexual health Appropriate waste disposal systems Quality water supply Safe food webs Control of vectors Antisepsis

Which 3 control methods would be an individual's responsibility? Which 3 control methods would be a communities responsibility? Appropriate storage and handling of food Appropriate storage and handling of food Quarantine Good hygiene Good hygiene Care in sexual health Care in sexual health Appropriate waste disposal systems Appropriate waste disposal systems Quality water supply Quality water supply Safe food webs Safe food webs Control of vectors Antisepsis

Control of Infectious Diseases Quarantine Antisepsis The use of antiseptics to eliminate pathogens Individual responsibility good hygiene care in sexual health appropriate storage/handling of food Community responsibility quality water supply safe food webs appropriate waste disposal systems The control of vectors

Can you now …. Name 5 types of pathogen Name a disease caused by each type of pathogen Name 6 methods infectious diseases can be transmitted from person to person Name 5 methods the transmission of infectious diseases can be controlled Describe both the individual and community responsibility of controlling transmission of infectious diseases

By the end of this section you will be able to ….. KA 3b: Epidemiological studies of infectious diseases By the end of this section you will be able to ….. Describe the role of epidemiologists Describe 3 possible control measures that can be considered State what is meant by sporadic, endemic, epidemic and pandemic Infectious diseases caused by pathogens, transmitted by direct physical contact, water, food, body fluids, inhaled air or vector organisms and controlled by quarantine, antisepsis, individual responsibility (good hygiene, care in sexual health and appropriate storage/handling of food), community responsibility (quality water supply, safe food webs and appropriate waste disposal systems) and vector control. Due to its role in maintaining health and combating infectious diseases on a global level, the immune system is at the centre of much of the research in public health. Infectious diseases are caused by pathogens such as viruses, bacteria, fungi, protozoa and multicellular parasites (b) Epidemiological studies of infectious diseases. Description of spread to include sporadic (occasional occurrence), endemic (regular cases occurring in an area), epidemic (unusually high number of cases in an area) or pandemic (a global epidemic). Control measures to include preventing transmission, drug therapy, immunisation or a combination of these. Epidemiologists study the outbreak and pattern of infectious diseases to determine the factors which affect the spread of infectious disease. Based on epidemiological studies control measures can be considered.

What is Epidemiology? Epidemiology is the study of patterns of health, illness and associated factors at the population level. Epidemiologists study the outbreak and pattern of infectious diseases to determine the factors that affect the spread of infectious disease.

Control measures Based on the results of their studies, epidemiologists can identify and consider a number of possible control measures to prevent further spread of infectious disease. Their recommendations may include: Preventing transmission (from person to person and region to region) Drug therapy (for those already infected) Immunisation (for people not yet infected) Or a combination of the above. Based on epidemiological studies control measures can be considered

Newspaper headlines Experts may be poised to declare swine flu epidemic. Search for vaccine speeds up as swine flu is declared pandemic. World Health Organization may declare an end to endemic as swine flu fizzles.

Confused? Epidemic? Endemic? Pandemic? Sporadic? Watch the BBC news report to view the look-back on the 2009 health scare on Swine Flu Which key words are used to describe the health scare? http://www.bbc.co.uk/news/10483218

The spread of infectious disease are classified as… Epidemic Endemic Pandemic Sporadic Occasional occurrence Regular cases occurring in area Unusually high number of cases in area A global epidemic Match them up!

Classification of spread patterns of disease Spread pattern of disease Description Sporadic Occasional occurrence Endemic Regular cases occurring in area Epidemic Unusually high number of cases in area Pandemic A global epidemic

Ebola was first identified in 1976 and occurs in regions of sub-Saharan Africa. There are normally fewer than 500 cases reported each year No cases were reported at all between 1979 and 1994. Between 1994 – 2014: see graph

Ebola Stats Most recent deaths: January 2016 (1 – Sierra Leone Dec 2013 - 2 year old dies of unidentified haemorrhagic fever, followed by mother, sister and grandmother (Guinea) March 2014 – first confirmed case (Guinea) 59 dead March 2014 – March 2016: 28,639 cases and 11,316 dead Most recent deaths: January 2016 (1 – Sierra Leone & 3 – Liberia) Confirmed in: Liberia – End of March Sierra Leone – May

Ebola outbreak – how would you describe it?

Ebola outbreak – how would you describe it?

Ebola outbreak – how would you describe it? Death rate 47% Liberia was reporting between 300 and 400 new cases every week.

Ebola outbreak – how would you describe it? Death rate 70%

Ebola outbreak – how would you describe it?

Ebola outbreak – how would you describe it?

Ebola outbreak – how would you describe it?

Summary video (Aug 2014 stats)

Tasks – 15 minutes Complete the PS activity about Swine Flu in Scotland

Answers 1. (bar graph) 2. Which region had the highest number of cases? Edinburgh and the Lothians 3. Which region had the lowest number of cases? Outer and Inner Hebrides 4. What percentages of cases were found in: Angus and Dundee? 9% Fife? 11.5% The Scottish Borders? 4.2% 5. During the next week the number of reported cases in Perthshire decreased by 20%. How many cases were reported? 24 6. Why do you think areas such as Glasgow and Clyde Valley had a higher number of cases than the Highlands? Higher population living in smaller area – much easier for disease to spread. 7. The actual number of swine flu cases is thought to be much higher than what was reported. Suggest a reason for this. Many people didn’t go to the doctor or report their illness.

Can you now …. Describe the role of epidemiologists Describe 3 possible control measures that can be considered State what is meant by sporadic, endemic, epidemic and pandemic

Quick Questions 1. For each statement below, classify them using the correct term: An average of 34 deaths in the space of 5 years Continued diagnosis of infectious people in a city Unexpected number of people diagnosed with an infectious disease in a local town Continued diagnosis of infectious people in a country 2. Give the definition of the missing term that has not been used! sporadic endemic epidemic endemic Pandemic-worldwide epidemic

Extended Answer Question Describe the causes and transmission of infectious diseases and the methods that can be used to control these diseases (8 marks)

1. Infectious diseases are caused by pathogens. 2 1. Infectious diseases are caused by pathogens. 2. Pathogens can be bacteria and viruses. 3. Two other examples of pathogens e.g. fungi, protozoa, (multicellular) parasites. 4. A specific example of a disease and its causative organism. 5. Transmission of the disease can be by physical contact, food, water, body fluids, 6. air or vector organisms. (1 mark for 3 or 4, 2 marks for 5) 7. A specific example of a disease and its means of transmission. 8. Control of transmission can be by quarantine / antisepsis / control of vectors . 9. Individual responsibility for control of transmission through good hygiene / safe food handling / care in sexual health. 10. Community responsibility for control of transmission through having a quality water supply / safe food webs / appropriate waste disposal. 11. Epidemiology looks at factors which affect the spread of diseases. 12. Diseases can be controlled by drugs / immunisation. 8 marks

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