Lecture 30: Diarrhoeal diseases

Question 1

what are diahorreal diseases?

Answer 1

• symptom characterised by stolls of decreased consistency and increased number
• epidemiological studies show that 3 of more loose or watery stools during a 24-hour period and the episode is terminated when you are at least 2 days free of diarrhoea

Question 2

what is the impact of diarrhoeal diseases?

Answer 2

• it is the 2nd leading cause of death in children <5
• 525,000 children die from diarrhoeal diseases every year
• there is a risk of dehydration due to losing fluids

Question 3

what is the diarrhoea mortality rate in individuals of all ages?

Answer 3

madagascar 15 times mortality rate of NZ
countries like NZ aren’t affected, while others are greatly affected

Question 4

how have mortality rates changed between 2005 and 2015?

Answer 4

Appears to be increases in australia, NZ, north america and western europes

Mortality rates were low to begin with. Not signoficant if it doubles.

Could be due to screening and reporting in these more developed countries

Countries with high mortality rates already seem to be improving. But it is still a problem here

Question 5

what is the mortality rate of diarrhoea in children younger than 5?

Answer 5

Chad, mali, niger, cantral african republic has highest mortaluty rates in children

Question 6

what is the change in mortality rate in children under 5 between 2005 and 2015

Answer 6

countries have seen a slight decrease, but the rates are still very high

Question 7

what are control strategies for countries with high diarrhoeal mortality rates?

Answer 7

• mortality rates generally improving in areas that are most affected

control strategies:

• access to safe drinking water
• use of improved sanitation
• hand washing with soap
• exclusive breastfeeding for the first 6 months of life
• good personal and food hygiene
• health education about how infections spread
• rotavirus vaccination

Question 8

which infectious agents is diarrhoea associated with?

Answer 8

• bacteria
• viruses
• parasites

Question 9

what are examples of bacteria which cause diarrhoea?

Answer 9

• eschericha coli
• salmonella
• campylobacter
• listeria

Question 10

what are examples of viruses which cause diarrhoea?

Answer 10

• norovirus
• rotavirus
• hepatitis A
• adenovirus

Question 11

what are examples of parasites which cause diarrhoea?

Answer 11

• cryptosporidium
• glardia

Question 12

what are examples of bacterial gastrointestinal infections?

Answer 12

• campylobacteriosis
• shiga toxin producing E.coli (STEC) infection
• listeriosis
• salmonellosis

Question 13

what are examples of viral gastrointestinal infections?

Answer 13

• Rotavirus (leading cause of mortality in children)
• norovirus
• hepatitis A
• adenovirus

Question 14

what are examples of parasitic gastrointestinal infections?

Answer 14

• giardiasis
• cryptosporidiosis

Question 15

what is the source, symptoms, strain and transmission pathways for Shiga-Toxin producing E.Coli (STEC)?

Answer 15

• *Source**
• faecal matter of cattle, sheep, pigs, poultry and wild animals
• *Symptoms**
• severe stomach cramps
• diarrhoea - bloody
• vomiting
• fever
• infections vary from mild to life threatening
• most people get better in 5-7 days
• *Strain**
• E. Coli O157-H7 Strain
• is virulent
• 5-10% develop haemolytic uremic syndrome (HUS)
• mostly affect children under 5 and adults over 60
• affects the kidneys and blood blottong functions of infected people
• *Transmission pathways**
• foodborne (undercooked meet or unwashed lettuce and berries)
• waterborne (contaminated water)
• environmental (animal contacts without washing hands)
• person to person

Question 16

what happened with john snow?

Answer 16

in 1854, there was a cholera outbreak and over 600 people died

people believed that it was casued by a miasma (poisonous air)

but there were cesspools in close proximinitry to the homes which were contaminated in a shallow well

households received their water from pumps on streets. in this case, one water pump was contaminated with human feces from a child infected with cholera

john snow belived this was being transmitted by water consumption instead of air pullution

he found the water pump that was within walking distance to most of those people who died from cholera

He worked with the affected neighbouthood to establish this water pump was the link between infected individuals

A questionnaire ws used which is used even today in outbreak management scenarious

Asked about contact with animals, water consumption, exposure to water, travel, social events and contact with others

Question 17

what is the reporting pyramid?

Answer 17

most surveillance and notification systems are affected by a degree of underestimation