iNF DISEASE BURDEN

Question 1

What is burden of disease? What factors affect burden of disease? What are DALYS?YLL?YLD?

Answer 1

Global Burden of Disease: The Who, What, Where, and How Bad of Disease in Populations

Burden of disease: the total human impact of fatal and non-fatal disease in a population

• Mortality → estimating the fatal burden of disease
• Morbidity → estimating the non-fatal burden of disease

Global Burden of Disease (GBD): picture of mortality and morbidity across different countries, time, age, and sex.

• Started in 1990, seven surveys conducted in past 30 years – latest in 2021
• Gathers data on 350+ diseases across 195 countries
• Quantifies health loss from disease, injuries, and risk factors so health systems can be improved and health inequities eliminated
• (ngo funded by B and M Gates, not peer reviewed)

Special Measures for the Global Burden of Disease Study

• Years Lived with Disability (YLDs): healthy years lost due to ill health
  
  • Measure of the non-fatal burden of disease
• Years of life lost (YLLs): years lost due to premature death
  
  • Measure of the fatal burden of disease
• Disability Adjusted Life Years (DALYs): healthy life lost due to premature death or living with disability
  
  • Total sum of YLL and YLD
  • 1 DALY = 1 year of healthy life lost
• Quality Adjusted Life Years (QALYs): measure of how well a health intervention will improve quality of life
  
  • Used in health economics
  • 1 QALY = 1 year of quality life gained

Key Trends in Global Burden of Disease

• The global burden of infectious disease has been declining since 1990 and chronic disease is increasing as the leading cause of disease burden worldwide.
  
  • e.g. respiratory diseases topped by cardiovascular and cancer
  • i.e. composition has changed
  • nb in 2021 COVD accounted for ~7% of GBoD
• Life expectancy declined in 84% of countries during the first two years of the COVID-19 pandemic.
  
  • increased in Australia

Age geography and economic status
- Age Correlation with Global Burden of Infectious Disease
- overall trend is stable as usually causes are congenital +/- few interventions available
- at <5 infectious diseases tend to predominate
- Infectious disease continues to be a leading cause of childhood morbidity and mortality.
- In 2021, 340,430 children between 0-5 years died from diarrheal diseases.

Geographic and Economic Disparities

• The **global burden of infectious disease is unequitable distributed geographically and correlates with economic status.
• Health systems in low-and-middle-income countries are facing **a ‘double burden’ – increasing burden of chronic disease and continuing high burden of infectious disease.
  
  • with limited resources very difficult to tackle both

Question 2

Describe burden of infectious disease in Australia

Answer 2

Trends in Australia

• Over the last 30 years, infectious disease has represented ~2-3% of total disease burden in Australia.
• Cancers are top, CVD decreasing due to better detection
• slight uptick in resp infections contribution possibly due to COVID
• Notifiable infectious disease:
  
  • Diseases that have been identified to present a risk to public health if there is an outbreak.
  • Each case of notifiable diseases must be reported to state/territory health departments.
• Non-Notifiable infectious disease:
  
  • Not routinely monitored.
  • Data collected from hospital presentations or mortality reports.
    Note: in general fatal burden outweighs non-fatal burden due to lack of routine monitoring and patient presentation. Similar case for ‘more severe’ notifiable infectious disease.
• The major source of fatal and non-fatal burden of infectious disease in Australia is from lower-respiratory tract infections.

Socioeconomic and Geographic Distribution
Australia shows inequitable distribution of infectious disease burden
- Socio-economically: highest burden in the lowest socio-economic sectors.
- Geographically: highest burden in the Northern Territory and in remote and very remote regions.

Inequitable burden on Indigenous Australian populations
* Burden of infectious disease in Indigenous
Australian populations decreased by 36%
(2013 – 2018)
* Mainly by reduction in fatal burden
from LRTIs
* However, burden of non-fatal
infectious disease has remained
relatively stable
* Inequitable burden of infectious disease
affecting Indigenous Australian populations
occurs across multiple categories of
infectious disease

Burden of infectious disease contributes to and compounds inequitable burden on chronic disease in Indigenous populations
* Recurrent infections can increase the risk
of developing chronic conditions
* Skin infections and scabies → chronic
kidney disease and cardiac failure
* Pyelonephritis → chronic kidney disease
* Otitis media → hearing impairment
* STIs → infertility, birth complications
* LRTIs → chronic suppurative lung disease
(CSLD)

Question 3

Describe deficit discourse

Answer 3

‘Deficit discourse’ refers to disempowering patterns of
thought, language and practice that represent people
in terms of deficiencies and failures. It particularly
refers to discourse that places responsibility for
problems with the affected individuals or communities,
overlooking the larger socio-economic structures in
which they are embedded.

Rejecting deficit discourse is not about pretending that
Aboriginal and Torres Strait Islander people face no
challenges, nor about downplaying those challenges.
Discussion of socio-economic disadvantage, and
ways to alleviate it, is important and necessary.
Rather, discourses of deficit occur when discussion of
Aboriginal and Torres Strait Islander affairs is reduced
to a focus on failure and dysfunction, and Aboriginal
and Torres Strait Islander identity becomes defined
in negative terms, eclipsing the complex reasons for
inequalities, and overlooking diversity, capability and
strength.

Question 4

Describe why infectious disease burden is inequitable and how this can be addressed

Answer 4

Historical and Ongoing Context

• Historical context: Infectious disease burden was greatly impacted by European colonization, which brought new diseases to Indigenous populations.
• Ongoing context: Social determinants of health (housing, education, access to healthcare) continue to drive disparity in disease burden.

Examples of Infectious Diseases

• Acute Rheumatic Fever (ARF) and Rheumatic Heart Disease (RHD):
  
  • Indigenous Australians have some of the highest rates of ARF/RHD in the world.
• Trachoma:
  
  • Australia is the only high-income country where trachoma is still endemic, predominantly in Indigenous communities.
• Tuberculosis (TB):
  
  • Rates of TB are higher in Indigenous Australians compared to non-Indigenous Australians.
• Scabies and related bacterial infections:
  
  • High prevalence in Indigenous communities, leading to secondary bacterial infections and severe health consequences.

A focus on GAS
![[Pasted image 20240627193209.png]]
- before the introduction of antibiotics the sequelae of GAS were decreasing due to changes in living and environmental conditions e.g. improved SES, reduced household crowding, increased healthcare access
- while GAS is usually non-notifiable unless invasive, and data is harder to obtain, it is known that Australia has one of the highest recorded rates due to prevalence n Indigenous populations where it occurs almost exclusively, and is increasing

Prevention strategies
- primordial prevention: prevent transmission by controlling environmental risk factors
- issue on central Au: 28% no facilities to bathe children, 37% no facilities to wash clothes, 38% in NT overcrowded
- overcrowding, poor quality housing, limited access to washing facilities –> poor ventilation and smoke exposure which is a risk for transmission via respiratory droplets, and limited laundry, nutrition, scabies a risk for skin contact, directly or through clothes, towels, bedding
- RHD endgame strategy example of this, a holistic approach (housing, wash facilities and laundry, community based healthcare)
- primary: IM of LAB at time of presentation with GAS infection

• secondary: IM of LAB once a month for 10 years
  
  • 80% adherence required
  • this is tricky in areas of high staff turnover
  • moreover it is
    
    • very painful
    • given to young and well (may decide they do not need it)
    • requires close case management to build rapport and encourage adherence
    • requires specific knowledge to administer safely and record in state database
    • requires refrigeration

Question 5

List common notifiable conditions and explain how and when disease should be notified

Answer 5

Nine categories of notifiable infectious diseases
- bloodborne
- GIT
- STI
- vaccine preventable e.g measles mumps rubella polio
- respiratory
- vesctor borne e.g. malaria
- zoonoses e.g. rabies, Q, anthrax
- listed human e.g. avian fly, COVID, MERS, SARS
- other e.g. GAS, leprosy, CJD

note: recent change to top notifiable, no flu (covid), gonorrhea (unclear?) –> Covid top, and VZV/shingles in top four

Still campylobact and chlamydia

Notifiable Infectious Diseases and non-notifiables
**notifiable
- Definition: Diseases that must be reported to health authorities upon diagnosis.
- Purpose: Enable monitoring, control, and prevention of disease spread.
- Examples:
- Measles
- Tuberculosis
- HIV
- COVID-19

**### **Non-Notifiable Infectious Diseases

• Definition: Diseases that are not routinely monitored by health authorities.
• Examples:
  
  • Common cold

Note it can vary by region

State vs national notifiable diseases
Nationally notifiable disease list
* Adding a disease to the list requires changes to
legislation (unless in an emergency)
* Diseases are added to the national list to:
* monitor national trends,
* respond to outbreaks of national significance
* develop public health policy to reduce disease
State/territory notifiable diseases
* Most include diseases on the national list
* Some diseases are only notifiable in 1 or 2 locations