SAQs - esp public health/IPC etc Flashcards
Define emerging disease and why they are important
An emerging disease is one that has appeared in a population for the first time, or that may have existed previously but is rapidly increasing in incidence or geographic range
(World Health Organization)
Importance: lack of awareness - transmission/pathogenicity/mortality etc, lack of diagnostics, lack of treatments,
Define NTDs and why they are important
Neglected tropical diseases (NTDs) are a group of twenty-one different diseases and infections that affect 1.65 billion
Tend to thrive in warm climates and in rural, poverty-stricken areas where access to clean water and healthcare is limited.
Why important: Can cause significant disfigurement, disability, and death. list are diseases which have broad control so can be controlled with effort.
What is eradication, elimination and extinction?
Elimination of infection: reduction to zero incidence of infection caused by a specific agent in a defined geographic area; Eradication: permanent reduction to zero worldwide incidence of infection caused by a specific agent; Extinction: the specific agent no longer exists in nature or the laboratory.
What criteria are used to decide if an infectious disease can be eradicated?
Is an effective intervention available to interrupt transmission? A technically feasible intervention must have been field-tested and found to be effective (2 marks)
Surveillance: Are practical diagnostic tools of sufficient sensitivity and specificity to detect levels of infection that can lead to transmission widely available? (2 marks)
Is there an animal reservoir? (2 marks)
Is there political commitment, and are funds available to support the eradication programme? (2 marks)
Describe the polio eradication efforts
- Activities required (4 marks)
The target is global eradication, to be achieved by vaccination with oral vaccine. This will include routine immunisation of children, supplementary “catch-up” immunisation and targeted “mop up” campaigns (2 marks)
Surveillance involves identifying cases of flaccid paralysis and collecting stool samples from them for virological confirmation. (2 marks) - Progress towards eradication (2 marks)
Huge progress has been made. Polio has been eliminated from the Americas and Europe and from all but a handful of countries, with ongoing transmission in only 4 countries in 2013 and a total of only about 400 cases reported annually in 2013 and 2014 - Challenges remaining (6 marks)
Problems with vaccine coverage in conflict situations. In 2013 the only cases were reported from Somalia, Pakistan, Syria and Northern Nigeria, and in 2014 cases were reported in neighbouring countries. It will be very difficult to achieve global eradication while these conflicts continue (2 marks)
Community mobilisation: the anti-vaccine lobby has been active in some countries (2 marks)
Some cases are due to reversion to virulence of attenuated vaccine strains – in other words they are caused by the vaccine. Some countries have switched to the killed vaccine to avoid this, but it is more expensive and has to be given parenterally (2)
Briefly describe currently available malaria control measures, including the limitations of different interventions, focusing on vector control and chemotherapy
Available control measures (10 marks)
Insecticide treated bednets (2 marks)
Limitations – insecticide resistance, distribution challenges e.g. need to replace old nets and maintain high distribution/coverage (2 marks)
Indoor residual spraying (2 marks)
Limitations – cost, logistics, insecticide resistance
ACT-based treatment (2 marks)
Limitations – cost (in private sector), resistance to artemesinins and companion drugs
Intermittent preventive treatment (up to 4 marks)
IPTp-SP – SP resistance and poor coverage due to weak antenatal health systems
IPT in infants – SP resistance and coverage
Seasonal malaria chemoprevention
Additional control measures e.g. larval source management, or vaccines (up to 2 marks)
As malaria control interventions are scaled-up in high transmission areas, and transmission is reduced, what consequences might occur? Describe how the epidemiology and clinical spectrum of malaria might change, and reasons for such changes (10 marks).
Changing epidemiology (10 marks)
Epidemiology of malaria varies with transmission intensity, and the clinical spectrum of disease varies with the level of transmission, age, and level of acquired immunity
In high transmission areas, young children are at highest risk, and severe anemia dominates, while in lower transmission areas, all age groups are susceptible to severe malaria, and cerebral malaria is more common
As transmission falls, initially the burden of malaria will decrease, but after some time, decreased exposure to parasites may result in a less immune population with the epidemiology shifting to resemble a lower transmission setting
Other potential consequences might include increase in imported malaria, increase in P. vivax malaria, clustering of cases geographically or in sub-populations, and changes in at-risk populations.
What is a PHEIC?
Public health emergency of international concern -> an extraordinary event which is determined to constitute a public health risk to other States through the international spread of disease and to potentially require a coordinated international response”, formulated when a situation arises that is “serious, sudden, unusual, or unexpected”
What does declaring a PHEIC mean?
PHEIC is a formal designation, giving a special status for an emergency caused by an infectious disease outbreak from the World Health Organization (WHO), tied to international law through the International Health Regulations (IHR).
IHR define what countries are supposed to do to prevent, prepare for, and respond to infectious disease emergencies or other public health events across borders.
A PHEIC is the strongest global alert the WHO can formally make and, when it is declared, countries have a legal duty to respond quickly, whereas with a pandemic there is no infrastructure around the decision-making process, agreed criteria, or agreement of what countries need to do in response.
Why were the outbreaks of SARS and Covid-19 different?
SARS causes much more severe illness than C-19 therefore easier to identify and isolate cases
Infectivity of SARS occurs once severe symptoms start. Infectivity of C-19 starts before symptoms occur
Basic reproduction number of C-19»_space; SARS
What is the definition of ‘containment’ in infectious diseases?
All chains of transmission have been interrupted
What is the difference between basic and effective R0?
Basic - average number of infected cases in naive cases
Effective - actual number of cases given increasing immunity or counter measures
What are the 10 priorities in a humanitarian emergency?
Ten priorities:
● Rapid initial assessment
● Measles and other vaccines
● Water and sanitation
● Food and nutrition programs
● Shelters and site planning
● Curative activities
● Control of communicable diseases and epidemics
● Surveillance
● Human resources and training
● Coordination
Five generic principles of public health interventions for preventing an infectious disease…
Education
WASH
Personal measures: repellant, clothing, nets
Vector control
Vaccines or PrEP
Surveillance + contact tracing
How to calculate fluids for a sick child?
Estimate weight:
Children 1-4 years: weight (kg) = 2 × (age + 5)
Children 5-14 years: weight (kg) = 4 × age
Three types:
Resus (i.e. shocked)
standard bolus of 10 mL/kg over <10 minutes
Replacement (i.e. dehydrated)
Fluid deficit (mL) = % dehydration x weight (kg) x 10ml
Maintenance (normal requirement) - Holliday-Segar formula:
100 ml/kg/day for the first 10kg of weight
50 ml/kg/day for the next 10kg of weight
20 ml/kg/day for weight over 20kg
