Disease And Disasters (PART 2) Flashcards
How do we monitor the effectiveness of control programmes?
- Estimate disease burden
- Identify risk groups
- Determine incidence trends over time
- Measure outcomes & impacts of preventive, treatment & public health interventions
• Evaluate the overall control interventions
What do you need to know when undertaking health programmes and disease control activities?
- Population makeup: Numbers, Ages! Sex ratios
- The health status of the population
- What diseases affect the population?
- Who might be affected?
- Any information about transmission (e.g. seasonal factors,
vectors) - What is the makeup, skills etc. of the health services?
- What health care facilities are available?
Define Epidemiology
The study of diseases in human populations in order to promote, protect & restore health
Define Disaster Epidemiology
The use of epidemiological methods to study and manage the public health aspects of disasters
Describe one epidemiological method to study and manage public health aspects of disasters
Time, Person & place
How can Time be used as an epidemiological method to study and manage public health aspects of disasters?
- When did the problem start?
- Is it still happening?
- If it has finished – when?
- What might have been happening at those times?
How can a person be used as an epidemiological method to study and manage public health aspects of disasters?
- Old?
- Young?
- Female?
- Male?
- Defined group?
- Characteristics?
How can a Place be used as an epidemiological method to study and manage public health aspects of disasters?
- By Finding out:
- Where is it happening?
- What are the characteristics of that place?
- How is the population distributed in that place?
How can numbers and rates be used as epidemiological methods?
- Number of cases: Assess needs for resources (Human & material). Can be misleading regarding disease situation
- Rates (Numbers per unit of population): Assess changes of disease levels in the population. Compare different locations. Used to calculate key indicators
List some small elements you need to be careful about with epidemiological methods
- Small datasets: Small changes can have big results
- Statistical significance: Is it statistically significant? If no then even if one dataset appears to differ from the other it does not mean that it is actually different
- See above #1 – you need a certain minimum size of sample for valid statistical analysis
List the key indicators of mortality #1
- Changes in mortality rates are often the first indicator of
health problems. - Crude Mortality Rate (CMR)
- The most important - indicates the severity of the problem: Changes in CMR show how a medical emergency is developing. Usually number of deaths / 10,000 persons / day
- CMR >1/10,000/day = acute emergency is developing
- The emergency phase lasts until the daily CMR falls to 1/10,000/day or below
List the key indicators of mortality #2
- Age-specific mortality rate - mortality rate for a specified age group.
- In children usually given as: No. deaths in <5y & >5y / 1,000 children of each age / day
- Cause specific death rates (case fatality rates)
- % of cases of a specified condition fatal within a specified time.
List the key indicators of mortality #3
- Maternal mortality rate: No. of mothers dying from puerperal causes within x days of giving birth / y births / z time
- Maternal death: the death of a woman whilst pregnant
or within 42 days* of the termination of the pregnancy,
from any cause related to the pregnancy or its
management. (* Can be 1 year) - A sensitive indicator of the effectiveness of health care
systems.
What is the incidence rate and Prevalence rate of Morbidity?
- Incidence Rate: The number of new cases during defined period of time
- Prevalence rate: The total number of cases in a population at a given time
List other indicators
- Nutritional situation: Prevalence of: Global acute malnutrition, Severe acute malnutrition, Micronutrient deficiencies. Number of children needing selective feeding programmes (SFP)
- Immunisation: Need for programme, Effectiveness of programme
- Vital needs: Water, Sanitation, Food & Shelter
- Health service activities: Consultations, hospital admissions, laboratories, cold chain
Provide an example of an Outbreak investigation
- Angola: October - November 2007
- Investigation of outbreak of neurological illness undertaken by Angolan Ministry of Health (MINSA)
- Supported by WHO (Angola, AFRO region & Geneva offices)
What happened in Angola in 2007
On 24th October 2007, the Direction Provinciale de la Santé (DPS) in Angola reported that 42 cases of a “neurological illness” with 3 fatalities had occurred in the municipality of Cacuaco to the north-east of the capital Luanda since the beginning of October.
What were the symptoms presented by people in this case?
- General symptoms:
- Affected patients normally & previously healthy
- fever, headache, diarrhoea, abdominal pain, vomiting
- Neurological symptoms: Dizziness, Weakness, Muscular spasms, Ataxia, Somnolence or semi-coma
Provide a case definition for Angola 2007
Any person who presents with sleepiness, deep asthenia, blurred vision, dizziness, difficulties in speaking and difficulties in walking
Describe the epidemiology for Cacuaco Municipality
- 461 cases in Cacuaco Municipality
- Mainly children, majority female
- No exclusively breastfed infants
- Households of 8/19 bairros (neighbourhoods) affected
- Additional 17 cases in Caxito, Bengo Province (north of
Cacuaco)
What was the hypothesis for Cacuaco Municipality?
- Cases due to a toxin rather than an infectious agent.
- Samples of food & blood sera tested at labs in UK &
Germany for over 8000 possible toxins: all negative
What was the cause of the Cacuaco Municipality?
- Bromide poisoning suggested as cause.
- Blood sera from cases +ve
- High concentrations of sodium bromide (>80%) found in table salt
- None in other foods
- Cause was probably ingestion of table salt contaminated with sodium bromide
Describe Sodium Bromide
- White crystalline compound
- Looks like sodium chloride
- Tastes weakly “salty”
- Widely used as an anticonvulsant & a sedative in the late 19th & early 20th centuries
- In Angola, used extensively in the oil industry
- Very large amounts transported in 25kg bags on trucks
What was the significance of sex and age in this case?
- Females more affected than males because at home more, cooking & tasting food.
- Children are at home & (especially female) taste food when helping mothers cook. (Also lighter & toxic dose smaller).
What were the public health measures carried out for this case?
- Remove contaminated salt from the community: Identification of safe salt supply, Recall and replacement process
- Develop public health messages
- Source investigation: Investigation of other food sources
- Prevention of similar incidents: Improved security of chemicals, Education
Summary
