Epidemics, Pandemics and the Protection of the Public (17) Flashcards
Types of transmission
Direct, Indirect or Airborne
Direct
Direct - STIs, Scabies
Feacal-Oral - Viral GE
Indirect
Vector-borne - Malaria, Dengue
Vehicle-borne - Viral GE, Hep B
Airborne
Respiratory - TB, Legionella
Epidemic
Serious outbreak in a single community, population or region
Pandemic
Epidemic spreading around the world affecting hundreds of thousands of people, across many countries
Nasty diseases
Acute encephalitis, Leptospirosis, Ophthalmia neonatorum, Relapsing fever, Scarlet fever, Viral hepatitis
Vaccine preventable diseases
Acute poliomyelitis, Diphtheria, Measles, Meningitis and Meningococcal septicaemia, Mumps, Rubella, Tetanus, Whooping cough
Infectious diseases that can be controlled
Food poisoning, TB, Viral hepatitis
If you suspect a notifiable disease..
notify Public Health England asap
Influenza B
Sporadic outbreaks, children, prone to mutation, human virus
Influenza C
Mild symptoms, stable human virus
Influenza A
- Can infect pigs, cats, horses, birds and sea mammals
- Very prone to mutation (no proof reading mechanism)
- Antigenic drift - flexibility causes seasonal epidemics
- Segmented into 8 genes
- Genes swapping occurs during co-infection with human and avian flu virus > antigenic shift
Haemagglutinin
Virus binding and entry to cells, 15 subtypes, immunity confers protection but only to specific subtype
Neuraminidase
Release of newly formed viruses from infected cells, 9 subtypes, immunity to subtype reduces amount of virus released from cells resulting in less severe disease
All 15N and 9N subtypes have been detected in
birds
Seasonal Influenza
Every year ‘flu jab’
Avian Influenza
Disease of birds H5N1, H7
mild disease in birds - ruffled feathers and depression
Swine Flu
Disease of pigs
Pandemic Influenza
Change/mutation in a flu virus to produce a new virus that can be transmitted easily between humans
Pandemic flu will cause
- High morbidity
- Excess mortality
- Social disruption
- Economic disruption
20th century pandemics influenza
1918 Spanish flu
1957 Asian flu
1968 Hong Kong flu
What to expect from Pandemic Flu?
- Incubation 1-4 days
- Infectious from onset of symptoms - 5 days after
- 10% infectious before symptom onset
- Take 4-6 months before vaccine available
Most seasonal influenza get..
Secondary bacterial pneumonia
H5N1 causes
A primary viral pneumonia
Controlling Avian Flu
- Cull affected birds
- Biosecurity and quarantine
- Disinfecting farms
- Control poultry movement
- Vaccine workers
- Antivirals for poultry workers
- Personal Protective Equipment (PPE)
- Reduce change of co-infection
H1N1 is
Swine Flu
Swine Flu
- Human to human transmission
- Sensitive to Oseltamivir and Zanamivir
- Seasonal influenza vaccine not effective
- People over 40 have some immunity
- 474 deaths in UK
Staff issues
- Anxiety (unwilling to work)
- Adequate protection
- Access to antivirals
- Risk to family
- Child care
- Segregation of staff
- Redeployment of staff
- Recycling of staff
- Organisations sharing staff
Vaccines
- 6-10 months to develop
- Limited availability - who first?
- Two doses required for at risk groups
Consequences of Measles
Measles encephalitis, thrombocytopenia, subacute sclerosing pan-encephalitis, death
1 child with measles will infect … others
15
MMR vaccine
12-13months and 3.5 years, single dose offers 95% protection, two doses >99%
Wakefield Controversy (1998)
8/12 parents linked onset of behavioural problems with MMR, but parents were less clear about timing of abode symptoms (MMR linked to Autism)
Issues with Wakefield Controversy
Bowel and behavioural pathologies may have occurred by chance, selection bias or lack of biological basis
