Communicable Diseases Flashcards
What are the initial symptoms of pertussis?
Cold-like symptoms
Runny nose
Watery eyes
Sneezing
Fever
Mild cough (that gets worse)
How is pertussis spread?
Droplets
What age group is in the most dangerous if they get pertussis?
Children <1yr
What is the incubation period of pertussis?
6-20 days
When are you infectious with pertussis?
From 6 days after exposure to 3 weeks after cough onset
How long are you ill with pertussis for?
2-3 months
What are the complications with pertussis?
Collapsed lung and/or pneumonia
Convulsions, permanent brain damage or death
Severe weight loss and dehydration due to vomiting
Sudden death (apnoeic attakcs)
How is polio transmitted?
Though contact with faeces or droplets of infected person
What is the incubation period of polio?
3-21 days
What proportion of polio will become paralytic?
<1%
How long after illness does paralytic polio develop?
1-10 days
Why was the live polio vaccine replaced by an inactivated one?
Virus sometimes (rarely) reverts back to wildtype
What are the symptoms of measles?
Runny nose
Cough
Red and watery eyes
Small white spots inside the cheeks
Slight raised rash
Loss of appetite and loose stools
What age group is measles most common in?
1-4 year olds
How is measles spread?
Droplets
What is the incubation period of measles?
7-18 days
When are you infectious with measles?
From beginning of first symptoms to four days after the appearance of the rash
What proportion of measles cases develop complications?
30%
What are the complications of measles?
Severe diarrhoea
Pneumonia
Otitis media
Convulsions
Encephalitis
Subacute sclerosing panencephalitis
Death
How is HIV spread?
Sexual
IV-drug use
Blood transfusion
Mother-child (birth or breast milk)
What are the families of arbovirus?
Mosquitobourne
Tickbourne
Licebourne
What is the main issue with arboviruses?
They’re routinely untreatable
What are the reasons for the emergence and re-emergence of arboviruses and other exotic viruses?
Global warming
New vector species
Introduction of new species
Human interference with ecosystems
Extensive and rapid human travel
What are some examples of ‘common’ arboviruses?
Rift valley fever
Crimean-Congo haemorrhagic fever
West Nile virus
Dengue
Zika
What infectious diseases have been eradicated?
Smallpox and yellow fever
What % of deaths were caused by infection in 2010?
3%
What are the 5 infectious diseases in LICs?
Lower respiratory tract infection
HIV/AIDS
Diarrhoea
Malaria
TB
Why is the geographic distribution of arboviruses so broad?
Transmitted by birds and other such things which travel big distances (and therefore spread disease large distances
What are some reasons why life expectancy has increased?
Childhood immunisations
Heart disease treatment
Antibiotics
What % of deaths were caused by infection in 1910 and 2010?
1910 - 46%
2010 - 3%
What are the biological reasons vaccines dont exist?
Mutations
Evolution of protective mechanisms
Integration into the host genome
Dormancy in immune privilege sites
Strain variation beyond immunological memory
What new and emerging infections cause vaccines to not exist?
Increasing zoonotic infections
Infections that only infect LMICs are of little commercial interest
What commercial reasons are there for vaccines not existing?
Vaccines are expensive and complicated to develop
LMIC problems are not commercially attractive
What logistical reasons prevent vaccines from existing?
Limited infrastructure in developing countries
The cold chain
Political/religious intervention
What are vaccine investment disincentives?
High development costs
Demand for new vaccines at lowest prices
What % of the worlds population depends on plants to treat illnesses?
75%
How many deaths/year are from 6 major vaccine preventable diseases?
4.25 million
What are the WHO priorities in terms of vaccines?
Reduce cost of vaccines and introduce more vaccines
Avoid needle use
Simplify immunisation regimes
Remove the need for a cold chain
What infections is post-exposure prophylaxis usually used for?
Rabies
Tetanus
HIV
Hep A, B and C
Ebola
What are the advantages of using passive immunisation?
Immediate protection
Effective in healthy and immunocompromised patients
More consistent response than vaccines
What are the disadvantages of passive immunisation?
Quality control and uniformity of product
Safety of production system
Repeated administration -> serum sickness
Cost and availability
Short-lived protection
Escape mutants
What are the two types of rabies?
Furious and paralytic
What happens in furious rabies?
Hyperactivity and excited behaviour
Fear of water and sometimes air movement
After a few days, death occured by cardio-respiratory arrest
What happens in paralytic rabies?
Gradual muscle paralysis starting at the site of the bite
A coma slowly develops and eventually death
What animal controls can be used to stop rabies?
Sterilisation
Euthanisation (doesnt work)
Vaccination