Diseases Flashcards
Duration of yellow fever vaccine
Exemptions
Precautions
Lifelong
Exemptions: age
Yellow fever:
- Genus
- Incubation period
- Infectious period
- Flavivirus
- 3-6 days
- Just before fever for 3-5 days
Measles
- Incubation period
- Reproductive rate
- Infectious period
- Timing of rash
- 7 - 18 days (usually 10 days)
- 15-18
- 1 day prior to prodromal illness to 4 days after rash appearance
- rash appears day 3-4 and lasts 4-7 days
Listeria
- Incubation period
- Period of communicability
- Risk factors
- Source
- Diagnosis
- 3-70 days (median 3 weeks)
- 7-10 days (mother to baby)
- Pregnant women/fetuses, newborns, immunosuppression
- contaminated food particularly cheese, ready-to-eat meals and salads, deli meats, pate
- Usually blood cultures or another sterile site (e.g. CSF)
Define a community outbreak of IMD
3 or more confirmed or probable cases of IMD with no direct epidemiologic link within a defined area within 3 months with a primary attack rate of 10 per 100 000
What changes in epidemiology of meningococcal disease are suggestive of an outbreak? (3)
- increased rate of disease (or increase in number in small populations)
- clustering of cases in an age group or a shift in the age distribution of cases
- phenotyphic or genetic similarity among cases
Define an organisation-based outbreak of IMD
2 or more probable or confirmed cases within 4 weeks among an organisation e.g. high school but no close contact with each other
What are the national case definitions for measles:
- Confirmed case
- Probable case
- Confirmed case = lab definitive evidence, or
clinical and epi evidence - Probable case = lab suggestive evidence and clinical evidence.
clinical evidence = generalised maculopapular rash for 3 or more days + fever>38 at time of rash onset + [cough or coryza or conjunctivitis or koplik spots]
**epi evidence = contact with an infectious/suspected case
**lab-suggestive evidence: IgM detected by a non-reference lab (except if recently had measles vaccine)
Measles lab tests:
<3 weeks
>3 weeks
3 weeks: nasopharyngeal swab and urine for NAT and culture. Blood for serology and WGS
>3 weeks: serology
Measles
- what are the r/f for severe disease?
- what are the potential complications?
- what is the case fatality?
- R/F: young children, malnutrition, vitamin A deficiency
- haemorrhagic rash, protein-losing enteropathy, otitis media(6%), severe skin infections, pneumonia (9%)
- exacerbation of vitamin A deficiency -> blindness
Subacute sclerosing panencephalitis (1/100 000) several years after infection - Case fatality 3-5% in developing countries
What is the incubation period of hepatitis A?
15-50 days (commonly 28-30)
What is the infectious period of hepatitis A?
from a few days prior to illness to a few days after jaundice
Case definition for hepatitis A
- Confirmed case
- Probable case
- Confirmed = Lab-definitive evidence (IgM or NAT)
2. Probable = Clinical and epi evidence
- For hepatitis A contacts who should you consider post-exposure prophylaxis (vaccine or Ig)>
- which groups should receive NHIG?
- -household or sexual contacts
- if case in childcare centre -> contacts
- if case in food handler -> contacts who ate food prepared or other food handlers
Use NHIG for
-
What is the incubation period of IMD?
1-7 days (up to 10)
What are the case definitions for IMD?
confirmed and probable
Confirmed case = lab definitive evidence (isolation of N. meningitidis from a sterile site, or NAT)
OR lab-suggestive (gram neg diplococci or IgM) and clinical evidence (clinically compatible illness)
Probable case = clinical evidence
What are the main considerations during an outbreak of IMD?
- Establish a team, lab-communication and comms
- Confirm the diagnosis and serotype
- Active surveillance: age-specific or region-specific rates
- Information provision early: public (media releases, press conference), HCW, prepare for increase in calls
- Manage contacts: clearance ABx
- Consider vaccination depending on strain and size of organisation or community
Who are the at-risk contacts and other groups for meningococcal disease?
contacts: -household or other intimate -childcare/school/uni -HCW - lab workers Other: -Immunosuppressed -ATSI -crowding/smoke exposure
What is the incubation period for Legionella?
Legionnaires disease: 2-10 days (usually 5-6)
Pontiac fever: 5-72 hous (usually 1-2 days)
What are the diagnostic tests for Legionella?
LP antigen in urine (in Tas just LP1)
4-fold rise in titre of LP of 3-6 weeks
Culture
When do you start investigating a cluster of Legionnaire’s disease?
2 or more cases with a common exposure (within 100m) over a 3 month period
What are the most likely potential sources of a legionella outbreak?
Aerosolised water (e.g. veg section of supermarket)
- car washes
- cooling towers (e.g. shopping centres, clubs)
- spas
- fountains
- warm water systems
What is the incubation period for zika virus?
What is the typical duration of illness for Zika virus?
3-12 days
duration: 4-7 days
What is the incubation period for pertussis?
4-21 days (usually 7-10)
What is the incubation period for varicella zoster (chickenpox) virus?
10-21 days (usually 14-16)
What is the SAFE strategy for trachoma?
Surgery
Antibiotics
Facial cleanliness
Environmental health
What is considered endemic trachoma?
Prevalence of active trachoma >5% in ATSI children aged 5-9 years or prevalence of trichiasis of >0.1%in the adult ATSI population
What are the case definitions for Zika virus?
Confirmed and probable notifiable as flavivirus infection (unspecified)
Confirmed: lab definitive evidence (NAT, virus isolation, IgG seroconversion or fourfold rise in titre, IgM in CSF) and clinical evidence
Probable: lab suggestive evidence and epi evidence (travel to zika country within 2 weeks or sexual exposure to a confirmed/probable case)
Clinical evidence: acute illness within 2 weeks of exposure and 2 or more of fever, headache, myalgia, arthralgia, rash, non-purulent conjunctivitis
What are the current diseases of concern under the Biosecurity Act 2015?
SARS MERS Viral haemorrhagic fever Human influenza with pandemic potential Plague Smallpox Yellow fever (in northern Australia)
What is meningococcal disease and how many serogroups are there?
- which are the most common?
Neisseria meningitidis, gram negative bacteria
16 serogroups known
ABCWY are the most common globally
What is the case fatality for pertussis in babies < 6 months?
0.5-0.8%
Measles post-exposure prophylaxis
<72 hours
>72 hours
<72 if not immune (born after 1966 and no record of 2xMMR or serology): MMR vaccine
- NHIG if: immunocompromised, babies<8 months, pregnancy
>72 hours: NHIG if <18 months, pregnant, immunocompromised. Also HCW and close contacts if NO previous vaccines.
What are the recommendations for isolation of susceptible contacts of a case of measles?
- childcare attendees or primary schools
- adult in regular workplace or tertiary education
- isolate for 14 days after initial case developed rash
- 3 days only if given MMR
- 6 days if given NHIG - don’t isolate, just educate
Who are the priority contacts to follow up for a case of pertussis?
Children <5 years, particularly babies<6 months
People in contact with babies <6 months (e..g childcare workers)
Pregnant women in T3
What are the current antibiotic options for treatment of pertussis?
azithromycin, clarithromycin, erythromycin, Bactrim
Definition of a contact of pertussis
- close contact
- general contact
- high risk
during infectious period:
close contact: stayed overnight or lived in house together
general contact: face-to-face exposure (within 1 metre) for atleast 1 hour
high-risk: babies<6 months or people who may transmit pertussis to them (including maternity wards, nurseries)
Who should receive antibiotic prophylaxis against pertussis?
If within 14 days of contact with an infectious case and <6 months of age or close contact of baby <6 months of age
ie. all household contacts of a baby <6 months and all childcare contacts (other kids in room and staff of a baby <6 months, pregnant women in T3, maternity or nursery staff)
