CD - diptheria, Hep A, Hep B-part 1 Flashcards
What is the agent for hepatitis A
HAV - hep A virus
what is the reservoir for hep A
humans
what are risk factors for acquiring hep A (endemic-2; sex/substance-2 (MI); occupation-3; med condition-1) (9)
I.e. MI-CLOT - O-> LMV
Men who have sex with men (MSM)
IV and non-IVDU
Clotting factors - recipient of plasma-derived clotting factors
Living in communities at risk of HAV outbreaks (e.g. northern SK)
Occupational - lab personnel working with HAV vaccine; military; vets; humanitarian workers
Travellers to endemic areas
1-Travellers to HAV-endemic countries
2* Living in community at risk of HAV outbreaks or in which HAV is endemic
3* Household or close contacts of children adopted from HAV-endemic countries
4* Men who have sex with men
5* Injectable and non-injectable illicit drug users
6* Workers involved in research or production of HAV vaccine
7* Military personnel and humanitarian relief workers who are likely to be posted to areas with high rates of HAV
8* Zoo-keepers, veterinarians and researchers who handle non-human primates
9* People receiving repeated replacement of plasma-derived clotting factors
what is the mode of transmission for hep A (1)
1- Fecal oral i.e. Ingestion of contaminated food or water (e.g. frozen fruits)
how long can HAV last in the environment (1) - D-W
- Virus can persist for days or weeks in the environment
what is the incubation period for Hep A (2)
1- Average: 28 days
2- Range: 15 – 50 days
what is the communicable period for Hep A (1)
BLANK1 have prolonged shedding of HAV for up to BLANK 2
- 2 weeks prior to symptom onset up to 1 week after jaundice
-infants and children have prolonged shedding of HAV up to 6 months
what is the clinical presentation of hep A in children (1)
Jaundice occurs in BLANK1 of kids less than 6 yo
-majority asymptomatic
- jaundice occurs in < 10% of kids less than 6 years old
what is the clinical presentation of hep A in adults (3) - PJR; P - MANAF; 1P2J
Prodrome, jaundice, recovery w/o complications
- 1-7 day prodrome of flu like illness with fever, malaise, anorexia, nausea, abdominal pain
- followed by 1-2 weeks of mild and self-limited jaundice.
- Most recover without complications, fulminant hepatitis is rare
does hep A persist as chronic infection (1)
no - chronic hep A infection does not occur
what does anti-HAV IgM indicate (1)
HAV IgM is detectable BLANK1 days after infection
HAV IgM decrease to BLANK2 levels within BLANK3 months after infection
-recent infection
-HAV IgM is detectable 5-10 days after infection
-HAV IgM decrease to undetectable levels within 6 months after infection
what does anti-HAV IgG indicate (2) - NV
indicates either
1- natural or
2- vaccine- derived immunity to HAV
what are the indications of hep A vaccine (2) - pre/post
1- pre-exposure immunization of persons 6 months of age and older at increased risk of infection or severe HAV
2- PEP for contacts of cases
what kind of vaccine is the hep A vaccine (1) - N
non-live, inactivated antigen
what is the schedule for hep A vaccine (2)
two doses at
1- 0 months and
2- between 6 - 36 months
what is the effectiveness of hep A vaccine (1)
90-97% effective in preventing hepatitis illness.
how long does hep A vaccine protect against disease (i.e. how long do antibodies last) (1)
Can protection exist even when antibodies are no longer measurable? (1)
1- Protective antibody concentrations persist for at least 20 years -possibly for life
2- YES - Immune memory has been demonstrated, indicating that protection may persist even when antibodies are no longer measurable
Hep A case mgmt: what information do you ask on case history - TOCIS (5)
1- symptom onset date including onset of jaundice
2- determine infectious/communicable period (2 weeks pre-symp to 1 wk post-jaundice)
3- identify potential contacts during communicable period
4- any HAV vaccine received in last 2 weeks (to rule out false-positive)
5- identify potential source (see next Q)
Hep A case mgmt: what questions would you ask to identify potential source of infection (TOCIS + 5)
1- food history
2- attendee/employee of child care centre or other institution
3- MSM
4- IV drug user or non-IV drug use
5-attendance at large function in previous 50 days
TOCIS = travel hx, occupational hx, sick contacts, immunization status, symptom onset
Hep A case mgmt: what are questions you would ask in a risk assessment of a case in terms of their potential to spread HAV to contacts (9) - last 5 = HFPEH
1- At-risk populations served (e.g. LTCH residents,
immunocompromised)
2- Evidence of transmission to others
3- Immunization status
4- Opportunity to offer PEP within 14 day window
5- hand hygiene
6- food handling/practices
7- PPE
8- exposed to people during communicable period
9- how symptomatic they are
Hep A case mgmt: what would you provide education on to a case (2)
1- educate re: HAV transmission and personal hygiene (emphasize proper hand hygiene)
2- limit food handling and discourage
the sharing of food prepared by the case during infectious
period
Hep A case mgmt: which cases would fall under exclusion criteria (3) - FDH
1- food handlers
2- daycare staff/attendees
3- HCWs from high risk settings
Hep A case mgmt: how long should a case be excluded from work/daycare for
excluded for 14 days after symptom onset, or 7 days after jaundice onset, whichever comes earlier
Hep A contact mgmt: what is the definition of ‘contact’ (1)
a susceptible individual who was exposed to a case during the case’s communicable/infectious period
Hep A contact mgmt: which groups of people are considered contacts (5) - HNCFD “have no crappy food day”
1- household contacts
2- close non-household contacts (e.g. sexual partners, drug sharing partners)
3- coworkers of infected food handler who worked during communicable period
4- food establishment patrons if case is food handler who worked in their communicable period (need to consider role, glove wearing, if food was cooked) – consider if patrons can be ID’d and offered immunoproph within 14d from exposure to case
5- daycare and institutional attendees/staff (may have handled diapers, toileting, personal care of a case)
Hep A contact mgmt: what would you provide education on to a contact (4) - HIMM
1- hand hygiene
2- mode of disease transmission
3- incubation period and symptoms
4- (seek) medical care if symptoms develop
Hep A contact mgmt: why use HAV vaccine in contact management as part of PEP
in susceptible populations, HAV vaccine interrupts outbreaks
Hep A contact mgmt: when should you immunize contacts after exposure to a case as part of PEP
HAV vaccine is ~80% protective efficacy if used within 1 week of exposure - so give vaccine within 1 week for all contacts 6mo old and older
Hep A contact mgmt: when do you give HAV immunoglobulin to contacts after exposure to a case, as part of PEP
offer to susceptible contacts up to 14 days after exposure to case
Hep A contact mgmt: which groups of contacts meet criteria to recieve Ig (4) - I-PICA
1- infants <6mo old
2- people for whom HAV vaccine is c/i or unavailable
3- immunocompromized people
4- chronic liver disease
5- adults 60yo and older who are HH or close contacts of a case
why is Hep A immunoglobulin indicated (in addition to HAV vaccine) for people with chronic liver disease or immune compromise? (2)
1- an increased risk of severe disease
2- suboptimal immune response to HAV vaccine
why is Hep A immunoglobulin indicated (in addition to HAV vaccine) for those 60yo and older who are contacts to a case? (2)
1- reduced response to HAV vaccine
2- increased risk of severe disease with increasing age
Hep A contact mgmt: what are exclusion requirements for symptomatic contacts? (2)
1- exclusion from high risk settings is same as for cases (14d from symp onset or 7d from jaundice, whichever is earlier)
2- ensure contact is screened to confirm if they are acutely ill with Hep A (i.e. if they are anti-HAV IgM positive)
Hep A contact mgmt: what are exclusion requirements/criteria for asymptomatic contacts? (1, 2abc)
1- exclusion usually not warranted
2- BUT asymp food handler contact may be excluded if:
2a- they don’t get timely PEP
2b- do not have serological evidence of immunity
2c- assessed to be high risk of transmitting HAV via handling food that is uncooked, or handled after being cooked
HAV PEP summary: can infants have HAV vaccine within 7 days of contact to a case?
No
HAV PEP summary: can infants have Hep A immunoglobulin within 14 days of contact to a case?
yes
HAV PEP summary: can healthy children/adults 6mo to 59yo have HAV vaccine within 7 days of contact to a case?
yes
HAV PEP summary: can healthy children/adults 6mo to 59yo have hep A immunoglobulin within 14 days of contact to a case?
no (not eligible since this population is generally not contraindicated to have the vaccine)
HAV PEP summary: can healthy adults 60yo and older have HAV vaccine within 7 days of contact to a case?
yes
HAV PEP summary: can healthy adults 60yo and older have hep A immunoglobulin within 14 days of contact to a case?
you can consider (yes)
HAV PEP summary: can those who are immunocompromised or have chronic liver disease have HAV vaccine within 7 days of contact to a case?
yes
HAV PEP summary: can those who are immunocompromised or have chronic liver disease have hep A immunoglobulin within 14 days of contact to a case?
yes
what is the agent for diptheria
corynebacterium diptheriae
what is the reservoir for diptheria
humans
what is the mode of transmission for diptheria (2)
1- droplet (respiratory)
2- contact (directly with lesion)
what is the incubation period for diptheria (2)
1- average 2-5 days
2- range 1-10 days
what is the communicable period for diptheria (2)
1- usually 2-4 weeks for respiratory dip once virulent bacilli have disappeared
2- chronic carriers can shed for > 6mo
what is the clinical presentation of diptheria (4)
1- respiratory (hoarseness, nasal discharge, fever, sore throat; case fatality 5-10%)
2- systemic (myocarditis, CNS effects from toxin dissemination)
3- cutaneous (scaly rash, rarely associated with systemic complications)
4- chronic carrier (asymptomatic; colonized on skin or nasopharynx)
what kind of vaccine is the anti-diptheria vaccine? what is its current formulation? (2)
1- toxoid (inactivated toxins)
2- currently only available in combination with tetanus, acellular pertussis and polio vaccines
what is the efficacy of the diptheria vaccine (2)
1- after completing primary series of 3 doses, 97% of vaccinees develop protection against effects of the toxin
2- vaccine does NOT protect against infection, so immunized adults can become carriers
what are the schedule recommendations in terms of age for diptheria vaccines for primary series, and which vaccine formulation (how many antigens)? (2)
1- 2, 4, 6, (18) months for primary series
2- DTaP-IPV-Hib (5 antigens)*
*may also have Hep B to make 6 antigens
what are the schedule recommendations in terms of age for diptheria vaccines for school-age children, and which vaccine formulation (how many antigens)? (2)
1- 4-6 years old (school age)
2- DTaP-IPV or Tdap-IPV (i.e. 4 antigens)
what are the schedule recommendations in terms of age for diptheria vaccines for teenage years, and which vaccine formulation (how many antigens)? (2)
1- 14-16 years old
2- booster of Tdap (3 antigens)
what are the schedule recommendations for diptheria vaccines for adults previously immunized, and which vaccine formulation (how many antigens)? (2)
1- 1 dose Tdap if not previously given in adulthood (18yo and older) - 3 antigens
2- Td booster q10yrs (2 antigens)
what are the schedule recommendations for diptheria vaccines for unimmunized adults, and what vaccine formulation (how many antigens)? (2)
1- full primary series
2- DTaP-IPV-Hib (5 antigens)*
*can also include Hep B
what is the diptheria anti-toxin made from?
purified immunoglobulins from the plasma of horses hyper-immunized with diptheria toxoid
Diptheria case mgmt: how do you treat respiratory dip? (2 tx, 3 points)
1- antibiotics (procaine penicillin G or parenteral erythromycin)
2- give anti-toxin ASAP
3- provide either immediately without waiting for lab confirmation
Diptheria case mgmt: how do you treat asymptomatic carriers of toxigenic strains? (who are sufficiently vaccinated) (2)
1-antibiotics (10d course macrolide OR 1 single dose benzathine penicillin G)
2- nasal & throat swabs at least 24h post-antibiotics completion to confirm eradication
Diptheria case mgmt: how do you treat asymptomatic carriers of toxigenic strains? (who are under/unvaccinated) (3)
1- same as tx for asymp carriers who are sufficiently vaccinated, AND
2- immediate dose of dip toxoid-containing vaccine
3- complete primary series
Diptheria case mgmt: do you manage cases of cutaneous diptheria?
No - they do not meet case definition, but you manage them like carriers
diptheria contact mgmt: what groups would be considered as contacts of a case? (4)
1- household members
2- close contacts like intimate contact, face-to-face contact
3- HCWs exposed to pharyngeal secretions
4- those who provided wound care w/o PPE in 10 days prior to symptom onset in case
diptheria contact mgmt: how long should contacts surveille themselves for symptoms? (2)
1- 10 days from date of last contact with case, regardless of immunization status
2- seek medical care if any symptoms of Dip develop
diptheria contact mgmt: describe chemoprophylaxis for contacts (2)
1- same as carrier tx; give to all close contacts of a case regardless of immunization status
2- give after nose and throat swabs have been collected
diptheria contact mgmt: describe immunoprophylaxis for contacts (1)
close contacts should get an immediate dose of dip toxoid-containing vaccine if they haven’t received within the last 5 years
diptheria contact mgmt: which contacts should be excluded? (5)
1- HCWs
2- those who attend school
3- food handlers
4- close contact with children < 7yo
5- close contact with known unimmunized people
diptheria contact mgmt: what should excluded contacts do if nose/throat swab cultures return as negative
they can return to work or school while completing antibiotics course
diptheria contact mgmt: are contacts of cases infected with non-toxic corynebacterium species required to get chemoprophylaxis?
no - not routinely offered, as they are considered extremely low risk
what is the agent for Hepatitis B
HBV - hep B virus
what is the prevalence of chronic Hep B in Canada (2)
1- <1% - rare
2- immigrants from endemic countries account for the majority of chronic infections
what are risk factors for hep B infection - category “country” (3)
1- immigrants from countries endemic for HBV
2- children born in Canada who may be exposed to HBV carriers through family or when visiting country of origin
3- travellers to endemic areas
what are risk factors for hep B infection - categories “sex” and “substance use” (3 + 1)
1- high risk sex practices (e.g. unprotected sex with new partners; >1 partner in last 6 months; history of STI)
2- MSM
3- household and sexual contacts of acute HBV cases and HBV carriers
4- persons who use injection drugs
what are risk factors for hep B infection - category “institutional” (3)
1- children and workers at childcare settings where there is acute HBV case or HBV carrier
2- residents/staff of institutions for those with developmental disabilities
3- staff/inmates at correctional facilities
what are risk factors for hep B infection - category “medical condition” (6)
1- chronic renal and liver disease
2- hemophiliacs and others receiving repeated infusion of blood/blood products
3- congenital immunodeficiencies
4- hematopoetic stem cell transplant recipients, or awaiting solid organ transplant
5- persons with HIV
6- HCWs with potential occupational exposure to blood/blood products/bodily fluids
what is the reservoir for HBV
humans
what is the mode of transmission for HBV
blood borne exposure
what are examples of blood borne exposure routes that transmit HBV (3)
1- percutaneous (needle sharing, blood products)
2- sexual (semen, vaginal secretions)
3- vertical (mother -> fetus)
what are examples of non-blood borne exposure routes that transmit HBV (2)
1- exposure to other bodily fluids (saliva, CSF, pleural, peritoneal)
2- horizontal (household contacts)
what is the incubation period for hep B (2)
1- average: 60-90 days
2- range: 45-180 days
what is the communicable period for hep B - acute infection (3)
1- Communicable when HBsAg is detectable
2- Blood is infective for many weeks before onset of first symptoms
3- blood remains infective through the acute and chronic periods
what is the communicable period for hep B - chronic carrier (3)
1- Majority of individuals spontaneously clear the infection after 4 to 8 weeks
2- chronic carriers can shed for months (most likely children)
3- Risk of becoming a chronic carrier varies inversely with the age: 90% of
infants, 30-50% of children, and 5% of adults become chronically infected
what is the clinical presentation of acute Hep B infection (4)
1- asymptomatic in most infants/adults
2- asymptomatic in 50-70% of adults
3- if symptomatic, symptoms include: anorexia, fatigue, abdominal pain, fever, jaundice
4- 1-2% of infections result in fulminant hepatitis
what is the timeline for acute Hep B infection (how many months)?
<6 months of infection
what is the clinical presentation of chronic (carrier) hep B infection (2)
1- carriers often asymptomatic
2- 15-50% of chronic infections will develop cirrhosis, end-stage liver disease, or hepatocellular carcinoma
what is the timeline for chronic Hep B infection (how many months)?
> 6 months of infection
Hep B diagnosis: what is HBsAg and what does it indicate (4)
1- hep B surface antigen, protein on surface of virus
2- indicates that an individual has an active infection and is infectious
3- HBsAg is used to make the
HBV vaccine - can get transient HBsAg positivity up to 18d post-vaccination
4- up to 50% of people with chronic infection will clear HBsAg
Hep B diagnosis: what is HBcAg and what does it indicate (2)
1- Hep B core antigen
2- body doesn’t see it and you can’t see HBcAg on serology (only Ab towards it - i.e. anti-HBc)
Hep B diagnosis: what is HBeAg and what does it indicate (3)
1- Hep B envelope protein antigen
2- produced during active viral replication HBcAg and is secreted into cell plasma
3- it is not part of the mature virus therefore presence of HBeAg indicates high infectivity
Hep B diagnosis: what is anti-HBs and what does it indicate (3)
1- antibody to surface antigen
2- indicates immunity
from natural infection or from vaccination (titre > 10 IU/mL indicate definitive immunity)
3- titres may decline to undetectable levels but individual may retain anamnestic immunity
Hep B diagnosis: what is anti-HBc (2 types) and what does it indicate (5)
1- antibody to core antigen
2- indicates ongoing (IgM) or previous (IgG) HBV infection
3- produced because infected hepatocytes express HBsAg on their surface
4- total anti-HBc = IgM + IgG; remains positive for life
5- does not develop after vaccination as vaccine does not contain core antigen
Hep B diagnosis: what is anti-HBe and what does it indicate (3)
1- antibody to envelope antigen
2- indicates low infectivity and low viral replication
3- this antibody mops up eAg
