2021 Communicable Disease

Question 1

List two groups that are disproportionately affected by TB

Answer 1

foreign-born, Indigenous Canadians

Question 2

List 5 reasons for mandatory reporting of certain diseases?

Answer 2

1. to identify and control an outbreak
2. to prevent spread if the disease presents a significant threat to individuals or a subset of the population (e.g. Lassa Fever)
3. if the disease is preventable with immunization (e.g. polio, diphtheria, congenital rubella)
4. if infected individuals require education, treatment, and/or partner notification (e.g. gonorrhea, TB)
5. surveillance (to monitor disease trends over time)

Question 3

Define primary and secondary vaccine failure.

Answer 3

Primary vaccine failure: Failure to respond to vaccine (no antibody level) Secondary vaccine failure: Susceptible to disease, despite following the appropriate dosing of the vaccine.

Question 4

A baby was just born to a mother who is HBsAg positive, list three interventions that can reduce vertical transmission of hepatitis B?

Answer 4

1. HB Immunoglobulin ASAP but within 12 hrs post birth- An IM dose of 0.5 mL HBIg
2. HB Vaccine x 1 within 12 hrs post birth. 2nd dose @ 1 mo and 3rd dose @ 6 mo to complete the HB series
3. Testing - Test for anti-HBs antibody and revaccinate if non-responder

Question 5

List 4 conditions that must be met for vaccines to be considered interchangeable for a particular disease?

Answer 5

1) Vaccines must be authorized for the same indications and with equally acceptable schedules
2) Vaccines must be authorized for use in the same populations
3) Vaccines must contain comparable antigens
4) Vaccines must have similar safety, immunogenicity, efficacy

Question 6

You are the MOH of Nunavut. Infants in Nunavut are disproportionately affected by Respiratory Syncytial Virus (RSV). The incidence rates, morbidity and mortality from RSV in infants are much higher in Nunavut compared to other areas. A community GP has emailed you advocating for universal screening of all infants of RSV.

List 5 criteria you will look at to decide if such program should be funded?

Answer 6

1) Principles for introduction of population screening (DTTS)

Disease

Is this condition an important health problem?

Do we have adaquate understanding of the natural history of the condition, including the development from latent to active disease?

Is there a recognizable latent stage or early symptomatic stage?

Test

Is there a suitable test or examination with high level of accuracy? (high sensitivity, high specificity, Positive Predictive Value, Acceptable to the population, minimal discomfort)

Is the test acceptable to the populatin?

Treatment

Is there an acceptable treatment for recognized disease?

Is there an agree-upon policy on whom to treat as patients?

System

• Are there facilities available for diagnosis and treatment?
• Is the cost of screening (including diagnosis & treatment) economically balanced against the cost of medical care as a whole?
• Is the population screening an on-going effort?
• are there programming support to ensure the target population get screened (e.g. reminders, registry, retention strategy, informed consent and proper follow-up and linkage to care?

Question 7

You are the MOH of Nunavut. Infants in Nunavut are disproportionately affected by Respiratory Syncytial Virus (RSV). The incidence rates, morbidity and mortality from RSV in infants are much higher in Nunavut compared to other areas. A community GP has emailed you advocating for using a newly approved vaccine to vaccinate all infants.

What are some criteria you will look at to decide if such program should be funded?

Answer 7

ICEES FACED LEGS

Features of a good vaccine (ICEES)

Immunogenicity

Cost

Ease of administration

Effectiveness & preferabbly long-lasting immunity

Safety

Features of a good public health program (FACED LEGS)

Feasibility

Acceptability

Cost-effectiveness

Equitable

Disease burden

Legal

Ethical

clear Goals

good Strategy

Question 8

You are an MOH in a regional PHU. A GP calls you to say he has a 35 yo patient with a rash who he suspects has measles.

A) Identify 5 elements of the case’s history and/or presentation that would assist you in determining the likelihood of this case being measles

B) List ONE laboratory test/specimen you would request the doctor order

The specimen comes back positive with measles

C) Who is considered a contact of a case with measles during their infectious period?

D) List 3 pieces of information you would use to assist in determining whether a contact of a measles case is susceptible

Answer 8

A)

1. Is the case known to be previously vaccinated against measles or infected with measles?
2. Is the case a contact of a known measles case or traveled to a measles endemic/outbreak area?
3. What does the rash look like and where did it start then move to?
4. What are the other accompanying symptoms/signs (e.g. cough, conjunctivitis, coryza, koplik spots)
5. When did other symptoms occur in relation to timing of the rash?

B) Urine nucleic acid test

C) Anyone who shared the same air space with at the same time of the case and up to 2 hours case left the area

D)

1. Year of birth (born before 1970 is considered immune)
2. Documented evidence of previous vaccination against measles
3. Laboratory evidence of immunity (previous infection or vaccination)

Question 9

What are four communicable diseases that should be considered for screening for immigrants to Canada?

Answer 9

1) TB
2) HIV
3) HBV
4) HCV
5) Intestinal parasites (Strongyloides and Schistosoma)

Question 10

What are 4 measures that are currently used to prevent HBV transmission at the population level in Canada?

Answer 10

1. Universal HBV vaccination in childhood
2. Screening of all pegnant women during pre-natal visits
3. Screening of high risk populations e.g. IVDU, incarceration
4. Harm reduction programs e.g. supervised consumption site and needle exchange
5. Contact tracing and PEP of confirmed cases
6. Screening of immigrants from countries with high incidence of HBV

Question 11

You are the Chief Medical Officer of Health at Public Health Agency of Canada. You are considerating adding a new disease to the list of national notifiable disease list. What are some criteria you would consider to assess whether this new disease should be added?

Answer 11

Think Agent, Environment and Host: SICO? C-RN, CPR!

AGENT

Severity of the disease

Incidence of the disease

Communicability of the disease

Outbreak Potential

ENVIRONMENT

Changing patterns of disease over time

Regulatory programs (to inform and regulate certain programs such as immunization efforts)

Necessity for Public Health response

HOST

Cost of disease burden

Preventability

Risk perception of the public

Question 12

In a study of COVID UK variant, it was determined that the probability of transmission per contact was 30% and the average infectious period was 10 days, and that cases had an average of 1.5 new contacts per day.

A) What is the R0

B) What immunity is required in the population to achieve herd immunity

C) You have vaccinated 80% of staff and residents in a LTCF with a total of 200 staff and residents. An outbreak occurs in this LTCF with 50 cases. 30 cases were unvaccinated and 20 cases had received the vaccine. What is the VE%?

D) Using the VE from (C), what proportion of the population needs to be vaccinated in order to achieve herd immunity?

Answer 12

A) R) = p x c x d = 0.4 x 1.5 x 10 = 5.25

B) Immunity = 1-(1/R0) = 1-(1/5.25) = 81%

C)

ARv = (20/160) x 100% = 12.5%

ARu = (30/40) x 100% = 75%

VE = (75-12.5)/75 x 100%= 83%

D) Coverage = Immunity/VE = 81/0.83 = 97.5%

Question 13

You are an MOH in a regional PHU responsible for the TB program. One of the nurses reports to you they have an 8 yo child with a TST of 8mm

A) List 5 pieces of information you would request to help inform necessary recommendations/actions

You diagnose the child with latent TB and are selecting an appropriate regimen

B) List TWO key considerations when selecting a treatment regimen for latent TB

You decide to provide an isoniazid-only regimen for the appropriate time period, however, the child is reportedly malnourished.

C) Identify the supplement should be provided for the treatment and list the adverse effect it aims to prevent

D) List one other population group that should receive the supplement in (C) when receiving INH therapy

Answer 13

A)

1. Is the child a contact of a known active TB case?
2. Has the child previously had TB infection?
3. Does the child have any changes on chest XRAY suggestive of active TB
4. Does the child have an immunocompromising condition e.g. AIDS
5. Is the child on any immunocompromsing medication e.g. chemotherapy
6. Has the child previously received BCG?
7. Is the child from a community with a high prevalence of active TB?

B)

1. Ability/likelihood to comply with the treatment
2. Potential side effects
3. Contact of an active TB case with a form of drug resistant TB
4. Age (older age increases hepatotoxicity risk of INH)

C) Pyridoxine (Vitamin B6) - perhipheral neuropathy

D) Pregnant women

Question 14

List 2 possible causes of a

A) False positive TST

B) False negative TST

Answer 14

A)

1. Nontuberculous mycobacterium infection
2. Prior TB infection
3. Previous BCG

B) Host, Procedural, Reader factors

1. Poor immune response
2. Improper injection/preparation/storage of tuberculin
3. Reader error or reading at wrong point in time

Question 15

You are MOH on call and receive a call of a surgeon who received a needlestick injury while operating on a person known to inject drugs.

A) List 5 pieces of information you would seek to inform your risk assessment

You decide HIV PEP is warranted

B) Within what timefram must HIV pep be commenced?

Answer 15

A)

1. What type of needle was being used that caused the injury e.g. hollow-bore?
2. Is the source’s blood-borne infection status known and if so, what is their viral load?
3. How deep was the needlestick puncture?
4. Does the injured have documented immunity to HBV?
5. How long ago did the injury occur

B) HIV PEP - within 72 hours of exposure

Question 16

List 6 steps in an outbreak investigation and management

Answer 16

1) Confirm Diagnosis & Verify existence of outbreak
2) Assemble a team including epidemiologist, PHN, (potentially PHI if associated with commercial food products) communication, AMOH
3) Case definition creation - to help with line listing to find more cases and do contact tracing
4) Data organized in terms of person, place and time for epidemiological analysis
5) Develop a hypothesis and evaluate the hypothesis by a case-control or cohort study if possible and revise hypothesis as needed
6) Implement control and revise control as needed
7) Established communication throughout the investigation and management and summarize the findings at the end and share learnings with others

Question 17

List 4 essential elements of a case definition

Answer 17

1. Person
2. Place
3. Time
4. Clinical symptoms or signs or
5. laboratory testing

Question 18

Question 19

Question 20

Question 21

List 3 characteristics of a disease that would make it amendable for eradition.

Question 22

List the 6 steps of case management,.

Answer 22

1. Confirm case: based on LTPPS – lab result, timing, person, place, symptoms
2. Obtain TOCIS Hisotry - Travel, Occupation, Contacts before and after, Immunization Status, timeline of Symptoms
3. Ensure case has received proper medical treatment

4. Advise to self-isolate and work exlusion if applicable

5. Provide education and counseling about the disease, symptoms, public health meausres to take (e.g. hand hygiene, no food prep) and when to seek medical care.
6. Contact tracing & notification - collect information about exposure to others during period of communicability

Question 23

List the 5 phases of pandemic and 1 public health action associated with each phase

Answer 23

1. Investigation - New discovery

• Alert national level health authority and WHO
• Aggressive case and contact management to detect all cases and their contacts
• Source identification

2. Recognition - containment

• Communication of risk to public
• Rapid planning for wider transmission and pandemic
• Follow-up of identified cases and their contacts to prevent tranmission (containment strategy)
• Understanidng pathogen and public health action

3. Initiation of a pandemic - mitigation

• Planning with health sector and other stakeholders
• Consideration for broader interventions
• Reduce the burden of health care resources e.g. setting separate place to test disease such as assessment centres

4. Aceleration of a pandemic - mitigation with goal to attempt to slow down spread of sustained local tranmission

• Implement population interveiton e.g social distancing, universal masking, city-wide lock down.
• Advocacy for government investment in new treatment and vaccine

Deceleration of a pandemic wave

• Population health assement
• Recommendation about timeline of releaxing population public health measures (e.g. travel)

Question 24

What are the two forms of disease caused by Legionella? What two tests can you order?

Answer 24

Pontiac Fever: self-limiting flu-like illness; can affect anyone (~90-95%exposed)

Legionnaires’ Disease - severe form of pneumonia with average mortality ~10%; affecting vulnerable populations (~5% exposed; >40yo, smokers, chronic lung disease, immunocompromised)

Urine antigen testing (only L. penumophila serogroup1); lower respiratory specimen (e.g. sputum, bronchoalveolar lavage) for PCR and/or culture

Question 25

Name 4 of the list of priority organism for antimicrobial resistance surveillance in Canada?

Answer 25

1. Clostridium difficile 2. Extended-spectrum β-lactamase (ESBL) -producing organisms 3. Carbapenem-resistant organisms (CRO) 4. Vancomycin-resistant enterococci (VRE) or just enterococcus spp. 5. Neisseria gonorrhoeae 6. Drug-resistant Streptococcus 7. Drug-resistant Salmonella spp 8. Methicillin-resistant Staphylococcus aureus (MRSA) 9. Mycobacterium tuberculosis

Question 26

Regarding Antimicrobial Resistance and Use in Canada: A Federal Framework, list the 3 broad categories and give an example of each for addressing antimicrobial resistance

Answer 26

3 broad categories: Surveillance, Stewardship, Innovation and Resesarch **Surveillance (**Detect and monitor antimicrobial resistance trends ) - **CNISP-**Canadian Nosocomial Infection Surveillance Program - monitors antimicrobial use and resistance in hospitalized patients - **CIPARS -** Canadian integrated Program for Antimicrobial Resistance Surveillance - monitors antimicrobial use and resistance in humans, animals, and the food supply **-CARSS** - Canadian Antimicrobial Resistance Surveillance System **Stewardship:** IPAC guidelines, education, regulations, and oversight in human and veterinary medicine and industry (ex. agriculture) **Innovation and Research:** Health research to combat antimicrobial resistance and improve antimicrobial use

Question 27

List 5 reasons for Vaccine Hesitancy

Answer 27

- Complencency (Lack of appreciation of the incidence of vaccine preventable disease and the severity of infection) - Confidence (Perceived risk of receiving vaccine) - Culture (Sociocultural beliefs and social network influence) - Calculation (Lack of infromation, conflicting information, mistrust of the source) - Convience (geographic or temporal or economic barriers to accessing vaccine)

Question 28

List the 8 Rights of Immunization

Answer 28

1. Right product 2. Right patient 3 .Right dose 4. Right time (intervals) 5. Right route 6. Right site 7. Right reason 8. Right documentation

Question 29

Give two reasons why Cold Chain is important?

Answer 29

* Vaccines can lose their potency, become ineffective, even be destroyed when cold chain is broken (exposed to temperatures outside the target range). * Compromised vaccines can be less effective and potentially lead to a rise in vaccine preventable diseases.

Question 30

List 4 elements of the cold chain

Answer 30

* Most vaccines need to be stored at between 2-8 degrees Celsius * Vaccine fridges need to be exclusively for vaccines * Vaccines should never be stored on the door * Water bottles help to maintain temperature during a power cut

Question 31

Name 3 broad Immunization competencies for Health Professionals

Answer 31

1. Application of Basic Biomedical Sciences to Immunization * The Immune System and Vaccines * Vaccine-Preventable Diseases * Vaccine Development and Evaluation * The Types of Immunizing Agents and Their Composition * Population Health 2. Essential Immunization Practices * Communication * Storage and Handling of Immunization Agents * Administration of Immunizing Agents * Adverse Events Following Immunization * Documentation * Populations Requiring Special Considerations 3. Contextual Issues Relevant to Immunization * The Canadian Immunization System * Immunization Issues * Legal and Ethical Aspects of Immunization

Question 32

1. Who are considered close contacts of a case of measles? 2. What are close contacts offered?

Answer 32

1. Anyone who has shared airspace with the case for any length of time while the case was communicable, including up to 2 hours after case has left the area

Question 33

Compare the live and recombinant shingles vaccines

Answer 33

Question 34

List the 4 criteria for being consider a Public Health Emergency of International Concern (PHEIC)?

Answer 34

**RUSS** - Is there a significant risk of **Restriction** of international trade or travel? - Is the event **Un**usual or **Un**expected? - Is the public health impact of the event **SERIOUS**? - Is there a significant risk for international **SPREAD**?

Question 35

List the 4 disease that are always considered Public Health Emergency of International Concern (PHEIC)

Answer 35

1) Small Pox 2) Wide type Poliomyelitis 3) SARS 4) New sub-type of human Influenza

Question 36

Vaccine Effectiveness Calculation List the two ways to calculate VE.

Answer 36

1. VE=[(Attack rate in unvaccinated - Attack rate in vaccinated) / Attack rate unvaccinated] \* 100 2. VE=1 - Relative Risk (risk of disease in vaccinated vs unvaccinated - will be \< 1) Attack rate in unvaccinated = unvaccinated ppl with disease/# unvaccinated ppl Attack rate in vaccinated = vaccinated ppl with disease/# vaccinated ppl RR = AR in vaccinated/AR in unvaccination (will be \<1)

Question 37

List 3 potential partners involved in a national foodborne outbreak involving a commercially available sprouts.

Answer 37

1. Public Health Agency of Canada - coordinates outbreaks when involving \> 1 province / territory - Lead agency for communication - Conducts surveillance for disease - including testing at the national microbiology laboratory 2. . Provinicial/Territorial Public Health Agency (PHO in Ontario) 3. Health Canada - conducts health risk assessments by addressing the following questions: 1) What is the likelihood the food will cause illness? 2) What is the potential duration and severity of illness? - analytical capacity for analyzing hazards - The Food Directorate focuses on issues relating to microbial pathogens, chemical contaminants, marine biotoxins, undeclared food allergens or other potential health hazards in foods 4. Canadian Food Inspection Agency - conducts all food, plant and livestock inspections. - responsible for regulatory compliance and enforcement activities - doees the testing, tracing and recall ``` - responsible for requesting a health risk assessment on a food item from Health Canada and for implementing the food recall. Based on Health Canada's HRA, CFIA determine the most appropriate action, including whether or not to recall product. If a recall is necessary, CFIA decide what class to assign to the recall: Class I (high risk), Class II (moderate risk) or Class III (low and no risk). ```

Question 38

List 5 nationally notifiable borne diseases in Canada

Answer 38

https://diseases.canada.ca/notifiable/diseases-list **A**IDS/Anthrax/Acute Flaccid Paralysis (AFP) **B**otulism/Brucellosis **C**ampylobacteriosis/Chickpox/Chlamydia/Cholera/Congenital Rubella Syndrome (CRS)/Cryptosporidiosis/Cyclosporiasis/Creutzfeldt-Jakob Disease (CJD) **D**iptheria **G**iardiasis/Gonorrhea/iGAS/GBS Disease of Newborn invasive **H**ib/HAV/HBV/HCV/HIV **L**egionellosis/Listeriosis/Lyme Disease **M**alaris/Measles/Mumps/IMD **N**orovirus **P**ertusis/Plaque/IPD/**Poliomyelitis** **R**abies/Rubella Salmonellosis/**SARS/Smallpox**/Shigellosis/Syphilis/Congenital Syphilis **T**B/Tetanus/Typhoid/Tularemia **V**erotoxigenic Escherichia coli Infection (VTEC)/Viral Hemorrhagic Fever (VHF) **W**NV **Y**ellow Fever

Question 39

List 4 risk factors for community-acquired pneumococcal disease in adults.

Answer 39

* Substance use disorder * Alcohol use disorder * Smokers * Homelessness * Current residence in long term care facility * Immunosuppression * Diabetes * Chronic heart disease * Chronic lung disease (including Asthma, COPD, chronic bronchitis) * Chronic liver disease (including Hepatitis B or C) * Chronic renal failure and nephrotic syndrome * Neuromuscular or seizure disorders * Rheumatoid arthritis, Crohn disease, lupus * Poor dental health * Cochlear implant * Chronic leak of cerebrospinal fluid