Communicable disease concepts Flashcards
Name 5 examples of emerging/re-emerging infectious diseases
Human monkeypox; Chikungunya; Lassa fever; Dengue fever; Hantavirus pulmonary syndrome; Bunyavirus; E Coli O157:h7; Hendra virus, Nipah virus
Name 5 factors that influence the spread of an infectious disease
Transmissibility: R0 Speed of transmission: serial interval, incubation. latency, infectious period Pathogenicity Stage of epidemic Heterogeneity in transmission
What are the 7 diseases on the “Emerging priority diseases” list?
- Crimean-Congo haemorragic fever
- Ebola virus disease/Marburg virus disease
- Lassa fever
- MERS-CoV and SARS
- Nipah and henipaviral diseases
- Rift Valley Fever
- Zika
Explain ring vaccination as employed during the Congo Ebola outbreak
Once the index case is confirmed, then all close contacts (those who have had close contact with the patient/body fluids/linen, household members) and secondary contacts (household members of close contacts, extended family of close contacts) are vaccinated
What is the goal of the WHO R&D Blueprint for Action to Prevent Epidemics?
The goal is to improve the speed and effectivenss of clinical trial research before and during an epidemic
Name the 3 main features of the WHO R&D Blueprint for Action to Prevent Epidemics
- Improving coordination (global coordination mechanism, funding, communication)
- Accelerating R&D (disease prioritization, roadmaps and target product profiles, regulatory and ethical pathways)
- Developing norms and standards (clinical trial designs, data and sample sharing)
True or false: Lassa fever is asymptomatic/subclinical in 50% of cases
False: Around 80% of Lassa fever cases are asymptomatic or subclinical. In the remaining 20% of cases, non-specific symptoms develop within 2-21 days after infection
MERS-CoV is a viral respiratory disease caused by a novel coronavirus first identified in Saudi Arabia in 2012. What is its case fatality rate? A - 2% B- 5% C - 15% D - 40% E - 85%
D - 40%
Supportive care is the major treatment
What is the natural host and intermediate host of Nipah virus?
Natural host: fruit bats
Intermediate host: pigs
People have also become infected from consuming contaminated date palm sap and limited human-human transmission has also been observed
What are the at risk populations for Crimean-Congo haemorrhagic fever?
Farmers in endemic areas (in Africa, the Balkans, Middle East and Asia), abattoir workers, veterinary officers working with domestic animals, healthcare workers
What is the definition of Disease X (list 4 options)
Disease X is a pathogen currently unknown to cause human disease - there are 4 main subtypes
- Known pathogen that becomes more virulent
- Known pathogen that causes a large outbreak and reveals serious sequelae
- Known zoonotic pathogen that spills over to humans
- Unknown pathogen
What is the Ebola virus and what is Ebola virus disease?
The ebola virus is a RNA-filovirus, of which there are 5 subtypes (bundibugyo ebolavirus, Lake Victoria marburgvirus, Sudan ebolavirus, Tai Forest ebolavirus, Zaire ebolavirus). The clinical features of Ebola virus disease are as follows Phase 1 (days 0-3) early febrile Phase 2 (days 3-10) gastrointestinal (NVD) with associated persistent fever, headache, conjunctival injection, abdo pain, myalgias, delirium Phase 3 (days 7-12) shock or recovery Late complications (>10 days) - GI haemorrhage, secondary infections, meningoencephalitis, persistent neurocognitive abnormalities
Where was the initial outbreak in the 2014 West African Ebola epidemic? A. Sierra Leone B. Liberia C. Guinea D. Ivory Coast E. Senegal
C. Guinea
The epidemic was traced back to the district of Gueckedou on the border of Guinea and Liberia
What were some of the challenges in responding to the Ebola epidemic in West Africa?
Ebola virus disease has nonspecific symptoms in the early phases
Lack of effective treatments (supportive care only)
Lack of vaccine at the beginning of the outbreak
Hospitals and health centres closed due to multiple reasons - no one to deliver health care, diagnose/test infections
What are the key elements included in the definition of public health surveillance?
Ongoing (not a one-time survey) systematic collection analysis interpretation dissemination link to action
What is the difference between active and passive surveillance?
Active - health department staff call or visit health care providers on a regular basis to solicit case reports
Passive - health care providers, hospitals, labs send reports to the health department based on a set of rules and regulations
What are the attributes of a surveillance system that should be evaluated to ensure the system is meeting its objectives?
Simplicity Flexibility Data Quality Acceptability Sensitivity Positive Predictive Value Representativeness Timeliness Stability
What are some of the reasons that the outbreak of Ebola virus disease in DRC had a better outcome compared to the outbreak in West Africa?
Stronger health system
Previous experience with EVD
Rural/remote region - not in major cities
Fast response/community participants
What are the 5 goals of the Global Vaccine Action Plan?
- Achieve a world free of poliomyelitis
- Meet vaccination coverage targets in every region, country and community
- Exceed the Millenium Development Goal 4 target for reducing child mortality
- Meet global and regional elimination targets
- Develop and introduce new and improved vaccines and technologies
What is the difference between elimination and eradication of polio?
Elimination refers to the reduction to zero (or a very low defined target rate) of new cases in a defined geographical area
Eradication refers to the complete and permanent worldwide reduction to zero new cases of the disease through deliberate efforts
How many diseases have been eradicated?
One - smallpox
Discuss the achievements and challenges in global DTP vaccination
ARound 85% of infants worldwide received 3 doses of DTP vaccine in 2019. 125 member states had reached at least 90% coverage. A key challenge is that 14 million infants did not receive an initial dose of DTP vaccine and an additional 5.7 million are partially vaccinated. >60% of these children live in 10 countries: Angola, Brazil, DRC, Ethiopia, India, Indonesia, Mexico, Nigeria, Pakistan and the Philippines
Discuss key points in the global HPV vaccination campaign
Global HPV vaccine coverage is increasing and the pace of introduction is accelerating. HPV vaccine coverage varies substantially, regardless of income strata. 61% of cervical cancer cases occur in countries that have not yet introduced HPV vaccination
Name 5 vector borne diseases
Dengue fever, Yellow fever, Zika, malaria, Japanese encephalitis, Plague, Sleeping sickness, Schistosomiasis
Identify the vector, incubation and reservoir for Malaria
Vector - Anopheles mosquitos
Incubation period - 7-30 days
Reservoir - Humans
Name 5 prevention and control strategies for Malaria
Environmental management strategies to control vectors
Personal protective measures (repellent, mosquito nets)
control blood products
Early diagnosis and treatment
Chemoprophylaxis
What is the vector, incubation period and reservoir for sleeping sickness/African trypanosomiasis?
Vector - tsetse fly
Incubation period - months to years
Reservoir - cattle and other wild and domestic animals
List 5 different types of vector-borne disease control measures and an example of each type
Chemical - insecticides Biological - Wolbachia Physical - mosquito nets Vaccines - for yellow fever Behavioural - changes in behaviours eg emptying out water containers
What are some of the characteristics of Aedes aegypti that make it such an effective vector?
Lives around humans
Feeds almost exclusively on humans
Feeds intermittently - bites and transmits infections to many people per blood meal
What prompts a country to consider adding a vaccine to their national program?
Surveillance - high incidence or mortality from a VPD; increasing incidence or re-emergence
New or improved vaccine becomes available
New WHO recommendation
Availability of donor support
Offer of vaccine donation from pharmaceutical company
Political pressure
What is the global burden of disease from respiratory-borne diseases?
Upper respiratory infections caused 18.8 billion cases in 2013 with 4 million deaths.
Acute respiratory infection/pneumonia is a leading cause of death for children under 5 years globally - responsible for 15% of all deahts in children under 5.
Explain the role of the International Health Regulations with regard to respiratory diseases
The IHR require member states to meet core capacities in preparing for and managing diseases that may constitute a public health event of international concern. Influenza and SARS are events of international concern requiring immediate notification to WHO under the IHR
What do the Integrated Disease Surveillance Response Technical Guidelines require member states to do in relation to respiratory diseases?
The IDSR Technical Guidelines identify a number of respiratory diseases as priority diseases. These include where identification is required under IHR (human influenza and SARS); they are diseases with a high epidemic potential; they are main causes of morbidity and mortality.
Member states are required to build core capacities for surveillance, laboratory testing and response to these diseases as they may result in a public event of international concern
What are the key elements of success in managing pandemics?
Engagement Preparedness Resilience - absorbing capacity, buffering capacity, responsivness Governance and Agility Engagement
What is the definition of absorbing capacity? Give 2 examples
The ability to absorb the free energy of an event without sustaining damage. Examples: levees, building codes, bomb shelters, airbags
What is the definition of buffering capacity? Give 2 health related examples
The ability of a society to cope with damage and to function despite damage. The ability to maintain essential functions despite a change in available resources
Examples: national medical supply stockpile, capacity to cease elective surgery, capacity to move to telehealth, pandemic planning
What is the role of the International Health Regulations?
IHR core capacities denote the functions required for a country to detect, assess, notify and report events, and to respond to public health risks and emergencies of national and international concern
What are the eight core capacities of the IHR identified by the WHO?
Core capacity 1: National legislation, policy and financing Core capacity 2: Coordination and National Focal Point (NFP) communications Core capacity 3: Surveillance Core capacity 4: Response Core capacity 5: Preparedness Core capacity 6: Risk communication Core capacity 7: Human resources Core capacity 8: Laboratory
What is the purpose of Public Health Emergency Operation Centres?
A public health emergency operations centre (EOC/PHEOC) is a physical or virtual space dedicated to managing public health emergencies as per the requirements of The International Health Regulations (IHR 2005). This is accomplished by strengthening communications and coordination for effective public health response
