Emerging Infectious Diseases Flashcards
This deck contains all the emerging infectious diseases lectures given on Tuesday the 16th of January
1
Q
What are the major global threats in EID?(3)
A
- Biodiversity loss
- Global warming
- Zoonotic risk
2
Q
What are the main direct drivers of the increase in rate of global change? (5)
A
- Changes in land and sea use
- Direct exploitation of organisms
- Climate change
- Pollution
- Invasion of alien species
3
Q
What are the underlying causes of these main direct drivers?
A
- Twofold increase in the human population
- Fourfold increase in the global economy
- Tenfold increase in global trade
4
Q
Name the two key messages from the IPBES 2019
A
- Transformative changes are needed
- We have to steer away from the current limited paradigm of economic growth
5
Q
Why are ‘planetary boundaries’ used?
A
To categorize environmental impact from all human activities at the global scale
6
Q
Name the four planetary boundaries
A
- Climate change
- Biodiversity loss
- Land use change
- Disturbance of biochemical flows (N, P)
7
Q
What are human-animal interface factors?
A
Factors that contribute to the evolving risk for cross-species transmission of pathogens
8
Q
Name the human-animal interface factors important for cross-species transmission of pathogens (6)
A
- Domestication
- Agriculture
- Urbanization
- Colonization
- Trade
- Industrialization
9
Q
What is important to remember with respect to the human-animal interface factors?
A
That changes in the scope and range have been accompanied by the evolving risk for cross-species transmission of pathogens
10
Q
How did people from the human-gatherer society acquire new infectious diseases?
A
- Eating meat and moving into new territories
- Locally circulating endemic infections in wild animals
11
Q
What influenced animal-to-human spread of infectious diseases in the agricultural society?
A
- People learned to grow plants and to herd animals
- Living in settlements
12
Q
Zoonotic transmissions during the agricultural society (5)
A
- Tuberculosis (cattle)
- Smallpox (cattle)
- Measles (dogs)
- Leprosy (water buffalo)
- Influenza (horses)
13
Q
Important underlying causes of the increase of emergence of zoonoses (3)
A
- Increased human incursion into forests
- Increased numbers of farmed animals
- Increased trade/transport of animals
14
Q
Why are increased numbers of farmed animals and increased trade and transport causing this increase?
A
The numbers game. Increasing numbers of both allow infections to spread more easily
15
Q
Why do the increased human incursion into forests contributes to the emergence of zoonoses?
A
People become exposed to pathogens in animals with whom they did not previously have much contact
16
Q
Name the factors involved in the framework for categorizing drivers of emergence (3)
A
- Changes in human-animal interactions
- Proximate drivers
- Ultimate drivers
17
Q
Name the changes in human-animal interactions (3)
A
- Interspecies contact
- Range expansion
- Population growth/aggregation
18
Q
Name the proximate drivers (3)
A
- Habitat change
- Food/water change
- Migration/movement
19
Q
Name the ultimate drivers (3)
A
- Climate variability
- Land-use change
- Animal management change
20
Q
Which driver was important in the 2002 and 2019 SARS outbreak?
A
Increased trade/transport of animals
21
Q
Which driver was important in the 1980 AIDS outbreak?
A
Increased human incursion into forests
22
Q
Which driver was important in the 1997 and 2020 HPAI outbreaks?
A
Increased number of farmed animals
23
Q
Which driver was important in the 2013 ebola outbreak?
A
Increased human incursion into forests
24
Q
What is the definition of emerging infectious diseases?
A
Infectious diseases that have recently:
- Increased in incidence or geographic range in original host species
- Moved into new host species
- Been caused by newly evolved pathogens
25
Where do emerging infectious diseases come from?
More than 60% of emerging infectious diseases in the human population comes from animals
26
What is the definition of the (natural) reservoir host?
A species in which the pathogen endemically circulates and is considered to have co-evolved with
27
What is the definition of the intermediate (amplifying) host?
A species infected by a virus that is NOT the reservoir host, that plays an important role for spillover (to humans)
28
What is the definition of the vector?
A carrier of a disease-causing agent from an infected individual to a non-infected individual or its food or environment
29
What are vectors often used for?
Non-vertebrate reservoirs or objects
30
Which animal classes are important sources of emerging zoonotic viruses?
Birds and mammals
31
What species of mammal/bird is more likely to have a zoonotic virus?
It doesn't matter to which order a mammal/bird belongs
32
Why do zoonotic viruses occur more in bats and rodents than other wildlife species?
There are more bat and rodent species
33
Why are bats special? (2)
- They do not show illness for diseases that are very lethal to humans
- Their antiviral response is different than that of humans
34
Which factors are relevant to take into account for zoonotic viruses (3)
- Number of zoonotic viruses
- Transmissibility to humans
- Mortality
35
Why is it important to know reservoir species?
- Helps to target surveillance
- Helps to understand epidemiology
36
Most human cases of HPAIV result from contact with..
Chickens
37
Most human cases of Hendra virus result from contact with..
Domestic horses
38
Most human cases of MERS result from contact with..
Dromedary camel
39
True or false: 'Farmed animals often the reservoir host, while wildlife often the intermediate host'
False. Farmed animals are often the intermediate host, while wildlife is often the reservoir host
40
What are the risk factors involved in the wildlife trade driving the emergence of zoonoses?
- More intimate contact wildlife/livestock/humans
- Increased number and density of farmed animals
- Increased volume and longer distance of transport
41
Examples of wildlife trade driving the emergence of zoonoses
- Monkeypox
- SARS
- COVID-19
42
What does wildlife trade lack?
Pathogen surveillance
43
What is most regulatory oversight of wildlife trade aimed at?
Conservation, rather than prevention of disease incursion
44
How many bat species are there in The Netherlands?
17
45
What types of food do bats eat?
- Insects
- Fruit
- Pollen
- Nectar
- Fish
- Blood
46
What is the host of EBLV-1 in The Netherlands?
Serotine Bat
47
Host for rabies virus in South America
Vampire bat
48
Host for Marburg virus in Africa
Egyptian Rousette
49
True or false: "Animals are often the origin of EIDs, while human activity is the cause"
True
50
How much milk does the world now produce?
800 million tonnes
51
How much meat did the world produce in 2018?
340 million tonnes
52
Live animal markets have likely played a significant role in the spread of...
- SARS-CoV-2
- Avian Influenza
53
Name factors that enhance likelihood of pathogen shedding, transmission, cross-species spillover and illness that are intensified in live animal markets (5)
- Animals often held for long periods of time in overcrowded conditions
- Poor hygiene practices
- Mixed diverse species and close contact with traveling people
- Subsequent travel of purchased animals
- Complex trading chains
54
Which kinds of poultry farming are happening in Guangdong?
- Large scale poultry farming
- Smaller sale backyard farming
55
How many birds are annually imported into Guangdong?
200 million
56
Characteristics Influenza A virus (4)
- High diversity of host species
- High mutation rate
- 8 segments that can reassort
- Viruses named after HA and NA
57
Describe the process of the poultry market chain in Guangdong via large scale producers
- Day old chicken
- Large scale producers
- Automatic slaughtering facility
- Supermarkets/Fast food chains
- Consumers
58
Describe the process of the poultry market chain in Guangdong via small- and medium scale producers
- Day old chicken
- Small- and medium scale producers
- Wholesale poultry market
- Live bird market
- Consumers
59
Two which animal are hepatitis E-like viruses mostly related?
Rodents
60
How do viruses jump species? (3)
- Direct jump
- Adaptation
- Reassortment
61
Why are animal reservoirs important in livestock?
62
Characteristics poxviridae (5)
- Linear dsDNA
- Genome size: 130-375kb
- Brick-shaped and enveloped
- Envelope not needed for infection
- Replication only in cytoplasm
63
Which layer surrounds the core/nucleopratein complex?
Pallisade layer
64
How are the larger structures called that are located near the border of the pallisade layer?
Lateral bodies
65
What does IMV stand for with respect to the poxviridae?
Intracellular mature viruses
66
What does EEV stand for with respect to the poxviridae?
Extracellular enveloped viruses
67
What can be said about IMV and EEV particles?
Both particles are infectious, but antigenically distant
68
What division can be made host-wise for the poxviridae classification?
- Insect host
- Vertebrate host
69
What division can be made pathogen-wise for the poxviridae classification?
- Obligate human pathogens
- Zoonotic pathogens
70
Which viruses are obligate human pathogens (poxviridae)?
- Molluscum Contagiosum virus
- Variola virus
71
Which viruses are zoonotic pathogens (poxviridae)?
- Cowpox virus
- Vaccinia virus
- Monkeypox virus
72
What did Edward Jenner show in 1796?
Linkage between the presence of skin and mucosal lesions on cows and on the hands of they milk-maids, and the low percentage of smallpox between those milkmaids
73
When was M-Pox recognized as disease?
After Smallpox eradication
74
When was M-Pox identified?
in 1958 in laboratory animals
75
Which clades of M-Pox are circulating?
Clade I and II
76
Which clade of M-Pox is more pathogenic?
Clade I (11% vs 1-3%)
77
To which clade did the 2022 M-Pox outbreak strain belong to?
Clade II2B, most likely one single origin
78
To which disease are the large proportion of confirmed M-Pox deaths related to?
Development of encephalitis
79
Animal-to-human: describe the paths of M-pox transmission
- Bite/Scratch from infected animals
- Hunting: consume infected animals
- Contact with infected secreations/lesions
80
Human-to-human: describe the paths of M-pox transmission
- Respiratory droplets from close contact
- Direct contact with lesions
- Contaminated surfaces
81
What are the sequential phases of M-pox infection?
- Incubation period
- Prodromal phase
- Rash phase
- Desquamation phase
82
How long is the incubation period of M-pox?
7-14/21 days
83
How long is the prodromal phase of M-pox?
1-4 days
84
Which symptoms characterize the prodromal phase?
- Headache/Fever
- Myalgia
- Chills
- Sore throat
- Malaise/Fatigue
- Lymphadenopathy
85
How long is the rash phase of M-pox?
2-4 weeks
86
Which symptoms characterize the rash phase?
Skin rash that develops into papuples and vesicles and eventually crust and heal
87
What characterizes the desquamation phase?
Crusting and peeling off of lesions
88
True of false: "M-Pox lesions have a different development stage"
False. All lesions in M-Pox have the same development stage
89
True or false: "Chickenpox lesions have different development stage"
True
90
Describe the five stages of M-pox lesions
- Macule: rash starts as flat, red spots
- Papule: spots become hard, raised bumps
- Vesicle: bumps get larger and look like blisters with clear fluid
- Pustule: blisters fill with puss
- Scabs: spots crust over and become scabs that eventually fall off
91
Diagnostics: how do you determine if someone has smallpox or m-pox?
Swabbing of lesions to perform PCR
92
Human-to-human transmission: Describe the proposed pathogenesis of m-pox
- Viral entry and replication in Oropharyngeal or Respiratory mucosa
- Viral load circulates to LN draining mucosa
- Primary Viremia
- Lymphoid organs and distant LN: viral replication occurs
- Secondary viremia
- Tertiary organs/skin: clinical manifestation
93
Animal-to-human transmission: Describe the proposed pathogenesis of m-pox
- Viral load circulates to LN draining mucosa
- Primary Viremia
- Lymphoid organs and distant LN: viral replication occurs
- Secondary viremia
- Tertiary organs/skin: clinical manifestation
94
What delayed the detection of the M-pox outbreak in 2022?
Differential diagnosis of syphilis, chickenpox and other STDs
95
What were the symptoms of the 2022 M-pox outbreak?
- Lesions often in anogenital and oral areas
- Solitary genital skin lesions
- Lesions involving palms and soles; rarely more than 10 lesions
96
What is so special about the 2022 M-Pox outbreak?
Uncommon symptoms in the beginning hard to diagnose
97
M-pox risk factors in Africa (4)
- Living in forested areas near squirrels
- Disease burden in children and females
- Human-to-human transmission through close contact
- Nosocomial infection females
98
M-Pox prevention/treatments (4)
- Supportive care during infection
- Vaccinia Immunoglobulin (immunocompromised patients)
- Vaccines
- Antivirals
99
Describe smallpox vaccines
- 0 generation: Variolation
- 1st generation: Dryvax
- 2nd generation: ACAM 2000
- 3rd generation: MVA
100
Are smallpox vaccines cross-reactive to M-pox?
Yes, smallpox vaccination lowers probability of contracting M-Pox by 85%
101
Which antivirals are used to combat M-Pox?
- Tecovirimat
- Cidofovir
- Brincidofovir
102
How can you develop an antiviral to an eradicated disease?
FDA animal rule
103
What kind of genome do enteroviruses have?
Small (pico) positive strand RNA
104
To which family do enteroviruses belong?
Picornaviridae
105
When was poliovirus first identified?
1909
106
When did polio outbreaks occur in Europe and the US?
In the beginning of the 20th century
107
What happened in 1949 with respect to polioviruses?
Ability to propagate poliovirus in cultured cells led to:
- Identification of 3 serotypes
- Generation of vaccines
108
Poliovirus: clinical manifestations of human infections (5)
- Asymptomatic
- Non-paralytic polio
- Non-paralytic CNS disease (meningitis)
- Paralytic poliomyelitis (acute flaccid paralysis)
- Bulbar paralytic polio myelitis (brain stem)
109
Poliovirus: outcomes after paralytic disease
- 10% complete recovery
- 80% permanent paralysis
- 10% fatal
110
What is post-polio syndrome and when does it occur?
Muscle atrophy and weakness, pain, new disabilities, fatigue, sleep problems. Occurring 15-60 year post- paralytic or non-paralytic disease.
111
Which two vaccins are available for polio?
- Salk inactivated poliovaccine
- Sabin live-attenuated vaccine
112
What are the advantages and disadvantages of the Salk-inactivated poliovirus vaccine?
Advantages:
- Almost 100% seroconversion
- No severe side effects
Disadvantages:
- Expensive
- Needles required
- Low intestinal immunity - only reduced virus shedding
113
What are the advantages and disadvantages of the Sabin live-attenuated vaccine?
Advantages:
- Cheap
- Intestinal immunity
- Passive immunization of unvaccinated persons
- Does not require a cold-chain
- Oral drops - easy to administer
Disadvantages:
- Acquisition of virulence mutation
- Vaccin-associated paralytic poliomyelitis (VDPV)
- Circulation of VDVP
114
What is the goal of the Global Polio Eradication Initiative?
To complete the eradication and containment of all wildtype and vaccine-related polioviruses, such that no child ever again suffers paralytic poliomyelitis
115
True or false: "Eradication of poliovirus = eradication of acute flaccid paralysis?"
Nope --> neurotropic enteroviruses
116
Name four neurotropic enteroviruses
- Coxsackievirus
- Echovirus
- Enterovirus 71
- Enterovirus D68
117
Which symptoms are associated with enterovirus D68?
Predominantly:
- Severe respiratory illness
CNS diseases:
- Acute flaccid myelitis
- Cranial nerve dysfunction
- Encephalomyelitis
118
Where can you detect enterovirus D68 in the body?
Respiratory samples, occasionally in CSF
119
Which (sub)clade is responsible for the 2014 D68 outbreak?
Subclade B1 most prevalent
120
Is neurotropic potential a clade specific effect?
No
121
What is the difference in pathogenesis between EV-D68 and other enteroviruses?
Replication in the respiratory tract:
- behaves more like a rhinovirus
- acid sensitive
- replication optimal at 33C
122
What is a similarity between poliovirus and EV-D68 target-wise?
Both viruses target motor neurons in the spinal cord
123
What is difference between poliovirus and EV-D68?
Primary replication site differs (intestinal- vs respiratory tract)
124
What are the three steps of the pathogenesis of EV-D68?
- Respiratory infection
- Systemic dissemination
- CNS invasion
125
What are the characteristics of the respiratory phase of EV-D68 infection?
- Infection of ciliated respiratory epithelial cells
- Cell death and inflammation
- Severe disease often associated with asthma
126
What is a complication during the respiratory phase of EV-D68 infection?
Virus spreads to lower respiratory tract leading to pneumonia and severe asthma exacerbations
127
In which sites of the body can you confirm EV-D86 infection?
Lymphoid tissues and gastro-intestinal tract
128
Which cells are susceptible for EV-D68 in lymphoid tissues?
Lymphoid cells such as B cells
129
Which cells are susceptible for EV-D68 infection in the gastro-intestinal tract?
Intestinal epithelial cells
130
What are complications of systemic dissemination of EV-D68?
- Acute cardiac failure
- Skin rash
131
What are CNS complications observed in patients infected with EV-D68?
- Acute flaccid myelitis
- Cranial nerve dysfunction
- Encephalitis
- Aseptic meningitis
- Meningo-encephalitis
132
What are the routes of CNS invasion by EV-D68?
- Cranial nerves
- Viremia --> muscle cells --> motor neurons --> spinal cord
133
What is needed to control outbreaks?
- Identification and characterization of the pathogen
- Development of diagnostics to detect the virus in patients
- identify and isolate the individuals infected and place contacts in quarantine
- Lockdowns to protect the vulnerable when vaccines are not available
- Vaccination
134
Did MERS-CoV zoonotic transmission come from bats?
MERS-CoV is phylogenetically related to bat CoVs and replicates in a range of bat cell lines
135
What are risk factors for MERS illness?
- Dromedary farms
- Milking dromedaries while on farm
136
Why were vaccines not needed to control the 2003 SARS outbreak?
- Virus excretion in SARS patients peaked after lower respiratory tract symptoms occurred: isolation and quarantine of patients effective
- Few asymptomatic cases
137
What made SARS-CoV-2 hard to contain?
- Viral shedding peaks before symptoms occur
- Many infected individuals are asymptomatic
138
What are the steps in the diagnostic response to emerging infections?
- Problem definition
- Collection of background information
- Defining the criteria
- Choose the methods
- Validate
- Interpretation
139
What do you have to look out for during problem definition?
For which application is the assay needed
- Diagnosis of infection
- Determining the cause of illness
- Surveillance tool
- Research question
- Linking cases to a common source
140
What do you have to look out for during the collection of background information?
What is known about the pathogen/infection
- Pathogen, taxonomy, basic properties
- Clinical picture, age range, duration of complaints
- Kinetics of infection (shedding, immune response, relation to clinical symptoms)
- Incidence
141
What do you have to look out for during defining the criteria?
What are the assay requirements
- Turn-around time
- Costs
- Simplicity
- Need for high throughput?
- Safety requirements?
142
What do you have to look out for during validation?
- Assay sensitivity
- Assay specificity
- Detection limit
- Range/broadness
- Positive- and negative predictive values
143
What sensitivity and specificity are often used?
>90%
144
What do you have to look out for during the interpretation of results?
- Cut-off
- Qualitative or quantitative result
- Minimum number of specimens tested to assign outbreak to a pathogen
145
For correct interpretation of a test result, you need...
- Accurate specification of the assay
- Data on validation
- Basic information on patients
- Optimal sampling
146
