11.1 Emerging & re-emerging diseases Flashcards
1
Q
Emerging infectious diseases are ?
A
newly identified in a population
2
Q
examples of emerging infectious diseases ?
A
- ebola
- MERS-CoV
- SARS-CoV-2
3
Q
Re-emerging infectious diseases are ?
A
already known that have been previously under control but are reoccurring
4
Q
Infectious disease emergence has 2 main steps which are what ?
A
- an agent is introduced into new host population
- agent is established & transmitted within new host population
5
Q
Reasons for emergence of new infections ?
A
- microbial adaptation & change
- ecological changes
- human behaviour
- demographics e.g. poverty
- technology & healthcare
- travel, trade & industry (e.g. antibiotics in farm animals)
- public health measures e.g. sanitation
- lack of vaccination programs
- susceptibility to disease
6
Q
Why is microbial adaptation and change a reason for emergence of new infections?
A
Microbes continually adapt to environment, they may adapt to evade immune system or be provided with new ability to invade human cells.
They could develop AMR (antimicrobial resistance)
They could change, making vaccines less effective
7
Q
Examples of ecological changes that is a reason for emergence of new infections ?
A
- due to urbanisation, deforestation humans may come into contact with animals increasing exposure
- climate change = provide more favourable conditions for vectors to carry disease
- floods
8
Q
Why is urbanisation , deforestation a reason for emergence of new infections?
A
- Humans may come into contact with animals which can increase risk of human exposure to infectious disease
9
Q
Why is climate change a reason for emergence ?
A
might provide more favourable conditions for vectors to carry disease
10
Q
Why is human behaviour a reason for emergence of new infections?
A
- Sexual contact, drug use, outdoor activities = increased exposure (which can spread rapidly in populated areas)
11
Q
Why is demographics a reason for emergence of disease ?
A
Poverty, social inequality, politics
12
Q
Why is technology & healthcare a reason for emergence of new infections?
A
new procedures & medical treatments – e.g., blood transfusions, organ transplants
13
Q
Why is travel, trade & industry a reason for emergence of new infections?
A
- International travel & transport of animals & goods – makes it easier to spread microbes & vectors worldwide
- Widespread use of antibiotics in farm animals – contribute to AMR
14
Q
Why is public health measures a reason for emergence of new infections?
A
- Poor sanitary conditions
- hygiene
- lack of clean drinking water may provide potential for spread of existing infections and emergence of new infections
15
Q
Why is lack of vaccination programs/breakdown of Public helath measures a reason for emergence of new infections? e.g. mosquito spraying…
A
E.g., mosquito spraying for malaria can result in emergence of previously controlled disease
16
Q
Why is susceptibility to disease a reason for emergence of new infections?
A
Individuals may be more susceptible to infection due to low vaccine uptake, increasing age, malnutrition, disease
17
Q
Many infectious diseases can be managed by Public Health measures such as…
A
- good hygiene practices
- immunisation programs
18
Q
The UK …1…and ..2.. aim to detect possible outbreaks of disease & epidemics ASAP
A
- HSA (health security agency)
- PHE (public health england)
19
Q
On diagnosis of a suspected notifiable disease what must be completed ?
A
a notification form
20
Q
There is a list of notifiable diseases and causative agents notifiable to UKHSA under the Health Protection Regulations (2010).
Give some examples of notifiable diseases
A
- ebola
- tuberculosis
- measles
- mumps
21
Q
Why is global surveillance of infectious disease so important?
A
- Data serves as early warning systems for impending outbreaks that could become PH emergencies
- Enables monitoring/evaluation of impact of an intervention
- Monitors epidemiology of diseases
- Guides priority setting & planning
- Diseases can be detected QUICKLY before they spread, cost lives & become difficult to control
22
Q
Ebola caused by ?
A
ebolavirus
23
Q
what does ebolavirus cause in humans ?
A
viral hemorrhagic fever
24
Q
In ebola when do symptoms begin ?
A
2-3 weeks post-infection
25
Pathophysiology of ebola ?
1. Infected fluid comes into contact with breaks in mucosa / skin
2. monocytes, macrophages and dendritic cells are preferred replication sites
3. these infected immune cells migrate to the lymph nodes, liver & spleen and disseminate infection
4. extensive viral replication occurs in lymphoid tissue, liver & spleen
5. virus triggers expression of pro-inflammatory cytokines (TNF-alpha, interleukins)
6. this leads to endothelial activation, reduced vascular integrity & onset of coagulopathy due to release of tissue factor & increased NO levels
7. disseminated intravascular coagulopathy leading to hepatic impairment and bleeding complications
26
Complications of ebola ?
hepatic impairment
bleeding to death
27
What leads to the hepatic impairment and bleeding to death, which are complications of ebola ?
ebolavirus triggers expression of pro-inflammatory cytokines
which leads to endothelial activation, reduced vascular integrity & onset of coagulopathy due to release of tissue factor & increased NO levels
resulting in disseminated intravascular coagulopathy
28
Tuberculosis = pulmonary infection with ....?
mycobacterium tuberculosis
29
In latent TB patients with ....1.... have no ...2.... evidence of active TB
1. mycobacterium tuberculosis
2. clinical, bacteriological, radiographic
30
Groups at increased risk for developing active TB infection from latent TB
Homeless
Injecting drug users
Cigarette smokers
Immunocompromised people
31
examples of immunocompromised people that are at increased risk for devleoping active TB infection from latent TB ?
* people on corticosteroids
* diabetes
* end-stage renal disease
* malnutrition
* haematological malignancies
32
Pathophysiology of TB ?
1) Inhalation of droplets, which deposit in the alveoli
2) M. tuberculosis is engulfed by alveolar macrophages = multiplication in macrophages, kills macrophages & released.
3) Immune response activated
4) M. tuberculosis is either cleared (no TB), latent TB or progression to primary disease
33
In latent TB, Th1 response and macrophages form a ...... which prevent further growth/spread
granuloma
34
In Active TB the immune system cannot contain M. tuberculosis so it is .... & ...... infection
released
establishes
35
Treatment of latent TB
Isoniazid
Rifampicin
36
Treatment of HIV-negative and active TB
Isoniazid
Rifampicin
Pyrazinamide
Ethambutol
37
Why do HIV-positive patients with active TB who are on ART may need to considder alternative treatments to Rifampicin ?
contraindications on ART
38
what are the alternative medications that can be given to HIV-positive patients with active TB who are on ART ?
Rifabutin
39
Measles is a highly ..1... virus which is preventable by ..2...
1. infectious RNA
2. immunisation
40
Measles vaccine
1. how many doses required to ensure immunity with MMR vaccine ?
2. what's the main cause of the increase in measles cases ?
1. 2
2. failure to vaccinate on time with 2 doses of measles containing vaccines
41
Koplik's spots are a feature of...
measles
42
early complciations observed in measles ?
pulmonary involvement
43
later complications observed in measles ?
* bacterial superinfection with common bacterial pathogens leading to pneumonia
44
other complications of measles apart from bacterial superinfection & pulmonary involvement?
* otitis media (ear infection)
* pneumonia
* encephalitis
45
1. Which vitamin should be considered in children with complications of measles ?
2. Complications like what
3. or have what ?
1. vitamin A
2. malnutrition , immunodeficiency
3. emigrated from areas with high measles mortality rate
46
mumps is what disease ?
acute systemic infectious disease
47
mumps caused by what ?
mumps virus (RNA paramyxovirus)
48
Which gender is more likely to develop complications of mumps ?
men
49
Complications of mumps involves what ?
- Severe testicular pain, erythema of scrotum
- Testicular atrophy (orchitis)
- Decreased sperm count
- Aseptic meningitis
- Infertility
- Premature menopause
- Encephalitis
- Pancreatitis
- Deafness
50
What RNA viruses are coronaviruses ?
enveloped, positive stranded
51
Most coronaviruses infect animals such as ..1.. which act as ...2../ hosts of disease
1. bats, birds, mammals
2. reservoirs
52
1. number coronaviruses known to infect humans ?
2. how many cause common cold ?
3. how many cause more sever disease ?
1. 7
2. 4
3. 3
53
Of the coronaviruses which cause severe disease what are they ?
* SARS-CoV-1 = SARS = severe acute respiratory syndrome
* MERS = middle-east respiratory syndrome
* SARS-CoV-2 = COVID-19
54
SARS
1. caused by ?
2. .... and ..... contagious viral .... infection
3. transmitted via ....
4. viral .... that rapidly progresses to .... failure
1. coronavirus
2. severe , highly, lung
3. respiratory droplets
4. pneumonia, respiratory
55
MERS:
1. acute viral resp tract infection caused by ?
2. clinical spectrum varies from ?
3. may present in ways similar to .... e.g. ?
4. animal that is thought to be the primary animal host of MERS-CoV ?
1. MERS-CoV
2. asymptomatic to severe rapidly progressive pneumonia, septic shock & multi-organ failure
3. common cold e.g. fever, cough, dyspnea, hemoptysis
4. camels
56
What are the key diagnostic factors of MERS ?
- Residence in or travelling to Middle East in 14 days prior to onset
- Age >14
- Fever, cough, dyspnea
- Close contact with infected individuals (e.g., family clusters)
- Exposure to camel or camel products (e.g. camel meat, camel milk)
57
Patients with MERS who have comorbid conditions are more likely to have SEVERE disease symptomatology.
What comorbid conditions does this include?
diabetes, renal impairment, heart disease, obesity, smoking
58
COVID-19
1. ..... infection
2. caused by ?
1. acute respiratory
2. SARS-CoV-2
59
It is important to differentiate COVID-19 from community-acquired pneumonia, influenza, common cold & TB. It can be difficult to do this based on symptoms alone, this is why testing is so important.
Differentiating symptoms of TB include...
* weight loss
* night sweats
* endemic area
60
Risk factors for COVID-19
- Contact with cases
- Older age
- Male sex
- Ethnic minority
- Diabetes
- Pulmonary disease
- Hypertension
- Immunosuppression, HIV
61
Investigations for covid-19 ?
- PCR, rapid antigen test- confirms virus
* Pulse oximetry (hypoxia)
* CXR
* Rule out bacterial LRTI- blood cultures
62
complications of covid-19 ?
* Thrombosis- hypercoagulable state
* Cardiovascular complications
* Acute kidney injury (common in critically ill patients)
* Long COVID, post-covid-19 syndrome
* Sepsis, septic shock (ICU and hospitalised patients)
63
4 types of influenza viruses ?
* A
* B
* C
* D
64
What can cause an influenza pandemic?
The emergence of a new and very different Influenza A virus with the ability to infect people and sustain human-to-human transmission
65
Which type of influenza virus circulates among humans and causes seasonal epidemics?
influenza b virus
66
Besides humans, which other animal has recently been found to be infected by Influenza B viruses?
Recent data showed that seals can also be infected
67
Which animals can Influenza C viruses infect, and how severe are the infections typically?
Influenza C viruses can infect both humans and pigs, but the infections are generally mild and are rarely reported.
68
Which type of influenza virus primarily affects cattle?
Influenza D viruses
69
Are Influenza D viruses known to infect or cause illness in people?
No
70
Which influenza virus is the major cause of pandemic and epidemic infections?
Influenza A viruses are of most significant to Public Health due to their potential to cause influenza pandemics.
71
Influenza A viruses are classified into subtypes based on combinations of different virus surface proteins known as...
Haemogglutinin (HA) and Neuraminidase (NA)
Examples include avian influenza (bird flu) virus subtypes A(H5N1) and A(H9N2)
72
Avian influenza A viruses (H5N1 and H9N2)
Contagious disease caused by viruses which infect birds
73
Avian Influenza A/Influenza/TB/COVID-19/bacterial pneumonia/SARS/MERS all present with similar signs/symptoms…
What investigations should you consider to make an effective differential diagnosis from Avian influenza A virsues?
- PCR for COVID-19, Avian influenza A (H7N9, H5N1), SARS, MERS
- Sputum/blood culture for bacterial pneumonia
- Acid fast stain and culture for TB
- CXR (TB shows fibronodular opacities in upper lobes of lungs), also helpful for pneumonia (viral/bacterial), lung cancer (can detect masses)
74
Treatment for avian influenza A viruses
Antivirals = neuraminidase inhibitors e.g., Oseltamivir
Antimicrobials if clinical suspicion of secondary bacterial infection
75
Prevention of avian influenza A viruses
- Regular hand washing, proper drying of hands
- Good respiratory hygiene (cover mouth/nose when sneezing)
- Early self-isolation if feeling unwell
- Avoiding close contact with sick people
- Avoid touching eye's/nose/mouth
76
Tick-borne encephalitis (TBE)
1. caused by ?
2. leading to infection of ....
3. characterised by .. ?
4. which is transmitted by ?
1. flavivirus
2. CNS
3. biphasic meningoencephalitis
4. ticks
77
Encephalitis is inflammation of the ?
brain tissue
78
Encephalitis is pathological state of ..1... leading to an altered state of ....2... signs
1. brain parenchymal dysfunction
2. consciousness of focal neurological
79
Risk factors for tick-borne encephalitis (TBE)
- History of recent tick bite
- Outdoor activities
- Occupational exposure e.g., military training
- Age >50 years
- Summer
80
Parotitis (parotid swelling) are observed in what infectious disease?
mumps
