Characteristics of Diseases Flashcards
1
Q
Difference between meningococcal disease and meningitis
A
Meningococcal disease= infections caused by the bacteria Neisseria Meningitidis
Meningitis = inflammation of the meninges (could be caused by virus/bacteria/other chemicals)
2
Q
What are the symptoms of meningitis?
A
Headaches Fever Vomiting Neck stiffness Seizures Rash - if septicaemia
3
Q
When does meningitis occur?
A
Sporadically
Can occur in clusters - eg: start of university/school
4
Q
Where does meningitis occur?
A
Anywhere
Endemic of group A in SSA
5
Q
How is meningitis transmitted?
A
Respiratory droplets (airborne)
6
Q
How long is the incubation period?
A
3-4 days
7
Q
Name 4 reasons why an epidemic of meningitis may occur
A
Concurrent respiratory tract infections Reduced immunity of the pharynx Overcrowded pharynx Large population displacement Waning herd immunity Respiratory tract irritation
8
Q
How would you manage an individual case of meningitis?
A
Confirm diagnosis by - bood tests, serological, lumbar puncture
Characterise the pathogen if possible
Identify potential source of infection
Identify who else is at risk - close contacts
Give close contacts chemoprophylaxis
Treat
9
Q
How would you manage a cluster of meningitis cases?
A
Confirm that the cases are linked by organism, plae and time
Work with where the cluster is eg: school, university, nursery etc.
Define who the ‘at-risk’ population are
10
Q
How would you manage epidemics of meningitis?
A
Same steps as for an individual case
Mass vaccination
11
Q
Which vaccines are available for meningitis and where are they implemented?
A
Men A&C - if travelling to Africa Men C - UK schedule Men ACWY - UK Men B - UK MenAfriVac
12
Q
What type of surveillance would be used for meningitis?
A
Passive - as it is a notifiable disease
Enhanced if suspected outbreak
13
Q
What is a HCAI?
A
HealthCare Associated Infection
Either acquired in a hospital setting or acquired as a result of a healthcare intervention
14
Q
Name 5 common HCAIs
A
Catheter associated UTI Ventilator associated pneumonia SSI (staph aureus) Central line bloodstream infections GI infections
15
Q
Name 5 common organisms that cause HCAIs
A
MRSA MSSA C.diff E.coli Staph.aureus
16
Q
Name 6 risk factors associated with HCAIs
A
Extremes of age Immunocompromised Long length of stay Antibiotic treatment Poor infection control standards Presence of invasive devices/broken skin/pressure sores
17
Q
Who is at risk of MRSA?
A
Newborns
IVDUs
Elderly
Surgical patients - usually transmitted through broken skin
18
Q
How would you manage an outbreak of MRSA?
A
Investigate the outbreak Screen staff Review the infection control practices Restrict admissions to ward Limit no. of visitors
19
Q
Why is C.difficile so difficult to treat?
A
Widely distributed in the digestive tract
Very resistant to heat or drying
20
Q
When do outbreaks occur?
A
Sporadic - preceded by a background rate
21
Q
How is C.difficile transmitted?
A
Faeco oral route
22
Q
How is an individual case of C.diff managed?
A
Isolate
Enteric precautions
Stool sample testing
Treat - with metronidazole/vancomycin
23
Q
What is the main risk factor for developing C.diff?
A
Broad spec antibiotic use
24
Q
Name 4 broad ways to manage C.diff infections
A
Control antibiotic use
Surveillance
Infection control measures
Case finding
25
When do norovirus outbreaks most commonly occur?
Winter (known as the 'winter vomiting' bug
26
Name 4 risk areas for catching norovirus
Hospitals
Care homes
Schools
Cruise ships
27
How is norovirus spread?
Faeco oral
28
How is norovirus managed?
No specific treatment
| INFECTION CONTROL
29
What is CPE and what characteristic does it hold?
Carbapenemase producing Enterobacteria
| High level of antibiotic resistance
30
What increases the risk of CPE infection?
Long antibiotic course
Use of ventilators
Use of catheters
31
How should CPE infections be managed?
```
Surveillance
Sampling and testing
Isolate any high risk cases
Frequent re testing
Contact tracing
High standard of hygiene
```
32
What is the difference between a community acquired and a hospital acquired infection?
Hospital - symptoms start 48 hours after admission
| Community - symptoms start within 48 hours of admission
33
Why are hospitals prone to infection outbreaks?
```
Crowded spaces
Patients bring in infections
Invasive procedures
Shared facilities
Open wounds
Bodily fluids
Visitors
Patients who are immunocompromised/susceptible
```
34
What is Hepatitis B caused by?
HBV DNA virus
35
How is Hep B transmitted?
Blood borne - through bodily fluids through skin or mucous membranes
36
What is the reservoir for Hep B?
Human hepatocytes
37
What is the incubation period for Hep B?
60-90 days (long!!)
38
Where is Hep B prevalent?
Highest in Africa, Asia and parts of SA
39
How does Hep B present?
Jaundice, abdo pain, nausea and vomiting
40
Give 5 risk factors for being exposed to Hep B
```
Risky sexual behaviour (includes MSMs, sex workers)
IVDUs
MTCT
Occupational risk
Blood transfusions
```
41
Is Hep B acute or chronic?
Both!
| More commonly chronic in children (after MTCT)
42
How can Hep B be prevented?
Vaccination
Education on risk factors
HBIGs
43
Who would be considered for a Hep B vaccination in the UK?
MSMs
Sex workers
IVDUs
Health/social care workers
44
How would you manage a case of Hep B?
```
Vaccination
Wound care
Antibiotics
Pegylated interferon
Manage close contacts - test and give prophylaxis (vaccine)
```
45
What is gastroenteritis?
An infection within the gastrointestinal tract
46
Name 5 bacteria, 3 viruses and 3 parasites that could cause gastroenteritis
E.coli, salmonella, shigella, typhoid, cholera
Rotavirus, noravirus and Hep A/E
Giardia lambia, ameobiasis and cryptosporidium homicus
47
What is the the difference between a short, medium and long incubation period for these organisms?
Short: < 8 hours
Medium: 8 --> 48 hours
Long: > 48 hours
48
Is the incubation period for these organisms short, medium or long?
1. Staph aureus
2. Campylobacter
3. Bacillus cerues
4. Salmonella
5. E.coli
1. Short
2. Long
3. Short
4. Medium
5. Long
49
Name 4 risk factors associated with GE
Food handlers
Children under 5
Health/social care staff
Poor personal hygiene
50
What information do you need to identify the source of gastroenteritis?
Date of onset of illness
Incubation period
Risk exposure
51
How do you limit the spread of GE?
Proper food handling
Hygiene advice - washing hands etc.
Stay off work for 48 hours after symptoms have stopped
52
Are you more likely to have diarrhoea or vomiting if the incubation period of the organism is short?
Vomiting - hasn't had time to get into the digestive tract yet
53
What is an STI?
Sexually Transmitted Infection - an infection passed from one person to another via sexual contact
54
Name 6 STIs
```
HPV
Chlamydia
Gonorrhoea
Syphillis
Trichomonas vaginalis
HSV
```
55
Where are STIs more prevalent?
SEA, SSA and latin America - higher in underdevelopment countries
56
What are the 3 universal risk factors for catching STIs?
Several partners
Frequent partner change
Unprotected sex
57
Name as many things as you can that can be seen as epidemic drivers of STIs
```
Poverty
Stigma
Unprotected sex
Poor treatment services
Multiple partners
Early sexual debut
Political instability
Lack of education/awareness
Substance misuse
Asymptomatic infections
```
58
What are the potential consequences of STI infections (other than immediate symptoms)?
HIV transmission risk
Poor reproductive or maternal health
Poor newborn health
Anogenital cancers
59
Name the methods of primary prevention of STIs
Education on behavioural things eg: condom use, frequent testing, partner change etc
Immunisations
Targeted interventions at 'at risk' groups
60
Name the methods of secondary prevention of STIs
STI screening
Universal HIV screening
Rapid/POC tests
61
Name the methods of tertiary prevention
Treatment of disease - antibiotics etc.
Abstinence till end of treatment
Treat contacts
62
Where would data sources for STI surveillance come from?
GUM clinics
Voluntary lab reporting
PHE reference labs
63
What is Legionellosis?
Infection with Legionella pneumophilia
64
How is Legionellosis caused?
Inhalation of aerosols containing the bacteria - usually through taps/showers/humidifiers etc.
Stagnant water = a big risk factors
65
How does Legionellosis present?
Flu-like illness,muscle aches, tiredness, fever, cough
66
What type of surveillance would be carried out in a Legionellosis outbreak?
National active - is a serious environmental issue where the transmission needs breaking
67
What is the incubation period for Legionellosis?
2-10 days
68
Who are at risk of Legionellosis?
```
Travellers
Cruise ships (common place for outbreaks)
```
69
How can Legionellosis be prevented?
Code of practice for the water sypplies
Maintain water temperatures
Regular flushing/disinfectants
Adequate cleaning and chlorination
70
What is SARS?
Severe Acute Respiratory Syndrome - caused by SARS coronavirus
71
What are the symptoms of SARS?
High fever,cough, SOB, myalgia and diarrhoea
72
How is SARS spread?
Droplet (respiratory)
73
What is the incubation period for SARS?
2-7 days
74
What is influenza?
An acute onset of upper and lower respiratory tract infection symptoms caused by an influenza virus
75
What is the difference between influenza serotypes A, B and C?
A -causes major pandemics, found in horses/birds/pigs/humans
B- causes severe symptoms, most commonly affects school children and only found in humans
C -causes mild symptoms, only found in humans and is sporadic
76
How is influenza spread?
Droplet spread
77
When does influenza present?
usually seasonal outbreaks (in winter months in UK) as a result of antigenic drift
78
What is the difference between antigenic shift and antigenic drift?
Shift - major changes leading to pandemics and major morbidity
Drift - minor changes that have less serious consequences but do occur more commonly
79
Who are at risk of developing influenza?
Elderly
Immunocompromised
People with chronic disease
80
How is influenza diagnosed?
Culture from throat/nose
| PCR or nose/throat swabs
81
What is 'excess mortality' and why is it used in surveillance of influenza?
Death from influenza is hard to confirm so have to include all deaths from things like bronchitis, pnuemonia, CHD etc as these all increase during influenza epidemics
82
Name 3 ways to manage an influenza outbreak
Vaccination
Anti-viral drugs
Raise public awareness
83
What is schistosomiasis and what is it caused by?
A water-based disease
| Caused by a parasitic worm that lives inside the blood vessels of the intestine or bladder
84
Where is schistosomiasis caught from?
Contaminated fresh water
85
Who is most at risk of schistosomiasis?
Children
86
Where is schistosomiasis most prevalent?
Is an endemic in many countries across Africa/Asia but highest rate in Nigeria
87
Briefly explain the life cycle of schistosomiasis
Host --> Eggs --> Miracidia --> Snails --> Cercariae
88
Name 4 ways to prevent/control schistosomiasis
Improve quality of water
Reduce the need for contact with the infected water
Health education
Drugs to treat infected people
Sanitation - preventing faeces reaching the fresh water
Molliscicides (to get rid of the snails)
89
What is hepatitis C?
Inflammation of the liver caused by Hepatitis C RNA virus
90
Is Hep C chronic or acute?
Can be either but the majority of infections lead to chronic infection
91
How is Hep C transmitted?
Blood-borne (less contagious than hepB)
92
Name 4 key risk factors for getting Hep C
IVDU
HIV positive
Chronic haemodialysis (any other reason for regular blood transfusions)
Children born to Hep C positive mothers
93
How is Hep C prevented/controlled?
Vaccination
Advice to patients
Post-exposure management - pegylated interferon and ribavirin
94
What is hepatitis A?
Acute infection causing inflammation of the liver due to the Hepatitis A RNA virus
95
How long is the incubation period of Hep A?
15-40 days - LONG
96
How is Hep A transmitted?
Faeco-oral
97
Name 4 risk factors for Hep A
```
IVDUs
MSMSs
Poor hygiene
Food handlers
Working with children or the elderly
```
98
What does Hep A spread easily?
Long incubation period
Low infectious dose
Asymptomatic infections are v common (especially in children)
99
Name 3 preventative measures for Hep A
Hand hygiene education
Sanitation
Immunoglobulins (provide passive immunity)
HAV vaccine
100
What is Tuberculosis and how is it caused?
An infection caused by mycobacterium tuberculosis - predominantly affects the respiratory tract but may affect other areas of the body (lymphatic system etc)
101
How is TB transmitted?
air borne - aerosol droplets
102
Why is TB difficult to prevent spreading?
Slow growing - in the person and the lab!
| Has a v long incubationperiod
103
How does it present?
Fever
Cough
Night sweats
Asymptomatic in majority
104
Name as many risk factors are you can for TB
```
HIV positive
Elderly
Immunocompromised
Poverty
Overcrowding
Age and Sex
Malnutrition
Travel
Migration
Ethnicity
```
105
Where is TB most prevalent?
Africa
106
How can TB be prevented?
BCG vaccine - given to at risk neonates but not very effective in adults
107
How is TB treated?
```
DOTS
Direct sputum smear mircoscopy
Observation of treatment
Treatment monitoring
Short course - of RIPE (rifampicin, isoniazid, pyrazinmade and ethambutol)
```
108
What is important to consider in an outbreak of TB?
Has a v long incubation period so cases may present late
| Chronic carrier status - many people are symptomatic and carry TB for several years
109
What is HIV caused by?
Human Immunodeficiency Virus - infects immune cells
110
Name 4 factors of the HIV virus/disease which make it difficult to treat
Reproduces inside immune cells
V long incubation period
Transmitted via sex which is difficult to control
Mutates rapidly
111
What is the natural history of HIV?
Mild seroconversion illness for a few weeks
Long asymptomatic phase
Symptomatic HIV - fever, weight loss, night sweats, lymphadenopathy
AIDS
112
What other illnesses may HIV affect the presentation of?
```
Syphillis
STIs
TB
Tropical diseases
Hep B/C
```
113
Name 4 epidemic drivers of HIV transmission
Unprotected sex
IVDU
Lack of knowledge
Lack of services
114
What surveillance is carried out for HIV?
Passive - is a pandemic so regular surveillance is required
| In countries with high levels likely to have active surveillance
115
Name the preventative methods for HIV
```
Male circumcision
Condom use
Mircobicides
PMTCT
PrEP/PEP
HIV testing
Drug/alcohol use
STI screening and control
Anti retroviral therapy
```
116
What is Cholera caused by?
Bacterial infection - vibrio cholerae
117
How is cholera transmitted?
Either water-borne or sometimes faeco-oral
118
How does cholera present?
Profuse watery diarrhoea, vomiting, dehydration
119
Name the different ways in which cholera may be caught/spread
```
From crustacean hosts found in water
Poor food hygiene
Cross-contamination in health centres
Person to person contact
Seasonal variation
```
120
Who does cholera affect?
Children - more affected
| Adults - more deaths
121
What are the challenges associated with controlling a cholera outbreak?
Large number of asymptomatic infections
Severe cholera can cause mortality within hours
Large epidemics can spread very quickly
Poor health infrastructure in the commonly affected areas
122
How can cholera be prevented/controlled?
```
Community education/knowledge of transmission and prevention
Effective excreta disposal
Improve water supplies/drinking water
Good hygiene awareness
Care at funerals of cholera deaths
Isolation and hygiene practices in hospitals
Vaccination
Fluid replacement for patients
```
123
How is malaria caused?
Infection by a plasmodium parasite that is found in female mosquitos (vector)
124
What is the incubation period for malaria?
9-14 days
125
What are the symptoms of malaria?
Acute febrile illness
Muscle pain/fatigue
N&V
126
Where is malaria most prevalent?
SSA
127
Name 3 risk groups for malaria
Infants/children U5
HIV/AIDS
Pregnant women
128
Name preventative or treatment methods for malaria
DEET
Bed nets
Chemoprophylaxis
Treatment - Chloroquine
129
Give examples of the data that may be collected for a HIV surveillance
Neonatal heel prick testing
GUM clinic testing
Pregnant women testing
130
How can MTCT of HIV be prevented?
Start women on HIV therapy
131
Who is malaria chemoprophylaxis given to and why?
Restricted to high risk groups including travellers from non malaria areas (tourists/expats), non immune migrant workers from non endemic areas or indigenous to malarious area
Not for everyone due to cost, drug resistance, poor compliance and adverse effects
132
What is shigellosis?
Caused by shigella bacteria - causes bacterial dysentery
133
How is shigella transmitted?
Faeco-orally through water or food
134
Why is shigella easily spread?
Has a low infectious dose
135
Where is shigella most prevalent?
Asia and South America
136
What is trachoma?
An infection with chlamydia trachomatis
137
How is trachoma spread?
Due to poor sanitation
| From eye to eye
138
Who is at risk of getting trachoma?
Living in Africa, SA and Asia
Children
Women > Men
139
How is trachoma treated/controlled?
```
SAFE
Surgery
Antibiotics
Facial cleanliness
Environmental improvement
```
140
How is polio transmitted?
Faceo-oral
141
What is the risk associated with polio?
Paralysis
142
What increases the risk of polio?
Poor sanitation
143
How can polio be prevented?
Vaccination
144
What is giardiasis caused by?
A parasite - giardia lamblia
145
What increases the risk of giardiasis?
Tropical environment
Travellers
Poor hygiene
146
How is giardiasis transmitted?
Faeco oral - usually transmitted by food handlers or through faeces
147
What is typhoid caused by?
Salmonella typhi bacteria
148
How is typhoid transmitted?
Seawater contaminated by sewage
| Milk/dairy contamination
149
Where is typhoid endemic?
Tropical areas
150
How can typhoid be prevented and controlled?
Protection of water
Sanitary disposal of faeces
Treat water
Identify carriers (can have chronic carries of typhoid)
151
How is tetanus transmitted?
Soil, animal faeces and unsterile medical equipment
152
Why is tetanus easily spread?
Spores are very hard to kill
153
Which areas are at increased risk of tetanus?
Africa/Asia
Places with rudimentary birth practices
Where animal faeces are used for plastering
Agricultural areas
154
How can tetanus be controlled?
Vaccination
Good hygiene
Clean and proper wound care - also give penicillin
155
What is filariasis?
A disease characterised by swelling caused by a worm
156
Briefly explain the life cycle of filariasis
Microscopic larvae enter the body via mosquito bites --. they then migrate into the lymphatic system and develop into adult worms which block drainage systems and caused swelling
157
Where are filariasis worms often found?
In septic tanks/flooded toilets
158
What is the management of filariasis?
Chemotherapy
Integrated vector management - similar to malaria
Regular washing of the infected area
159
Name the 4 most common causes of food poisoning and their incubation period
staph.aureus - short
salmonella - medium
clostridium perfringens - medium
campylobacters - long
160
How is food poisoning managed?
Offer general hygiene advice for future
Usually self limiting - stay hydrated if profuse diarrhoea
Microbiology of stool samples
Exclude cases from attending school/work/nursery
161
How can you tell the difference between food poisoning and other causes of GE?
Date of onset - clustered with food poisoning to suggest a point source outbreak but in GE may occur in waves
FP usually affects those at the food source whereas GE may be transmitted from case to case so affect anyone
Clinical features/lab tests - in FP show that it has been spread by food/water but in GE show case-to-case transmission
Environmental practices - in FP show poor food handling practices or in GE show poor infection control
162
Give an example of a water-borne disease and how they can be prevented
Transmitted by ingestion of the water
Cholera, Typhoid, Hepatitis A
Improve the quality of the drinking water, prevent the use of contaminated sources, improve sanitation
163
Give an example of a water-washed disease and how they can be prevented
Transmitted by multiple methods - GI infection/eye infection/lice infection
Trachoma, scabies, diarrhoea
Increase the quantity of water, improve access to water supply, improve sanitation
164
Give an example of a water-based disease and how they can be prevented
Ingestion or penetration of the skin by a water-based animal with the disease
Guinea worm, schistosomiasis
Reduce the need for contact with infected water, control the vector host, improve sanitation, improve water quality
165
Give an example of an insect-vector disease and how they can be prevented
Spread by insects that breed or bite near water
Malaria, river blindness
Improve surface water management, destroy insect breeding sites, mosquito nets, insecticides
166
In a 'explain the characteristics and epidemiology of disease x' question - what should be covered?
```
Time
Place
Person - risk groups/generally who is affected
Prevalence - high or low
Mode of transmission
Reservoirs
Control
Cause
Clinical Presentation
```
