Core Microbiology - Part 2 Flashcards
1
Q
What is a parasite
A
Organism that lives on another organism (its host) and benefits by deceiving nutrient at the others expense
2
Q
What is symbiosis
A
Living togethers, long term interactions
3
Q
What is mutualism
A
Where both species benefit
4
Q
What is parasistim
A
Where the parasite gets benefits
The host gets nothing but always suffers injury
5
Q
What is commensalism
A
Parasite derives benefit without injuring the host
6
Q
What is a definitive host
A
Harbours the parasite for the adult stage of the parasite or where the parasite reproduces
Usually human in the human parasitic infections
7
Q
What is intermediate host
A
Harbours the laval or asexual stages of the parasite
8
Q
What is the paretic host
A
Host where the parasite remains viable without further development
9
Q
What is taenia
A
a cestode
10
Q
what is schistosomiasis
A
a trematode
11
Q
What is assures lumbricoides
A
Intestinal nematode
12
Q
What is wuchereria bancrofti
A
Tissue nematode
13
Q
What are cryptosporidium, guard,, entamoeba and falciparum
A
Protozoa
14
Q
What is direct parasitic life cycle
A
Where one animal sheds the parasite and the other animal consumes it straight away
15
Q
What are indirect parasitic life styles
A
Where their are intermediate hosts
16
Q
What causes ascariasis
A
an intestinal nematode
17
Q
Life cycle type in ascariasis
A
Direct - worm goes from intestine, eggs to faeces, ingest the larvae, passes into our intestine, into portal circulation and then transports to the lung and swallow them and pass to the intestine
18
Q
Type of disease in ascariasis
A
Lung migration phase –> causes loafers syndrome: dry cough, dyspnoea, wheeze, haemoptysis, eosinophilic proneness
Intestinal phase –> malnutrution and, migration and obstruction
19
Q
Prevelance of ascariasis
A
In areas of poor hygiene
Peak prevalence age 3-8
20
Q
Treatment of ascariasis
A
Albendazole - Prevents glucose absorption by worm, worm detaches and dies
21
Q
What is schistosomiasis
A
a trematode
predominantly affects those in africa
22
Q
Type of life cycle in schistosomiasis
A
Eggs hatch and infect snails in freshwater snails. The coercive leave the snails and penetrate the skin
23
Q
Symptoms of schistosomiasis
A
Swimmers itch
Katayama fever
Urinary (S. Haematoburium) - haematuruia, bladder fibrosis and dysfunction CAN GET SQUAMOUS CELL CARCINOMA
Hepatic - portal hypertension and liver cirrhosis
24
Q
Treatment of Schistosomiasis
A
Praziquentel
25
What is hydatid disease caused by
Echinococcus - helminth infection
26
Life cycle of hydatid disease
Humans accidental intermediate host (usually iyn dogs and sheep)
Dogs get it by eating cyst infected organ
Found wherever dogs and sheep are
27
Clinical symptoms of hydatid disease
Cysts (mainly liver and lungs)
Mass effect with secondary hypertension
Control by worming dogs to reduce egg production
28
When do we suspect malaria
Returning traveller with fever
29
What causes malaria
Protozoa
Plasmodium
Transmitted by anopheles mosquito
30
Symptoms of malaria
Fever, rigor, renal gailure, hypoglycaemia, pulmonary oedema, circulatory collapse, anaemia, bleeding, DIC
31
Treatment of malaria
Insectide spraying in homes
Larvicidal spraying in breeding pools
Larvivorous species introduced to mosquito breeding areas
Chemoprophylaxis
32
What causes Cryptosporidosis
Cryptosporidium parvum and hominis (sporozoa)
33
How is cryptospoidosis spread
Human to human but also animal reserves
Faecal - oral spread!
Direct life cycle
34
How is cryptosporidosis spread
Humans at risk in swimming pools, cild care workers, nursing home
Animal - human spread in backpackers, farmers, visitors to farms etc.
35
Symptoms of cryptosporidosis
Diarrhoea etc
36
Treatment of cryptosporidosis
Nitzoxanide and rehydration for symptomtic
If immunocompromised give paramomycin, nitazoxNISW, OCREOTIDE, HIV PATIENTS quickly initiation HAART
37
Commonly used antiprotozoals
Metronidazole, pentamidine, nitazoxanide, pyrimethamine, anti malaria
38
Commonly used antihelminthics
albendazole, mebendazole, ivermectin, praziquentel
39
Name notifiable disaeses
Meningitis, poiomyelitis, measles, mumps, rubella and smallpox
40
What Ig stays long tiem
IgG
41
What Ig is in the acute infection
IfM
42
What are the possibilities for a child with a rash
Chicken Pox
Measles
Parvovirus - slapped cheek disease
Rubella
43
What causes measles
Paramyxovirus - single stranded RNA
| Spread person to person by droplet
44
Infectivitiy in measles
4 days before to 4 days after rash
| 15 minutes contact time is highly significant
45
Incubation of measles
7-18 days (10-12) average
46
Features of measles
3C's conjuctivitis, coryza and cough
| + fever and malaise and Koplik spots
47
Complication of measles
Otitis media, pneumonia, diarrhoea, acute encephalitis
| Subacute sclerosing panencephalisits --> rare fatal and late response
48
Treatment of measels
antibitoics for superficial infections!
49
Prevention of measels
Live vaccine at age 1
| don't give to immunocompromised
50
Causes of chicken pox
Varicella zoster virus - human DNA virus
| Spread by respiratory/personal contact
51
Incubation and infectivity of chicken pox
14-15 day incubation
| Infectivity 2 days before rash to after the vesicle dry up
52
Features of chicken pox
Fever, malaise, anorexia
Centripetal rash
Much worse effects in adults
53
Complications of VZV
Prenuonitis, thrombocytopenic purpura, foetal variclla syndrome and congenital varicalla zoster
54
When do we give IgG in VZV
Test mother who is pregnant if no history of chicken pox - if no IgG five them immunoglobulins
55
Treatment of IgG
Only really treat symptomatic adults and immunocomprosimed children
Give Aciclovir oral but IV in severe cases
Chlorphenimarine can relieve the itch
56
Prevention of chicken pox
Live vaccine 2 doses
Give VZ immunoglobulins if significant exposure and pregnant or immunocompromised, neonates or no antibodies to VZ at all
57
What cause rubella
Togavirus an RNA virus
58
Incubation and infectivity of rubella
14-21 days
| Infective one week before rash to 4 days after
59
Features of rubella
Lymphadenopathy
Non specific rash - starts on the face and spreads to the rest of the body
Aching joints particularly in young females
50% of children are asymptomatic
60
Rubella in pregnany
Congenital rubella syndrome
Cataracts, deafness, cardiac abnormalities, microcephaly, retarded intra-uterine growth
Foetal damage rare if contracted after 16 weeks
61
Testing for rubella
IgM positive for about 1-3 months
| This means that women who is IgM positive even at 20 weeks may have contracted the disease much earlier
62
Treatment of rubella
No treatment
| But vaccine part of MMR
63
What causes slapped cheek diseases
Parvovirus RNA Virus
| Transmitted by respiratory secretion from other to child
64
Incubation and infectivity of parvovirus
4 to 14 days incubation
| Once you have the virus no longer ingective
65
Foetal diseases of parvovirus
anaemia, hydrops
| Can give intrauterine foetal transfusion for anaemia
66
Features of parvovirus
Minor respiratory illness
Rash - slapped cheek
Athralgia, plastic anaemia - may be prolonged in immunocompromised
Tends to peak in early summer/late spring
67
Treament of parvovirus
None if self limiting - blood transfusion
No vaccine available
Infection control difficulty prior to the rash arising!
68
Enterovira linfections
Transmission is faecal-oral and by skin contact - wide spread disease and can cause neonatal meningitis
69
Causes of respiratory problems in childrem
```
Respiratory Syncitial Virus
Metapneumovirus
Adenovirus
Parainfluenza
Rhinovirus
```
70
What is RSV
Pneumovirus
| Causes bronchiolitis - under 1s annual winter epidemics can be life threatening
71
Treatment of RSV
Oxygen and manage fever.fluids
DO not give bronchodilators or steroids
Give Ig and monoclonal antibodies - Palvizumab
72
What is metapneumovirus
Paraomyxovirus
Causes respiratory illness similar to RSV - mild URTI to peumonia
Supportive care only
Nearly universal by age 5
73
What is adenovirus
10% of all respiratory infection in childhood
| causes mild URTI occasional pneumonia and conjuctivitis
74
Treatment of adenovirus
No treatment but cidofovir in immunocompromised
75
What is parainfluenza
Paramyxovirus: 4 types, 3 in summer 1 in winter
Person- person transmission
Causes croup/bronchiollitis/inhalation
76
Rhinovirus
Causes common cold
| In 70% of children with mild URTI
77
Causes of childhood diarrhoaea
Rotavirus
Norovirus
Mumps
78
What is rotavirus
Reovirus - RNA Virus
Spread faecal-oral route
Season in UK
Causes diarrhoea and committing
79
Treatment of Rotavirus
Treat with rehydration - prevent now with oral live vaccine at 2-3 months
80
What is norovirus
Wintervomiting book
VOmiiting for 12-60 hours
Treat with rehydration
81
What is mumps
Paramyxoviridae virus
82
Transmission, incubation and infectivity of mumps
Direct contact/droplet spread
Infective several days before parotid swelling to several days after
Incubated for 2 - 4 weeks
83
Symptms of mumps
Initially low grade fever, anorexia, malaise and headache
Then earache, tenderness over ipsilateralpartoid
Then gradually enlarging parotid with severe pain
USUALLY BILATERAL pyrexia up to 40 degrees
Rapidly resolved after peak swelling and parotid returns to normal size within 1 week
84
Treatment of Mumps
Symptomatic only
| BUT live attenuated vaccine availbale
85
Other manifestations of mumps
CNS invovlement or Epididymo-orchitis
| Infection in first trimester increases the risk of foetal death
86
Ways of infection prevention and control
Eliminate the pathogenic organism, remove source/reservoir, minimise transmission, prevent entry/exit, reduce susceptibility
87
What type of rooms prevent infection
Positive Pressure Ventilated lobbies
88
Types of surveilance
Passive - clinical reporting and lab rrcords
| Active surveillance - seeking out trouble
89
What is sterilization
complete killing of all types of microorganisms
90
Types of sterilization
Heat (Dry or moist - in the autoclave), chemical, filtration or ionising radiation - used for single use disposable equipment
91
What is disinfection
Removal or destruction of sufficient numbers of potentially harmful micro-organisms to make safe to use!
92
What is antisepsis
disinfection applied to damaged skin or living tissues
93
What is the best method of sterilization
Heat as least hazardous
94
Chemical disinfection usually used for
envirnomental decontamination, antisepsis and heat sensitive items
95
Sterilisation of surgical instruments
Moist hear
96
sterilization of flexible endoscope
Chemical as has metal/plastic and sensitive parts
97
Sterilisation of syringe nedles
Gamma irradiation pre use - dispose after use
98
Disinfecting of central venous catheter insetion site
Chemical antisepsis
99
What is the single most effective medical intervention before (not including sanitation)
vaccination
100
What did Jenner do
inoculation with cowpox to protect against small pox
101
Who made vaccines against chickenpox, cholera, anthrax, diphtheria and rabies
Pastier
102
How long do maternal antibodies protect for
Upto 1 years
103
When can we inject human immunoglobulin
HNIG - pooled plasma
| Can give specific for tetanus, botulism, Hep B, rabies, varicella
104
Types of live vaccine
MMR, BCG, Yellow Fever, Varicella (acts like natural infection) don't give to immunocompromised
105
inactivated vaccines
pertussis, typhoid, IPV
106
components of organisms invaccines
influenza and pneumococcal
107
inactivated toxins in vaccines
diphtheria and tetanus
108
what is an antigen
anything that can be bound by an antibody
109
Advantages of live vaccine
Single dose sufficient
strong immune response provoked
local and systemic immunity produced
110
disadvantages of live vaccine
```
potential to become virulent
can't use in immunocompromised
interference by viruses or vaccines and passive antibody
poor stability
potential for contamination
```
111
advantages of inactivated vaccines
stable, constituents clearly defined, no risk of infection
112
disadvantages of inactivated vaccines
need several doses, local reactions common, adjacent needed, shorter lasting immunity
113
What is mass vaccination
aims to vaccinate enough of the population to reduce risk of infetion
114
How do antibodies produce immunity
Antigen binds to antibody --> triggers clonal expansion
IgM produced first then IgG
IgG binds antigen tightly and simultaneous complement binding facilitates destruction of the antigen bearing organisms
IgG decline when infection resolved but one of the IgG lymphocytes persists with the ability to recognise that specific antigen --> immunological memory
