Fungi & Parasites Flashcards
1
Q
what is the study of fungi called
A
mycology
2
Q
what type of organisms are fungi
A
eukaryotic organisms
3
Q
fungi are eukaryotic organisms that do not contain..
A
chlorophyll
4
Q
fungi are eukaryotic organisms that contain..
A
cell walls
filamentous structures
&
produce spores
5
Q
how many species of fungi are there
A
more than 100,000
6
Q
how many fungi species are known to be pathogenic for man
A
300
7
Q
what is the fungal structure similar to
A
bacteria, as has a cell wall and organelles such as mitochondria, endoplasmic reticulum & ribosomes
8
Q
list the types of fungal species
A
- moulds (damp walls, bread, cheese)
- yeast (single cell organism, baking bread, alcohol brewing)
- higher fungi (mushrooms)
9
Q
what is the name of filaments which most fungi form
A
hyphae
10
Q
what are hyphae surrounded by
A
cell wall made of polysaccharides (and may show cross walls/septa)
11
Q
what is a colony of hyphae referred to as
A
a mycelium
12
Q
why are lots of anti fungal drugs toxic to human tissues
A
human cells synthesis protein & DNA similar to fungi
fungi are eukaryotic cells and antibiotics do not effect eukaryotic cells but do effect prokaryotic cells
13
Q
what are individual cell types/units of hyphae
A
septa
14
Q
what do cross membranes form
A
septa
15
Q
which species exists in yeast and hyphae stages (dimorphic/two separate stages)
A
candida albicans
16
Q
what is candida
A
a yeast-like fungus commonly occurring on human skin, in the upper respiratory alimentary & female genital tracts (thrush & infestations of mouth)
17
Q
what does candida of the upper respiratory alimentary indicate
A
someone who is immuno suppressed
18
Q
what does fungal effects of the mucous membrane cause
A
thrush
19
Q
what are the three types of mycotic diseases
A
- hypersensitivity - an allergic reaction to moulds and spores, can inhale fungal spores and develop respiratory disease or allergy to fungi
- poisoning - due to fungal toxins eg mushrooms
- infection - gets into tissue an causes harm
20
Q
what is the result of the mycotic disease, hypersensitivity
A
an allergic reaction to moulds and spores, can inhale fungal spores and develop respiratory disease or allergy to fungi
21
Q
what is the cause of the mycotic disease, poisoning
A
due to fungal toxins eg mushrooms
22
Q
what is the result of the mycotic disease, infection
A
gets into tissue an causes harm
23
Q
what is the fungal infection of athletes foot
A
superficial mycoses (caused by damp places)
24
Q
what is the fungal infection of a fungal nail infection
A
subcutaneous mycoses
25
what is the fungal infection of ring worm skin infection
systemic mycoses
26
what is the fungal infection of oral thrush
opportunistic mycoses (infections with organisms of low virulence e.g. AIDS, immunosuppressed)
27
what can systemic mycoses occur due to
inhaled fungal spores or deep trauma
28
give examples of systemic mycoses
- aspergillus
| - pneumocystis carini
29
what does pneumocystis carini cause
pneumonia due to immuno suppression, so cannot fight off
30
how can inhaled fungal spores be treated
it is a mast cell mediated disease and treated with anti histamines
31
why is the cellular machinery both similar in fungi and mammal
as both are eukaryotic
32
what will most substances which may impair the invading fungus usually have serious side effects on
the host
33
what targets are impaired by substances which also impair the invading fungus
membrane sterols
&
ergosterols
34
give examples of anti fungal substances
- terbinafine - nail infection
- amphoteracin - oral or genital thrush
- nystatin - oral or gential thrush
- fluconazole - gential thrush
35
why is a superficial condition easy to cure
can apply drug on the infection
36
what is the definition of a parasite
an organism that obtains food and shelter from another organism and derives benefits from this association
37
what is the organism that harbours the parasite
the host
38
what is the definitive host
the host in which the parasite lives its adult and sexual stage
39
what is the intermediate host
the host in which a parasite lives as the larval stage
40
what is responsible for transmitting the parasitic infection and what is it known as
an insect
| known as the vector
41
which country is fungal keratitis more common in
india, due to climate
42
what are the three classifications of parasites
- protozoa eg toxoplasma species
- helminths eg toxocara species (worms)
- arthopods eg ticks
43
what do arthopod parasites live in in the eye
eyelash follicles which cause inflammation e.g. blepharitis
44
what does protozoa comprise
a number of diverse groups of unicellular microorganisms
45
how large is protozoa
from 5um to 1mm (large)
46
where do most protozoa live
water and are parasites of a range of species
47
what do all protozoa have mechanisms of
locomotion via flagella, cilia or pseudopodia
48
what can protozoa form
cysts helping them to survive in the environment for a long time
49
what are protozoa divided into 4 groups based on
mobility
50
list the 4 groups of protozoa and name examples
1. mastigophora
- giardia (tropical intestinal infection)
- trichomonas
2. sarcodina/rhizopodia
- acanthamoeba (eye disease)
- entamoeba
3. sporozoa
- plasmodium
- toxoplasma (eye disease)
4. ciliata
- balantidium
51
what are acanthamoeba
free living amoebae
52
where are acanthamoeba found
everywhere
| most prevalent in soil, fresh water and other habitats
53
what two things can acanthamoeba be
opportunistic
or
non-opportunisitic
54
what three syndromes can the acanthamoeba genu cause
1. granulomatous amoebic encephalitis
2. disseminated granulomatous amoebic disease (e.g. skin, sinus and pulmonary infections)
3. amoebic keratitis
55
how many stages does the acanthamoeba life cycle consist of and what are they
two
1. an actively feeding stage called, trophozoite
2. a dormant cyst
56
what do trophozoites feed on
bacteria, yeast, algae and cells
57
in which ways can acanthamoeba enter humans
- through the eye
- through nasal passages to the lower respiratory tract
- through ulcerated broken skin
58
what is seen in the early stages of acanthamoeba kerititis
eye appears to look fine but corneal nerve can be seen inflamed in the surroundings, px experiences severe pain
59
what is the outcome for a px with acanthamoeba kerititis which has not been treated
no treatment is possible, not even a corneal graft and no potential for vision
60
what do acanthamoeba trophozoite feed on
micro-organisms in biofilms
61
how do acanthamoeba trophozoite detect prey
by chemotaxis
62
what are the prey items usually which acanthamoeba trophozoite feed on
bacteria
63
what is toxoplasmosis caused by
the protozoa, toxoplasma gondii
64
how many people in the UK have been infected with T.gondii
7-34% however most would not have experienced the symptoms
65
when can toxoplasmosis be a dangerous and potentially fatal disease
toxoplasmosis encephalitis (brain infection) in immunocompromised patients
66
what can a pregnant woman do to cause toxoplasmosis
congenitally infect her child
67
what can the life cycle of toxoplasma only be completed in
cats (definitive hosts) thar excrete resistant oocysts in their faeces
68
what type of animal can oocysts (eggs) of toxoplasma infect
virtually all warm blooded animals
69
how can infection by oocysts of toxoplasma occur
either directly by ingesting substances contaminated with cat faeces
or
indirectly by ingesting undercooked infected meat if species which have themselves become infected from cats
70
what is the appearance of the tacyzoite form of toxoplasma
crescent shaped
2-3um wide & 5-7um long
usually found in intracellular clusters of 8 to 32 parasites
71
what is the name of cystic dormant toxoplasma
oocysts
72
what is the name of toxoplasma in its feeding stage
tachyzoite
73
what type of infection is toxoplasmosis
protozoal, self limiting infection
74
what sign does congenital ocular toxoplasmosis cause
pigmentation of the retina
75
what will happen if congenital ocular toxoplasmosis forms on the macula
will effect vision
76
what will happen if congenital ocular toxoplasmosis forms on the periphery of the retina
nothing. px will not know about it
77
what three groups do the helminths of man belong to
1. nematodes (round worms)
2. cestodes (tapeworms)
3. trematodes (flukes)
78
which group of helminths is associated with the eye
nematodes (round worms)
79
what is toxocara canis
a roundworm parasite of dogs and foxes
80
how long can the eggs of the toxocara canis parasite survive for in the environment
many years
81
how can humans & generally children acquire toxocara canis eggs
by ingesting soil
by direct contact with dogs (usually puppies)
or by consumption of uncooked or undercooked food contaminated with eggs, possibly transmitted by flies
82
how does toxocara canis get into the soil
by dog/fox faeces
83
what is visceral toxocariasis
the migration of larvae through the internal organs of humans
84
what does the migration of larvae through the internal organs of humans caused by visceral toxocariasis cause in the body
inflammatory reaction
85
what symptoms can visceral toxocariasis cause
- hepatosplenomegaly (enlargement of liver & spleen)
- fever
- respiratory signs
- pallor
- skin lesions
- neurological manifestations eg convulsions
86
what is ocular toxocariasis
migration of larvae into posterior segment of the eye
87
when does ocular toxocariasis tend to occur
in older children and young adults
88
what are the signs of ocular toxocariasis
- decreased vision
- red eye
- leukocoria (white appearance of the pupil)
89
list the ages and corresponding number (%) of toxocara cases between 1989-2002 in the UK
- less than one year - 4 (1%)
- 1-4 years - 73 (25%)
- 5-14 years - 64 (22%)
- 15-24 years - 28 (10%)
- 25-44 years - 45 (16%)
- 45-64 years - 29 (10%)
- 65 years and over - 19 (7%)
- age not recorded - 26 (9%)
90
what can be the result of toxocara canis on the retina
a full thickness macular granuloma
| worm eventually dies but damage is done
91
which region of the macula does toxocara canis mainly effect
the periphery
| can rarely effect the macula, a large central scotoma & will have peripheral vision
