Parasitology Flashcards
Parasitic infection that develops in human body & multiply themselves is known as?
Cyclopropagative
•Cyclodevelopment = Pathogens undergo development from one stage to another but do not multiply (only stage)
Eg. Filarial worm in Culex Mosquito , O. volvulus in onchocerciasis
•Propagative = Only increase in number
E.g. dengue & plague disease (Yersinia pestis in xenopyslla flea)
Tape-like segmented worm which may grow to several meter length. The mature segment have both male & female reproductive organ (monoecious)
Cestode
- Suckers with hooks
- No alimentary canal & body cavity
- 2 hosts, multiple stages -> by larvae
This protozoa has broad pseudopodia which allows it to move to one direction at a time.
Amoeba
- Flagellates -> flagella/undulating membrane
- Ciliate -> cilia
- sporozoa & microsporidia -> no locomotor organelles
A 50-yo man is diagnosed with cercarial dermatitis caused by larvae of an animal trematode. What is his most likely occupation related to the above infection?
Paddy farmer
•Cercarial dermatitis is propagated by snails and birds , basically fish
**Schistosomiasis - in paddy farm water
Poultry = Birds
- Cercaria & metacercaria (larvae stages of trematodes)
- Rhabditiform & filariform (larvae stages of nematodes)
- Cysticercus & hydatid cyst (larvae stages of cestodes)
A group of students presented with periodic episodes of fever after a field trip to study macaque monkeys. The most probable zoonosis is
Simian malaria (Simian = monkey)
- Babesiosis= from rodents & ticks
- Leishmaniasis = sandfly
- Trypanosomiasis (Sleeping sickness) = Insect-borne -Tsetse fly ~ Chagas disease
Microscopic examination shows a minute, elongated organism with four pairs of stumpy legs. The organism is most likely
Demodex folliculorum
Define the following:
A) definitive host B) intermediate host C) paretenic host D) carrier E) incidental host F) reservoir G) obligate parasite H) facultative parasite I) parthenogenesis
A) adult worm in human body. Sexual reproduction
B) larvae form in human body. Asexual reproduction
C) not important for life cycle to be in human body. Often just for carrier purpose
D) asymptomatic host, just carry for reproduction
E) unintended host; unusual host
F) animal host as to ensure parasites supply in nature
G) needs a host to reproduce
H) optional host (boleh ada boleh takde)
I) fertilization of ovum of female without male
What kind of horizontal transmissions are these?
A) T. Gondii, Leishmania Donovani B) Acanthamoeba, Naegleria spp. C) Strongyloides, Enterobius (pinworm -> perianal puritus) D) Hookworm, Schistosomiasis E) Amebiasis, Giardiasis
A)Organ transplantation (Iatrogenic) B)Inhalation (free living amoeba) C)Autoinfection D)Skin E)Oral
Ova -> Cysticercus -> _________ -> Proglottid
Fill in the blank and what group is this?
Hydatid cyst; cestodes
What is the developmental stages of nematodes?
Ova -> Microfilaria -> Rhabdotiform -> Filariform -> Adult worm
Describe a few immunological parasitic evasive mechanisms.
A) Protected from serum Ig
- intracellular parasites, luminal parasites
B) Suppression of macrophage activity
-Leishmania develops inside macrophage, so takkan macrophage nak makan diri sendiri
C) Suppression of immune system
-Leishmania & Schistosomes
D) Complement inactivation (Taenia & Echinococcus larva) & Ab inactivation (Schistosomes)
•Leucocyte fx inhibition
-Mast cell degranulation of Schistosoma
E) Host tissue antigenic mimicry
-Absorb molecules produced by host into its surface to pretend like self
F) Shift in Ag structure
- change a.a & glycoprotein, Ab cannot recognize new antigen
- Trypanosome & Plasmodium (blood 👀)
G) Granuloma formation
H) Continuous movement
- protect from inflammatory process
Define:
a) True pathogen
b) Opportunistic pathogen
c) Normal flora
a) True pathogen (primary) - Microorganisms that cause disease in immunocompetent and immunocompromised people.
e. g. Mycobacterium tuberculosis
b) Opportunistic pathogen - Microorganisms that rarely cause disease in immunocompetent people but cause serious infections in immunocompromised people.
e. g. Normal flora when introduced to unusual sites
c) Normal flora - Microorganisms that are permanent residents of skin and mucous membrane of healthy people.
e. g. Bacteroides fragilis, Lactobacillus
State the normal flora residing in these locations:
a) skin
b) colon
c) vagina
a) Staphylococcus epidermidis
b) Bacteroides fragilis, Escherichia coli
c) Lactobacillus
- Virus & parasites - not normal flora
- Body areas free from normal flora - blood, cns, liver, spleen, peritoneal cavity
Describe 3 factors involve in pathogenesis of a disease:
a) pathogen - the number & virulence of pathogens
b) host - degree of susceptibility or resistance of host immune system
c) environment - conducive or not
Describe two underlying mechanisms involve in bacterial pathogenicity:
a) Invasiveness:
- the ability to invade tissues or overcome host defence mechanisms.
- this encompasses mechanisms for
i) colonisation (adherence and initial multiplication)
ii) production of invasins (extracellular substances which facilitate invasion)
iii) evasion of host defenses
b) Toxigenesis:
- the ability to produce toxins namely endotoxin and exotoxin
