Parasites 1&2 Flashcards
examples of protozoal parasites
entamoeba hystolytica
giardia intestinalis
toxoplasma gondii
Lice, Mites and Ticks are what kind of parasites?
Ectoparasites
parasite definition?
metabolically dependent organism
what is a reservoir host?
animal can be infected and also infect people
what is intermediate host?
parasite doesn’t reach sexual maturity
what is paratenic host?
parasite does not undergo development but remains infective
what is definitive host?
parasite reaches sexual maturity
Lice is broad or focused as a species?
focused, pubic lice can’t infect your head and vice versa
what is pediculus humanis?
lice that infects body hair
lice infection aka:
pediculosis
what is ‘crabs’?
phthirus pubis
body louse lay eggs where?
on clothing
why would there be a resurgence in lice nowadays?
resistance to insecticide
why is lice a stigma?
used to be lice = poor hygiene
what were vectors of rickettsia, typhus and trench fever?
lice
Mites aka?
scabies
what happens if you scratch mites?
drives the eggs farther into your skin
size of scabies?
less than 0.5 mm in size
mites/scabies life cycle? where do they prefer to live?
single host in fingerwebs, elbows, axillae, genitals
treatment for mites/scabies?
ivermectin
mites will survive long time without a host?
nope will die pretty quickly
Ticks are vectors for?
infectious agents: viral, bac, protozoal, rickettsial
ticks and paralysis. Go.
secrete neurotoxin to anesthetize area and can cause ascending paralysis and possible Guillan-Barre
what is Ixodes holocyclus?
tick that causes rapid ascending paralysis
Lyme disease in Australia?
no epidemiological evidence really.
how to treat ticks?
remove them
are protozoa parasitic?
not really, can live freely outside of hosts
2 forms of the protozoa?
cyst - inactive robust
trophozoate: active, invasive
what is the most common amoeba human infection?
enamoeba histolytica
how is enamoeba histolytica transmitted and where does it invade?
invades in colon
transmitted faecal-oral
can enamoeba histolytica cause extra-intestinal infection? where?
yes
liver and brain abcess
enamoeba histolytica causes what kind of diarrhoea?
dysentry
large volume
treatment for enamoeba histolytica?
metronidazole + paromomycin, drainage of abscess
immunity for enamoeba histolytica?
nope, re-infection common
how long can Giardia intestinalis survive without host?
few months
Giardia intestinalis transmission? 2 things.
faecal-oral
zoonotic
presentation of Giardia intestinalis ?
subacute diarrhoea for some weeks, could resolve
treatment for Giardia intestinalis ?
tinidazole
toxoplasma gondii cysts are where usually?
muscle
toxoplasma gondii a parasite?
yes. obligate intracellular
toxoplasma gondii in Australia usually found where?
domestic cats
undercooked meat
toxoplasma gondii symptoms in regular folk?
asymptomatic. lifetime infection
when is toxoplasma gondii dangerous? 2 scenarios
organ transplant
fetus in pregnant woman
treatment for toxoplasma gondii?
bactrim or nil
diagnosis for toxoplasma gondii?
serology
3 major types of helminths?
roundworms
tapeworms
flukes
helminths have organ systems?
limited, not really.
what is the only helminth that can complete full cycle in human?
roundworm: strongyloides
what are nematodes?
roundworms
name 3 roundworms
pinworms
ascaris
strongyloides
what is schistosoma?
flukes
name two tape worms
echinococcus
Taenia
Which worm crawls out of anus to lay eggs at night and crawl back in?
pinworm
what is enterobius vermicularis?
pinworm
pinworm symptoms? how long it lasts?
itchy. lasts 4-6 weeks untreated if you can break the cycle
where do male and female pinworms mate?
in your cecum. Giggidy Giggidy.
treatment for pinworm?
antihelminthic
is pinworm chronic?
not really. frequent re-introduction
what’s the main problem with ascaris lumbricoids?
physical size of the worms: 30-40cm long causing GI obstruction
how many eggs does ascaris lumbricoids lay per day?
200 000
where do the eggs hatche for ascaris lumbricoids?
in soil
how can ascaris lumbricoids infection mimic asthma, bronchitis, pneumonia?
larvae penetrate small intestine>hepatic circulation>lungs>alveolar space>trachea>reswallowed
ascaris lumbricoids in cold soil?
likes warm soil better
how can you rule out ascaris lumbricoids?
if they have been out of endemic area for 2 years or more
Strongyloides stercoralis infects how?
penetrates skin via feet
where does embryonisation occur?
in colon
what dangerous about skin penetrating Strongyloides stercoralis?
can bring gram -ve bacteria with it, dangerous in immunocompromised or cause sepsis
Strongyloides stercoralis needs soil to complete life cycle?
nope. can have autoinfection in humans
obstruction in Strongyloides stercoralis?
nope. many symptomatic
dx of Strongyloides stercoralis?
eggs in faeces and serology
2 disease control for Strongyloides stercoralis?
shoes and sewage disposal
what are trematodes?
flukes
are flukes parasitic?
yes must live on host
what is schistosoma mansonii?
fluke
where does schistosoma mansonii live?
mucosal associated intestinal veins
how is schistosoma mansonii transmitted?
fresh water snails
schistosoma mansonii larva penetrate how?
through skin through fresh water
are reinfections of schistosoma mansonii common?
yes
tape worms parasitic?
yes all are
example of tape work?
Echinococcus granulosus
humans host for Echinococcus granulosus?
accidental intermediate hosts
Echinococcus granulosus what kind of infection?
zoonotic
what do hydatid cysts come from?
Echinococcus granulosus (tape worm)
Echinococcus granulosus common?
less than 5 cases/year in victoria
what is hyperendemic dur to transmission by dingos, feral pigs, etc.?
tape worms: Echinococcus granulosus
can Echinococcus granulosus in liver and lungs persist?
yes for years, compressing organs
what is the PAIR treatment for Echinococcus granulosus cyst? or hydatids disease?
puncture
aspiration
injection
re-aspiration
immune response to hydatid cysts?
not really unless the cyst breaks (anaphylaxis)
What causes neurocystercercosis?
Taenia parasite
Taeniasis infects how?
zoonotic infection
What is taeniasis worm?
tapeworm up to 10m long
how many eggs do taeniasis produce per day?
300 000
taeniasis is major cause of what in endemic countries?
neurological disease
do you normally remove a Taenia solium cyst in the brain?
nope, usually leave for risk of burst/seizures
avoid raw pork, it might have?
Taenia solium(tapeworm)