INF2 - E. OTHER PROTOZOAN PARASITES-COVERED Flashcards
1
Q
trichomoniasis
A
- most treatable STI
- caused by parasite trichomonas vaginalis
- infects males aswell: urethra and prostate gland
- transmission by UPSI
2
Q
symptoms of trichomoniasis in women
A
- symptomatic or become so in 6 months post-infection
- irritation, strawberry cervix, malodorous vaginal discharge, itching, pH increases to 5≥ (normal is 4.5) and this won’t stop growth of other microbes, thrush?
- pregnant women: premature or LBW babies
- increased risk of HIV and HSV2 acquisition and transmission
3
Q
symptoms of trichomoniasis in men
A
- asymptomatic
- decrease sperm counts and motility
- prostatitis
- urethritis
4
Q
diagnosis of trichomoniasis
A
- Wet mount
sample from vagina or prostate gland
microscopy - culture
sample of fluid from area, culture to grow more trophozoites by binary fission so a bigger sample to look at
more sensitive - PCR
amplify and examine DNA - POC test
urine dipstick test for men
5
Q
treatment for trichomoniasis
A
- oral metronidazole (Flagyl)
- single 2000mg dose or 400mg twice daily for 7 days
- can be used during pregnancy but not recommended
- 2nd choice - tinidazole
6
Q
what do trichomonads possess that we don’t
A
- hydrogenosome
- metabolises pyruvate to gain energy to replicate etc
- metronidazole is activated in hydrogenosome leading to nitroso free radical
7
Q
prevention of trichomoniasis
A
- partner treatment by partner referral or patient-delivered partner treatment (ie take treatment back for them)
- repeat infection common due to reinfection from untreated partner or resistance to drug
- nontoxynol-9 (spermicide in condoms) has anti-trichomonal activity
8
Q
Giardia lamblia/Giardia duodenalis/Giardia intestinalis
A
- resides in small intestine
- causes giardiasis
- infection from cysts of parasite
- doesn’t migrate to other areas (ie - doesn’t penetrate epithelium) so often asymptomatic
- chronic/acute diarrhoea, flatulence, bloating, abdominal cramps
- travellers diarrhoea - drinking tap water when not advised
- can infect other animals
9
Q
cysts in giardia
A
- cysts are resistant forms, responsible for transmission
- cysts and trophozoites can be found in faeces
- cysts are hardy, survive several months in cold water, surfaces, units etc
- trophozoites are thin, delicate and dry out in the environment
- infection by ingestion of cysts in contaminated water, food, faecal-oral route
- excystation to release trophozoites
10
Q
what does Giardia have to attach itself to the intestinal brush border
A
- adhesive disk
- keeps us infective otherwise we would have diarrhoea and get rid of parasite
11
Q
diagnosis of Giardia
A
- stool examination
- microscopy to detect cysts (wet mounts or stains)
- 3 stools with intervals of 2 days
- entero-test
- gelatine capsule with absorbent nylon string swallowed
- migrates to duodenum and absorbs GI fluid
- retrieved after 4 hours to overnight
- distal string section scraped (wet mounts and permanent slide staining - microscope)
12
Q
treatment of giardiasis
A
- metronidazole
- over multiple days - 85% cure rate
- tinidazole single dose
- quinacrine (antimalarial)
- paromomycin (broad spectrum amino glycoside antibiotic) - can use in pregnancy
13
Q
Entamoeba histolytica
A
- causes amebiasis (amoebic dysentery)
- humans only hosts
- transmitted by faecal-oral route
- parasites reside in colon
- asymptomatic but can become fatal
14
Q
cysts in amebiasis
A
- cysts can survive days to weeks
- cysts responsible for transmission
- trophozoites passed ins tool rapidly, destroyed outside body, don’t survive gastric passage
- excystation in small intestine to colon of cysts
- can invade intestinal mucosa or pass through blood infecting other organs
- invasive form = E. histolytica
- non-invasive form = E. dispar (only in colon)
- trophozoites, precyst, cyst, megacyst
15
Q
diagnosis of amebiasis
A
- microscopy of trophozoites in faeces
- E. histolytica have a amorphous shape
- histolytica and dispar are morphologically indistinguishable
