Intestinal and Urinogenital Protozoal Infections
Session 38: Intestinal and Urinogenital Protozoal Infections
Total Session Time: 120 minutes
Pre-requisites
Students Learning Tasks
By the end of this session students are expected to be able to:
common diseases caused by intestinal and urinogenital protozoa
(Giardiasis, Amoebiasis, Cryptosporidiosis, Trichomoniasis)
urinogenital protozoa diseases
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |5 minutes |Presentatio|Introduction, Learning Tasks |
| | |n | |
|2 |30 minutes |Presentatio|Giardiasis |
| | |n | |
|3 |35 minutes |Buzzing/ |Amoebiasis |
| | |Presentatio| |
| | |n | |
|4 |20 minutes |Presentatio|Cryptosporidiosis |
| | |n | |
|5 |20 minutes |Presentatio|Trichomoniasis |
| | |n | |
|6 |5 minutes |Presentatio|Key Points |
| | |n | |
|7 |5 minutes |Presentatio|Evaluation |
| | |n | |
SESSION CONTENTS
STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning tasks and clarify
ASK students if they have any questions before continuing
STEP 2: Giardiasis (30 minutes)
o It is the infestation of the upper small intestine caused by the
flagellate protozoan Giardia Lamblia (or G. intestinalis), cytopathic
effects of which leads to malabsorption and diarrhea
o Giardiasis can be asymptomatic or cause symptoms ranging from
intermittent flatulence to chronic malabsorption
o Giardiasis is transmitted through faecal-oral route by ingestion of
faecal contaminated food or water.
o Life cycle
water, or fecal-orally
trophozoites, with each cyst producing two trophozoites
asexually and either float free or are attached to the mucosa of
the lumen
are infectious immediately or shortly afterward
[pic]
o Abdominal cramps
o Abdominal distension
o Flatulence
o Intermittent nausea
o Epigastric discomfort
o Chronic Diarrhoea
o Steatorrhea due to malabsorption
o Anorexia
o weight loss
o Treatment
o Prevention
STEP 3: Amoebiasis (35 minutes)
o Amoebiasis is an infection caused by the protozoa organism Entamoeba
histolytica, which can cause colitis and other extra-intestinal
manifestations
o It is commonly asymptomatic, but symptoms ranging from mild diarrhoea
to severe dysentery may occur
o The infection is primarily acquired through ingestion of contaminated
food and water and occasionally can be acquired through oral-anal
sexual practices
o Life cycle
typically found in diarrheal stool
cysts in faecally contaminated food, water, or hands
released, which migrate to the large intestine
Number 5, and both stages are passed in the faeces
survive days to weeks in the external environment and are responsible
for transmission
the body, and if ingested would not survive exposure to the gastric
environment
lumen (non-invasive infection) of individuals who are asymptomatic
carriers, passing cysts in their stool
(Intestinal disease), or through the bloodstream, extraintestinal
sites such as the liver, brain, and lungs (extraintestinal
amoebiasis), with resultant pathologic manifestations
o Liver abscess
o Cutaneous amoebiasis
[pic]
•
|Activity: Buzzing (5 minutes) |
| |
|ASK students to pair up and buzz on the following question for 2 |
|minutes |
| |
|What are the signs and symptoms of amoebiasis? |
| |
|ALLOW few pairs to respond and let other pairs to add on points |
|not mentioned |
| |
|WRITE their response on the flip chart/board |
| |
|CLARIFY and SUMMARIZE by using the content below |
o Bloody diarrhoea
o Crampy abdominal pain
o Tenesmus (Irresistible urge to go to the toilet)
o Fever
o Weight loss
o Peritonitis in severe forms
o Evidence of motile trophozoites or cysts on saline wet mount from a
stool specimen
o Extraintestinal amoebic disease originates from infection in the
colon and can involve any organ, but a liver abscess is the most
common
o Liver Abscess
pleural cavity, right lung, or other adjacent organs (e.g.
pericardium)
o Cutaneous Amoebiasis (Skin lesions)
buttocks in chronic infection, and may also occur in traumatic or
operative wounds
o Treatment
o Metronidazole
o Tinidazole
o Secnidazole
o Prevention
before eating
STEP 4: Cryptosporidiosis (20 minutes)
o Cryptosporidiosis is a watery diarrhoeal infection caused by
Cryptosporidium parvum
o Illness is typically self-limited in immunocompetent patients but can
be persistent and severe in immunocompromised patients example those
with AIDS
o It is transmitted through
public and residential pools, hot tubs, water parks, lakes, or
streams)
o Life cycle
possibly other routes (e.g. respiratory secretions)
faecal-oral transmission is possible
sporozoites and parasitize epithelial cells of the GI tract or other
tissues (e.g. respiratory tract)
then sexually, producing microgamonts (male) and macrogamonts
(female), which mate and produce oocysts
produced: thick-walled oocysts, which are commonly excreted by the
host, and thin-walled oocysts, which are involved primarily in
autoinfection.
[pic]
o Onset is abrupt, with profuse watery diarrhoea, abdominal cramping,
and, less commonly, nausea, anorexia, fever, and malaise
o Symptoms usually persist 1 to 2 weeks, rarely ≥ 1 months and then
abate
o Faecal excretion of oocysts may continue for several weeks after
symptoms have subsided
o Asymptomatic shedding of oocysts is common among older children in
developing countries.
o In the immunocompromised host, onset may be more gradual, but
diarrhoea can be more severe. Unless the underlying immune defect is
corrected, infection can persist, causing profuse intractable
diarrhoea for life.
o Treatment
infection
dose nitazoxanide
o Prevention
infectious, strict stool precautions should be observed
STEP 5: Trichomoniasis (20 minutes)
o Trichomoniasis is infection of the vagina or male genital tract
with Trichomonas vaginalis
o The disease can be asymptomatic or cause urethritis, vaginitis, or
occasionally cystitis, epididymitis, or prostatitis
o T. vaginalis is a flagellated, sexually transmitted protozoan that
more often infects women than men
o Infection may be asymptomatic in either sex, but almost always
asymptomatic for men.
o In women
vulva and perineum
“strawberry” spots
o In men
transient, frothy, or purulent or that causes dysuria and frequency,
usually early in the morning.
o Treatment
o Prevention
STEP 6: Key Points (5 minutes)
persists for weeks after symptoms resolve, a very small number of
oocysts are required for infection, and oocysts are difficult to
remove by conventional water filtration and are resistant to
chlorination.
intermittent flatulence to chronic malabsorption
vaginitis or sometimes urethritis
STEP 7: Evaluation (5 minutes)
References
Hugo and Russell (2011), Pharmaceutical Microbiology 8th Edition, Willey-
Blackwel publications
Karen C. Carroll et al (2013); Jawetz, Melnick and Adelberg’s Medical
Microbiology 26th Ed. McGraw Hill Co. Inc.
Greenwood et al (2012); Medical Microbiology, 18th edition Churchill
Livingstone
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