Unit 4 - Part 9 Introduction to Protozoa of medical importance Flashcards
what are the two main stages in the life cycle of cyst- or occyst- forming protozoa
trophozites
cysts or oocysts
what is the trophozites stage
actie feeding stage
reproduce by binary fission
does a protozoan produce both cysts and oocysts
usually produces one of the other but not both of these stages
what are cysts
metabolically inactive
what are oocysts
products of sexual reproduction
can cysts and oocysts remain infective or infectious outside the host
yes
are cysts and oocysts involved in reproduction
they can be
oocysts and cysts are able to survive in the enviornment for a long period of time
yes
resistant to water, disinfectants
what is the life cycle for trophozoites, cysts and oocysts
trophozite (active, feeding stage)
drying and lack of nutrients leads to early cyst wall formation
mature cyst (dormant, resting stage)
mositure and nutrients are resotred
cyst wall breaks open and trophozite is reactivated
what two reproductive strategies are observed among protozoa
simple and complex
do protozoa produce sexually or asexually
some reproduce only asexually while other reproduce both sexually and asexually in a more complicated life cycle
what are the 2 modes of asexual reproduction
binary fission
multiple fission
what is binary fission
parent cell gives rise to two daughter cells
what is multiple fission
a parent cell gives rise to multiple daughter cells
what are three other terms for parent cells
schizont
meront
segmenter
what is another term for multiple fission
schizogony (remember schizophrenia)
what occurs in sexual reproduction
fusion of gametes or gametocytes to produce zygotes
What is the causative agent for the protozoan disease maraia
plasmodium spp
what is one of the leading causes of infection-related deaths world wide
malaria
what is the MR for malaria
humans
what is the MT for malaria
female mosquits (anopheles) bites
what is the incubation period for malaria
1-2 weeks
what are the S & S or malaria
fever chills sweats cough diarrhea respiratory distress headache shock renal and liver failure pulmonary and cerebral edema coma and death
are anopheles mosquitos indigenous in canada
no, can still contract it travelling
how many cases of malaria are there in canada per year
~500
what is the protozoan disease giardiasis also known as
bever fever
what is the etiological agent for giardiasis
giardia lamblia
what is the MR for giardiasis
humans and possibly other animals
what is the MT for giardiasis
ingestion of cysts
how does one ingest the cysts to contract giardiasis
water contaminated with fecal material containing cysts
contaminated fingers or objects (hand-to-mouth transfer)
anal-oral sexual contact
What is the IP for giardiasis
3-25 days
what are the S & S of giardiasis
chronic diarrhea abdominal cramps bloating frequent loose and pale greasy stools fatigue weight loss
what is the treatment for giardiasis
usually self-limited
rehydration therapy and antibiotics such as metrondiazaole
trophozites in giardiasis have what characterisitc
smiley face
what is the AC for the protozaon disease crytposporidiosis
cryptospridium parvum
what is the MR for the protozoan disease cryptosporidiosis
humans, cattle and other domestic animals
what is the MT for the protozoan disease crytosporidiosis
self/auto infection
commonly caused by thin-walled oocysts
ingestion of oocysts via contact or from environment
water and food contaminated with oocysts containing feces
anal-oral sexual contact
what usually happens with thick walled oocysts in the protozoan disease cryptosporidiosis
typically excreted with feces in to the environment -enhanced survival immediately infections
what is the IP for the protozoan disease cryptosporidiosis
1-12 days
what are the S&S of the protozoan disease cryptosporidiosis
profuse & watery diarrhea with abdominal cramps malaise fever anorexia vomiting
what % of AIDs patients will suffer crytosporidiosis at some time during their illness
10-20%
what is the treatment for for the protozoan disease cryptosporidiosis
rehydration therapy and antibitocis such as azithromycin
the protozoan diseaes cryptosporidiosis creates what two types of oocysts
thick and thin walled
cats and feline animals are resevoirs for what protozoan diseaes
toxoplasmosis
What is the MR for the protozoan disease toxoplasmosis
cats and other feline animals
other animals such as cattle and rodents
what are the definitive hosts for the protozoan disease toxoplasmosis?
what are the intermediate hosts
definitive: cats and other feline animals (where sexual reproduction of the protozoa takes place and oocysts are produced)
intermediate: rodents, cattle
what is the MT for the protozoan disease toxoplasmosis
ingestion of oocysts from the fecal droppings of cat
ingestion of contaminated water, undercooked raw meat
transplacental infection
congenital toxoplasmosis is one of a group of pathogens called ______ that can cause miscarriage and or serious physical and developmental damage to the fetus/newborn
TORCH
What is the IP for the protozoan disease toxoplasmosis
5-23 days
what are the S & S for the protozoan diesase toxoplasmosis
fever lymphadenopathy and lymphocytosis cerebritis pneumonia mycoarditis death in the immunocompromiesd
what is the treatment for toxoplasmosis
antibiotics such as pyrimethamine or spiramycin (for pregnant woman) if needed
what happens to the fetus in congential toxoplasmosis
infected fetus may suffer from birth defects and death due to damage to the brain, liver and spleen
what protozoan disease is only transmitted by sexual activity
trichomoniasis
what is the CA for the protozoan disease trichomoniasis
trichomonas vaginalis
does trichomoniasis produce cysts or oocysts
no
what is the MR for trichomoniasis
humans
what is the MT for trichomoniasis
sexual intercourse
what is the IP for trichomniasis
4-20 days
is trichomoniasis sometimes asymptomatic
yes
what disease does trichomoniasis coexist with in up to 40% of cases
gonorrhea
are symptoms of trichomoniasis more severe in men or women
women
what are the symptoms of trichomoniasis in men
infection of the prostate and urethra
what are the symptoms of trichomoniasis in women
vaginitis charachterised by small, pinpoint, non raised, round, red strawberry like rash
profuse thin, foamy greenish-yellow discharge with roul odor
cervical inflammation as well as itching and buring sensation in the infected
what is the treatment for trichomoniasis
metronidazole
