Parasites Intro Flashcards
obligate v facultative parasites
obligate can’t live outside (Ascaris Lumbricoides)
facultative- can grow free living as well as in host ( stronglyloides)
endoparasite
parasite the lives inside host
leishmania
ectoparasite
lives outside of host (phtrhus pubis)
definitive hosts
hosts in which a parasite reaches sexual maturity and reproduces ( malaria mosquito– for schistosome mansoni)
intermediate hosts
host in which some development of parasite occurs but doesn’t mature
(boar– trichinella spirals)
reservoir host
animals that harbor a species of parasite that is infective for humans
(armadillo- trypanosome cruzi)
vector host
arthropod or other carriers that transport pathogenic parasite from infected to non infected host
(Aedes Aegypti)
dead end host
organisms that harbor intermediate life stage BUT do no transmit parasite to another host
(Dirofilaria minis, heart worm)
I. protozoan size and movement
unicellular organisms, 1 micron– 100 microns
locomotion by:
- flagella-
-cilia- hair like that also serve as organelles
- pseudopodia: temporary projections of cytoplasm used for ingestion of food and locomotion
or undulating membranes
protozoal GI and membranes
outer cell membrane controls fluid and food uptake
cytoplasm consists of a thin ectoplasm (where digested particles are extruded) and a thick endoplasm
protozoan nucleus
has outer nuclear membrane inner reticulum
chromatin
karyosome (tight amount of dna)
function of endoplasm in protozoa
nutrition
contains food vacuoles, reserves and foreign bodies
function of contractile vacuoles in protozoa
regulate osmotic pressure and eliminate waste materials
protozoan Sex
- asexual- binary fission
- asexual- multiple fission (schizogony)
- asexual - internal budding (endodyogeny)
- sexual- fertilization (syngamy)
II. Flat worms (class Trematodes) size and morphology
flattened elongated leaf like
schistozosomes - ovoid and cylindrical
1-5 cm
they have a non cellular integument that has spines and tubercles
body of trematodes
- they have suckers or spines that used for attachment of host
don’t have a body cavity
trematode life cycle always includes?
SNAILS as an intermediate host
trematode sex
schistosome sex?
Hermaphroditic!- Ovaries and testes present in each individual
eggs are released into body cavity of host
schistosomes– dioecious- either ovaries or sperm
III, Cestodes – tapeworms
body
ribbon like segmented and inhabit intestinal tract
microvillus like structures make it continuous from one segment to another - body wall is an active tegument
cestodes
- scolex
- proglotid
- strobilus
scolex- anterior attachment organ
proglotid- segments
strobila- chain of segments
sex of cestodes
HERMAPHRODITIC
each proglottid has reproductive organs that allow self fertilization- each one is considered a reproductive unit
larva of cestodes
mature- inhabit GI tract
larva- tissues and organs (brain)
Nematodes (round worms) body
1- 30 cm
stiff clear non cellular cuticle
has teeth hook and lips used for tissue abrasion or attachment
nematode digestive sistem
well developed
- feed by sucking host blood or ingesting lysed tissues or GI contents - has midgut handout and anus
how do nematodes grow
molting to increase body size
- these skins cause an immune response
nematode sex
BOTH MALE AND FEMALE* dioecious
- Arhtropods body
exoskeleton- external rigid tegument with chitinized membranes
3 legs0 insect
4 legs arachnids
arthropod GI
forgot midgut handout rectum anus
arthropod growth
molting - complete/ incomplete metamorphosis
sex arthropods
dioecious
oviparious
viviparous
oviviparous- larvated eggs
GI tract trematodes
- they just have a digestive tract rather than a body cavity
starts with a pharynx and bifurcates into two posterior tubes
GI tract cestodes
absent GI tract
but their integument is enzymatically active = so they absorb their host food
non specific host resistance to parasites
chemical barriers
physical barriers
microbial antagonism– anti parasitic factors in serum and competition of nutrients by normal flora
pathological changes caused by parasites
- parenchymatous degeneration
- fatty degeneration
- necrosis
- hyperplasia
- hypertrophy
- metaplasia
- neoplasia
parenchymatous degeneration
damage to cells- characterized by swollen cells packed with fatty granules, indistinct nuclei and pale cytoplasm (washed out)
liver heart kidney
fatty degeneration
deposition of large amounts of fat in cells- yellowish color
necrosis
death- gives an opaque appearance
hyperplasia v hypertrophy
hyperplasia increase in cell number due to accelerated cell division (due to an increase in body repair activity due to inflammation)
hypertrophy increase in cell size
metaplasia
conversion of one tissue into another without intervention of embryonic tissue
neoplasia
abnormal cell growth- producing an entirely new cell structure
lab diagnosis of parasites
- fecal concentration
- trichrome stain
- acid fast stain
- KOH
- Giemsa
- wrights
fecal concentration test
use of flotation (bc parasite eggs float in zinc sulfate solutions of high osmolarity)
so they are picked up and observed
trichrome stain
stain parasites in fecal matter- stain protozoans cells pink with blue green organelles
acid fast stain
stance cells pink with a blue background
KOH preparatun
for presence of arthropods and parasites
tissues dissolve away leaving the clinical specimens
giemsa stain
looking for intracellular structures
blue colored intracellular parasites
wright stain
for identification of cell types in blood smears
