Trichinella Flashcards
What is the smallest nematode parasite of humans
trichinella
true or false: trichinella is food born zoonosis
true
prevalence of swine trichinellosis and the incidence of human greater where?
china, thailand, mexico, argentina, bolivia and some central european countries
what is the worlds largest intracellular nematode parasite
trichinella
true or faslse: trichinella is host specific
false: it is not host specific
what is the smallest worms amongst the nematode
trichinella
true or false: trichinella is super rare
nope lol
it is one of the most widespread and clinically important nematode in the world
in trichinella: the same individual serves as both the…. and the …..
the definitive and the intermediate host
where does trichinellosis come from in canada
wild game aka hunting
distribution and major hosts of t spiralis
-cosmopolitan
-domestic pigs and wild mammals
t nativa distribution and major hosts
-artic
-bears and walrus
t pseudospiralis distribution and major hosts
-cosmopolitan
-wild mammals and birds
which trichinella are non encapsulating
-pseudospiralis
-papuae
-zimbabwensis
reservoirs of t brivoti
fox, pig, wild bears, horse, jackals, cat
reservoir of t nelsoni
bush pigs and warthogs
where is trichinella pseudospiralis
north america, europe, asia, tasmania
characteristics of t spiralis
-high reproductive capacity
-no freezing resistance
characteristics of t nativa
-low reproductive capacity
-freezing resistance
t pseudospiralis characteristivs
-low reproductive capacity
-no freezing resistance
-no capsule
t nelsoni characteristics
-low reproductivity capacity
-no freezing resistance
where is T nelsoni
africa
where is t britovi
temperate zone
t britovi characteristics
-low reproductive capacity
-freezing resistance
when was trichinella first described and why who
-in 1835 by own from a cadaver muscle on london
who baptised trichinella spiralis and when
raillet in 1895
true or false: nematodes are usually host specific
true
true or false: trichinella can adapt to a multitude of hosts
true
which countries are free of trichinella
puerto rico and australia
why does trichinella have a unique life cycle
-because of its intracellular localization at 2 different tissues sites:
-enterocytes
-skeletal striated muscle cell which represents the habitat
all stages of the life cycle of trichinella occur where?
in the same host
true or false: almost any mammal can be infected by trichinella
true
which are the most important hosts from a medical and vetenary point of view for trichinella
-humans
-swine and horses
-but birds and reptiles can be affected
juveniles of trichinella are carried away by what
-by the hepatoportal through the liveer, heart, the lungs and the arterial system
juveniles of trichinella are found in which tissue?
in almost all tissues
-eventually they reach the skeletal muscle
which parasite is kinda like a virus
trichinella
why is trichinella like a virus
-they subvert and redirect the host cell activities to their survival
-they alter the gene expression of host cell
-they change their vocation from that of a contractile fiber to that of a nurse cell and they become intracellular
during their life cycle, trichinella larvae undergo what
-4 molts over a period of 30 hs developing into adults
the female and the male trichinella measures how long
3mm in lenght
-male: 1.5mm
how long is the larvae for trichinella
0.8mm
patency of trichinella begins when
-it begins 5 days after mating
-males can copulate several times and die shortly after adult females release live offsprings
what are the steps leading to encystation of trichinella
-larvae enters the muscle fiber cells
-fiber loses its myofilaments
-fiber nuclei enlarge
-fiber smooth endoplasmic reticulum increases
-fiber mitochondria degenerates
-encapsulation of the unit with collagen secreted by neighboring fibroblast
calcification of the encysted larvae or trichinella occurs in…..
18 months
-encysted larvea remain alive for years
true or false: t pseudospiralis had a capsule
nope it does not
what is the stichosome
it consists of a row of discoid cells containing secretory granules
what is the name of the cells in the stichosome
they are called stichocytes and they secrete antigens into the nurse cell parasite complex during nurse cell formation
it has been hypothesized that secretory excretory substances from the stichocytes…..
not only are immunogenic but also mediate alteration of host gene expression
do we know why some muscles are more invaded by trichinella than others
no
what are the most invaded muscles in trichinella
-eye
-tongue
-masticatory musles
-diaphragm
-intercostals
-arms and legs
true or false: in trichinella: nurse cells don’t form in the heart muscle cells
true
-they do not encyst in smooth muscles
true or false: in trichinella: myocarditis is transitory
true
true or false: nurse cells form in the nervous system in trichinella
false: they don’t
in trichinella: the invasion of muscles is associated with an intense…..
inflammatory reaction
edema develops … days after penetration of the muscle cell
14 days
the inflammatory reaction is rased after ….
the release of secretory-excretory antigens
a first infection with mycobacterium tuberculosis will protect against what?
trichinellosis
aquired immunity to trichinella is of the .. type
th1
-mtb stimulates a th1 type of immune response
what type of other parasite protects against trichinella, why and what type of immunity is it
toxoplasma because it also stimulates a th1 type immune response
-non specific acquired immunity
Resistance to infections may be classified into 3 categories
-innate resistance
-non specific acquired immunity
-specific acquired immunity
example of innate resistance for trichinella
Natural resistance to infection. For example, Trichinella is
not infective to fish, or amphibians. In addition, the genetic background of
the host has an influence on the outcome of the infection. Mechanisms of
innate immunity like mucus acts as a barrier.
what is non specific acquired immunity
resistance acquired after a first contact with an unrelated infectious agent or an immunogenic substance
what is specific acquired immunity
-resistance acquired after a first contact with the same infectious agent
trichinellosis: specific acquired immunity give the example
-in trichinellosis, both the th1 and th2 type of immunity play a role
what is the role of th1 and th2 response in trichinellosis
-Serum antibodies of the IgM, IgG, and IgE isotypes are detected. IgA antibodies are detected in the gut.
-T cells and ADCC also play a role.
true or false: blood eosinophilia is a typical response to nematodes
true
why are eosinophils important in trichinella
because they reach levels of that are super high aka 19 000 cells/ul
the control of eosinophil levels by T cells is exerted why what
activation of th2 cells which produce high levels of il5
Eosinophil induction, recruitment and products during Trichinella spiralis infection. WHat are the things that are gonna get activated?
-alternatively activated macrophages
-arginase 1
-chininase like molecule
-eosinophil
-galectin
-granulocyte macrophage colony stimulating factor
-interleukin
what are the 3 stages of development of trichinellosis
-intestinal stage
-migrating larvae
-muscle
intestinal stage trichinellosis
worms migrating in the intestinal epithelium cause traumatic damage to the tissue
-inflammation causes nausea, vomiting, sweating and diarrhea
migrating larvae stage trichinellosis
-juveniles damage blood vessels resulting in localized edema
-they may cause pneumonia, encephalitis, eye damage and etc
muscle stage trichinellosis
-formation of nurse cells cause muscle pain, difficulty in breathing and swallowing
-presence of eosinophilia and edema in tissues
what are the 4 cardinal features of acute trichinellosis
-fever
-orbital oedema
-myalgia
-eosinophilia
nailbed haemorrhages are a frequent sign of what
acute trichinellosis
true or false: in trichinella, even subclinical stages can be detected
false, they go undetected
why are subclinical cases undetected in trichinella
-adult worms cannot be detected in a stool specimen
-migrating juveniles cant be detected
how are muscle nurse cells detected in trichinella
by biopsy
in trichinella: serology is… sensitive method in the acude phase
not very sensitive
pcq is useful for what in trichinella
epidemiological studies
treatment of trichinella
It is basically given to relieve the symptoms by using analgesics and immunosuppressive drugs like prednisone and corticosteroids to reduce the inflammation
T zimbabwensis has been recorded in 40% of farmed …..
Nile crocodiles
T papuae have been identified in …. of villagers in the south-west corner of Papua New Guinea
1/3
