Nematodes pt. 2 Flashcards
Enumerate 3 nematodes whose diagnostic stage is the ova stage
● Ascaris lumbricoides
● Trichuris trichiura
● Enterobius vermicularis
“True roundworms”
Nematodes
Non-segmented, has parallel sides, elongated, not flat
Bilaterally symmetrical
Nematodes
“True roundworms”
Phylum of nematode
Phylum Nemathelminthes
Nematodes lack
Not flat because
endoskeleton (bones in humans)
Cylindrical
Not flat because of hemolymph - a fluid present in their body that will actually make them distended
that makes them cylindrical
Complete set of digestive system means that they
have:
mouth, intestine, and exit point (or excretory
organ) by which they can eliminate their waste
product.
Nematodes have what organ systems:
Digestive System
Nervous System
Reproductive system
Nematodes’ nervous system is in the form of __ and are found in __
Receptors
Cuadal (head) – Chemoreceptors
They can
reproduce and have separate sexes
separate male and separate female nematode
Dioecious
Nematodes MOT
Ingestion of eggs
TRUE OR FALSE
In parasites, there is a corresponding
stage of a parasite that can infect man. This
means that all other stages are non-infective to
the host.
There is only a particular state that
can infect the host
TRUE
2 Types of Eggs
■ Unembryonated:
■ Embryonated:
Types of Egg
○ immature, non-segmented egg
■ Unembryonated
Types of Egg
There is already a developing larva inside
■ Embryonated
Types of Egg
Segmented – Also called a segmented egg.
■ Embryonated
Types of Egg
infective to man/host.
■ Embryonated
stage that can penetrate the skin
Larva: another possible infective stage
Vector
filarial worms
The infective L3 or the filiform is to be introduced to the human host by means of a mosquito vector (vector-borne).
Unusual modes of acquiring:
➢ Inhalation
➢ Close-contact
■ Ex. Normal route of acquiring E. vermicularis
is through ingestion. However the same
parasite can also be acquired through
inhalation or close-contact (sexual intimacy)
and other modes.
5 stages of Nematode
Egg L1 - Rhabditiform L2 L3 - Filariform Adult (mature)
If we are doing the harada mori method of culture,
after 7 days of incubating, we expect to harvest what larva
L1 rhabditiform larva
Distinct characteristics of Male vs. Female parasite
Size:
F - Larger
M - Smaller
Length:
F - Longer
M - shorter
Posterior-end:
F - pointed
M - Curved
Pan-like structure for some worms
bursa (there is a spicule?)
For Male ascaris there is a
spicule
Sometimes in female worms, you will be able to
see a round-like structure that is present
mid-way the body of the adult worm; this is called the
It is also a marker that the
parasite is female
Genital
girdle/genital ring
Female parasite can be
parthenogenetic
a reproductive strategy that involves development of a female (rarely a male) gamete (sex cell) without fertilization.
Types of Female parasites
Oviparous
Larviparous / Viviparous
Type of Female parasite:
“egg laying”
Oviparous
examples of Oviparous
Ascaris, Trichuris, Enterobius
Type of Female parasite:
lays larva
Larviparous/ Viviparous
Examples of Larviparous/ Viviparous
Trichinella, filiariae
only the first
generation of capillaria is larviparous female
then it will transform to oviparous female
Capillaria Philippinensis
free-living; may or may not require male
for fertilization / may or may not require male for
copulation or reproduction.
Parthenogenic:
Self-fertilization
Parthenogenetic:
Example of Parthenogenetic
Strongyloides Stercoralis - Parasitic form
Strongyloides Stercoralis has 2 possible forms:
Free living form - male and female; can be
Parasitic form - exhibit parthenogenesis
Parasitic form is found inside the body of the host.
What type of adult worm is present inside
the body of a human host infected by
Strongyloides Stercoralis?
mature form → Adult
TRUE OR FALSE
Both male and female Strongyloides
stercoralis are found in the body of the infected host
FALSE
Only the female Strongyloides
stercoralis is found in the body of the
infected host because they can exhibit
parthenogenesis.
type of nematode Typically common among third world countries and
those with humid temperatures
ASCARIS LUMBRICOIDES
The socio demographic factors where you can find Ascaris lumbricoides is
within the poor
common among school-age children. According to
DOH ages:
6-12 years old children are common individuals
found with an infection due to Ascaris lumbricoides
It is very possible that the other (2)
parasites will be present when one of the (3) is found.
UNHOLY 3:
Ascaris, Trichuris, Hookworm
Embryonation happens in
soil
common in rural areas. They use human
feces as fertilizer and this allows for
embryonation to happen.
night soil
Embryonation is possible
with the ff. Factors:
➢ Humidity ➢ Oxygen ➢ Soil ➢ pH ➢ Temperature
This parasite is capable of heart-lung migration
Ascaris lumbricoides
It will first enter the body and when the larva hatches
it will undergo heart-lung migration. The moment
that it becomes larva (L3), once you swallow, it will go
to the digestive system where it will grow into adult
forms and experience a reproductive cycle (it will lay
eggs again).
Ascaris lubricoides can cause irritation to the lungs that can be seen
together with
Ascaris pneumonitis or Loeffler’s
syndrome.
Hyperinfection of Ascaris lumbricoides It can infect other organs such as
bile duct and pancreas
A severe infection of Ascaris lumbricoides is manifested
when a stomach enlarges.
Indication/s of malnutrition: Big belly, small face,
slouched shoulders.
○ Malnutrition is an outcome of parasitic infection.
TRUE OR FALSE
Malnutrition is an outcome of parasitic infection.
true
Indication/s of malnutrition:
Big belly, small face,
slouched shoulders.
Worms can come out from the nose, mouth, ears.
Only way to remove this is through surgery. this is called
Bolus
the copulatory organ of the male
spicule
TRUE OR FALSE
Mature or immature adults may be found in feces or may
spontaneously migrate out of the anus, mouth, or nares
TRUE
A. lumbricoides has three lips called
Trilobate / Trilobes / Trilips
2 ventral
1 dorsal with sensory papillae
Margin of teeth is lined with minute teeth
female filled with eggs (in uterus)
gravid
TRUE OR FALSE
Adult form
Will show whitish appearance
FALSE
Adult form
○ Will show pinkish appearance
A. lumbricoides has what type of muscle layer allows Ascaris lumbricoides (adult forms) to move
around and to have a stabilized body
longitudinal muscle layer
will help the structure of adult forms to
become cylinder-like (looks like a pencil)
Pseudocoele:
FERTILIZED DECORTICATED
● Composed of two layers:
Glycogen layer
Lecithin / Vitelline layer (lipid)
the layer that Gives protection/ resistance from stomach acid
Glycogen layer
the layer that Makes feature of the egg golden-brown in color
Added protection to Ascaris lumbricoides
Lecithin layer / Vitelline layer (lipid)
with coarse lecithin granules
A. Fertilized corticated
B. Fertilized decorticated
A. Fertilized corticated
3 layers of fertilized corticated egg
Mammillary Coat / Albuominous coat
Middle glycogen
Lecithin / vitelline layer
TRUE OR FALSE:
A fertilized corticated Ascaris egg, still at the UNICELLULAR
stage, as they are passed in stool.
TRUE
A. LUMBRICOIDES
Where it hatches:
Where development and maturation takes place:
small intestine
Lungs
Geographic prevalence highest in what climates
warm and wet climates
in order to be infected by A. lumbricoides you need to ingest
both the female and male ?????
giant intestinal roundworm in
hogs/pigs - doesn’t mature in Man because we are
not their FH
Ascaris suum
finals host of Ascaris suum
hogs/pigs not humans
Caused by larva of non-human infecting Ascaris
It undergo heart-lung migration when the
embryonated egg hatches pero hindi siya
nagmamature sa katawan ng tao
Visceral larva migrans
○ Pneumonia-like symptoms
○ This happens when hatched larva undergo heart-lung
migration
○ Possible sample specimen to identify is
Sputum/Phlegm to observe larva
Ascaris pneumonitis/Loeffler syndrome
○ Migration of larva to heart and to lungs causes
irritation.
○ Presence of larva (a foreign matter) can trigger
inflammation which then causes
irritation to the intestinal mucosa
Bolus
acumulation of adult forms in intestine
Migration of adult forms to other organs especially to
hyperinfection or several infection to other organs
Erratism
PATHOLOGIES OF ASCARIS LARVA
Visceral Larva migrans
Ascaris pneumonitis / Loeffler syndrome
Irritation of intestinal mucosa
Bolus
Erratism
Epigastric pain
Diarrhea
Malnutrition
Asymptomatic
Allergic reaction
DETECTING A. lumbricoides
In the CBC of the patient, there is Increase in
eosinophil in the PBS of the patient.
You will also see Charcot-Leyden crystals in a patient’s
stool which is an indicator of this cell: active
metabolism. You can see this in helminthic infections.
DIAGNOSIS of A. lumbricoides
DFS (wet smear or lugol’s iodine)
● FECT - n helminthic infections, 3
Samples within 10 days, and can be extended to 14
days.
Kato-Katz Technique (quantitave)
Kato (qualitative)
● X-ray
○ Very helpful to see Ascaris pneumonitis
● *Zinc Sulfate Floatation CT
● PCR (molecular technique)
○ Not economical
Flesh colored or pinkish slender worm
TRICHURIS TRICHIURA
Anterior 2/3 of the trichuris trichiura is
posterior 1/3 is
attenuated and thin
Fleshy and robust
Life cycle of trichuris trichiura
- Ingestion of embryonated egg
- Travel to small intestine
○ Maturation will happen here - Travel to large intestine
○ Adult worm na dito and copulation will happen
○ Oviposition (laying eggs) will also happen here - Then eggs will be found in the stool
○ Diagnostic stage
○ It will allow the introduction of this egg to the soil
where embryonation will happen - Repeat cycle
TRUE OR FALSE
there is heart-lung migration in trichuris trichiura
FALSE
No heart lung migration unlike Ascaris lumbricoides
Thick smooth and brown egg
Trichuris trichiura egg
Japanese lantern appearance with bipolar
plugs / Football / Barrel / Lemon
Trichuris trichiura egg
Rounded and made of hyaline
Bipolar /
Hyaline plug
Bile-stained (yellowish / golden brown)
Trichuris trichiura egg
Pathology include Anemia
○ Sometimes can present hypoalbuminemia is caused by
Trichuris trichiura infection
Pathology of Trichuris trichiura
Anemia (hypoalbuminemia)
Rectal prolapse
Secondary bacterial infection
Pinworm / society worm / seat
worm / Tiwa (tagalog)
Enterobius vermicularis
Habitat or E. vermicularis
Large intestine
MOT of E. vermicularis
Ingestion of embryonated egg (can also be inhalation, retroinfection, or autoinfection)
Diagnostic stage of E. vermicularis
Ova/egg and adult worm
Life span of E. vermicularis
1-2 months
Embryonation og E. vermicularis
4-6 hours
Familial MOT
E. vermicularis
Smooth, thick and transparent egg
E. vermicularis egg
D-shaped and lopsided (other
portion is flattened)
E. vermicularis egg
Layers of the E. vermicularis egg
● Thick albuminous coat/layer
● Lipoidal or lipid layer
During the collection for the cellophane swab, you
are collecting an
embryonated egg
E. vermicularis
Oviposition: happens at
Collection: happens at
night
early morning
Pathology of E. vermicularis include
Nocturnal pruritus ani
Secondary bacterial infections
Insomnia
caused by nocturnal pruritis ani. Hindi makatulog sa sobrang kati
Vulvovaginits
Cephalic alae is only seen in
E. vermicularis male adult
