Parasitosis of Central Nervous System
Protozoa
Species
Naegleria
fowleri
**So far, there is
no reported
case of PAM in
Malaysia
Mode of Transmission
 Accidental
drinking of
contaminated
o Fresh water
pools
o Ponds
o Hot springs
 The infection is
reported after 3-7
days after
swimming at those
areas
 The protozoa
gained entry from
the nose
o Penetrate the
Cribriform plate
of the Ethmoid
bone
o Then multiply at
the base of the
Cranial cavity
 Life cycles
o In human, only
in the
TROPHOZOITES
form
o NO cysts are
seen
Amoeba
Clinical Manifestation
Diagnosis
This agent causes
1. Microscopic
Primary Amoebic
Examination
Meningoencephalitis
a. Wet preparation
(PAM)
of CSF
 Affecting both
i. Indicates
healthy
Trophozoites
o Children
which are
o Young adults
1. Active
 Common signs of
2. Motile
meningeal
3. Having broad
inflammation
pseudopods
o Fever
ii. May shows red
o Nausea
cells
o Vomiting
iii. Bacteriologically
o Severe frontal
strerile
headaches
2. Culture
o Blocked nose
a. Inoculate CSF in
o Stiff neck
non-nutrient agar
 PAM characterized
i. This agar is
by
previously
o Diffuse
seeded with
o Necrotic
Eschericia coli
o Heamorrhagic
(E.coli)
encephalitis
 The course of the
disease is dramatic
o Death ensures
within 3-6 days
after the infection
Treatment
So far there is no
definitive treatment
for PAM
But, these choice of
treatments have
been reported to
cure the infection
 IV and Intrathecal
of Amphotericin B
 Large dose of
o Amphotericin B
o Miconazole
o Rifampicin
Prevention
 Do not swim
in stagnant
water at
o Pools
o Ponds
 Adequate
chlorination
of public
water
supplies
 Public
education
and
awareness
Protozoa
Amoeba
Mode of
Transmission
Species
Acanthamoeba
spp.

Acanthamoeb
a castellanii
o The most
frequently
identified
species in
 CNS
infection
 Ocular
infection
This
Acanthamoeba
spp. often seen in
immunosompromi
sed patient,
without any
previous contact
with
o Polluted soil
o Contaminated
water
 Therefore it is
thought to be an
opportunistic
organism

Clinical Manifestation
Diagnosis
Acanthamoeba spp. is the causative
agent of Granulomatous Amoebic
Encephalitis (GAE)
 Focal granulomatous encephalitis
is the main feature
o One or more lesions on the
brain
o Presented as SPACE
OCCUPYING lesions
o Resulting in neurological deficits
same to that of
 Brain tumor
 Brain abscess
 Patient presented with altered
mental status
 Can be either
o Subacute
o Chronic
Acanthamoeba spp. can also cause
Acanthamoeba keratitis
 Due to usage of contaminated
soft contact lenses
o Contamination because of
 Polluted cleansing solution
 Contaminated lens storage
 Characterized by
o Corneal ulceration
o Unilateral eye lesion
o Severe ocular pain
o Stromal infiltrate in the shape
of complete or partial ring
 Acanthamoeba keratitis is a
chronic condition
1. Microscopic
Examination
a. CSF smear for GAE
i. Must be
promptly done
ii. Examine for
motile amoeba
b. Corneal scrapping
for
Acanthamoeba
keratitis
i. The specimen is
stained by
either
1. Giemsa
2. PAS
3. Immunoflour
escent
2. Inoculation in mice
a. To observe any
neurological
deficits presented
3. Culture
a. Non-nutrient agar
b. With previous
seeding of either
i. Pseudomonas
aeruginosa
ii. Enterobacter
aerogenes
iii. E.coli
4. Upon autopsy,
numerous
Tropphozoites can be
found
Treatment
IV and
Intrathecal of
Amphotericin B
 Large dose of
o Amphotericin
B
o Miconazole
o Rifampicin

Prevention
Do not swim in
stagnant water
at
o Pools
o Ponds
 Adequate
chlorination of
public water
supplies
 Public
education and
awareness

Comparison
Naegleria spp.
Acanthamoeba spp.
Trophozoites with BROAD pseudopods
Actively motile
Form FLAGELLATE in external environment
SINGLE-walled cysts
Cysts are NOT found in tissue
Trophozoites with FILAMENTOUS pseodopods (acathopodia)
Sluggishly motile
Does not form flagellate in external environment
DOUBLE-walled cysts
Cysts may be found in tissue
Protozoa
Amoeba
Species
Entamoeba
histolytica
Mode of
Transmission
 Heamatogen
ous spread
from the
previous
Dysenteric
Amoebiasis
Clinical Manifestation
Entamoeba histolytica will cause 
Amoebic Brain Abscess
 Accounts for 4.2-8.5% of
death from amoebiasis

 Signs and symptoms similar to
that of brain abscess and
brain tumor
o Increase ICP
o Severe headache
o Vomiting
o Delirium
o Convulsive disorder
o Hemiplegia
o Meningitis
o Hemorrhage
 The patient will comatose and
succumb to death
Diagnosis
The actual case
of the disease is
unsuspected
Diagnosis only
made during
autopsy
Treatment

Metronidazole
Prevention


Avoid
drinking
contaminate
d water
supply
Adequate
chlorination
of public
water supply
Protozoa
Sporozoa
Species
Plasmodium
falciparum




Mode of
Transmission
Vectorborne
disease
o Transmitted
by
Anopheles
spp.
mosquito
Through the
infected red
cells
The red cells
become
distorted and
tend to clump
together
(sludging)
This clump of
red cells tend
to lodge to
small arteries
and
capillaries
and lead to
ischemic
attack to
respected
tissues
Clinical Manifestation
Diagnosis
Plasmodium falciparum may
cause Cerebral Malaria
 Risk factors
o Children under 10 years old
o Living in the endemic area
 The blockage of blood flow
compromises the oxygen
supply
 Manifested as
o Severe headache
o Drowsiness
o Confusion
o Delirium
o Change of mental status
o Comatose
 Death usually ensures within
24-72 hours in comatosed
patients if prompt treatment is
not done
 The outcome of cerebral
malaria could be
o Cortical blindness
o Hemiperesis
o Generalized plasticity
o Cerebral ataxia
o Severe hypotonia
1. Microscopic
Examination
a. Peripheral
blood smear
i. Blood
trophozoites
ii. Gametocyte
s
Treatment

Prompt IV
admin of
either
o Qunine
o Quinidine
Prevention
Vector
control
 Preventation
by giving
prophylactic
treatment in
o Susceptible
host
o People
living in
endemic
area
 Vaccination
is still on
development

Protozoa
Species
Toxoplasma
gondii
Mode of Transmission
Definitive host is Cats
 Humans come into
contact with the
cysts through
contaminated soil
with cats feaces
 It is an opportunistic
infection, which
normally affect the
o HIV patients
o Hodgkin
lymphoma
o Patient on chemo
Pathogenesis
 Ingestion of the
cysts will lead to
infection
 The initial infection
takes place at the
intestion and
regional lymph
nodes
 The cysts formation
occurs at the
o CNS
o Eyes
o Cardiac muscle
o Skeletal muscle
Amoeba
Clinical Manifestation
CNS disseminated
Toxoplasma gondii can
lead to
meningoencephalitis or
Toxoplasmic Encephalitis
 During an acute
infection, patients
usually appear
assymptomatic
 But when the cysts
forms in the CNS,
patients will develop
o Fever
o Headache
o Lethargy
o Altered mental
status
o Focal neurological
deficits
o Convulsions
 May end with fatality
 Single or multiple lesions
can be seen at the
o Basal Ganglia
o Junction between
the white and gray
matter
Diagnosis
 Microscopic
Examination
o Tissue biopsy
 Cysts with
bradyzoites
 Serological
Examination
o Finding of
specific
antibody
against the
organism


Treatment
Sulfonamide
Pyrimethamin
e




Prevention
Cook meat
properly
Wash hand
properly
before
o Handling
foods
o Eating
Raw meat
should not be
given to cats
o Instead
give only
 Cooke
d meat
 Canne
d food
Wear gloves
during
gardening
Species
Trypanosoma
spp.
1. Trypanosoma
brucei
rhodesiense
a. Cause fast
onset
human’s
Trypanosomi
asis
2. Trypanosoma
brucei
gambiense
a. Causes slow
onset
human’s
trypanosomi
asis
Protozoa
Flagellates
Mode of Transmission
Clinical Manifestation
Diagnosis
Treatment
Vectorborne
Both of the species can
 Microscopic
1. For the 1st stage
disease, transmitted
cause the African Sleep
Examination
treatment
by
Disease/ Sleeping
o Peripheral
a. For
 Tsetse fly/
Sickness/ African
blood smear
Gambiense
Glossina spp.
Trypanosomiasis
 Crescent
i. IV/IM
o Upside down  May present with diffuse
shaped
Pentamidine
o Meningoencephalitis
axe-shaped
trypanosom
b. For
o Meningencephalitis
wing venation
es
Rhodesiense

Pateints
presented
with
Pathogenesis
 Serological
i. IV Suramine
o Fever
 Brain is the final
Examination
2. For the 2nd stage
o Severe headache
site of infection of
o Antibody
treatment
o
Focal
neurological
the disease
production
a. IV Melasorprol
deficits
 This is when the
o Daytime sleeping
Trypanosome has
o Psychological
invaded the CNS
changes
o Lethargy
o Slurring of speech
o Tremors
o Convulsion
o Finally the patient
will comatose
 Death is due to
o Intercurrent infection
o Starvation due to
severe decline in
physical activity
Prevention
 Control of
Tsetse flies
 Prophylaxis
in
susceptible
host
 Medical
screening
Helminths
Nematoda (Roundworms)
Mode of
Transmission
Species
Strongyloides
stercolaris

o

o

o

o
Infective stage
Filariform
Diagnostic
stage
Rhabditiform
Pathogenic
stage
Adult worm
Final habitat
Large
intestine
Toxocara
spp.


Direct
penetration by
Filariform
through the
intact skin
Reinfection
through the
swallowing of
Filariform larvae
from the larynx
The definitive
hosts are
o Cats
o Dogs
 Transmitted via
ingestion of
infective eggs
deposited in the
soil
 After infecting
the intestine, it
will migrate to
other organs
including the
brain

Clinical Manifestation
Strongyloides stercolaris may cause a
severe disease known as Hyperinfection
Syndrome in Immunocompromised
patients
 The parasites replicate and reinfect
the host without even needing the
normal external life cycle
 Massive infestation of helminths in
the large intestine has made it
possible to disseminate across the
body system
 Dissemination may lead to
o Meningitis
o Encephalitis
o Septiceamia
Toxocara spp. can lead Visceral Larva
Migrans
 Patients presented with
o Focal neurological deficits
o Stiff neck
o Vomiting
o Seizures
o Blur vision
o Epileptiform attack
 Death is common
Diagnosis


Stool Examination
o Finding of
Rhabditiform
Serological
Examination
o Rise in the IgE
o ELISA
Stool Examination
o Finding of
Infective Eggs in
the feaces
 Serological
Examination
o ELISA

Treatment




Prevention
1st line drug
o Ivermectin
o Thiabendazo
le
2nd line drug
o Albendazole

Metronidazole
Ivermectin




Keep personal
hygiene
Wash hands
before eating
Prophylaxis
treatment in
susceptible hosts
Keep self
hygiene
Wear gloves
during
gardening
Helminths
Species
Trichinella
spiralis
It is an Intestinal
Nematode
**So far, there are
no reports of
Trichinellosis in
Malaysia

Angiostrongylus
cantonentis
Rat’s lungs
worms
o Normally
found in the
rat lungs
 Not endemic in
Malaysia
Mode of Transmission
Nematoda (Roundworms)
Clinical
Diagnosis
Manifestation
Ingestion of contaminated
meat that harboured the
Encysted Larval form
Pathogenesis
 Release from the cysts in the
intestine and develop into
adult form
 The female adult produces
larva
o Viviparous production
 Directly give birth to live
larva
 The free larva migrates to the
circulatory system disseminate
into various organs
 The have predilection to
striated muscle for them to
ENCAPSULATE
 This capsule may produce
space-occupying lesion
Trichinella spiralis is the
causative agent of
Trichinellosis
 Enteritis is presented
when
o Larvae released
from the cysts
o Develop into adult
form in the
intestine
 When the larva
disseminate to the
CNS, patients may
present with focal
neurological deficits

Results from eating infected
Snail
Crabs
Prawns
Unwashed vegetables
This is because, the first stage of
larval form excreted via rat
feaces
This larva will infect the
intermediate hosts like those
above
Angiostrongylus
cantonensis is the
causative agent of
Eosinophilic Meningitis
 High level of
esinophils in
o CSF
o Blood
 Sign and symptoms
of meningeal irritation
o Neck rigidity
o Headache



o
o
o
o



Treatment
Microcopic
Examination
o Finding of cysts
(capsule)
containing larva in
the skeletal
muscle
 Serological
Examination
o ELISA


Microscopic
Examination
o CSF
 High level of
Eosinophils
 Low glucose
level
 High protein
level
 Occasional
finding of
Angiostrongylus
larvae

Metronidazole
Albendazole
Prevention


Symptomatic
relieve
o Analgesics

Used of cooked
material as feed
stocks for pigs
Proper cooking
method of pork
Prepare food
properly,
escpecially
o Snail
o Crabs
o Prawns
o Vegetables
Helminths
Species
Schistosoma
japonicum


The most virulent
humans’s
schistosome
species
Mainly affect
the large
intestine
Paragonimus
westermani

Prevalence in
o Thailand
o Indochina
Mode of Transmission
Trematoda (Flat/Fluke Worms)
Clinical Manifestation
Diagnosis
Feacal oral route
o Non-hygienic
sanitation
 The ova being
filtered in the
circulatory system
 Lodge in the liver
 Ova can also lodge
in the brain leading
to encephalitis
 Ova is the sole
pathological causes
of the disease
Schistosoma japonicum is
causative agent of Cerebral
Schistosomiasis
 Major pathological
features
o Pseudotubercles
o Granuloma
o Fibrosis
 If left untreated leads to
o Hepatosplenic
impairment
o Cognitive impairment
o Neurological deficit

Results from eating
infected
o Freshwater crabs
 Freshwater crabs
harbour the Infective
Metacercaria
 Once ingested,
Metacercaria
mature into adult
stage and stay in the
LUNGS
 The adult nematode
deposits ova in the
alveolar spaces
 May migrate to the
brain
Paragonimus westermani is
the causative agent of
Cerebral Paragonimiasis
 Signs and symptoms
o Epilepsy
o Hemiplegia
o Monoplegia
o Paresis
o Visual disturbances
o Cough
o Hemoptysis
 Prognosis is generally
poor



Microscopic
Examination
o Identification of
eggs in
 Urine
 Stool
 Serological test
o ELISA for
specific
 Antibodies
 Antigens

Medical History
o History of
 Cough
 Hemoptysis
 **often
misdiagnose
d with
pulmonary
TB
 Serological test
o ELISA to detect
specific
 Antobodies
 Antigens

Treatment
Praziquantel


Supportive
treatment with
Corticosteroid


Prevention
Proper
sanitation
Avoid use of
human stools
for fertilizers
Hygienic food
preparation
Proper
cooking
method
Helminths
Cestoda (Tapeworms)
Species
Taenia solium 
Larval stage
of Taenia
o
solium is
called
o Cysticercus
cellulosae
o
 Sac-like
 Fluid
filled

 Also
known as
Bladder

worm
 Adult worms
have
o 4 suckers
o Top
o
rostellum
with hooks


o
o
Mode of
Transmission
Ingestion of
undercooked
pork meat
The worm
encyst in the
muscle of the
pig
Infection is due
to ingestion of
viable larvae
May also due to
accidental direct
ingestion of ova
The larva
migrates to the
muscle tissue and
encyst there to
form Cysticercus
This condition is
called the
Cysticercosis
Cysticercosis may
also disseminated
to other organ
such as
Brain
Eyes
Clinical Manifestation
Taenia solium is the causative
agent of Neurocysticercosis
 Signs and symptoms
o Severe headache
o Dizziness
o Nausea
o Vomiting
o Blurred vision
o Personality change
o Photophobia
o Diplopia
o Acute encephalitis
o Localized anasthesia
o Aphasia
o Amnesia
o Epileptic seizure
 During attack, patient
may suddenly fall and
injured himself
Taenia solium is also a
causative agent of Ocular
Neurocysticercosis
 Signs and symptoms
o Iritis
o Retina dislocation
o Complaint of
 Vision disturbance
 Floating shadows
Diagnosis


Microscopic

Examination

o Subcutaneous 
biopsies
(accidental
findings)
 Finding of
Cysticercus
Opthalmoscopy
o Finding of
motile
bladder worm
in the eye
Treatment
Prevention
Praziquantel

Albendazole
Surgical
removal of

bladder worm
whenever

possible


Early
diagnosis and
treament
Improvement
of sanitation
Prophylactic
chemotherap
y for workers
in pig rearing
Adequate
meat
inspection
Avoid
improperly
cooked meat
Helminths
Species
Echinococcu
s granulosus

Larval form
also know as
Hydatid Cyst
Mode of Transmission






Spirometra
mansoni

Plerocercoid
larva is
called
Sparganum
Ingestion of meat of herbivores that
harbour the hydatid cysts
o
Sheep
o
Cattle
The definitive host would be
o
Foxes
o
Humans
The intermediate host may also
contaminate the grassland and
pasture through defecation
o
Definitive host like human can
be affected through ingestion
of the infective ova (feacal oral
route)
Embryo hatches from the ingested
matured eggs in the intestine
The embryo circulates the blood
and form a cysts in organs (Spaceoccupying Lesion)
The lesion happen at
o
88% at the liver and lungs
o
1% at the brain
Ocular infection is due
to
o Use of frog/snake
skin as bandage to
eleviate pain in eye
injuries
o Common in
Indochina
o The larvae from the
intermidiate host skin
migrate to definitive
host (human)through
direct contact
 The larva can migrate
to the brain as well

Cestoda (Tapeworms)
Clinical Manifestation
Diagnosis
Larvae of Echinococcus
 Serological test
granulosus is the
o ELISA
causative agent of
 Laboratory test
Cerebral Hydatidiosis
o X-ray
 Signs and symptoms
 Medical history
o Increase ICP
o Epilepsy
Sparganum of Spirometra
mansoni is the causative
agent of Ocular
Sparganosis
 Signs and symptoms
o Severe conjunctivitis
o Lacrimation
o Ptosis
Sparganum of Spirometra
mansoni is also the
causative agent of
Cerebral Sparganosis
 Signs and symptoms
o Brain abscess
o Eosinophilia

Isolation of
Sparganum
from the lesion
(Ocular
Sparganosis)


Treatment
Surgical
removal of
the cysts
Albendazole





Surgical
removal of
Sparganum
Praziquantel

Prevention
Adequate
meat
inspection
Avoid
improperly
cooked meat
Improvement
of sanitation
Public
education
Insects
Species
Fly Larvae/
Maggots
Mode of Transmission
 Infestation of
maggots from
o Dermatobia
hominis
o Hypoderma
bovis
o Lucia sericata
Arthrapoda
Clinical Manifestation
Fly larvae may cause

 Cutaneous myiasis
(most common)
 Nasal myiasis
 Oral myiasis
 Intestinal myiasis
 Ocular myiasis
 Aural myiasis
 Genitourinary myiasis
 Cerebral myiasis
Nasal myiasis is very
dangerous, as the larva
may migrate to the brain
and causing Cerebral
Myiasis
Diagnosis
Isolation of fly
larvae from the
lesion

Treatment
Surgical

removal of
maggots from 
the lesion


Prevention
Usage of
insecticides
Improvement
of sanitation
Personal
hygiene
Wash off
clothes
regularly