Symbiosis
Commensalism
Mutualism
Parasitism
Endoparasite
Ectoparasite
Erratic
Obligate parasite
Facultative parasite
Accidental/incidental
parasite
Permanent parasite
Temporary parasite
Spurious parasite
Definitive/final host
Intermediate host
Paratenic host
Reservoir host
Biologic vector
Mechanical/phoretic vector
Epidemiology
Incidence
Prevalence (%)
Cumulative prevalence
Intensity of infection
(Worm burden)
Morbidity
Deworming
Cure rate (%)
Egg reduction rate
Selective treatment
Targeted treatment
Universal treatment
Coverage
Efficacy
Effectiveness
MUST TO KNOW IN PARASITOLOGY
Living together of unlike organisms
2 species live together
One species benefits from the relationship w/o harming or benefiting the other
Ex. Entamoeba coli
2 organisms benefit from each other
Ex. Termites and the flagellates inside their digestive system
1 organism lives in or on another for its survival at the expense of the host
Ex. Entamoeba histolytica
Lives inside the body of the host
“Infection”
Lives outside the body of the host
“Infestation”
Parasite found in an organ w/c is not its usual habitat
Need a host to complete their development
May exist in a free-living state
May become parasitic when the need arises
Parasite that established itself in a host where it does not ordinarily live
Ex. Echinococcus granulosus
Remains on or in the body of the host for its entire life
Lives on the host only for a short period of time
Free-living organism
Passes through the digestive tract w/o infecting the host
Parasite attains sexual maturity
Harbors the asexual/larval stage of the parasite
One in which the parasite does not develop further to later stages
Parasite remains alive and is able to infect another host
Allows the parasite’s life cycle to continue and become additional sources of
infection
Transmits the parasite only after the the latter has completed its development
within the host
Ex. Aedes mosquito
Only transports the parasites
Ex. Flies and cockroach
Study of patterns, distribution and occurrence of disease
Number of new cases of infection in a given period of time
Number of individuals estimated to be infected w/ a particular parasite
% of individuals in a population infected w/ at least 1 parasite
Number of worms per infected person
Clinical consequences of infections or diseases that affect an individual’s wellbeing
Use of antihelminthic drugs in an individual
Number of previously positive subjects found to be egg-negative
% fall in egg counts after deworming
Individual-level deworming
Group-level deworming
Population-level deworming
Proportion of the target population reached by an intervention
Effect of a drug against an infective agent
Measure of the effect of a drug against an infective agent
lec.mt 04 |Page | 112
Information-educationcommunication
Environmental
management
Environmental sanitation
Sanitation
Eradication
Elimination
Protozoan
Metazoan
Sarcomastigophora
Sarcodina
Mastigophora
Ciliophora
Apicomplexa
Microspora
Nematoda
Intestinal
Extraintestinal
A health education strategy that aims to encourage people to adapt and
maintain healthy life practices
Planning, organization, performance, and monitoring of activities for the
modification and/or manipulation of environmental factors
Interventions to reduce environmental health risks
Provision of access to adequate facilities for the safe disposal of human excreta
Permanent reduction to zero of the incidence of infection caused by a specific
agent, as a result of deliberate efforts
Reduction to zero of the incidence of a specified disease in a defined geographic
area as a result of deliberate efforts
Unicellular organism
Multicellular organism
Classification of Protozoan Parasites
Acanthamoeba
Endolimax
Entamoeba
Iodamoeba
Naegleria
Chilomastix
Dientamoeba
Giardia
Trichomonas
Leishmania
Trypanosoma
Balantidium
Babesia
Cryptosporidium
Cyclospora
Isospora
Plasmodium
Toxoplasma
Enterocytozoon
Encephalitozoon
Vittaforma
Trachipleistophora
Pleistophora
Brachiola
Microsporidium
Classification of Metazoan Parasites
Ascaris
Capillaria
Enterobius
Hookworm
Strongyloides
Trichuris
Angiostrongylus
Filarial worms
Trichinella
lec.mt 04 |Page | 113
Cestoidea
Cyclophyllidea
Pseudophyllidea
Trematoda
Arthropoda
Arachnida
Chilopoda
Crustacea
Diplopoda
Insecta
Pentastomida
Ascaris lumbricoides
Enterobius vermicularis
Trichuris trichiura
Capillaria philippinensis
Necator americanus
Ancylostoma duodenale
Ancylostoma braziliense
Ancylostoma caninum
Strongyloides stercoralis
Dipylidium
Echinococcus
Hymenolepis
Raillientina
Taenia
Diphyllobothrium
Spirometra
Artyfechinostomum
Clonorchis
Echinostoma
Fasciola
Fasciolopsis
Heterophyids
Opisthorchis
Paragonimus
Schistosoma
Mites
Scorpions
Spiders
Ticks
Centipedes
Copepods
Crabs
Millipedes
Flies
Flea
Beetle
Bees
Lice
Wasp
Bugs
Mosquitoes
Tongue worms
Common/Other Names
Giant intestinal roundworm
Lumbricus teres
Pinworm
Oxyuris vermicularis
Seatworm
Social or Society worm
Whipworm
Pudoc worm
American hookworm
American murderer
New world hookworm
Old world hookworm
Cat hookworm
Dog hookworm
Threadworm
lec.mt 04 |Page | 114
Trichinella spiralis
Wuchereria bancrofti
Brugia malayi
Loa loa
Onchocerca volvulus
Dirofilaria immitis
Dracunculus medinensis
Anisakis
Toxocara canis
Toxocara cati
Fasciola hepatica
Fasciola gigantica
Clonorchis sinensis
Fasciolopsis buski
Echinostoma ilocanum
Heterophyes heterophyes
Paragonimus westermani
Schistosoma japonicum
Schistosoma mansoni
Schistosoma haematobium
Taenia saginata
Taenia solium
Hymenolepis nana
Hymenolepis diminuta
Dipylidium caninum
Diphyllobothrium latum
Echinococcus granulosus
Cyst
Trophozoite
Sporozoites
Trypomastigote
Promastigote
Embryonated egg
Larva
Filariform larva
3rd stage larva (filiform)
Muscle worm
Garbage worm
Bancroft’s filarial worm
Malayan filarial worm
Eye worm
Blinding worm
Dog/canine heartworm
Guinea worm
Fiery serpent of the Israelites
Medina worm
Dragon worm
Fish and Marine mammal roundworm
Herring’s worm
Dog ascarid
Cat ascarid
Sheep liver fluke
Giant liver fluke
Oriental liver fluke
Chinese liver fluke
Giant intestinal fluke
Garrison’s fluke
Von Siebold’s fluke
Oriental lung fluke
Oriental blood fluke
Profile of a man
Bladder fluke
Beef tapeworm
Pork tapeworm
Dwarf tapeworm
Rat tapeworm (Norway rats)
Dog tapeworm
Double-pored tapeworm
Broadfish tapeworm
Hydatid worm
Infective Stages
Protozoans (amoebas)
T. vaginalis
Plasmodium
Trypanosoma
Leishmania
“HATE”
H. nana
A. lumbricoides
T. trichiura
E. vermicularis
T. spiralis
C. philippinensis
Hookworm
S. stercoralis
W. bancrofti
B. malayi
lec.mt 04 |Page | 115
Cercaria
Metacercaria
Cysticercus bovis
Cysticercus cellulosae
Plerocercoid larva
Hydatid cyst
Cysticercoid larva
Separate sexes
Life cycle
Aphasmids
Phasmids
Amphid
Oviparous
Ovoviviparous/oviviparous
Viviparous/larviparous
Frequency
Small intestines
Large intestines
Heart-to-lung migration
Extraintestinal Nematodes
Visceral Larva Migrans
Triad of infection/Unholy 3
Characteristics
Fertilized Egg
A. cantonensis
L. loa
O. volvulus
Mansonella
S. japonicum
S. haematobium
S. mansoni
F. hepatica
F. buski
C. sinensis
O. felineus
P. westermani
E. ilocanum
Heterophyids
T. saginata
T. solium
D. latum
E. granulosus
H. diminuta
D. caninum
Nematodes (Roundworms)
Female = larger, pointed tail
Male = smaller, curved tail
Egg stage > Larval stage > Adult stage
Lacks phasmids or caudal chemoreceptors
“TCT”: Trichuris-Capillaria-Trichinella
w/ caudal chemoreceptors
Hookworm
S. stercoralis
W. bancrofti
B. malayi
Cephalic chemoreceptors
Lays eggs in unsegmented stage (unembryonated)
Lays eggs in segmented stage (embryonated)
Larva
“EAT”: Enterobius > Ascaris > Trichuris
“CASH”: Capillaria, Ascaris, Strongyloides, Hookworms
“ET”: Enterobius, Trichuris
“ASH”: Ascaris, Strongyloides, Hookworm
Filarial worms = lymphatics and subcutaneous tissues
T. spiralis = muscles
A. cantonensis = meninges
T. canis and T. cati
“HAT”: Hookworm, Ascaris, Trichuris
Ascaris lumbricoides
Resembles common earthworm
3 layers:
-Inner: Vitelline membrane
-Middle: Glycogen layer
-Outer: Mammilation (corticated)
lec.mt 04 |Page | 116
Unfertilized Egg
Adult
MOT
Symptoms and Pathology
Lab. Diagnosis
Characteristics
Egg
Adult
MOT
Symptoms and Pathology
Lab. Diagnosis
Characteristics
Egg
Adult
MOT
Symptoms and Pathology
Lab. Diagnosis
Characteristics
Egg
Adult
MOT
IH
Symptoms and Pathology
2 layers:
-Inner: Glycogen
-Outer: Mammilation
Has lecithin granules
Buccal cavity: Triangular, trilobate lips
Ingestion
Larval migration: Eosinophilia (resembles Loeffler’s syndrome)
Adult: Erratic  Extraintestinal sites
Intestinal perforation
1. Stool exam
= Egg: Diagnostic stage
= If (-) stool exam:
a. No infection
b. Early infection
c. All MALE WORM infection
Enterobius vermicularis
Autoinfection: Same host (EV, SS)
External autoinfection
Elongated, flattened on 1 side
D-shaped
w/ lateral wings or cephalic alae
Ingestion
Mother’s complex:
-Pruritus ani
-Lack of sleep
-Extraintestinal enterobiasis
1. Perianal swab: Scotch tape swab
= Egg: Diagnostic stage
Trichuris trichiura
Causes trichocephaliasis
Barrel-shaped w/ bipolar mucus plug
Resembles Japanese lantern
Slender or attenuated in the anterior
Resembles a whip
Ingestion
Rectal prolapse (Heavy infection)
1. Stool exam
= Egg: Diagnostic stage
Capillaria philippinensis
Causes pudoc disease or mystery disease
w/ bipolar mucus plugs that are not as protruded as T. trichiura egg
Guitar, peanut-shaped
Male: w/ chitinized spicule (spicule sheath)
Female: have eggs in utero
Ingestion of freshwater fishes
Fresh water fishes:
-Hypselotris bipartite (ipon)
-Birot
-Bagsang
-Bagtu
Malabsorption (CP, GL)
Borborygmi = peculiar abdominal gurgling sound
lec.mt 04 |Page | 117
Lab. Diagnosis
Characteristics
Egg
Adult
Rhabditiform larva
Filariform larva
MOT
Symptoms and Pathology
Lab. Diagnosis
Characteristics
Adult
Rhabditiform larva
Filariform larva
MOT
Symptoms and pathology
Characteristics
LBM alternating w/ constipation
1. Stool exam
= Egg: Diagnostic stage
Hookworms (Necator, Ancylostoma)
Agent of laziness in poor white population and tropical anemia in Puerto Rico
Same for all species
Ovoidal, thin-shelled, colorless
“Morula ball”
N. americanus: S-shaped, w/ semilunar cutting plates
A. duodenale: C-shaped, w/ 2 pairs of teeth
Male copulatory bursa:
-Bipartite (2 digits): Barbed & bristle like
-Tripartite (3 digits): Simple & not barbed
1st stage larva
Short and stout
Open mouth: feeding stage
Buccal cavity: long
Genital primordium: small or inconspicuous
2nd stage larva
Long and slender
Closed mouth: nonfeeding stage
Sheath: (+)
Tail: Pointed
Skin penetration
Mazza Mora/Water sore or ground itch
Severe itching/allergic reaction at the site of skin penetration
IDA
Cutaneous larva migrans (Creeping eruption): A. braziliense and A. caninum
(animal hookworm)
1. Stool exam
= Egg: Diagnostic stage
2. Harada Mori Culture technique
= Filter paper culture technique
= For hookworm and threadworm larvae
3. Baermann funnel technique (Strongyloides)
Strongyloides stercoralis
Causes Cochin-China diarrhea
Facultative nematode:
-Parasitic: small intestine
-Free-living: soil
Female: capable of parthenogenesis (fertilization w/o the benefit of male)
Buccal cavity: short
Genital primordium: prominent or conspicuous
Sheath: (-)
Tail: Notched
Skin penetration
Skin: Allergic reaction
Larval migration: pneumonia
Intestines: abdominal pain, diarrhea, vomiting
Trichinella spiralis
Adult: in intestines
Larva: in muscles
lec.mt 04 |Page | 118
Adult
MOT
Symptoms and pathology
Lab. Diagnosis
Characteristics
Adults
Microfilaria
Lab. Diagnosis
Habitat
Vector
Specimen
Microfilaria
Periodicity
Habitat
Vector
Specimen
Microfilaria
Periodicity
Habitat
Vector
Specimen
Microfilaria
Periodicity
Requires 2 host to complete its life cycle
Propagated by black and brown rats
Man: both DH and IH, dead-end host
Freezing destroys the larva
Male: w/ conical papillae
Female: w/ club-shaped uterus (viviparous/larviparous)
Ingestion of meat
Larva: muscle
-Edema, muscle pain, difficulty in breathing and swallowing
Adult: intestines
-Abdominal pain, diarrhea
1. Muscle biopsy
= Encysted larva: Diagnostic stage
2. Immuno-tests:
a. Bentonite flocculation (TS, EG)
b. Intradermal test (Bachmann)
3. Xenodiagnostic tests (TS, TC)
= Beck’s albino rats/mice
Filarial Worms
Vector-borne nematodes
DH: man (IS: filiform larva/3rd stage larva)
IH: vector (IS: microfilaria)
DS: Microfilaria
In lymphatics and subcutaneous tissue
In blood
1. Knott’s technique
= Isolation of microfilaria
= Blood + formalin + Giemsa stain
Wuchereria bancrofti
Lymphatics
Aedes
Anopheles
Blood
Sheathed
Nuclei absent in tail
Nocturnal (10PM-2AM)
Brugia malayi
Lymphatics
Mansonia
Blood
Sheathed
Tail w/ 2 separate nuclei
Subperiodic
Nocturnal
Loa loa
Subcutaneous tissue
Chrysops
Tabanid (mango fly)
Blood
Sheathed
Nuclei continuous up to the tip of the tail
Diurnal
lec.mt 04 |Page | 119
Habitat
Vector
Specimen
Microfilaria
Periodicity
Habitat
Vector
Specimen
Microfilaria
Periodicity
Habitat
Vector
Specimen
Microfilaria
Periodicity
Characteristics
Characteristics
IH
DH
MOT
Characteristics
IH
DH
Adult
Characteristics
1st IH
2nd IH
3rd IH
DH
MOT
Onchocerca volvulus
Subcutaneous tissue
Simulium (black fly)
Skin snips/shavings
Unsheathed
Nuclei absent in tail
Nonperiodic
Dipetaloma perstans (Acanthoculonema perstans)
Body cavities
Culicoides
Blood
Unsheathed
Nuclei up to the tip of the tail
Nonperiodic
Mansonella ozzardi
Body cavities
Culicoides
Blood
Unsheathed
Tail is free of nuclei
Nonperiodic
Dirofilaria immitis
Human infection: solitary, peripheral nodules in the lung (coin lesions), or as
subcutaneous nodule
Dracunculus medinensis
Longest nematode of man
Cyclops (copepods): aquatic crustacean
Man
Ingestion of crustacean
Angiostrongylus cantonensis
Causes human eosinophilic meningoencephalitis
Mollusks:
-Achatina fulica
-Japanese snail
-Pila luzonica (kuhol)
-Brotia asperata (suso)
Rats
Female: “Barber’s pole appearance”
Looking of whitish uterus to red digestrive tract
Anisakis
Causes Herring’s disease
Various marine crustaceans
Smallest fishes
Larger fishes
Dolphins/whales
Ingestion of raw fish (ex. sashimi)
lec.mt 04 |Page | 120
Trematodes
Phylum
Class
Characteristics
Attachment
Life cycle
1st IH
2nd IH
Fish
Crab
Plant/vegetation
Snail
Habitat
Characteristics
Egg
Adult
Platyhelminthes
Trematoda (Flukes)
All except blood flukes [Schistosomes] Schistosomes:
1. Flat, leaf like
1. Elongated and cylindrical
2. Hermaphrodite
2. Separate sexes
3. Egg: operculated
3. Egg: Non-operculated
4. MOT: ingestion
4. MOT: skin penetration
5. IS: metacercaria
5. IS: Cercaria (fork-tailed)
6. IH: 2 IH
6. IH: 1 IH (snail)
Eggs:
a. Mature when laid (embryonated): “SHOC”
-Schistosoma
-Heterophyes
-Opistorchis
-Clonorchis
b. Immature when laid (unembryonated): “PEFF”
-Paragonimus
-Echinostoma
-Fasciola
-Fasciolopsis
2 suckers: oral and ventral (acetabulum)
-Heterophyes: 3 suckers (3rd: genital sucker [gonotyle])
Egg > Larva (Miracidium>Sporocyst>Redia>Cercaria>Metacercaria) > Adult
Snail
Fish, crab, plant/vegetation, snail
Schistosoma
H. heterophyes
O. felineus
C. sinensis
P. westermani
F. hepatica
F. gigantica
F. buski
E. ilocanum
Liver:
-F. hepatica
-F. gigantica
-C. sinensis
-O. felineus
Small Intestines:
-F. buski
-E. ilocanum
-H. heterophyes
Lungs:
-P. westermani
Fasciola hepatica
Causes sheep liver rot
Prevalent in sheep raising countries
Resembles F. gigantica and F. buski
w/ cephalic cone
Leaf-like hermaphrodite
lec.mt 04 |Page | 121
Characteristics
Egg
Characteristics
Egg
1st IH
2nd IH
MOT
Characteristics
Characteristics
Egg
1st and 2nd IH
Characteristics
Adult
1st IH
2nd IH
MOT
Characteristics
Egg
Adult
1st IH
2nd IH
MOT
Lab. Diagnosis
Characteristics
Adult
Lab. Diagnosis
Pathology
Characteristics
Habitat
Egg
IH
Characteristics
Habitat
Egg
IH
Fasciola gigantica
Infects cattle in the Philippines
Resembles F. hepatica and F. buski
Clonorchis sinensis
Most important liver fluke of man
Old-fashioned electric light bulb
Snail
Fishes
Ingestion
Opisthorcis felineus
Resembles C. sinensis
Fasciolopsis buski
Largest fluke parasitizing man
Hen’s egg shaped
Indistinguishable from Fasciola
Echinostoma ilocanum
Snail
Heterophyes heterophyes
Smallest but deadliest fluke of man
w/ 3rd sucker (gonotyle)
Snail
Fishes
Ingestion
Paragonimus westermani
Causes endemic hemoptysis
w/ thickened abopercular end opposite the operculum
Resembles coffee bean
Snail
Crabs
Ingestion
1. Examination: sputum and stool
Schistosomes
Most romantic parasite of man
Male: w/ gynecophoral canal where the female is held
1. Demonstration of egg in feces, rectal or liver biopsies, and urine
2. Faust and Meleney’s egg hatching technique
3. Circumoval precipitin test (COP) of Oliver and Gonzales
Larval penetration
-Human sp: slight allergic reaction
-Nonhuman sp: Swimmer’s itch
Tissue damage by eggs
Schistosoma japonicum
Causes Katayama’s disease
Superior mesenteric veins in the small intestines
w/ small knob-like or recurved hook on one side
Oncomelania quadrasi
Schistosoma mansoni
Smallest of the blood flukes
Superior mesenteric veins of the colon and rectum
w/ lateral spine
Biomphalaria
lec.mt 04 |Page | 122
Characteristics
Egg
IH
Specimen
Phylum
Class
Characteristics
Cestode body
Order Pseudophyllidea
Order Cyclophyllidea
Require vertebrate IH
Require invertebrate IH
May or may not require IH
Characteristics
Uterus
Lab. Diagnosis
Scolex
Length
# of proglottids
Gravid proglottid
Eggs
Larva
Pathogenesis
Australorbis
Tropicorbis
Schistosoma haematobium
Vesical blood fluke causing bilharziasis or urinary schistosomiasis (hematuria)
w/ terminal spine
Bulinus
Physopsis
Biomphalaria
24-hr unpreserved urine
Trematodes
Platyhelminthes
Trematoda
Living worms: creamy white and yellowish
Adult: flat and ribbon-like (masking tape)
1 IH only
Scolex = anterior attachment organ
Neck = region of growth
Strobila = chains of segments or proglottids
-Immature, mature, ripe/gravid (filled w/ eggs)
False tapeworm (Ex. D. latum)
Scolex: Spoon-shaped w/ bothria (slit-like sucking grooves), no hooklets
Strobila: Anapolytic (not shedding segments)
Egg: operculated w/ aboperculum, immature when laid
Stages: Coracidium > Procercoid > Plerocercoid
IH: 2 IH (Copepods and fresh water fish)
True tapeworm
Scolex: Quadrate, w/ 4 cuplike suckers (rostellum w/ or w/o hooklets)
Strobila: Apolytic (shedding segments)
Egg: non-operculated, embryonated (mature when laid), hexacanth embryo
IH: 1 IH
T. solium (IH: pig)
T. saginata (IH: cattle)
D. caninum (MOT: ingestion of “pulgas”)
H. nana
Diphyllobothrium latum
Largest tapeworm of man
Causes Vit. B12 deficiency anemia
Rosette formation
1. Stool examination
= Egg: Diagnostic stage
Taenia saginata
Taenia solium
None, no rostellar hooks
w/ rostellum armed w/ 2 rows of
large and small hooklets
25 m
7m
1000-2000
<1000
15-20 lateral branches
7-13 lateral branches
(dichotomous or tree-like)
(dendritic or fingerlike)
Spherical, striated, inside is an embryo Spherical, striated, inside is an embryo
w/ 6 hooklets
w/ 6 hooklets
Cysticercus bovis
Cysticercus cellulosae
Taeniasis saginata
Taeniasis solium, cysticercosis
lec.mt 04 |Page | 123
Characteristics
Scolex
Eggs
IS
DH
Proglottids
Eggs
IH
DH
Characteristics
Eggs
IH
DH
Lab. Diagnosis
Hymenolepis nana
Hymenolepis diminuta
Smallest tapeworm of man
w/ rostellum armed w/ a ring of 20w/ an unarmed rostellum
30 spines
w/ oncosphere enclosed in an inner
w/ oncosphere enclosed in an inner
membrane w/ 2 polar thickenings,
membrane w/ 2 polar thickenings, but
from each w/c arise 4-8 polar
w/o filaments
filaments
Direct: Eggs
Cysticercoid larva
Indirect: Cysticercoid larva
Man
Rat
Dipylidium caninum
w/ double set of reproductive organs and genital pore on each side of the
lateral margin
Mature & gravid proglottids: melon seed/pumpkin seed/rice grain-shaped
Egg packet (8-15 eggs)
Ctenocephalides canis (dog flea)
Ctenocephalides felis (cat flea)
Pulex irritans (human flea)
Dogs or cats
Man: accidental host
Echinococcus granulosus
Shortest tapeworm (only 3 segments: immature, mature, ripe/gravid)
Anti-P1
Resembles Taenia egg
Sheep (IS: eggs)
Man: accidental IH
Dog
1. Exploratory cyst puncture
2. Roentgenogram (x-ray)
3. Immunologic tests:
= Bentonite flocculation test (TS, EG)
= Casoni (intradermal test)
Protozoans
Characteristics
Hemotogranules
Trophozoites
Unicellular
Animal-like protists
Division: Fission
No cell wall w/ outer membrane (periplast)
Cytoplasm: ectoplasm (outer) and endoplasm (inner)
Contains at least 1, and some several nuclei
Some contain vacuoles: for storage and transport
Special organs for locomotion
-Sarcodina/Rhizopoda = Amoeba (pseudopods)
-Mastigophora/Flagellata
-Ciliophora/Ciliata
-Sporozoa = no definite locomotory organelle
Class Rhizopoda
Motile
Feeding stage
Diarrheic/liquid stool
Destroyed by iodine
lec.mt 04 |Page | 124
Cyst
Characteristics
Life cycle
Entamoeba
Endolimax/Iodamoeba
Trophozoite
Cyst
Endolimax nana
Iodamoeba butschlii
Iodamoeba williamsi
Entamoeba gingivalis
Characteristics
Non-motile
Nonfeeding stage
Well-formed stool
Infective stage
w/ cystic stage except Entamoeba gingivalis
Inhabit the large intestine except Entamoeba gingivalis
Commensals except Entamoeba histolytica
Trophozoite > Precystic > Cystic > Metacystic stage
True amoeba
Peripheral chromatin (trophozoite and cyst)
Chromatoidal bars (cyst)
Other amoeba
No peripheral chromatin
No chromatoid bars
Entamoeba histolytica
Entamoeba coli
-Motility: Unidirectional & progressive -Motility: several directions, sluggish
-1 pseudopod (finger-like)
-Many pseudopods (blunt & rounded)
-Endoplasm: w/ RBC but no bacteria
-Endoplasm: w/ bacteria, yeasts and
or cell detritus (clean-looking)
cell detritus (dirty-looking)
-Nucleus: not visible when stained;
-Nucleus: when stained, consists of
consists of thin nuclear membrane w/ thicker nuclear membrane w/ layer of
layer of uniformly sized fine
variously sized chromatin granules
chromatin granules distributed along
unevenly distributed along the inside
inside the border of nuclear memb.
border of nuclear membrane
-Karyosome: fine, centrally located
-Karyosome: large, eccentrically
(Bull’s eye)
located
-Chromatoidal bars: coffin/rod/cigar/ -Chromatoidal bars: splinter-like/
sausage-shaped
witch-broom/whisked broom
-Mature cyst w/ 1-4 nuclei
-Mature cyst w/ 1-8 nuclei
Smallest amoeba
Size = RBC
[Trophozoite]
-Karyosome: large round dot
[Cyst]
-Usually oval
-Nuclei: 4 (cross-eyed)
[Trophozoite]
-Karyosome: w/ cluster of achromatic granules
[Cyst]
-Large iodine-staining glycogen vacuole
Associated w/ gum infection
[Trophozoite]
Karyosome: small and centrally located
Pseudopodia: similar to E. histolytica but does not exhibit true progressive
locomotion
Opportunistic Amoeba
Free-living amoeba
Inhabits the CNS
Does not indicate fecal contamination
Cause PAM (fatal)
Includes: Naegleria, Acanthamoeba, Hartmanella
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Naegleria fowleri
Major causative agent of PAM
Amoeboflagellate (trophozoite)
Acquired while diving & swimming during hot weather in brackish/freshwater
CSF: purulent, w/ motile amoeba
Acanthamoeba
Causes keratitis (from contaminated contact lens care solution)
Causes GAE
Culture: BAP flooded w/ E. coli
Class Mastigophora (Flagellata)
Characteristics
Possesses whip-like locomotory organelle called flagella
Motor component: flagella and axonemes
Neuromotor apparatus: kinetoplast w/c consists of blepharoplast and
parabasal body (energizing portion)
Digestive tract &
Enteromonas hominis
Genital flagellates
Embadomonas intestinalis
Chilomastix mesnili
Giardia lamlia
Trichomonas hominis
Trichomonas tenax
Trichomonas vaginalis
Blood and Tissue flagellates Leishmania tropica
Leishmania braziliensis
Leishmania donovani
Trypanosoma rhodesiense
Trypanosoma gambiense
Trypanosoma cruzi
Embadomonas intestinalis [Trophozoite]
-Cleftlike cytostome
Chilomastix mesnili
[Trophozoite]
-Pear-shaped
-Spiral groove curving across the body
-Spiral boring, jerky movement
-3 anterior flagella and 1 w/in the cytostome
[Cyst]
-Lemon to oval-shaped
-Protrusion at end
-Nipple-like cyst
Giardia lamblia/
Associated w/ Gay bowel syndrome
Lamblia intestinalis
[Trophozoite]
-Pear-shaped
-Bilaterally symmetrical
-2 nuclei, each w/ a large karyosome, lying w/in the sucking disk
-Falling leaf motility
-Old man’s face/old man w/ eyeglasses
[Cyst]
-2-4 nuclei
-Football-shaped
Trichomonas
Characteristics
Trophozoite stage only
Pear-shaped
4-5 flagella
Jerky motility
Undulating membrane: aids in locomotion
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Habitat
Size
Nucleus
Undulating membrane
Inclusion bodies
Specimen
Habitat
Size
Nucleus
Undulating membrane
Inclusion bodies
Specimen
Habitat
Size
Nucleus
Undulating membrane
Inclusion bodies
Specimen
Characteristics
Lab. Diagnosis
Characteristics
Amastigote
Promastigote
Epimastigote
Trypomastigote
Agent of
Habitat
Costa: thickening of membrane
Trichomonas tenax
Oral cavity
Smallest
Rounded
2/3 of the costa
None
Oral scrapings
Trichomonas hominis
Intestine
Medium
Ovoidal
As long as the costa
None
Stool
Trichomonas vaginalis
Genitalia
Largest
Ovoidal
< ½ of the costa
Siderophil granules
Urine
Vaginal swab/discharge (female)
Prostatic secretion (male)
Causes Pingpong’s disease
Male: carrier
-Asymptomatic chronic urethritis
-Epididymis, prostate & urethra
Female:
-Burning sensation
-Strawberry cervix
1. Modified Diamond medium
2. Feinberg-Whittington medium
Hemoflagellates
Include the trypanosomes and leishmanias
May infect the blood, lymph nodes, muscles and RES
Leishman-Donovan body
Leishmanial form
Leptomonal form
Anterior to nucleus
Crithidial form
Near nucleus
Trypanosomal form
Posterior to nucleus
Leishmania tropica
Old world cutaneous leishmaniasis
Oriental sore
Aleppo button
Baghdad or Jericho boil
Dry lesions
Endothelial cells
Monocytes
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Vector
Pathology
Agent of
Habitat
Vector
Pathology
Lab. Diagnosis
Agent of
Habitat
Vector
Pathology
Lab. Diagnosis
Agent of
Vector
Habitat
Winterbottom sign
Lab. Diagnosis
Agent of
Vectors
Habitat
Characteristics
Romaña’s sign
Lab. Diagnosis
Balantidium coli
Phlebotomus
Lutzomyia
Localized cutaneous infection (macule  papule)
Leishmania braziliensis
American mucocutaneous leishmaniasis
Espundia
Bubas
Mucocutaneous junctions (nasal septum, mouth, pharynx)
Phlebotomus
Lutzomyia
Wheeping lesions
1. Dr. Montenegro’s (skin test)
Leishmania donovani
Visceral leishmaniasis
Kala-azar (black fever)
Dum-dum fever
Endothelial cells of RES
Macrophages
Phlebotomus
Lutzomyia
Splenomegaly
Severe anemia
1. Culture:
= NNN: Novy-McNeal-Nichole medium (culture for Leishmania & Trypanosoma)
Trypanosoma rhodesiense & Trypanosoma gambiense
African sleeping sickness
-East Africa: T. rhodesiense
-West Africa: T. gambiense
Glossina (tsetse fly)
Febrile: blood, lymph node
Sleeping sickness: CSF
Inflammation/swelling of lymph nodes
1. Febrile stage: blood, lymph node aspirate
2. Sleeping sickness stage: CSF
Trypanosoma cruzi
American trypanosomiasis
Chagas’ disease
Triatomid bugs
Kissing bugs
Reduviid bugs
Assasin bugs
Cone nose bugs
Triatoma rubrofasciata = Philippines
RES, cardiac muscle, CNS
C-shaped
Unilateral swelling of eye lids
1. Chang’s medium
2. Xenodiagnostic test (TS, TC)
Ciliates
The only significant ciliate
Host: Pigs
Largest parasitic protozoan
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Characteristics
Life cycle
Characteristics
IS
Asexual Life cycle
Sexual Life cycle
Symptoms and Pathology
Resistant to malaria
Hypnozoites
Mixed infection
Lab. Diagnosis
MOT: ingestion of cysts (from swine feces)
S/S: Dysentery
[Trophozoite]
-Macronucleus: kidney-shaped, vegetative
-Micronucleus: dot-like, reproductive
-Cilia, oral cytostome (mouth)
[Cyst]
-Refractive double wall enclosing cilia
-Nonmotile
Sporozoa
Obligate intracellular
No apparent means of locomotion
Sexual (sporogony) = DH (arthropod vector)
Asexual (schizogony) = IH (man)
Plasmodium
Cause of malaria (“bad air”)
IH (man): Sporozoites
DH (mosquito): Gametocytes
Female Anopheles ---(sporozoites)---> Man ---> Liver (Exoerythrocytic cycle)------>Infected cells (liver) will rupture & release merozoites --> Erythrocytic cycle
Erythrocytic cycle:
1. Merozoites (RBC) ---> Trophozoites ---> Schizont ---> Release merozoites
2. Merozoites ---> Microgametocytes (Male)/Macrogametocytes (Female)
3. Merozoites ---> Destroyed by immune system
Macrogametocytes & Microgametocytes ---> Anopheles mosquito
Anopheles ---> Macro- + Microgametocytes = Zygote (ookinete)
Ookinete ---> Oocysts (contains sporozoites) --->Matured: release sporozoites
Sporozoites ---(Female Anopheles)---> Man
1. Recurrent chills and fever
-every 36 hours: malignant tertian malaria = P. falciparum
-every 48 hours: ovale malaria = P. ovale
-every 48 hours: benign tertian malaria = P. vivax
-every 72 hours: quartan malaria = P. malariae
2. Anemia (RBC destruction), splenomegaly, joint pain
3. P. falciparum: fatal
-Cerebral malaria: RBC, organisms and pigment block brain vessels
-Blackwater fever: intravascular hemolysis + hemoglobinuria
G-6-PD deficiency
Fy (a-b-)
Sickle cell disease
Dormant stage
Found in the liver
Once activated, releases merozoites
Responsible for relapse (P. vivax, P. ovale)
P. vivax & P. falciparum
1. Examination of blood film
a. Thick blood film = Screening purposes
-Dehemoglobinize RBCs
-Stain w/ Giemsa
b. Thin blood film = Identification of species
-Fix w/ methanol
-Stain w/ Giemsa
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Characteristics
# of Merozoites
Trophozoite
Gametocyte
Characteristics
# of Merozoites
Trophozoite
Gametocyte
Characteristics
# of Merozoites
Trophozoite
Gametocytes
Characteristics
# of Merozoites
Characteristics
DH
MOT
Symptoms and pathology
2. QBC: Quantitative buffy coat
-Fluorochrome: Acridine orange
3. Immunotests
a. Optimal assay
-Detects pLDH (parasitic LDH) = malarial organism
b. Malaquick test
-Detects HRP-2 or HRP II Ag (P. falciparum)
Plasmodium vivax
Prevalent worldwide
Single large ring succeeded by amoeboid form in pale large red cell
Schuffner’s dots (condensed Hgb)
Relapse: Hypnozoites
Infects reticulocytes only
Infected RBCs: enlarged
Usually 16
Amoeboid
Round
Plasmodium malariae
Single large compact ring or band forms
Invades old RBCs
Ziemann’s dots
Schizont arranged around central pigment (rosette/daisy head/fruit pie
arrangement)
8
Band
Ovoid
Plasmodium falciparum
Prevalent in the Philippines
Ring forms: small (1/6 diameter red cell), appliqué forms/marginal/accole
formation/double chromatin dots
Maurer’s dots (Stephen Christopher/Cuneiform dots)
Multiple parasitization of red cells
Infects all age of red cells
24-32
Ring
Crescent/sausage/banana-shaped
Plasmodium ovale
Single compact ring
Schuffner’s dots/James’ dots
Relapse: Hypnozoites
Infected RBCs: serrated/fimbriated
8-9
Babesia microti
“Maltese-cross” formation
Resembles P. falciparum rings
-No malarial pigment
-No growing trophozoite
Deer
Ixodes tick bite
Blood transfusion
Headache & fever
Hemolytic anemia + hemoglobinuria
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Characteristics
Characteristics
Infective stage
Isospora belli
Cryptosporidium
(C. parvum/C. hominis)
Cyclospora cayetanensis
Sarchocystis
(S. hominis/S. suihominis)
Characteristics
DH
IH
Lab. Diagnosis
Blastocystis hominis
Dientamoeba fragilis
Babesia bigemia
Causes “red water fever” in cattles
Coccidia
Schizogony (asexual) = nucleated cells
Sporogony (sexual) = intestinal mucosa of DH
Oocyst (feces)
IH: cattles, pigs
DH: man
MOT: sporulated oocyst in contaminated food and water
Diseases:
-Asymptomatic
-Diarrhea, flatulence
-Acalculous cholecystitis
C. parvum: bovines
C. hominis: man
Diseases:
-Watery, frothy diarrhea among immunosuppressed patients
-Acute and gangrenous cholecystitis
Lab. Diagnosis:
1. Sheather sugar flotation
2. Stool examination
3. Modified acid fast stain (CIC)
Originally called a cyanobacterium-like body (CLB)
Causes chronic and intermittent watery diarrhea
Zoite: simplest form (banana-shaped)
Diseases:
-Gastroenteritis w/ diarrhea
-Eosinophilic enteritis
-Myalgia (mild increase in CK)
Toxoplasma gondii
Common cause of congenital infection
Cat
-Oocyst in cat feces may infect man
Man
-Bradyzoite = inactive form
-Tachyzoite = actively dividing
1. Sabin-Feldman dye test
-Methylene blue staining of tachyzoites is inhibited by prior addition of patient
serum containing antibodies to Toxoplasma
Other Intestinal Protozoans
Vacuolated form (most predominant):
-A large central vacuole pushes the cytoplasm and nuclei to the periphery of the
cell
Former amoeba
Now classified as a flagellate
Trophozoite stage only
-2 nuclei (“Binucleated trophozoite”)
MOT: via transmission of E. vermicularis eggs
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Copepods (Cyclops)
Pthirus pubis
Myiasis
Cantharidin
Periplaneta americana
Blatella germanica
Blatta orientalis
Aedes aegypti
Aedes albopictus
Culex
Anopheles flavirostris
Aedes poecilus
Mansonia bonneae
Musca domestica
Sarcophaga
Calliphora
Lucilia
Phaenicia
Muscina
Arthropods
IH of D. latum, D. medinensis and Gnathostoma spinigerum
Crab louse
Agent of “crabs”
Invasion of mammalian tissues by dipterous larvae (diptera/flies)
Volatile vessicating substance produced by the blisters of beetles of the family
Meloidae
American cockroach
Lays about 50 egg capsules (ootheca), each containing about 15 eggs
German cockroach
Oriental cockroach
Tiger mosquito
Vector of urban dengue
w/ silvery stripe on the mesonotum
Vector of rural dengue
Vectors of Japanese encephalitis
Primary vector of malaria
Mosquito associated w/ Bancroftian filariasis
Vector of the Brugian type of filariasis
Common housefly
“Chess-board appearance”
Bluish fly covered w/ yellow hairs
Greenish fly w/ white genae
Bronze-bottle fly
Slightly larger and more robust than the housefly
Laboratory Methods
Examination of Blood
Detect agents of
Malaria
Babesiosis
Trypanosomiasis
Leishmaniasis
Filariasis
Thick blood films
Screening (malaria)
Thin blood films
Identification of malarial species
Concentration techniques
1. Preparation of buffy coat smears:
-L. donovani
-Trypanosomes
-Microfilaria
2. Knott’s concentration membrane filtration
-Detection of microfilaria
3. Fluorochrome acridine orange in microhematocrit centrifuge format
-QBC blood parasite detection method
Examination of Fecal Specimens
Stool fixatives
1. Formalin = all purpose fixative
= 5% conc.: protozoan cysts
= 10% conc.: helminth eggs and larvae
2. Schaudinn’s fluid = w/ HgCl2
3. Polyvinyl alcohol (PVA) = for Trichrome stain (w/ HgCl2)
4. Merthiolate-iodine-formalin (MIF) = a.k.a. Thimerosal
= Merthiolate and Iodine: staining components
= Formalin: preservative
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Direct wet mount
5. Sodium-acetate-formalin (SAF)
= Advantage: does not contain HgCl2
1. Saline mount = 0.85% NSS
2. Iodine mount = protozoan cysts (not trophozoites)
Permanent stains
1. Wheatley’s trichrome stain
2. Iron hematoxylin stain
3. Modified acid fast stains (Cryptosporidium, Isospora, Cyclospora)
Concentration Methods for Protozoan Cysts and Helminth Eggs and Larva
Sedimentation
Best for eggs of:
-Schistosoma
-Operculated egg
-Trematodes
-Cestodes
-T. trichiura
-C. philippinensis
1. Acid-ether concentration
= Ether: dissolves fats and CHO
2. Formalin-ether concentration
= Formalin: preserves the eggs
Flotation
1. Brine Flotation = NaCl
2. Zinc Sulfate centrifugal flotation technique
= SG (ZnSO4): 1.18
= for Protozoan cysts
= for Nematode eggs except T. trichiura and C. philippinensis (sedimentation)
= NOT for Schistosomal and operculated eggs (sedimentation)
Cultural Methods for Protozoa
Culture media for intestinal 1. Boeck and Dorbohlav’s diphasic medium (Modified by Dobell and Laidlaw)
amoeba
2. Cleveland Collier’s medium
NNN
Medium for Trypanosoma and Leishmania
(Novy-McNeal-Nicolle)
Additional Techniques for Examination of Enteric Parasites
Cellulose tape technique
For pinworms
Egg studies
1. Direct smear method of Beaver
2. Stoll dilution egg count
3. Kato thick smear = qualitative (Cellophane paper, glycerine, malachite green)
4. Kato Katz smear (Cellophane fecal thick smear) = quantitative
Nematode culture and
1. Harada-Mori paper strip culture
recovery techniques
2. Baermann funnel techniques (Strongyloides)
Examination of Other Specimens
Detection of T. vaginalis
Specimens:
-Vaginal and urethral discharge
-Prostatic secretions
-Urine
Sputum
Recovery of protozoal and helminthic parasites
Biopsy
1. Skin biopsy = Onchocerca, Mansonella
2. Muscle biopsy = Trichinella spiralis
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