PARA 1 - protozoan

Intestinal Ameba

● Usually Sarcodina
● Generalities
○ Inhabit the large intestine except Entamoeba gingivalis (oral)
○ All undergo encystation except Entamoeba gingivalis
○ Entamoeba possess peripheral chromatin in its nucleus
■ Peripheral chromatin is found in the edge of the
nucleus
○ The infective stage is the cyst except in Entamoeba
gingivalis (IS: Trophozoites, possess no cyst form).
○ All are commensal except Entamoeba histolytica

Entamoeba histolytica

• Usual Size: 15-20 um
• Movement: Progressive;
  Unidirectional
• Pseudopodia: Finger-like Hyaline (clear)
• Nucleus: Trophozoite stage: 1
• Peripheral Chromatin: Fine,
  Smooth, Even
• Karyosome: Centrally located, Small
• Cytoplasm Cytoplasmic Inclusion:
  Clean looking; Presence of
  ingested RBCs (diagnostic)
• Cyst (non motile stage): 12-15 um
• # of Nuclei up to 4 (quadrincleated)
• Chromatoidal Bar: Cigar-shaped

Entamoeba coli

• Usual Size: 20-25 um
• Movement: Non-progressive; Sluggish
• Pseudopodia: Blunt Granular
• Nucleus: Trophozoite stage: 1
• Peripheral Chromatin: Course, Rough, Uneven
• Karyosome: Eccentric - off center, Large
• Cytoplasm Cytoplasmic Inclusion: Dirty looking; Presence of ingested RBCs (diagnostic)
  Ingested bacteria, yeasts
• Cyst (non motile stage): 15-25 um
• # of Nuclei up to 8 (10/11 [other
  references])
• Chromatoidal Bar: broomstick/splinter

Amebiasis

● Most infections are asymptomatic (90%)
● Symptomatic (Intestinal and
Extraintestinal)
○ Amebic Dysentery (Bloody
diarrhea)
○ Flask-shaped Ulcers
○ Colitis; Amebomas
(cancer-looking)
○ Extraintestinal amebiasis
■ Liver - most common
site
■ Proximal or near to the
colon
■ leads to Amebic Liver
Abscess (ALA)
● Virulence Factors
○ Lectin: Attachment, kapit
○ Amebapores: makes holes,
butas
○ Cysteine proteases:
Destruction, sira
● Transmission
○ Oral/anal
○ Sexual contact

Lectin

attachment

Amebapores

makes holes

Cysteine proteases

destruction

Entamoeba hartmanni

small race of Entamoeba histolytica, looks like histolytica but smaller in size

Entamoeba polecki

• Amoeba of pigs
• Characteristic chromatoidal bars; angular or pointed
• Morphologically similar to E. chattoni
  ● Differentiate molecular

Entamoeba gingivalis

• No cyst stage
• Able to ingest WBCs
• Kissing; sharing of personal items
• Specimen: mouth scrapings

Iodamoeba butschlii

• Presence of large glycogen vacuole
• Absence of peripheral chromatin
• "Basket of Flowers" appearance of the karyosome
• Associated with contact with pigs
• Wet mount: Brown glycogen vacuole
• Permanent mount: Colorless vacuole

Wet mount

Brown glycogen vacuole

Permanent mount

Colorless vacuole

Endolimax nana

• Cross eyed cyst
• Eccentric karyosome

Free living amebae

● found in the environment (bodies of water) inhabiting
lakes, pools, tap water, air conditioning units and heating units
● In humans: found in the CNS
● Endosymbionts with bacteria such as Legionella (sharing same habitats

Naegleria fowleri

● amoeboflagellate

• virulent
  ● MOT: Entry to Olfactory
  Epithelium, Respiratory Tract, Skin and,Sinuses
  ● Infective Stage: Trophozoite
  ● Ameba form: "Limax form"
  ● Flagellate motile form
  ● Cyst Stage - not found in the
  host; environment only
  ● Amebic Meningoencephalitis very fatal
  ● Risk Factor: Swimming in contaminated pools
  ● Meningitis, Coma,
  Headache, Trophozoite in CSF
  ● Primary Amebic
  Meningoencephalitis (PAM)
  ● Lab diagnosis: Usually
  post-mortem; CSF Exam, Culture, PCR, IF

Acanthamoeba (culbertsoni, castellanim, polyphaga)

● MOT: entry through nose,
break in skin
● IS: Cysts & Trophozoites
Cyst: Double walled (Wrinkled and Polygonal)
● Troph: presence of acanthapodia
● Other spp:
Balamuthia - similar to
Acanthamoeba causing GAE
● Amebic Keratitis: risk factor
contaminated contact lens
solutions
● Cutaneous lesions - among HIV patients
● Granulomatous Amebic Encephalitis (GAE)

• usually infects immunocompromised patients
• more chronic
  Lab diagnosis: Brain biopsy,
  corneal scrapings (Calcoflour white, for keratitis), culture

Amebic Keratitis

risk factor contaminated contact lens solutions

Granulomatous Amebic Encephalitis (GAE)

• usually infects immunocompromised patients
• more chronic

Giardia lamblia

• Reservoir: Animals (Beaver)
  Zoonotic (through contact with animals)
• Troph: bilaterally symmetrical; pear shaped; pyriform
• Appearance: Old-man's face
  with glasses, Someone is looking at you
• Motility: Falling leaf
• 8 flagella, 2 nucleus
• Axostyle: for support
  Ventral sucking disk: for attachment -> malabsorption
• Parabasal/Median body
• Cyst: double walled
• Giardiasis
• Beaver Fever
• Traveler's Diarrhea (for para, ETEC for bacte); Backpacker's
  diarrhea
• Gay Bowel Syndrome
• Manifestation: Explosive Watery Diarrhea
• Chronic: Steatorrhea
  (presence of fats in stool)
• Weight loss
• Malaise
• Foul Smelling stools

Giardia lamblia

Laboratory diagnosis:

• Stool Exam
• Concentration Techniques
• Permanent Stains
• Serology
• Molecular Techniques
• Enterotest (Bealet's string
  test)
  ● wait for 4 hours then
  pull string
  ● Should be yellow green to ensure it reached the duodenum
• Treatment: Metronidazole

Dientamoeba fragilis

• Cyst stage: now confirmed
  present but rare
• Trophozite: 2
• Nuclei: Rosette-like
• MOT: ingestion alongside
  nematode eggs
• Resembles Trichomonas
• Diarrhea (intermittent, pruritus)
• Detected through stained
  preparations/permanent smears
• Lab dioagnosis: Trophonsite
  identified in stained in
  specimens, maybe missed out in
  direct fecal smears (fragile
  nature)

Chilomastix mesnili

• Commensal flagellate
  residing the colon
• Trophozoite: Asymmetric:
  Pear Shaped
• Cyst
• 4 flagella
• Motility: Boring, Rotary motility
• Cytostome: mouth
• Cytostomal fibril: shepherd's crook
• Presence of Spiral Groove
• Cyst: nipple looking or
  american lemon shaped
• Commensal
• Lab diagnosis: Stool exam

Trichomonas spp

No cyst: 4-5 flagella

Trichomonas vaginalis

• Habitat: Urogenital Area
• MOT: Intimate Contact; Infant
  Delivery; Contaminated
  Underwear and Towels
• Nucleus Ovoidal Undulating
• Membrane: ½ the length of
  body
• Most common non viral STD/STI
  worldwide
• Largest (very vig - vaginalis)
• Siderophile granules - iron
• Undulating membrane -
  Wavelike, structure
• Infection: Trichomoniasis

Trichomonas vaginalis

Laboratory diagnosis

• Permanent Stained Smears (paps, giemsa)
• Culture - considered as
  confirmatory
• Diamond Modified Medium, Feinberg Wutingrin, Cysteine Peptone Laver Mahove, Simplified
  Trypticase, Serum, Semen Culture Serology, Antigen Detection
  Molecular
• Treatment: Metronidazole

Trichomoniasis

S/S: Females:
● Vaginal Pruritus
● Strawberry Cervix
● Frothy Discharge
(Green)

Males: Asymptomans

Pentatrichomonas hominis

• Habitat: Colon
• MOT: ingestion
• Nacie: Rounded
• Undulating Membrane: Full
  Body
• Commensal
• Lab diagnosis: Stool exam

Trichomonas tenax

• Habitat: Oral Cavity
• MOT: Direct Contact
• Nucleus: Ovoidal Undulating
• Membrane: 2/3 of the body
• smallest (tiny - tenax)
• Commensal (Can be seen in
  patients with periodontal
  disease and with respiratory
  infections)
• Lab diagnosis: Direct Examination of Mouth Scrapings - Sputum may also be used since it
  be encountered in respiratory
  infections

Trypomastigote

Elongated; anterior flagella, full body undulating membrane;
posterior kinetoplast

Epimastigote

Elongated; anterior,flagella, ½ body undulating membrane

Promastigote

Elongated; anterior flagella with no undulating membrane

Amastigote

Intracellular, no flagella

Trypanosoma cruzi

• Vector: Reduviid Bug/kissing/
  assassin bug/triatoma
• MOT: Feces of
  the vector entering the bite
  wound; blood transfusions;
  organ transplants
• Causes Chagas Diseases or
  South American Trypanosomiasis
• Acute Phase: Chagoma (lesion
  around bite); Romana's Sign
  (periorbital swelling)
• Chronic Phase: Enlargement of
  Vital Organs (Proliferation of
  Amastigotes) -> Megacolon; Megaesophagus, Cardiomegaly
• Lab diagnosis:
  ● Diagnostic Stage: Trypomastigote (Blood) and Amastigote (Biopsy, Intracellular)
  ● Giemsa Staining of CSF, Blood,
  Lymph Xenodiagnosis (get bitten by reduviid bug -> examine bug
  feces)
  ● Culture: Novy Mac Neal Nicolle
  Serology

Trypanosoma brusei rhodesiense

• Rhodesian/East African Sleeping
  Sickness
• East African Sleeping Sickness Acute, Rapidly progressing: CNS stage takes place early

Trypanosoma brucei gambiense

• Gambian/West African Sleeping
  Sickness; more common
  because it affects man
• Vector: Tse-tse fly (Genus:
  Glossina)
• MOT: Bite of the vector
• West African Sleeping
  Sickness Chronic Progression
• Manifestation: Chancre, Winterbottom's Sign (cervical
  lymphadenopathy); Kerandel Sign

Trypanosoma brucei

Lab diagnosis

• Dx Stage: Trypomastigote
• Examination of
  Buffy Coat, Blood, CSF
• Serology: IHAT, ELISA, Rapid
  Test
• Animal Inoculation, Culture
  Molecular Methods
• Presence of Mott Cells in CSF

Leishmania

intracellular
● Vector: Sand fly (Phlebotomus)
● MOT: Bite of infected vector, organ transplants; blood transfusion

Leishmania tropica

• Endothelial Cells of skin capillaries; phagocytic monocytes
• Cutaneous Leishmaniasis; Old
  World Leishmaniasis, Aleppo Button, Delhi Boil, Baghdad Boil,
  Jericho Boil

Leishmania braziliensis

• Mucocutaneous junctions (nasal
  septum, mouth, pharynx)
• Mucocutaneous Leishmaniasis
  (American, New World
  Leishmaniasis)
• Espundia. Tapir nose, chiclero ulcers

Leishmania donovani

• most virulent
• Endothelial Cells of the RES
• Visceral Leishmaniasis (Kala-azar, Dumdum Fever, Black Fever — affects the RES)

Leishmania

● Diagnostic Stage: Intracellular
Amastigotes
● Can be mistaken for: Histoplasma yeast
● Demonstration of Lesions; Tissue, Skin
Biopsies
● Examination of BM, spleen, lymph node
● Scrology; Montenegro Skin Test; Culture
(NNN, Schneider's, Drosophila medium)

Neobalantidium coli

• largest protozoan infecting man
  ● Final Host: Man
  ● Reservoir Host: Pigs
  ● Habitat: large intestine
  ● Infective Stage: Cyst

Neobalantidium coli

Anterior: Tapered
Motility: Thrown ball/ rotary
Presence of 2 Nuclei:
● Macronucleus - bean shaped
● Micronucleus - circular
Cytostome - mouth; "funnel-like"
Cytopyge - slit-like structure opposite cytostome
Balantidiasis
● Bloody Diarrhea
● Flask Shaped Ulcers (Wide and Rounded Ulcers)
● Extraintestinal Spread may occur
Virulence Factor: Hyaluronidase
Lab diagnosis:

• Stool Exam
• Biopsy
• Treatment: Metronidazole

Balantidiasis

● Bloody Diarrhea
● Flask Shaped Ulcers (Wide and Rounded Ulcers)
● Extraintestinal Spread may occur

Plasmodium falciparum

Most virulent; also most common in the Philippines

Plasmodium vivax

most widespread; can be found in different continents of the world except Antarctica

Plasmodium ovale

least virulent; least common

Plasmodium knowlesi

• zoonotic, Simian malaria (primates)
  ○ Most cases are found in southeast asia
  ○ Cases in Palawan and neighbor countries
  ○ Method for identification: Molecular
  i. Microscopic: Looks like malariae

Malarial parasites

● Intracellular Parasite
● Undergoes alternating sexual (sporogony) and asexual stages
(schizogony) in its life cycle
○ Sporogony in final host
● Vector Borne Disease
○ Final Host: Mosquito
○ Vector: Female Anopheles
○ Night-biting mosquito
● Intermediate Host: Man
● Infective stage to mosquito: Gametocyte
● Infective stage to man (transmission stage): Sporozoite
● Mode of Transmission: Mosquito Bite; Blood Transfusion; Congenital
● Relapse: reactivation of hypnozoites
○ Nagka-malaria, nawala na yung parasites, may naiwan na
hypnozoites sa liver, mag-schizogony sila ulit
○ Ovale and vivax
● Recrudescence: low level of parasitemia; malarial parasites
sequestered
○ Akala wala na pero meron
○ Malariae and falciparum
○ Other books: all species can undergo recrudescence
○ not all stages can be seen: Falciparum (ring form &
gametocyte only)
● S/S: Most Cases of malaria occur in Africa
● Symptoms and Complications include:
○ Paroxysms (Chills, Fever, Sweating — in that order),
○ Anemia, Splenomegaly
○ Blackwater Fever, Cerebral Malaria
■ Falciparum
○ DIC, Proteinuria;
○ Nephrotic Syndrome
■ Malariae (involves kidneys)

Thick smears

For malarial count

• Fixative: none
• Dehemoglobinize using distilled water
• To lyse/remove the red cells

Thin smears

Species identification

• Fixative: Methanol

Babesia microti

● Intracellular parasites that causes malaria-like infections
● Definitive Host: Ticks (Ixodes)
● Intermediate Hosts: White footed mouse, deer, livestock, cattle, man
(accidental host)
● MOT: Bite of an infected tick; blood transfusion; vertical transmission
● Morphology:
● Presence of merozoites "maltese cross" pattern
● No schizonts, no gametocytes
● Ring forms may be mistaken as P. falciparum
● Disease Manifestation: Babesiosis; Redwater/Texas cattle fever
○ Severe babesia among splenectomized patients and those with Lyme disease
● Diagnosis:
○ Microscopy; Serology; Molecular Methods
○ Travel History: North Eastern US

Toxoplasma gondii

● Parasites of cats
● Tissue Coccidians
● Definitive Host: Members of the Felidae Family
● Intermediate Host: Birds, Rodents, Pigs
● Accidental or Dead End Host: Man
● Infective Stages: Oocyst and Tissue Cysts (Tachyzoites, Bradyzoites)
MOT:
● Ingestion of infected undercooked meat
● Consumption of food or water contaminated with cat feces
○ Presence of oocyst
● Blood transfusion or Organ Transplant
● Vertical Transmission
● Parasite Stages in Humans
● Tachyzoites (A) - rapidly multiply and infect cells of the intermediate
hosts and non intestinal epithelial cells of cats
● Bradyzoites (B) - Multiply slowly
● Develop mostly in neural and muscular tissues
● May also develop in visceral organs
Disease Manifestations
● Usually Asymptomatic among immunocompetent (Brain Focal Lesions)
● Immunocompromised: Encephalitis; retinochoroiditis,
lymphadenopathy, splenomegaly
● Congenital Defects to the Newborn- Stillbirth, abortion
Laboratory Diagnosis
● Sabin Feldman Test - classic serologic
test
○ Sample: serum to detect
antibody
○ Reagent: live Toxoplasma and
methylene blue
○ Positive Result: Non-staining
of Toxoplasma
● Frenkel Test; ELISA, HAT, FAT
● TORCH Testing, Examination of tissue sections, CSF
● Molecular Methods
Most common method in diagnosis of Toxoplasma: Serology (convenient)

Tachyzoites

rapidly multiply and infect cells of the intermediate hosts and non intestinal epithelial cells of cats

Bradyzoites

Multiply slowly

Sabin Feldman test

• classic serologic test
  ○ Sample: serum to detect
  antibody
  ○ Reagent: live Toxoplasma and
  methylene blue
  ○ Positive Result: Non-staining of Toxoplasma

Serology

Most common method in diagnosis of Toxoplasma