2. Objectives:
At the end of the lecture, you should be able to at
least learn the:
Parasite Biology
Pathogenesis and Clinical
Manifestations
Diagnosis
Treatment
Prevention & Control
6. General Characteristics
Infect humans (DH) and animals (IH)
Sarcosporidiosis or sarcocystosis - infection
Spread throughout various organs and tissues
MOT – ingestion of uncooked or undercooked
meat containing the SARCOCYSTS
Infective Stage: Human – SARCOCYSTS
IH - SPOROCYSTS
7. Parasite Biology
Zoite – simplest form
Banana-shaped cell
Pointed end – equipped for entering the host cells
Sporocyst = 4 zoites sporozoites
Sarcocyst = formed from sporozoites
Asexual cycle – occurs in IH
Sexual cycle – occurs in DH
8.
9. Parasite Biology (contd.)
S. hominis S. suihominis
IH cattle swine
DH human human
Sporocyst bigger smaller
Effect Intestinal Intestinal
sarcocystosis sarcocystosis
12. Diagnosis
Fecal flotation method – sporocysts
9-16um in length
Oblong or cylindrical
4 long teardrop-shaped sporozoites
Western blot
IFA and ELISA
13. Treatment & Prevention
No effective treatment is known
Corticosteroid – treat muscular inflammation
Trimethoprim-sulfamethoxazole – treat
intestinal infections
“Cook the meat well before eating!!!”
15. Parasite Biology
Cryptosporidiosis – infection
Causes severe diarrhea (immunocompromised)
and transient diarrhea (healthy persons)
Water-borne transmission – is the most
common source of this infection
MOT: ingestion of oocysts
IS: oocysts containing sporozoites
1 oocyst = 4 sporozoites
Oocyst = 4 to 5 um
Watch this!
22. General Characteristics
House Cat – definitive host
MOT – consumption or handling of infected
meat or from contact with cat feces
IS – oocysts
Cysts – found in muscles and CNS
Watch the video here I’m cute but
deadly!!!
23.
24. Parasite Biology
Oocyst = 2 sporocysts, each encloses
4 sporozoites
(passed in the feces)
Similarin appearance to those
of Isospora belli but smaller
Trophozoites – found in the mesenteric lymph nodes
and other organs of the cat
Tachyzoites – multiply quickly and spread the infection
Bradyzoites – slow-developing and form cysts
26. Pathogenesis & Clinical Manifestations
Toxoplasmosis – commonly asymptomatic
Cysts – can be found in the brain, skeletal and heart
muscles, and retina
Encephalitis, myocarditis & focal pneumonia –
immunocompromised
Stillbirth & abortion – 1st trimester of pregnancy
Congenital toxoplasmosis
27. Diagnosis
Examination of tissue imprints stained with Giemsa
Sabin-Feldman methylene blue dye test –
detect Ab against T. gondii
Biopsy
PCR
ELISA
Latex Agglutination Test
28. Treatment & Prevention
Pyrimethamine + sulfadiazine – for 1 month
-To keep under control but do not kill it
Cook food well
Pregnant women should avoid contact with cats
Avoid unpasteurized milk
30. General Characteristics
4 sporocysts , each containing 2 sporozoites
Causes bloody diarrhea
E. tenella
E. maxima
E. necatrix
E. fraterculae
33. Isospora hominis
Host: men
Vector: Dog
MOT: Ingestion of mature oocyst
Symptoms:
Stomach pain
Diarrhea
Steatorrhea
Anorexia
Fever
34. General Characteristics
I. hominis I. belli
Other name Cytospermium hominis Cytospermium
intestinalis
Oocyst shape Oblong papaya
Layer Double-layer One layer
Presence of microphyle yes no
sporocysts 2 2
sporozoites 4 4
Host Men Men
MOT Ingestion of oocyst Ingestion of oocyst
37. MALARIA
Is still considered the most important parasitic
disease affecting man, responsible for 1.5 to 2.7
million deaths annually
One of the three major infectious disease threats,
along with HIV and tuberculosis (WHO)
Transmitted by the bite of an infected female
Anopheles mosquito
A protozoan disease caused by members of the
genus Plasmodium characterized by recurring
fever, chills and sweats.
38. MALARIA (contd.)
P. falciparum responsible for over 90%
P. vivax of all the cases of human malaria
P. ovale
P. malariae
Pigment producers – malarial parasites feed on
Hgb
Ameboid in shape
39. Parasite Biology
Asexual Cycle Sexual Cycle
Human (IH) Anopheles mosquito (DH)
Schizogony merozoites Sporogony sporozoites
Gametogony gametocytes
MOT: bite of vectors & blood transfusion
40. Parasite Biology (contd.)
• life cycles of all four human species of malaria are
similar
• sporozoites – infective stage to human
• Injected to human and carried to the liver
• Merozoites – enter the rbc
- Develop into microgametocytes (male) and
macrogametocytes (female) which are picked up by the
mosquito for completion of the cycle
• Hypnozoites – produced by P. vivax and P. ovale ;
resting stage
• Trophozoites – developed in the rbc
41. Exo-erythrocytic Stage
sporozoites
enters hepatocytes of liver
schizonts
dividing forms of liver stages
merozoites
are released by hepatocytes
hypnozoites
resting liver stages
42. Blood Stages
merozoites
enter erythrocytes
trophozoites
feeding and growing stages
in red cells
schizonts
multinuclear stages
in red cells
gametocytes
sexual blood stages
43. 1. early trophozoite
2. early trophozoite (double infection)
3. early trophozoite double chromatin with a few Maurer's dots
4. late throphozoite with Maurer's dots and crenated red cell
5. Mature schizont with merozoites and clumped pigment
6. macrogametocyte with bluish cytoplasm and compact chromatin
7. microgametocyte with pinkish cytoplasm and dispersed
chromatin.
Watch the life cycle
44.
45. Pathogenesis & Clinical Manifestations
P. P.vivax P. ovale P. malariae
falciparum
Other name Malignant Benign tertian Ovale malaria Quartan
tertian or malaria malaria
subtertian
malaria
Pre-patent 11-14 days 11-15 days 14-26 days 3-4 weeks
period
Incubation 8-15 days 12-20 days 11-16 days 18-40 days
period
Erythrocytic 48 hours 48 hours 48 hours 72 hours
Cycle
Chromatin Maurer’s Schuffner’s Schuffner’s Zieman’s
dots (coarse red (fine red
granules) granules)
46. P. P.vivax P. ovale P. malariae
falciparum
trophozoite Ring & comma Signet-ring Ring to Band form
forms shape rounded
gametocytes Banana- Oval Round Round
shaped
Merozoites 8-40 12-24 14-16 6-12
Schizont Single dark Loose mass Concentrated concentrated
pigment mass mass
47. Pathogenesis & Clinical Manifestations (contd.)
Regular Paroxysms of fever with asymptomatic
intervals
Prodromal symptoms
Weakness and exhaustion
Desire to stretch and yawn
Aching bones, limbs and back
Loss of appetite
Nausea and vomiting
Sense of chilliness
Malaise
Diarrhea
Epigastric discomfort
48. 3 Stages of Classical Malaria Paroxysm
Cold Stage Pressure goes down
Chilling Intense headache
Loss of appetite Dry skin which lasts for 2-4 hours
Goose flesh
Convulsion of children which Sweating Stage
lasts for 1-2 hours Profuse sweating
Temp. Is going up Gradually, temp. Goes down
Less intense headache which lasts
Hot Stage for 2-5 hours
Sensation of great heat Patient feels exhausted until falls
Restlessness asleep
Pulse is full and pounding
Vomiting
49. Diagnosis
Thick and thin blood smears – “gold standard”
Quantitative Buffy Coat (QBC) Method – screening
RDT = Immunochromatographic Methods – detect
Plasmodium Ag
Serologic Tests – IHA, IFAT, ELISA and PCR
50. Diagnostic Points
1. Red Cells are not
enlarged.
2. Rings appear fine and
delicate and there may be
several in one cell.
3. Some rings may have two
chromatin dots.
4. Presence of marginal or
applique forms.
5. It is unusual to see
developing forms in
peripheral blood films.
6. Gametocytes have a
characteristic crescent
shape appearance.
However, they do not
usually appear in the blood
for the first four weeks of
infection.
7. Maurer's dots may be
present.
51. Diagnostic Points
1. Red cells containing
parasites are
usually enlarged.
2. Schuffner's dots are
frequently present in
the red cells as shown
above.
3. The mature ring
forms tend to be large
and coarse.
4. Developing forms
are frequently
present.
52. Diagnostic Points
1. Ring forms may have a squarish appearance.
2. Band forms are a characteristic of this species.
3. Mature schizonts may have a typical daisy head appearance with up to ten merozoites.
4. Red cells are not enlarged.
5. Chromatin dot may be on the inner surface of the ring.
53. Diagnostic
Points
1. Red cells
enlarged.
2.Comet forms
common (top
right).
3. Rings large
and coarse.
4. Schuffner's
dots, when
present, may be
prominent.
5. Mature
schizonts similar
to those of P.
malariae but
larger and more
coarse
54. Treatment & Prevention
Chloroquine – treatment of choice
Sulfadoxine-pyrimethamine or quinine – alternative
for chloroquine-resistant
Artemisinin and derivatives
Use mosquito nets
Use insect repellants
Wear light-colored clothing