This document provides information about various protozoan pathogens including Acanthamoeba, Naegleria fowleri, Babesia, Balantidium coli, Cyclospora, Isospora belli, and Microsporidia. It discusses the pathogenesis, clinical features, life cycles, and laboratory diagnosis of each protozoan. The key information provided includes how the protozoans infect hosts and cause disease, common symptoms of infection, their life cycle stages, and methods for laboratory diagnosis such as microscopy, staining, culture, and PCR techniques.

2. ❑ Assignment:
Pathogenesis, clinical features, life cycle and
lab diagnosis of protozoan pathogens

3. ❑ MycologyAnd Parasitology
SUBMITTED TO:
SIR ALI AHSAN
SUBMITTED BY:
SYED HASSAN SARDAR
SAP ID:
70104259
SECTION:
A

4. ❑ Protozoa:
➢ Protozoa (alsoprotozoan, plural protozoans) is an informal term for a group of single-celled
eukaryotes, either free-living or parasitic, which feed on organic matter such as other
microorganisms or organic tissues and debris.

5. ❑ Minor Protozoan Pathogens:
▪ ACANTHAMOEBA
▪ NARGLERI
▪ BABESIA
▪ BALANTIDIUM COLI
▪ CYCLOSPORA
▪ ISOSPORABELLI
▪ MICROSPORIDIA

6. ❑ Acanthamoeba:
➢ THEY HA
VEALSO BEEN CALLED AMPHIZOIC
AMOEBAEBECAUSE THESEAMOEBAEHAVE THE
ABILITYTO EXISTASFREE-LIVING ORGANISMS
INNATURE AND ONLY OCCASIONALLYINVADE A
HOST AND LIVE ASPARASITES WITHIN HOST
➢ AMICROSCOPIC, FREE-LIVINGAMOEBATHAT CAN
CAUSE RARE, BUT SEVERE INFECTIONS OF THE
EYE, SKIN, AND CENTRAL NERVOUS SYSTEM.

7. ➢ Several species of Acanthamoeba, including A. culbertsoni, A.
polyphaga, A. castellanii, A. astronyxis,
A. hatchetti, A. rhysodes, A. divionensis, A. lugdunensis, and A.
lenticulata are implicated in human
disease
➢ Acanthamoeba have been found in: soil, heating,ventilating,
fresh, brackish, sea air conditioning
systems water,mammalian,Sewage,Vegetables, swimming
pools,human nostrils

8. ❑ There are two morphological forms:
❖Trophozoite:
▶ A trophozoite is 20-50µm in size
▶Rough exterior with several spine like
projections(acanthopoda).
❖ Cyst:
▶ Spherical and 15µm in diameter.
▶Both forms can be the source of infection

9. ❑ Pathogenicity and Clinical Features:
➢ Granulomatous Amebic Encephalitis (GAE) and disseminated
infection primarily affect people with
compromised immune systems.
➢ Commonly seen in immunocompromised patients, including
those with neoplasia, systemic lupus
erythematosus, human immunodeficiency virus and
tuberculosis

10. ❖ Risk Factors: Alcoholism ,Drug abuse , Chemotherapy,
Corticosteroids, Organ
transplantation
❖ Symptoms: Headache,Confusion,fever, Lethargy,Nausea
and vomiting, Seizures
❖ Signs: Photophobia• Neck stiffness • Neck stiffness.• Focal
neurological deficits • Patients may become• Patients may
also develop frankly psychotic.

11. ❑ Life cycle:

12. ❑ Laboratory diagnosis:
▪ Early diagnosis and prompt delivery of appropriate
medical therapy is essential to
secure a good prognosis.
▪ If effective therapy is delayed for 3 weeks or more,
prognosis deteriorates.
▪ AK should be considered in any case of corneal
trauma complicated by exposure o soil or
contaminated water and in all contact lenswearers.

13. ❑ Naegleria fowleri:
▪ An amoeba , Single celled living organism.
▪ Heat loving organism , Grows best at temperatures up to 115
°F
▪ The thermo-tolerant free-living ameba Naegleria fowleri
causing a fulminant (sudden and severe) brain infection
called Naegleriasis or Primary amebic Meningoencephalitis
(PAM) is a fatal disease.The amoeba was identified in the
1960s inAustralia but appears to have evolved in the United
States. Naegleria Fowleri "Brain-Eating Amoeba"

14. ❑ Pathogenesis:
Amoeboid form
Entersthrough nasal mucosaI
invades criform plate
Olfactory nerve to brain
Primaryanebic meningoencephalitis

15. ❑ Clinical features:
• Incubation period : 2- 15
days (Average 5 days)
• Severe fontal headache
• Fever (39-40deg. C)
• Meningeal irritation
• Visual distrabance
• Confusion
• Seizures
• Coma

16. ❑ Life cycle:

17. ❑ Laboratory diagnosis:
❖ Specimen:
▶ CSF is collected for
demonstration of amoebae
❖ Microscopy:
▶ Staining with Wright or Giemsa
stains or Fluorescent stains
▶ Appeared as small pink nuclei
with sky blue cytoplasm

18. ❖ Culture:
▶ Culture media: Non-nutrient
agar
▶ Inoculated overnight at
37deg.C
▶ Grown on moist agar
surface
❖ Histologic examination:
▶ Immunoflurescence &
immunoperoxidase methods

19. ❑ Babesia:
➢ Babesia is a tiny parasite that infects your red
blood cells. Infection
with Babesia is called babesiosis. The parasitic
infection is usually transmitted by a tick bite.
Babesiosis often occurs at the same time as Lyme
disease. The tick that carries the Lyme bacteria can
also be infected with the Babesia parasite.

20. ❑ Pathogenesis:
➢ Pathogenesis Animals are effected after an infected tick bites
and feeds on a susceptible host for a
minimum of three days.
➢ when the Babesia organism is introduced into the host, it
attaches to erythrocyte membranes and
endocytosed.
➢ Hemolytic anemia and hypotensive shock are typical
clinical syndromes of infection.

21. ➢ Hemolytic anemia results from direct erythrocyte
damage by the parasite, and both intravascular and
extravascular immune- mediated destruction of red
blood cells. infection can produce
thrombocytopenia, the mechanism of which
consists of immune- mediated destruction and
sequestration in the spleen.

22. ❑ Clinical features:
▪ Fever is the first clinical sign one to three weeks after an
infective tick bite.
▪ following the bite , the parasites invade red blood cells
where they multiply and invade more red blood cells the
destruction of increasing number of red blood cells causes
anemia, shock and also release large quantities of
haemoglobin into the circulation

23. ▪ the sick animals are usually depressed, loss
appetite, and their ayes and gums are
pale from anemia and jaundiced due to bile
pigments in their circulation.
▪ red coloured urine can usually be observed in
these animals. pregnant animals often abort. in
severe B. bovis infection cases, nervous signs
such as incoordination. paralysis and coma are
presented which often lead to death.

24. ❑ Life cycle:

25. ❑ Lab Diagnosis:
▪ History of presence of tick and signs like hematuria are
diagnostic. infection with B. canis or B.
gibsoni is definitifely diagnosed by demonstration of the
parasites on red cells.
▪ Blood smears may be stained with preferable wright's or
giemsa stain. stained smears demonstrate
2.4mm x 5.0mm, piriform-shaped, intraerythrocytic parasites
which are usually paired.

26. ▪ Serologic tests, include the indirect fluorescent
antibody test (IFA) which is used most frequently,
and a more recently developed dot ELISA test,
complement- fixation test , indirect
hemagglutination test, card aggulination test,
capillary aglutination test etc.
▪ Animal transmission test and hematology also
help in diagnosis. the hemoglobin
content goes blow 3g/dl and to erythrocyte count
as low as 2 million/l of blood.

27. ❑ Balantidium coli:
➢ Balantidium coli is a parasitic species of ciliate alveolates
that causes the disease balantidiasis. It is
the only member of the ciliate phylum known to be
pathogenic to humans.

28. ❑ Pathogenesis:
▶ Opportunistic commensals
▶ Act as secondary invaders
▶ Produce hyaluronidase –enlarges already existing
lesions
▶ May cause superficial to deep ulcerations –
associated with mild enteritis
▶ Inman: pathogenic; diarrhoea and dysentery;
produces similar lesionsto
Entamoeba histolytica
▶ Ulcers –coagulative necrosisand haemorrhages

30. ❑ Clinical features:
➢ Generally, it is a self-limiting and asymptomatic
infection
➢ Causes Balantidiasis or ciliate dysentery
▪ Diarrhoea alternating with constipation is
typical symptoms in mild infection
▪ Stool contains blood and mucus in acute
infection

31. ➢ Symptoms are similar to amoebic dysentery headache, fever,
nausea, vomiting, severe abdominal
pain and intestinal colic
▪ Ulceration of gut wall
▪ Perforation of intestine
▪ Haemorrhage, shock and even death may occur
▪ Diarrhoeal stool contains rare trace of blood and lots of
mucus

32. ❑ Life cycle:

33. ❑ Lab Diagnosis:
➢ Microscopic examination of stool
▪ Trophozoites can be easily detected in saline
smears by their size and their slow motion
▪ Morphology of the macronucleus can be easily
recognized in both trophozoites and cysts in
temporary smears stained with iodine
▪ Other staining methods such as hematoxylin-
eosin or trichrome are also useful
▪ Concentration method by centrifugation

34. ➢ Molecular technique: Genetic analysis by
sequencing, PCR
➢ Sigmoidoscopy
➢ Serological test: Immuno-assay, Immuno-
fluorescent assay and ELISA

35. ❑ Cyclospora:
➢ Cyclospora is an infection of the bowel caused by a tiny
parasite called Cyclospora cayetanensis.
It's usually caught from eating raw fruit and vegetables
contaminated with human faeces (poo).
➢ Diarrhoea, which can often be severe, is the most common
symptom of cyclospora.

36. ❑ Pathogenesis:
➢ Cyclospora sp. infect enterocytes of the small bowel and
can produce disease (Bendall et al.,
1993). Both symptomatic and asymptomatic states have
been described.
➢ A moderate to marked erythema of the distal duodenum
can occur with varying degrees of villous atrophy and
crypt hyperplasia (Connor et al., 1993), but little is known
of the pathogenic mechanisms.

37. ➢ As yet, no virulence factors have been described
for Cyclospora sp. No animal or human feeding
studies have been undertaken. As for Giardia and
Cryptosporidium, it is assumed that the organisms
are highly infectious, and that doses lower than
100 sporulated oocysts carry a high probability of
infection.

38. ❑ Clinical features:
➢ symptoms similar to Cryptosporidiumand isospora
▪ watery diarrhea/frequent stools
▪ 1-2 weak duration typical
▪ relapses over 1-2 months
➢ associated with foe-borne outbreaks -37/64
attendees at luncheon near Charleston
➢ SC were positive for Cyclospora

39. ❑ Life cycle:

40. ❑ Laboratory Diagnosis:
▪ Stool examination-Shows round oocysts
▪ Wet mount examination
▪ Acid fast stain—shows variably acid fast
oocysts
▪ UV epifl uorescence microscopy—shows
auto fluorescence oocysts
▪ Molecular diagnosis—rt-PCR
▪ Serology (antibody detection)
▪ Histopathology of intestinal biopsies

41. ❑ Isospora belli:
➢ Cystoisospora belli, previously known as Isospora belli, is a
parasite that causes an intestinal disease known as
cystoisosporiasis. This protozoan parasite is opportunistic in
immune suppressed human hosts. It primarily exists in the
epithelial cells of the small intestine, and develops in the cell
cytoplasm.

42. ❑ Pathogenesis:
➢ Isospora belli can cause marked villous atrophy,
and crypt hyperplasia in the small intestine.
Inflammatory infiltrates in the lamina propria
include eosinophils, neutrophils, lymphocytes and
plasma cells.
➢ The precise mechanism causing these changes is
unknown, but they result in
steatorrhea and malabsorption.

43. ➢ Infection of the biliary tract by I. belli is also possible. The
parasite can complete it’s life cycle in
the biliary tract and oocysts can be observed in bile.Stages are
located in the bile duct epithelium

44. ❑ Clinical features:
▪ Isospora belli infection include steatorrhea,
headache, fever, malaise, abdominal
pain, vomiting, dehydration, and weight loss.
▪ Blood is not usually present in the feces. The
disease is often chronic with
parasites present in the feces or biopsies for
several months to years.
▪ Recurrences are common. Isospora belli can
cause a serious and sometimes fatal disease in
immune competent patients.

45. ▪ In patients with AIDS, or other immune compromised hosts,
infection is often severe with a fluid, secretory-like, diarrhea
that may lead to dehydration requiring hospitalization. This
can be associated with fever and weight loss.

46. ❑ Life cycle:

47. ❑ Laboratory Diagnosis:
▪ Isospora belli is diagnosed by detection of the oocysts in
stool or rarely bile samples. Universal
precautions should be followed when handling fresh stool
samples.
▪ Oocysts can be observed in wet preparations, iodine
stained preparations or acid-fast stained
smears of concentrated stool specimens.
▪ Isospora belli oocysts are acid fast and will also stain
positive using the auramine o protocol commonly used to
detect mycobacteria

48. ▪ The sporont and sprobast fluoresce green when a
fluorescent microscope is used to examine stool
smears after auramine o staining. Autofluorescence
of I. belli oocyst walls has been reported and can
be used in diagnosis.
▪ Autofluoresence was superior to iodine staining in
one study. Areal-time PCR
assay has been developed to detect I. belli in stool
samples.

49. ❑ Microsporidia
➢ Microsporidia are a group of spore-forming unicellular
parasites. They were once considered protozoans or protists,
but are now known to be fungi, or a sister group to fungi.
They have recently been discovered to infect on Coleoptera a
large scale, in a 2017 Cornell study.

50. ❑ Pathogenesis:
➢ Microsporidia have been reported as pathogens in
patientswith HIV disease.
➢ Infection is probably by ingestion, inhalation or inoculation
ofspores.
➢ Microsporidia species frequently associated with AIDS are:
▪ Enterocytozoon bieneusi
▪ Enchepalitozoon hellem
▪ Encephalitozoon intestinalis
➢ Intestinal microsporidiosis-commonest infection
causedmainly by E. binneusi.

52. ❑ Life cycle:

53. ❑ Laboratory Diagnosis:
Specimen
▪ Small Intesinal Biopsy – for histopathological examination
▪ Faeces
Biopsy examination
▪ Intestinal microsporidiosis – most common type of infection
▪ Diagnosed by microscopy of small intestinal biopsy sections.
▪ Light microscopic and electron microscopic examinations
used for demonstration
of spores.

54. Faeces Examination
▪ Spores detected in faeces and content of
duodenum-jejunum using
modifiedTrichome stain.
➢ Culture – culture of spores.
➢ Polymerase Chain Reaction (PCR) –
Microsporidial DNA amplified and detected.

55. THANK YOU