(M) Coccidia (lecture-based) part 2 Flashcards
Sarcocystis spp., C. cayetanensis, B. hominis
First reported in 1843 by Miescher as white threadlike cysts (Miescher’s tubules) in striated muscles of a house mouse
Sarcocystis
- While a majority infect mammals, about a dozen infect snakes
- This species was debated whether it is a protozoa or fungus. The debate was resolved in 1967 when bradyzoites in the sarcocysts were studied under the electron microscope and were seen to possess organelles found in other apicomplexan parasites such as Toxoplasma and Eimeria
- There are 130 recognized species under this
Sarcocystis spp.
Sarcocystis spp.
Who was the first to report this?
Meischer (1843)
Sarcocystis spp.
Was renamed in 1899 to?
Sarcocystis meischeriana
Sarcocystis spp.
How many species were recognized under this
130
Sarcocystis spp.
Humans serve as definitive hosts for the first 2 species (hominis and suihominis) but can occasionally act also as intermediate hosts for the 3 species (+ lindemanni)
TOF
T
Sarcocystis spp.
This stage shows a banana shaped; the anterior end is rounded
Mature trophozoites
Sarcocystis spp.
- 15-19 um by 8-10 um
- Contain 4 sporozoites and a discrete refractile residual body
Sporocyst
Sarcocystis spp.
Mode of Transmission for S. hominis
ingestion of raw beef
Sarcocystis spp.
MOT of suihominis
Ingestion of raw pork
Sarcocystis spp.
How many days does it take for sporocysts of S. hominis to be excreted after ingestion?
14-18 days
Sarcocystis spp.
How many days does it take for sporocysts of S. suihominis to be excreted after ingestion?
11-13 days
Sarcocystis spp.
pls read thru the life cycle nalang thx mwah
mwahmwah
Sarcocystis spp.
Infective and diagnostic stage (2)
- Sporocyst and thin-walled oocyst passed in the feces
- Cysts w/ bradyzoites ingested in undercooked meat
nasa picture
Sarcocystis spp.
Mono/heteroxenous
hetero
Sarcocystis spp.
Definitive host
dog or human
Sarcocystis spp.
susceptible intermediate host
cow or pig
Sarcocystis spp.
infective stages (3)
trophozoites, cysts, and sporulated oocysts
Sarcocystis spp.
Stage: As the infective stages travel down the small intestines, plates forming the sporocyst wall separate and releases 4 sporozoites that migrate through the gut epithelium to the endothelial cells in small arteries
schizogony or merogony process or ASEXUAL reproduction (ACUTE PROLIFERATIVE PHASE)
Sarcocystis spp.
How long does the acute proliferative phase lasts?
15-16 days after ingestion of sporocysts.
Sarcocystis spp.
Merozoites at this stage form metrocytes and encyst in the muscles forming?
sarcocysts or Miescher’s tubes
Sarcocystis spp.
Identify stage: Merozoites at this stage form metrocytes and encyst in the muscles forming sarcocysts or Miescher’s tubes
CHRONIC CYSTIC PHASE
Sarcocystis spp.
give rise to infectious, crescent-shaped bradyzoites.
metrocytes
Sarcocystis spp.
How long does it tahe for the sarcocyst to mature?
2 1/2 months
Sarcocystis spp.
What enters intestinal cells and change into the male (microgamonts) and female (macrogamonts)forms.
Active bradyzoites
Sarcocystis spp.
Active bradyzoites enter intestinal cells and change into the male (microgamonts) and female (macrogamonts) forms. Fusion results into an?
oocyst
Sarcocystis spp.
TOF. Human infection is considered prevalent with more than 100 published cases of invasive disease (approx. 46 cases reported by 1990).
F (rare with less than 100)
Sarcocystis spp.
What country had the highest report of beef specimens?
42.9%
TIBET
Sarcocystis spp.
Philippines: muscles of water buffaloes, cattle, pigs, goats revealed?
S. cruzi
Sarcocystis spp.
How many human tongues were obtained post mortem in Malaysia?
100 (revealed 21%)
Sarcocystis spp.
INCUBATION PERIOD
9-39 days
Sarcocystis spp.
2 Types of Pathology
- Invasive form (lindemanni)
- Intestinal form (more common; suihominis/hominis)
Sarcocystis spp.
Presents with vasculitis and myositis
Invasive form (lindemanni)
Sarcocystis spp.
- presents with nausea, abdominal pain, diarrhea, anorexia, abdominal distention, vomiting, dyspnea, tachycardia
- While normally mild and lasting under 48 hrs, the intestinal form may occasionally be severe or life -threatening
Intestinal form (more common; suihominis/hominis)
Sarcocystis spp.
TOF. All symptoms were transient and lasted about 36 hrs; some reports may last for as long as 5 years.
T
Sarcocystis spp.
Diagnosis available
Stool Examination, biopsy of an infected muscle using PAS, PCR targeting
Sarcocystis spp.
What is identified in feces that may require several stool exams done on separate days during infection
Sporocysts
Sarcocystis spp.
done to visualize sporocysts using bright-field microscopy
Fecal flotation wet mount
Sarcocystis spp.
preferred methods over formalin ether/ethyl acetate and other sedimentation methods
High-density flotation methods using NaCI, CeCI, ZnSO4, sucrose, Percoll, Ficoll-Hypaque a
Sarcocystis spp.
microscopic in cattle muscle; the wall is up to 6 um thick, appears radially striated from villar protrusions that are up to 7 um long
S. hominis sarcocysts
Sarcocystis spp.
macroscopic in pig muscle; the wall 4-9 um thick, with villar protrusions up to 13 um long
S. suihominis sarcocysts
Sarcocystis spp.
This diagnosis was useful in distinguishing S. hominis from S. fusiformis and S. cruzi sarcocysts and oocysts
PCR targeting 185 rRNA
Sarcocystis spp.
Reagent to use in order to store that sample for as long as 6 years
potassium dichromate
Sarcocystis spp.
TOF. Because asymptomatic, treatment is rarely required
T
Sarcocystis spp.
What medication/treatment is have been used in myositis?
Albendazole, metronidazole, co-trimoxazole
Sarcocystis spp.
prevention
- Avoid eating raw or undercooked beef or pork
- Avoid eating or drinking contaminated food with feces of cat, dog, or other carnivorous animals
- This organism was thought to be a member of cyanobacteria because it showed photosynthetic organelles and autofluorescing particle characterized by blue-green algae
- It was originally called cyanobacterium-like body (CLB)
Cyclospora cayetanensis
- same as Cystoisospora belli
- mainly a human disease; no animal reservoir have been found
- Reported in Nepal, Peru, Haiti and the US
Cyclospora cayetanensis
Cyclospora cayetanensis
Diagnostic stage
excretion of unsporulated oocysts in the stool
Cyclospora cayetanensis
Infective stage
sporulated oocysts enter the food chain
Cyclospora cayetanensis
The released sporozoites invade the epithelial cells of the small intestines although the site of predilection was the
jejunum
Cyclospora cayetanensis
oocysts undergo complete sporulation within how many days in a warm environment
7-12
Cyclospora cayetanensis
Definitive
man
Cyclospora cayetanensis
MOT
Ingestion of contaminated (with oocyst) water and food
Cyclospora cayetanensis
paaral ng clinical manifestation
thx
Cyclospora cayetanensis
Diagnosis:
- Direct microscopic examination (wet mount) of fecal
- Various concentration techniques and acid-fast staining (Kinyoun’s stain) are also helpful
- ZN staining: oocysts are acid-fast and stain red
- Oocysts are autofluorescent and under fluorescent microscopy appear as blue or green circles depending on the filter (365 - 450 DM)
- PCR to differentiate Cyclospora from closely related Eimeria
Cyclospora cayetanensis
The only effective drug
TMP/SMX 160/800 mg BID x 7 d
- Previously considered a yeast; recently reclassified as a protozoan
- Strict, anaerobic, colonic protozoan in humans
Blastocytis hominis
Blastocytis hominis
Seen in stool, 8 um in diameter, with a large central vacuole which pushes the cytoplasm and the nucleus to the periphery; multiplies by binary fission
Vacoulated
Blastocytis hominis
- Polymorphous cell slightly
- larger than the vacuolated form; multiplies by sporulation
Amoeboid
Blastocytis hominis
10-60 um in diameter and seen in old cultures
Granular
Blastocytis hominis
pls read life cycle
ok
- Found worldwide
- Prevalence as high as 58% (15% of stool specimens in the USA are +)
- Oral-fecal route is postulated
- Studies suggest possible zoonotic isolates with frequent animal-to-human and human-to-animal
Blastocytis hominis
Causes traveler’s diarrhea, rectal bleeding, and irritable bowel syndrome
Blastocytis hominis
- Displays extreme genetic diversity which is indicative of the pathogenicity of the organism
- At least 7 zoonotic subtypes
- Cyst survive in water for 19 days at normal temperatures
Blastocytis hominis
Available treatment
metronidazole 750 mg/tab 1 tab TID x 10 days or iodoquinol 650 mg/tab 1 tab TID x 20 days
Blastocytis hominis
Prevention
- Wash fruits and vegetables using a mild detergent before eating
- Keep cooking surfaces clean
- Strict handwashing
- Avoid eating foods that could not be cooked with heat
- Avoid drinking or using tap water for personal activities. Use boiled, purified and bottled water for brushing teeth, drinking etc.
