(M) Coccidia (lecture-based) part 1 Flashcards
Coccidia, C. parvum, C. hominis, C. belli, T. gondii
- Largest group of apicomplexan protozoans
- They are considered opportunistic in immunocompromised and immunodeficient
Coccidia
This is recognized as one of the major problems in animal farming and in zoo management
Coccidiosis
Eimeria
Phylum, Class, Subclass, Order, Genus
Familiarize
Apicomplexia
Conoidasida
Coccidiasina
Eucoccidiorida
Eimeria
All are true about the genera of coccidia, except:
A. Spore-forming
B. Single celled
C. Obligate intracellular parasites
D. Has an organelle of locomotion
D
rather movement is thru body flexion, gliding, or undulation of longitudinal ridges
3 phases of the life cycle
- Sporogony
- Schizogony (asexual stages)
- Gametogony phase (sexual)
Life cycle
Forms a sporoblast, that will create a wall for itself by secreting materials, , at the same time the protoplasm forms two sporozoites within the sporocyst wall
SPOROGONY/SPORULATION PHASE
Life cycle
the development of an oocyst which came from a zygote.
SPOROGONY/SPORULATION PHASE
Life cycle
TOF. Thick shelled oocysts are passed unsporulated in the feces of the host, these consist of a single nucleus in a large pool of protoplasm.
T
Life cycle
Once the sporozoites have been formed, the oocyst is an infective sporulated oocyst that is ingested by the host for the life cycle to continue.
SCHIZOGONY/MEROGONY PHASE
Life cycle
When the sporozoites have invaded an epithelial cell they become rounded and are called?
trophozoites (merogony phase)
Life cycle
This trophozoite will then divide into a number of elongated nucleated merozoites, collectively known as a?
meront (merogony phase)
Life cycle
What type of meronts is recycled in the system to infect nother small intestinal ECs
Type 1
Life cycle
This type of meront is designated to undergo the gametogony phase
Type 2
Life cycle
Phase: Ends with the production of a zygote, which begins when the merozoites, type 2, will transform into undifferentiated gamete which will undergo sexual differentation to finally become a zygote.
GAMETOGONY
- Causes diarrhea in animals (1971)
- First case in humans (1976)
- Frequent case of intractable diarrhea in immunocompromised patients
Cryptosporidium parvum
Cryptosporidium parvum
First observed in the gastric mucosal crypts of lab mice by
Tyzzer (1907)
Cryptosporidium parvum
Inhabits
small intestine, stomach, appendix, colon, rectum, biliary tree and pulmonary tree
sa module “brush borders of the mucosal epithelium of the stomach or the intestine” yan lang
Cryptosporidium parvum
Infective form
mature oocyst
Cryptosporidium parvum
causes auto infection
Thin-walled oocysts
Cryptosporidium parvum
passed out from the body through feces.
thick-walled oocysts
- Worldwide distribution.
- Common cause of diarrhea among travelers and patients of day-care centers more common among children than adults.
- It can occur as water-borne infection or zoonotic.
- In man, this parasite inhabits the brush borders of the mucosal epithelium of the stomach or the intestine. They may also inhabit the gall bladder and the pancreatic duct.
Cryptosporidium parvum
Causative agent of the disease Cryptosporidiosis
Cryptosporidium parvum
Cryptosporidium parvum
Host
Man
Cryptosporidium parvum
TOF. Heteroxenous.
F (mono)
Cryptosporidium parvum
Reservoirs
Cattle, cat, dog
Cryptosporidium parvum
Mode of Transmission
- Ingestion of contaminated food and water (water-borne is most common)
- Autoinfection
Cryptosporidium parvum
Incubation period
2-14 (7 average) days
Clinical manifestation: Biliary tract can be involved: RUQ pain, sclerosing cholangitis, cholecystitis
Cryptosporidium parvum
Clinical manifestation: chronic, persistent profuse diarrhea, weight loss, electrolyte imbalance, emaciation, and abdominal pain
Cryptosporidium parvum
- Depend on the immune status
- Immunocompetent: asymptomatic or self-limiting febrile illness with diarrhea, abdominal pain, nausea, and weight loss
- Immunocompromised: chronic, persistent profuse diarrhea, weight loss, electrolyte imbalance, emaciation, and abdominal pain
Cryptosporidium parvum
Cryptosporidium parvum
TOF. Stool can be voluminous (1 - 25 L/day).
T
Cryptosporidium parvum
Diagnosis to demonstrate colorless, spherical oocysts (4-5 um) with small and large granules
Stool Examination (DFS)
Cryptosporidium parvum
Diagnosis:
- Method of choice
- Oocysts appear as red acid-fast spheres against a blue background
Modified acid-fast stain of stool samples
Cryptosporidium parvum
May may also be done to recover the oocyst.
other than DFS and modified acid-fats stain
enterotest
Cryptosporidium parvum
What are the available serologic tests?
- Fluorescent staining: auramine-phenol or acridine orange
- Indirect IF: definitive identification
Cryptosporidium parvum
If oocysts are not demonstrable in the previous diagnosis, what can be done?
Sheather’s sugar flotation and zinc sulfate flotation can be done
Cryptosporidium parvum
Diagnosis: antibody against parasite is seen within 2 months of acute infection
Serodiagnosis
Cryptosporidium parvum
Diagnostic tool: using light and EM at the apical surface of intestinal epithelium (jejenum is preferred)
Histopathological examination
Cryptosporidium parvum
Diagnostic: lasts for 1 yr and seen using ELISA (highly sensitive and specific) or IF
Anti-oocyst ab
Cryptosporidium parvum
this diagnostic dentifies 17 kDa and 27 kDa sporozoite agn
Western blot
Cryptosporidium parvum
Self limiting typically within?
2-3 weeks
Cryptosporidium parvum
has approved for treatment of diarrhea in people with healthy immune systems, however, its effectiveness among immunosuppressed is still unclear.
Nitazoxanide
Nitazoxanide 500 mg BD x 3 day — effectiveness is still unclear
Cryptosporidium parvum
an antimicrobial used to treat a number of parasitic infections
Paromomycin
Cryptosporidium parvum
What are the Supportive management?
fluid, electrolyte and nutrient replacement
Cryptosporidium parvum
TOF. No chemotx effective.
T
di ko gets
1. Cryptosporidium parvum
TOF. Chlorination does not affect the parasite.
T
Cryptosporidium parvum
Prevention
- Synergistic effect of multiple disinfectants and combined water treatment processes may reduce C. hominis oocysts in drinking water
- Natural water and swimming pool water should not be swallowed
- Contamination of drinking water by human and animal feces should be prevented.
- Found mainly in humans
- It has a universal distribution with infections reported worldwide
- Most epidemics are associated with water usually with calf feces
- An additional species identified through genetic analysis
- All stages of development are completed in the host GI tract (monoxenous life cycle)
- It was not well recognized prior to AIDS; Nosocomial infections have been reported among health workers caring for AIDS pts
Cryptosporidium hominis