Cryptosporidiosis Flashcards
Pathogenic significance unclear unCl 1955‐Slavin described infecCon in turkeys
Cryptosporidium
Apicomplexan parasite described in 1907 by Tyzzer in gastric gland of mice (hidden sporocyst)
Cryptosporidium
Low mortality but severe diarrhea
cryptosporidiosis
Releases sporozoites and can be found in the intestine
oocysts
attached to the epithelial cells
sporozoites
undergo ASEXUAL reproduction by merogony (endopolygeny)
Tropozoites
What are the two types of meronts?
Type 1 meron
Type 2 meron
form 8
merozoites released from
the PV when mature.
Type 1 meront
form 8
merozoites released from
the PV when mature.
Type 2 meront
form 8
merozoites released from
the PV when mature.
Monoxenous life cycle
T or F: Zygote undergo asexual development
producing a sporulated oocyst with 4
sporozoites.
True
Toxoplasma gondii
invasion depends only on _________
parasite actin
Incubation period: crypto
2-4 days
Clinical symptoms
Watery and profuse diarrhea, abdominal cramps, nausea,
vomiCng, weight loss and low‐grade fever.
• Self‐limited disease in immuno‐competent individuals
• Prolonged duraCon in immuno‐compromised host.
Diagnosis
Detection of endogenous developmental stages: Most stages are basophilic and stain well with
hematoxylin and eosin or giemsa stains.
What makes it different from other apicomplexan parasites?
It lacks a plasCd
• It has a highly simplified mitochondrion
which does no longer perform oxidaCve
phosphorylaCon
• It has lost many of its biosyntheCc enzyme
genes and depends almost completely of
host cell derived nutrients
Cryprosporidium is HIGHLY resistant. T or F? Why? or why not?
True
Two possible explanaCons for the drug resistance:
1) Drugs do not reach the parasite because it lives in a specialized
compartment
2) The drugs used against other Apicomplexa are metabolically
inappropriate
Prevention
Hygiene/disinfecCon‐prevenCon of oocyst transmission‐difficult.
Oocyst very stable in aqueous soluCon; 3 months at 20oC and 1
year at 46oC
• InfecCvity lost upon heaCng (65oC, 30 min) or desiccated for 4h
or snap freezing
Chemotherapy
Parasire is highly resistant to it
Transmission
Fecal-oral spread of oocysts
Zoonotic transmission
Contaminated food
person-to-person
Definitive host
non-specific
mostly terrestrial mammals
Intermediate host
NONE
Cryptosporidium infects what?
Humans
livestock
pets
almost any domesticated animal
Illnesses caused by Cryptosporidium.
Flu-like symptoms Diarrhea may be life-threatening in immunosuppressed people
Epidemiology
Shed in the feces of infected animals and humans • Low infecCve dose: 1‐10 (oo)cysts • (Oo)cysts immediately infecCous • Environmental dispersal • (Oo)cysts are stable, survive long periods in environment • Zoono0c
Pathogen of cryptosporidiosis
Cryptosporidium parvum
Rservoir
Cattle
water
Diagnosis
Acid-fast stain
Treatment
Oral rehydration
