1. CRYPTOSPORIDIUM
HOMINIS
By Stephanie Chiong BSBI3A
Parasite Biology
Pathogenesis and Clinical Manifestations
Diagnosis
Treatment
Epidemiology
Prevention and Control
2. PARASITE BIOLOGY
Oocysts are found in feces of human and animals (each oocyst contains four
sporozoites)
The oocysts are infectious and when ingested, sporozoites attach to the
gastrointestinal tract
Sporozoites develop into trophozoites and become intracellular but extracytoplasmic
The trophozoites divide by schizogony, producing mesozoites
Macro and microgametocytes are eventually produced
A zygote develops and later, an oocyst
Oocysts pass in the feces and contaminate food and water
4. PATHOGENESIS AND CLINICAL
MANIFESTATIONS
Self-limiting diarrhea(2-3 weeks), abdominal pain, anorexia, fever, nausea, weight
loss for immunocompetent hosts
Severe and progressively worse diarrhea for immunocompromised patients
Bile duct and gall bladder heavily affected acute and gangrenous cholecystitis
Respiratory infections chronic coughing, dyspnea, bronchiolitis and pneumonia
Villi of intestines become blunted and infiltration of inflammatory cells
Varying degrees of malabsorption and excessive fluid loss
DEATH
5. DIAGNOSIS
Stool exmination methods
Sheather’s sufar flotation
Formalin-ethyl-acetate concentration technique
Kinyoun;s modified acid-fast stain
Indirect fluorescent antibody
Enzyme immunoassay and DNA probes specific for C. hominis
Acid-fast stain preferred
6. TREATMENT
NO ACCEPTABLE TREATMENT
Nitazoxanide proven effective in preliminary trials
Bovine colostrum, Paramomycin and Clarithromycin severe
diarrhea
Azithromycin
7. EPIDEMIOLOGY
Universal distribution
Infections reported worldwide
Unusual in North America over many cases in Wisconsin, USA due to
faulty water purification system
Mostly associated with water, in many cases, contaminated with calf feces
Other sources of infection: unpasteurized milk and apple cider
Nosocomial infections in health workers
8. Crptosporidium parvum bovines
Cryptosporidium hominis humans
Prevalence in developing countries: 3-20%
Philippines 2.6%
Study in San Lazaro Hospital: 8.5%
Study in Philippine General Hospital: 1.7%
9. PREVENTION AND CONTROL
Water-borne transmission = synergystic effect of multiple
disinfectants and combined WATER TREATMENT processes
Chlorination no effect on parasite
Natural water and swimming pool water NOT TO BE
SWALLOWED
Contamination of drinking water NO NO