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

3. C. HOMINIS LIFECYCLE

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

10. ~End~