CRYPTOSPORIDIUM

HOMINIS

Parasite Biology

Pathogenesis and Clinical Manifestations

Diagnosis

Treatment

Epidemiology

Prevention and Control

By Stephanie Chiong BSBI3A

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

C. HOMINIS LIFECYCLE

PATHOGENESIS AND CL IN ICAL

MAN IFESTAT IONS

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

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

TREATMENT

NO ACCEPTABLE TREATMENT

Nitazoxanide proven effective in preliminary trials

Bovine colostrum, Paramomycin and Clarithromycin severe

diarrhea

Azithromycin

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

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%

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

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