Cryptosporidium

Characteristics

Morphology

Cryptosporidium “Crypto” is an intracellular apicomplexan parasite. The oocyst is the infectious form that resides in the environment. After entry into the vertebrate host, the oocyst leaves the cyst form (excystation) and sporozoites are released.  The latter forms target epithelial cells of the gastrointestinal or respiratory tract. Within the epithelial cell, new schizogony and merogony develop. Male and female gametogony also develop within the epithelial cell and upon fertilization, new oocysts are formed. The thick-walled oocyst is excreted from the host and the thin-walled oocyst perpetuates the infection in the host. Oocyst are infective upon excretion permitting direct fecal-oral transmission.

Growth Conditions

Infection of target cells and assays for life cycle development are well established.

Health Hazards

Host Range

There are many species of Crypto that infect animals and some infect humans.

Modes of Transmission

Drinking contaminated water or consuming contaminated food are the most frequent modes of transmission. Oocysts may also be inhaled.

Signs and Symptoms

Crypto causes the majority of waterborne diseases among humans in the US. The most common symptom is watery diarrhea. Other symptoms include stomach cramps, dehydration, nausea, vomiting, and fever. Some people are asymptomatic. Symptoms last approx.2 weeks (maximum 30 days) in an immunocompetent host.

Infectious Dose

5-10 oocysts

Incubation Period

2-10 days, average 7 days.

Medical Precautions/Treatment

Prophylaxis

None

Vaccines

None

Diagnosis & Treatment

Diagnosis of Crypto infection is made by microscopic examination of stool samples. Most individuals will recover without treatment. Prescription medicine is available for the treatment of Crypto. Immunocompromised individuals should contact a primary care physician.

Surveillance

Cryptosporidiosis is a nationally notifiable gastrointestinal illness.

Emory Requirements

Report all incidents using PeopleSoft

Containment Requirements

BSL2/ABSL2

All work with Cryptosporidium-infected samples or propagation of parasites must be conducted inside a Biological Safety Cabinet (BSC) Class II. Use face shield, surgical mask and eye protection for open bench work.

Hand washing procedures must be carefully followed.

Animal work should be conducted in the BSC. Infected animals will shed oocysts and therefore there is a risk of exposure for animal care personnel during daily husbandry procedures.

Supplemental References

Spill Procedures

Small

Notify others working in the lab.  Allow aerosols to settle.  Don appropriate PPE.  Crypto is chlorine-resistant.

An EPA-registered disinfectant should be used to remove contaminating matter from surfaces (e.g., of bench tops and equipment). After organic material has been removed, 3% hydrogen peroxide (i.e., undiluted, commercial hydrogen peroxide, identified on the bottle as 3% or “10 vol” hydrogen peroxide) can be used to disinfect surfaces. Alternatively, use hydrogen peroxide wipes. Leave hydrogen peroxide for 30 minutes before repeating, at least a second time. All decontamination litter and other disposable materials should be autoclaved or similarly disinfected before disposal.

Large

For assistance, contact Emory’s Biosafety Officer (404-727-8863), or the EHSO Spill Team (404-727-2888)

Exposure Procedures

Mucous membrane

Flush eyes, mouth or nose for 15 minutes at eyewash station.

Other Exposures

Wash area with soap and water for 15 minutes.

Reporting

Immediately report incident to supervisor, complete an employee incident report using PeopleSoft.

Medical Follow-up  

7am-4pm (OIM):

EUH (404-686-7941)

EUHM (404-686-7106)

WW (404-728-6431)

After Hours:

OIM NP On Call

404-686-5500

PIC# 50464

Needle Stick (OIM):

EUH (404-686-8587)

EUHM (404-686-2352)

Yerkes: Maureen Thompson

Office (404-727-8012)

Cell (404-275-0963)

Viability

Disinfection

Cryptosporidium is susceptible to 3% hydrogen peroxide solution.

Inactivation

Inactivated by moist heat, 121C  for 18 minutes

Survival Outside Host

Long term survival outside the host and it is resistant to chlorine disinfection.

Personal Protective Equipment (PPE)

Minimum PPE Requirements

At minimum, personnel are required to don gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with ­­­­­­­Cryptosporidium-infected samples.   Additional PPE may be required depending on lab specific SOPs.

Additional Precautions

All procedures that may produce aerosols, or involve high concentrations or large volumes should be done in a BSC.

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