Zoonoses and Select Agent Laboratory (ZSAL)

Laboratory Activities

The Zoonoses and Select Agent Laboratory (ZSAL) of the Bacterial Special Pathogens Branch (BSPB) provides a variety of reference activities for the following bacteria:

  • Bacillus anthracis
    • Detection and isolation
    • Culture identification and genotyping
    • Serology
  • Leptospira spp. (including but not limited to L. interrogans)
    • Molecular Detection
    • Isolation
    • Culture identification and genotyping
    • Serology
  • Brucella spp. (including but not limited to B. abortus, B. canis, B. melitensis, B. suis)
    • Detection and isolation
    • Culture identification and genotyping
    • Serology (B. canis and B. abortus RB51 serology currently not available)
  • Burkholderia spp. (including B. mallei, B. pseudomallei and other members of the B. pseudomallei complex such as B. thailandensis)
    • Detection and isolation
    • Culture identification and genotyping
    • Serology (limited to B. pseudomallei)

Those working with Burkholderia spp. specimens should follow recommendations for management of accidental laboratory exposure to B. psuedomallei and B. mallei.

ZSAL accepts specimens from state public health laboratories and other federal agencies for analysis. Private healthcare providers and institutions should contact their local or state health department laboratory (state, county, city) to ensure appropriate processing.

Specimens for Testing

State public health laboratories may request testing using the test order codes found in the CDC Test Directory.

Click the relevant test code below for a link to the CDC Test Directory with detailed submission requirements.
Test Name Test Code Approval Needed Acceptable Specimen Minimal Volume Required
Bacillus anthracis detection in clinical specimens CDC-10204 Yes Plasma, Blood, Pleural fluid, Cerebrospinal fluid, Ascites fluid, Lesion swab, Lesion exudate, Rectal swab, Tissues from biopsy or autopsy 0.10 ml
Bacillus anthracis genotyping and AST CDC-10203 Yes Isolates NA
Bacillus anthracis serology CDC-10196 Yes Paired acute and convalescent serum samples submitted at the same time 0.25 ml
Bacillus anthracis study CDC-10205 Yes To be determined To be determined
Bacillus cereus genotyping CDC-10206 No Isolates NA
Brucella species identification, genotyping, and AST CDC-10207 No Suspected or presumptive Brucella isolates should be submitted for identification. Multiple specimen types may be submitted for Brucella culture including human whole blood, body fluids such as bone marrow, joint fluid, cerebrospinal fluid (CSF), breast milk, abscess fluid and tissue biopsies. Acceptable animal specimen types include fresh or frozen whole blood and tissue samples from lymph nodes, kidney, liver, and reproductive organs. Food products such as unpasteurized milk and cheese are suitable for Brucella culture. 1 ml of fresh blood or body fluid for culture. Tissue samples and biopsy material should be at least the size of a pea.
Brucella species molecular detection CDC-10208 No Whole blood is the preferred specimen for Brucella molecular detection. Serum may also be tested. 0.25 ml
Brucella species serology CDC-10197 No Paired serum samples are preferred (acute and convalescent) 0.1 ml
Brucella species study CDC-10209 Yes To be determined To be determined
Burkholderia mallei/pseudomallei identification, genotyping, and AST CDC-10210 No Isolates, clinical specimens (blood, bone marrow, sputum or bronchoscopically obtained specimens, abscess material or wound swabs, and urine) NA
Burkholderia mallei/pseudomallei molecular detection CDC-10211 No Whole blood is the preferred specimen for Burkholderia molecular detection. Serum may also be tested. 0.25 ml
Burkholderia mallei/pseudomallei study CDC-10212 Yes To be determined To be determined
Burkholderia pseudomallei serology CDC-10198 No Paired acute and convalescent serum samples 0.1 ml
Leptospira species identification and genotyping CDC-10199 No Cultured isolates in appropriate media or appropriate media inoculated with clinical specimen (whole blood, tissue, or urine) NA
Leptospira species molecular detection CDC-10200 No Clinical specimens (whole blood, CSF, serum, and urine) 0.25 mL (CSF, serum, and whole blood) and 10 mL (urine)
Leptospira species serology CDC-10201 No Paired acute and convalescent serum samples 0.1 ml
Leptospira species study CDC-10202 Yes To be determined To be determined

Specimen Rejection Criteria

Please review the rejection criteria below prior to submission. ZSAL may reject specimens that are improperly labeled or submitted, or that are in unacceptable condition:

Unacceptable specimen labeling:

  • No labeling
  • Only one unique identifier on the specimen container (requirement is two unique identifiers on the specimen)
  • No submission form (50.34)
  • Unique identifiers on the specimen container do not match the form
  • Multiple labels on container with conflicting patient identifiers

Unacceptable specimen submission process:

  • Submitter is not authorized person by state law
  • Test requested is not performed at CDC
  • Specimen was sent to CDC in error

Unacceptable specimen or condition:

  • Specimen has leaked
  • Specimen is of poor quality
  • The volume of the specimen submitted was insufficient
  • The specimen type/site of collection is unacceptable for the testing requested
  • Specimen collection device or transport media are unacceptable
  • Specimen is improperly processed (i.e. serum collection tube not spun down)
  • Specimen is received in an expired specimen collection device
  • Specimen was shipped using unacceptable transport condition
  • Specimen is submitted in an unacceptable timeframe

In addition to the criteria above, the CDC CLIA Technical Supervisor may determine that a specimen should be rejected based on the following:

  • Required submission information not provided as specified according to the CDC Test Directory
  • Improperly completed 50.34 form
  • Specimens submitted directly to CDC without authorization by the jurisdictional Public Health Laboratory
  • Specimen is submitted in an inappropriate manner


All isolates and specimens for analysis by ZSAL should be sent and processed through the state public health laboratory. All bacterial isolates being sent for culture identification, except Leptospira spp., should be grown on solid media in tightly sealed containers (e.g. slants). Leptospira spp. should be grown in semi-solid EMJH and shipped at room temperature tightly sealed.

Serum samples for serological testing should ideally be sent in pairs, including an acute (≤7 days after symptom onset) and a convalescent-phase (14–35 days after symptom onset) specimen. It is recommended that the convalescent-phase specimen be taken 2 weeks after the acute specimen. Serum samples should be sent in a Sarstedt 2 ml microtube with an O-ring in the lid (Catalog Number #72.694.006) or the equivalent. Sera for anthrax serology should be sent frozen. Sera sent for other diseases can be sent refrigerated, however, if the sample was previously frozen, it should be sent frozen. Whole blood samples should NOT be sent for serological testing.

PCR samples for Leptospira should be acute whole blood (≤4 days post symptom onset) collected in tubes containing any anticoagulant EXCEPT heparin, or urine collected in a sterile specimen container ≥7 days post symptom onset. Samples for PCR should be shipped as soon as possible after collection, or frozen and shipped on dry ice if not shipped within a week of collection.

Specimens submitted for testing must be accompanied by CDC Form 50.34 pdf icon[PDF – 590KB]. Samples sent for serology or Leptospira spp. testing should be addressed to unit 91. Samples sent for culture, identification, or PCR testing of B. anthracis, Burkholderia spp., and Brucella spp. should be addressed to unit 91. Select Agent forms may be required for these samples; see below for select agent shipping and reporting requirements.

More information is available on Recommended Specimens Needed for Testing for Anthrax and for Collecting, Preparing, and Shipping Serum Samples.

CDC does not accept routine shipments on weekends or holidays. Please make sure packages arrive Monday–Friday. All samples must be shipped in accordance with all applicable local, state and federal regulations.

Shipping address for specimens is:

[Insert CDC Point of Contact]
Centers for Disease Control and Prevention
ZSAL/STATT [Unit # 91]
1600 Clifton Road, NE
Atlanta, GA 30329
[Insert CDC Point of Contact’s Telephone Number]

Select Agents

Confirmed isolates of select agents sent for further characterization require an approved Form 2 from the Federal Select Agent Program (FSAP) prior to shipping. Also, confirmed isolates of select agents identified in a clinical or diagnostic lab must be reported via Form 4. See the FSAPexternal icon for the rules, regulations, and forms for transferring and reporting select agents.

Additional Information

If additional information is needed about the reference activities performed at ZSAL, please call 1-800-CDC-INFO (1-800-232-4636).