Rabies Testing

This information provides guidance to people who submit animal specimens to the Wisconsin State Laboratory of Hygiene for rabies testing.

Background

The Rabies Laboratory at the Wisconsin State Laboratory of Hygiene (WSLH), located on the University of Wisconsin-Madison campus, is the only rabies diagnostic laboratory in Wisconsin.  The WSLH Rabies Laboratory works closely with epidemiologists at the Wisconsin Division of Public Health and personnel from other state and federal agencies as part of a comprehensive rabies control program.

The WSLH Rabies Laboratory receives between 2,000 and 2,500 animal specimens from throughout Wisconsin for rabies testing each year. Immunofluorescent tests are performed directly on samples of selected regions of the brain of animal specimens. Additional testing of positive samples is performed to determine the type of rabies virus present.

In addition to providing diagnostic testing services, the WSLH also administers a rabies proficiency testing program for rabies laboratories throughout the U.S.

 

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Contacts

Specimen Handling/Laboratory Testing:   

  WSLH Rabies Laboratory   

  (608) 262-7323 (7:45 a.m.- 4:30 p.m. M-F)

Human Exposure Management:     

  James Kazmierczak, DVM , MS

  Wisconsin Division of Public Health

  (608) 266-2154

(After hours emergency contact:  608-258-0099; this emergency telephone number is for the use of health care professionals only.)

Animal Exposure Management:     

  Yvonne Bellay, DVM, MS

  State Humane Officer

  Division of Animal Health, DATCP

  (608) 224-4888

 

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Human Testing

Testing of human specimens for rabies virus is performed by the Centers for Disease Control and Prevention (CDC). The WSLH Rabies Laboratory can assist with the shipment of human specimens to the CDC.

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Submitting Animal Specimens

Prior to submitting animal specimens to the WSLH for rabies testing, consult with your local health department, healthcare provider (in cases of exposure of humans to animals suspected of infection with rabies), and/or veterinarian (in cases of exposure of domestic animals to other animals suspected of infection with rabies).  A listing of local health departments in Wisconsin is available at http://dhfs.wisconsin.gov/localhealth/index.htm.

Rabies testing is the only animal testing performed at the WSLH. If you submit a Wisconsin Veterinary Diagnostic Laboratory (WVDL) test request form along with the WSLH rabies requisition form, the Rabies Laboratory will forward tissues to WVDL for additional diagnostic testing of the animal.

  • Euthanize all animals (including bats) humanely prior to submission to the laboratory, avoiding trauma to the head. Refrigerate the animal postmortem.
  • Submit animals whole if they are squirrel-sized or smaller.
  • Submit only the head if the animal is larger than a squirrel. Allow the head of the animal to exsanguinate prior to packaging to avoid leakage during transit.

    Note that the WSLH is no longer performing necropsy on large animal (bovine, equine) specimens.  To expedite testing of these animals, it is recommended that you remove and submit only the brain for rabies testing.  Large animal heads that are received at WSLH will be sent out for necropsy which will result in a delay in rabies testing.  If you have questions regarding large animal brain removal, please call the Rabies Laboratory at 608-262-7323    .
  • If you are submitting only the brain of an animal, be sure to remove and submit the entire brain. Reliable rabies diagnosis requires full cross-sections of the brainstem and cerebellum (across both lobes). Cross-sections from both hippocampi may be substituted for cerebellum when the latter is unavailable. Dorsal (figure 1) and ventral (figure 2) views of gross brain anatomy are provided as a starting reference.  Brain extraction should only be performed by veterinary staff who have completed a review of a neuro-anatomy reference or already have detailed knowledge of the gross anatomy of the brain. 

figure 1           (Images courtesy Centers for Disease Control)           figure 2


  • If any of the required tissues described above are missing, specimens will be reported as indeterminate, which may require exposed individuals to receive rabies post-exposure treatment.
  • Damaged / Decomposed / Treated Specimens:
    1. Damaged Specimens: Unless it is obvious that no brain tissue remains, we recommend that damaged animal heads be submitted for testing since identification of rabies in the required areas of the brain may still be possible.
    2. Decomposed Specimens: We recommend that specimens in the early stages of decomposition be submitted for testing, as rabies diagnosis may still be possible.
    3. Chemically Treated Specimens: Rabies testing cannot be performed on specimens that have been chemically treated, e.g., fixation of tissue in formalin; these specimens are unsatisfactory for testing.
    4. Specimens Exposed to Excessive Heat: Rabies testing cannot be performed on brain tissue that has been exposed to excessive heat; these specimens are unsatisfactory for testing.
     
  • Completing the Specimen Requisition Form
    1. Complete a WSLH rabies requisition form for each specimen in a shipment; complete information is required for effective follow-up of rabies exposures by the Wisconsin Division of Public Health, the Department of Agriculture, Trade and Consumer Protection, the WSLH and Local Health Departments.
    2. In cases of human exposure, include the name, address and phone number of the physician who will take responsibility for patient care so the rabies laboratory result can be rapidly reported.
    3. Include the name and address of the submitter (e.g., veterinary clinic, humane society, etc.) on the requisition form, otherwise the submitter will not receive a laboratory report.
    4. Clearly document on the requisition forms if multiple specimens are submitted in one shipping container to ensure that all specimens are tested.
    5. If specimens from different exposure cases are submitted in the same shipping container, clearly identify (on the specimen and the form) which specimen is associated with each case.
    6. Completed specimen requisition forms should be placed on top of the lid of the foam container, not inside the shipping container with the specimens where they could become contaminated. 

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Packaging Specimens

  • It is the submitter's responsibility to ensure that specimens are appropriately packaged to prevent leakage and to maintain refrigerator temperatures during transit.
  •  
    • Leaking or inappropriately packaged specimens may result in exposure of anyone who handles the package; please ensure the safety of handlers by packaging rabies specimens responsibly.
    • If you use your own packaging, duplicate the containment layers in the following description of the WSLH shipper.
 
  • Seal the animal specimen in thick plastic bags (e.g., multiple layers of heavy garbage bags or individually sealed ziplock bags).
  • Place the bag in a seamless styrofoam container to insulate the specimen during shipment and provide another barrier to leakage.
  • Include a sufficient number of “Cool packs” with the specimen to keep it cool during transport.
  •  
    • Do not use ice cubes as coolant since they invariably leak during transit.
    • Do not use dry ice or freeze the specimen prior to shipment; thawing a frozen specimen will delay testing.
 
  • Place the styrofoam container inside another thick garbage bag as a final barrier to leakage.
  • Place the bagged styrofoam container inside a heavy cardboard box (200 lb/sq. in. burst strength) to protect the specimen during shipment. Foam containers alone are not suitable for transport of rabies specimens.

  • If the specimen weighs more than 8.8 lb., it must be transported by ground.  To transport by USPS, specimens weighing more than 8.8 lb. must be labeled “Surface Transport Only”.   

  • Completed specimen requisition forms should be placed on top of the lid of the foam container, not inside the shipping container with the specimens where they could become contaminated.  

  • Labeling the Package for Transport

If the package will be transported by USPS

  •  
    • Attach a “Biohazard symbol” to the inner (secondary) container.
    • Unless the outer package is labeled for “Surface Transport Only”, the inner container must be capable of withstanding a pressure differential of 0.95 kPa in a temperature range of -40°F to 130°F.
  • If the package will be transported by air (e.g., DHL, Federal Express) or USPS (and is not labeled for “Surface Transport Only”), an itemized list of contents must be attached to the inner (secondary) container. 

Attach the following labels to the outside of the package:

  •  
    • “Biological Substance, Category B / UN3373” label
    • “Contact” label with the name and telephone number of someone who has knowledge of the package contents
    • Return address label
    • WSLH address label
    • “Surface Transport Only” label, if the specimen weighs more than 8.8 lbs and is being sent by USPS. 

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Transporting Specimens

  • Commercial Carriers:
    • Arrange transport of specimens for rabies diagnosis so that they are received at the WSLH (465 Henry Mall, Madison) within 24 hours.
  •  
    • Check with your carrier to determine what service should be used to provide overnight delivery.
    • If shipping on a Friday, confirm that the carrier will deliver on Saturday; specify that Saturday delivery is required so the specimen is not held for Monday delivery.
     
  • Personal Transport:
  •  
    • Specimens must be appropriately packaged to prevent leakage and exposure of anyone handling the specimen, even when delivering the specimens personally.
    • Specimens can be delivered to the WSLH (465 Henry Mall, Madison) between 7:45 a.m.-4:30 p.m. , Monday- Friday, or 7:45 a.m.-2:00 p.m. on Saturdays.
    • See map and directions here. 
      • Specimens should be delivered via the loading dock door near the back of the building, following the instructions posted on the door. On Saturdays, ring the bell at the loading dock door for delivery of specimens.
    • To deliver specimens to the WSLH outside the above hours, contact University of Wisconsin Police and Security (608-262-2957), who will place the specimen in the WSLH specimen storage facility.
     

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Testing and Reporting of Rabies Specimens

  • Monday through Friday, specimens received prior to 1:00 p.m. are tested the day that they are received, with results available after 3:00 p.m.
  • Specimens received after 1:00 p.m. will be tested the next working day, with results available after 3:00 p.m.

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Weekend Testing

  • WSLH staff will accept and store specimens that are received on Saturdays prior to 2:00 p.m.
  • Specimens that arrive on Saturday will be tested the following Monday, unless special arrangements have been made through the Communicable Disease Epidemiology Section (CDES) of the Division of Public Health.
    • After hours emergency contact:  608-258-0099; this emergency telephone number is for the use of health care professionals only.
  • The State Public Health Veterinarian or other assigned CDES staff will decide whether Saturday testing is warranted, based on whether someone will need to begin rabies postexposure prophylaxis unless weekend testing is performed.
  •  
    • You must provide a contact name and phone number to receive telephoned results if you request weekend testing.  The contact may be a local public health department staff member or a health care provider who will contact the patient and arrange for prophylaxis, if required. Results will not be telephoned to the animal owner or exposed person.


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Laboratory Result Reports

(Available after 3:00 pm Monday - Friday)

  • Human Exposure cases:
    • “Positive” results are phoned to the designated physician, the submitter and the local health department with jurisdiction in the case.  Hard copy reports are mailed to all of the above.  
    • “Indeterminate” or “Not Done” results are phoned to the physician and the local health department of jurisdiction.  The physician, the submitter and the local health department receive hard copy reports. 
    • “Negative” results are phoned by request only.  Hard copy reports are mailed to the physician, submitter and local health department.
     
  • Animal Exposure cases:
    • "Positive" results are phoned to the veterinarian of record, the submitter if different than the veterinarian and the local health department of jurisdiction.  All of the above receive hard copy reports. 
    • “Indeterminate” or “Not Done” results are phoned to the veterinarian (or submitter) and the local health department of jurisdiction.  The veterinarian/submitter and local health department of jurisdiction receive hard copy reports.
    • “Negative” results are phoned by request only. Hard copy reports are mailed to the veterinarian/submitter and the local health department of jurisdiction. 

 

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Fees for Testing

There is a fee  for rabies testing but it may be waived in cases where testing is approved by the local health department. Testing can be performed on a fee-for-service basis in cases that are not approved. Find the latest fees in our labwide fee schedule. Contact the WSLH Rabies Laboratory (608-262-7323) if you have questions about testing fees.

Forms and Shipping Containers

WSLH Rabies Requisition Form (PDF)

To order forms:  Contact Clinical Orders Department (1-800-862-1088) to order WSLH requisition forms with your facility's name and address preprinted.

Shipping Containers:  Contact the WSLH Clinical Orders Department (1-800-862-1088) to order a standard rabies shipping container. WSLH rabies shipping containers are provided at no cost to Wisconsin facilities. Containers are usually received within 2 work days after the order is placed.

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Other Resources

CDC National Center for Infectious Diseases Rabies Webpage

MedlinePlus Health Topic Rabies Webpage

Wisconsin Division of Health Services Rabies Fact Sheet

 

 

 

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