Controlling Spread of Rabies

Table of Contents

A. Human Isolation and Quarantine Requirements

Minimum Period of Isolation of Patient

Standard Precautions for the duration of illness (e.g., until death).

Minimum Period of Quarantine of Contacts

None for humans.

B. Protection of Contacts of a Case

1.  Protection of Humans Exposed to Animals

Under Iowa Code Chapter 351.39, Local Boards of Health are responsible for collecting human exposure reports and enforcing animal confinement.  

The need for post-exposure rabies prophylaxis should be evaluated in three steps and can be phrased in the form of three questions:

  1. is the animal species known to carry rabies? 
  2. did an actual exposure occur? and
  3. can the animal be tested?

Step 1.  Is the animal species known to carry rabies?

Wild Animals:

In wild animals the rabies risk varies by species:

  • High-risk animals are those that commonly carry rabies.  In Iowa, these include skunks, bats, raccoons, foxes, and coyotes.
  • Medium-risk animals have very rarely been found to carry rabies in the US (extremely rare in Iowa) large rodents such as beaver, muskrat, groundhog, and woodchuck.
  • Low-risk animals that almost never carry rabies include small rodents, opossum, and lagomorphs.  This includes mice, squirrels, chipmunks, and rabbits.
Dogs, Cats, Ferrets, Horses and Livestock:

These animals can be infected with rabies virus. Exposures to dogs, cats, horses, and livestock need to be carefully evaluated, since a potential exists for these animals to harbor the virus. 

Other Species:

CADE is available for consultation call 800-362-2736 during business hours or 515-323-4360 after hours. 

Once it has been determined that the animal involved is a potential carrier of rabies, the clinician should move to the second step. (Whether or not an animal has been vaccinated is immaterial to assessment because, though vaccination decreases the risk of the animal being rabid, it is not a guarantee).

Step 2.  Did an exposure actually occur?

Rabies is transmitted by introducing the virus into open cuts or wounds in skin or via mucous membranes.  The virus will not cross intact skin.  Since the virus is present in saliva, actual exposures to the virus require bites, saliva contact to mucous membranes, or  contamination of fresh, open cuts, wounds, or abrasions with saliva. 

Other nonsalivary exposures to rabies virus rarely occur, and include exposure to large amounts of aerosolized rabies virus (e.g. explorers of caves colonized by rabid bats); infected organs (e.g., corneas) transplanted from patients who died of unrecognized rabies; and exposure of open wounds or mucous membranes to other potentially infectious material (nervous tissue) from a rabid animal.  If the material containing the virus is dry, the virus can be considered noninfectious.  Other contact, such as petting a rabid animal or contact with the blood, urine, skunk spray, or feces, does not constitute an exposure and is not an indication for prophylaxis.

Bats pose a unique problem. The bite of a bat can be so small that it may be undetected. People found in rooms with bats, who are unable to state, “I know I was not bitten,” should be considered potentially exposed. For example persons that awaken to find a bat in the room or children alone with a bat in a room should be considered exposed to rabies.

Once it has been determined that a potential exposure occurred, the clinician should move to the third step. (Can the animal be tested?).

Step 3.  Can the animal be tested? 

Bats:

If available, the bat should be tested for rabies.  If the bat is unavailable for testing, PEP should be considered.

Wild Animals:

High risk animals should be euthanized and submitted for rabies testing. Since viral shedding periods are not known for these animals, quarantine is not appropriate.  In cases in which the animals are unavailable for testing, they should be assumed rabid.

Medium-risk animals have rarely been found to carry rabies in the US and have very rarely if ever been found to be rabid in Iowa.  If the animal is available, it should be submitted for testing.  If the animal is not available, the exposed person should consult with their personal physician to determine whether prophylaxis is warranted.   

Lower-risk animal exposures almost never require human rabies PEP, unless the circumstances surrounding the exposure were unusual (such as an unprovoked bite by an animal acting strangely).

Dogs, Cats or Ferrets:

Dogs, cats and ferrets that have bitten or otherwise exposed a human and appear healthy may be quarantined for 10 days in lieu of euthanasia and testing. If at any time during the quarantine period, a dog, cat, or ferret shows signs of rabies the animal should be immediately euthanized and tested. 

Dogs, cats and ferrets that are incubating rabies will begin to exhibit signs of the disease very soon after they begin shedding virus in saliva. If an animal remains healthy during the 10-day quarantine, it could not have been shedding rabies virus in its saliva at the time of the bite or exposure.  This does not guarantee that the animal is not incubating rabies; it only indicates that the animal was not infectious at the time in which the human was exposed. 

A dog, cat, or ferret that is not available for observation or testing should be considered potentially rabid and post-exposure prophylaxis should be initiated.  If capture of the dog, cat, or ferret is likely in the near future, prophylaxis may be delayed up to 72 hours.  If the animal is not located within 72 hours PEP should be initiated.  

Livestock:

Recommendations for livestock that expose humans are determined on a case-by-case basis. Contact IDPH (800) 362-2736 for consultation.

Other Animal Species:

For exposure to other animal species, recommendations are made on a case-by-case basis. Contact Iowa HHS at (800) 362-2736 for consultation.

Note:  If a patient is bitten above the shoulder, IDPH recommends that the health care provider consider starting Post Exposure Prophylaxis immediately, as opposed to waiting and observing the animal for 10 days.  The closer the point of exposure is to the brain, the shorter the distance in which the virus must travel, potentially resulting in a shorter incubation period. If the animal subsequently tests negative for rabies, or if the animal is quarantined and is healthy at the end of 10 days (quarantines can only be conducted in dogs, cats, and ferrets) Post Exposure Prophylaxis can be discontinued at that time.  If Post Exposure Prophylaxis is discontinued before the series is completed and the patient is exposed again in the future, the entire Post Exposure Prophylaxis series should be administered.  If the Post Exposure Prophylaxis series is completed and the patient is exposed again in the future, only two doses of rabies vaccine on days 0 and 3 should be administered. 

Laboratory Submission of Animal Specimens:

Rabies testing requires examination of the animal’s brain, so the animal should be euthanized without damage to the head. Samples should be refrigerated prior to submission to the laboratory, and freezing should be avoided. Samples determined to be unsuitable for testing or indeterminate should be assumed positive and PEP should be administered accordingly. 

There are two laboratories in Iowa that provide animal rabies testing services: State Hygienic Laboratory and Iowa State University Veterinary Diagnostic Laboratory.

State Hygienic Laboratory (SHL):

SHL is the designated state public health laboratory in Iowa.  SHL receives state funding enabling them to provide free testing services for diseases of public health concern.  Therefore, SHL will test potentially rabid animals that have exposed humans free of charge.  SHL does not provide testing for animal to animal exposures; therefore those samples should be submitted to Iowa State University Veterinary Diagnostic Laboratory.    

Iowa State University Veterinary Diagnostic Laboratory (ISU VDL):

ISU VDL has historically provided animal rabies testing as a service to veterinarians who may be ruling out rabies as one of several differential diagnosis.   However, in recent years ISU VDL has received an increasing number of requests for rabies testing of domestic, livestock, and wildlife species where the submitter is only requesting rabies testing without additional diagnostics.  While ISU VDL is willing and able to provide that service to the public, healthcare, and veterinary communities, they do not receive any state or federal funding to support testing.  Therefore, ISU VDL must charge for the testing to cover their operating expenses.  ISU VDL will provide rabies testing for cases of animal and/or human exposure. 

Specimen Submission and Transportation: 
Specimen Preservation:
  • If the specimen will not be submitted for testing immediately, it should be refrigerated until transported or shipped.
  • DO NOT FREEZE THE SPECIMEN
Specimen Transport:
  • Private vehicle is the fastest and preferred way to get the specimen to the laboratory.
    • Double bag the specimen
    • Place the specimen in a hard sided container, such as a Styrofoam cooler
    • Place ice packs around the double bagged specimen to keep it cool during transport
    • Include the appropriate Rabies Test Request Form from SHL or ISU
    • Call the appropriate laboratory before departure
  • Commercial courier service, such as FedEx, can also be used.
    • Double bag the specimen
    • Place the double bagged specimen in a hard sided container, such as a Styrofoam cooler.
      • Place ice packs around the double bagged specimen to keep it cool -DO NOT FREEZE.
    • Place the completed Rabies Test Request Form in a separate plastic bag to prevent it from becoming wet or contaminated. Place the bagged Rabies Test Request Form in the hard sided container.
      • Firmly secure the lid of the hard sided container. 
      • Package (place in a box) the hard sided container and ship. 
      • Ship via overnight courier.

NOTE: Improper packaging and/or delayed delivery may compromise the integrity of the brain material rendering the specimen unsatisfactory for testing.

Specimen submission guidelines:
  • Large/medium animals- If only requesting rabies testing, a veterinarian needs to remove the head and only the head should be submitted for testing*.
  • Bats- Try not to crush the skull of the bat.  Submit the entire animal.
  • Small animals (mice, squirrels, etc): Submitting the entire animal is preferred.

* If a veterinarian is requesting other diagnostics from ISU VDL all appropriate samples should also be included.  In some cases, this may mean that the entire animal should be submitted. 

Laboratory Contact Information:

SHL: 
319-335-4500 or 800-421-4692 (answered all hours)  

ISU VDL:
During business hours call 515-294-1950 – after hours call 515-290-1969  

2.  Protection of Domestic Animals Exposed to a Rabid or Potentially Rabid Animal

Longer quarantine periods are required for domestic animals exposed to a rabid or potentially rabid animal (without human exposure). Quarantines may range from 45 days to 6 months depending on the animal’s vaccination status. Euthanasia may sometimes be recommended. The latest recommendations and requirements concerning the quarantine of animals exposed to a rabid or potentially rabid animal can be obtained from the Compendium of Animal Rabies Prevention and Control, 2008 National Association of State Public Health Veterinarians, Inc. (NASPHV) www.nasphv.org/Documents/RabiesCompendium.pdf

3.  Protection of Humans Exposed to a Rabid or Potentially Rabid Animal or Human

Severe Bites above the Shoulder

If a patient is bitten above the shoulder, IDPH recommends the health care provider consider starting post exposure prophylaxis immediately.  The closer the point of exposure is to the brain, the shorter the distance in which the virus must travel, therefore potentially resulting in a shorter disease incubation period.

If the animal subsequently tests negative for rabies, or if the animal is quarantined and is healthy at the end of 10 days (quarantines can only be conducted in dogs, cats, and ferrets) Post Exposure Prophylaxis can be discontinued at that time.  If Post Exposure Prophylaxis is discontinued before the series is completed and the patient is exposed again in the future, the entire Post Exposure Prophylaxis series should be administered.  If the Post Exposure Prophylaxis series is completed and the patient is exposed again in the future, only two doses of rabies vaccine on days 0 and 3 should be administered. 

Human Post Exposure Prophylaxis

  • Immediately and thoroughly wash all bite wounds and scratches with soap and water.  Simple wound cleaning has been shown to markedly reduce the risk of rabies. 
  • Tetanus prophylaxis should be considered
  • Risk of bacterial infections should be assessed and addressed.
1. Treatment of persons who have not previously received rabies vaccine or have not previously received rabies post-exposure treatment.
Immunocompetent patients:
  • Four 1-mL vaccine doses of HDCV or PCECV should be administered intramuscularly to previously unvaccinated persons as soon as possible after exposure on days 0, 3, 7, and 14 (day 0 is the day the post exposure prophylaxis is started). 
  • One dose of rabies immunoglobulin (HRIG), 20 IU/kg, should also be administered on day 0.
  • If anatomically feasible, the full dose of HRIG should be thoroughly infiltrated in the area around the wound. The rest should be administered intramuscularly at a different site than the vaccine.
  • If HRIG is not given with the first post-exposure dose of vaccine, it must be given within eight days after the first dose of vaccine. 
Immunocompromised patients:
  • Five 1-mL vaccine doses of HDCV or PCECV should be administered intramuscularly to previously unvaccinated persons as soon as possible after exposure on days 0, 3, 7, 14, and 28. 
  • One dose of rabies immunoglobulin (HRIG), 20 IU/kg, should also be administered on day 0.
  • If anatomically feasible, the full dose of HRIG should be thoroughly infiltrated in the area around the wound. The rest should be administered intramuscularly at a different site than the vaccine.
  • If HRIG is not given with the first post-exposure dose of vaccine, it must be given within eight days after the first dose of vaccine. 

How is immunocompromised defined in terms of rabies vaccination?

The decision of whether individuals are immunocompromised should be determined by a physician. However, to assist with this determination, persons with the below conditions may need to receive five doses of rabies vaccine (consult with their healthcare provider).

Persons with  immunocompromising conditions or on specific medications (non-HIV)

Examples include but are not limited to:

  • Congenital immunodeficiency
  • Leukemia
  • Lymphoma
  • Generalized malignancy
  • Therapy with alkylating agents, antimetabolites, radiation, or large amounts of corticosteroids.
  • Antimalarial medications
Persons with HIV infection
  • Both symptomatic and asymptomatic patients with HIV infection
Persons with conditions that cause limited immune deficits

Examples include but are not limited to:

  • Renal failure
  • Diabetes (uncontrolled)
  • Alcoholic cirrhosis
  • Asplenia

When rabies pre- or postexposure prophylaxis is administered to an immunosuppressed person, one or more serum samples should be tested for rabies virus-neutralizing antibody by the RFFIT test to ensure that an acceptable antibody response has developed after completing the series. 

If no acceptable antibody response is detected after the final dose in the pre- or postexposure prophylaxis series, the patient should be managed in consultation with their physician and appropriate public health officials.

2. Treatment of persons who have either received pre-exposure vaccination or have previously received rabies post-exposure treatment (according to the current protocols and with approved products, if unsure contact CADE for consultation):
  • Two IM doses (1.0 ml each) of vaccine should be administered on days 0 and 3.  Human Rabies Immune Globulin should NOT be administered.
Exposure to a Human Potentially Infected with Rabies

Standard Precautions for respiratory secretions should be in place for persons suspected or confirmed to have rabies. Articles soiled with saliva should be disinfected. Attending personnel should be protected (gloves, gowns, face protection) against any exposure to saliva. If a patient who has rabies (or is suspected of having rabies) exposes another person to saliva (through a bite or via infectious material exposure to an open wound or mucous membrane), rabies PEP of the contact should be started. Other people from the patient’s home, social, and work environment should be contacted to review their potential exposure. 

4.  Precautions and Contraindications to Rabies Prophylaxis
  • Immunosuppression. Corticosteroids, other immunosuppressive agents, or immunosuppressive illness can interfere with the development of active immunity and predispose the patient to developing rabies. Immunosuppressive agents should not be administered during post-exposure therapy, unless essential for the treatment of other conditions. 
  • Pregnancy.  Because of the potential consequences of inadequately treated rabies exposure, pregnancy is not considered a contraindication to post-exposure prophylaxis. Several studies have shown no indication of increased incidence of abortion, premature births or fetal abnormalities associated with rabies vaccination.  Rabies exposure or diagnosis of rabies in the mother is not an indication for pregnancy termination.
  • Allergies.  When a patient with a history suggesting hypersensitivity to any rabies vaccine component must be given the vaccine, antihistamines can be used; epinephrine should be readily available to counteract anaphylactic reactions, and the person should be carefully observed in a medical setting during vaccination.

C. Preventive Measures

Environmental Measures

Human rabies control relies on controlling rabies in the animal population, therefore animal quarantine regulations and vaccination laws should be enforced.  Under Iowa Code Chapter 351.39, Local Boards of Health are responsible for collecting human exposure reports and enforcing animal confinement.  In Iowa, all dogs over 6 months of age are required to be vaccinated against rabies.  Rabies vaccination is strongly encouraged in all companion animals (including horses) and valuable livestock. 

Pre-Exposure Vaccination

Pre-exposure vaccination is recommended for persons in the following categories:

  • Veterinarians
  • Animal handlers
  • Laboratory workers who handle rabiew virus
  • Persons living in or visiting countries where rabiew is endemic
  • Others whose occupations or hobbies bring them into contact with potentially rabid animals

Pre-Exposure Vaccination Protocol:

  • Three 1.0 ml injections of vaccine given intramuscularly on each of days 0, 7, and 21 or 28.

NOTE:  Pre-exposure vaccination does NOT eliminate the need for prompt post-exposure prophylaxis.  If persons who have completed the pre-exposure vaccination series are subsequently exposed to rabies, the following protocol should be followed (as stated on page 7):

  • Two IM doses (1.0 ml each) of vaccine, on days 0 and 3.  Human Rabiew Immune Globulin should NOT be administered.

Monitoring Pre-Exposure Vaccination Titers:

Persons who work with live rabies virus in research laboratories or vaccine production facilities and are under continuous risk of inapparent rabies virus exposure should have their serum rabies antibody titer measured every 6 months.  Acceptable antibody level is 1:5 titer by the rapid fluorescent focus inhibition test (RFFIT) technique. See page 15 for laboratories performing the serologic tests.  If the antibody level is less than 1:5, booster doses of vaccines should be administered to maintain a serum titer corresponding to at least complete neutralization at a 1:5 serum dilution by RFFIT.  

Persons who frequently come in contact with potentially rabid animals, such as veterinarians, veterinary technicians, animals control officers, or wildlife officers, should have a serum sample tested for rabies antibody every 2 years.  If their antibody level is less than complete neutralization at a 1:5 serum dilution by the RFFIT, the person should receive a single booster dose of vaccine. 

Education

Offer the following advice to the public to help prevent rabies:

  • Vaccinate pets; dogs are required by law to be vaccinated. Although not required by state law, cat, ferret, horse and valuable livestock vaccinations are recommended.
  • Do not feed or handle wild or stray animals. Avoid sick animals or those that act strangely.
  • Do not touch or handle dead animals.
  • Contact local animal control officer with questions about the capture of an animal or handling of a carcass.
  • Cover garbage cans and keep pet food indoors, so wild animals are not attracted.
  • Do not keep wild animals as pets, which is often illegal as well as dangerous.
  • Never handle bats. A bat bite or scratch may be small and go unnoticed. People who awaken to find a bat in the room or children awake or asleep with a bat in a room may require PEP.
  • Recommend that travelers to developing countries with endemic rabies receive pre-exposure prophylaxis if they will be visiting in situations where exposure is likely (e.g., camping, hiking, backpacking, or away from areas where treatment for a bite

Note: For more information about international travel and rabies, contact the CDC Traveler’s Health Office at (877) 394-8747 or via the internet.

Iowa Dept. of Public Health, Revised 7/15