Anthrax Information for Practitioners

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Anthrax Information for Veterinary Practitioners

Anthrax is endemic in Saskatchewan; therefore, practitioners may have or will in the future be encountering situations where anthrax is suspected. Please read the following information and contact the provincial Chief Veterinary Officer (CVO) at 306-787-5547 with any further questions.

Case Definition

Case Definition: Any positive test kit result will be treated as a positive sample. If a test kit is negative, but the Disease Control Lab tests indicate anthrax positive, the case will be determined to be positive. Samples sent to Prairie Diagnostic Services (PDS) in Saskatoon will be determined to be positive when reported by PDS as “Bacillus anthracis seen” or “Bacillus anthracis isolated”.

Suspicion of Anthrax

Private veterinarians act as the primary contact for producers for consultation and/or testing for anthrax. The Saskatchewan Ministry of Agriculture will act upon all positive cases diagnosed for anthrax and provide consultation to veterinary clinics.

Producer’s Role

Under the Province of Saskatchewan Anthrax Response Plan, producers have the following role:

Herd Veterinarian’s Role

Under the Province of Saskatchewan Anthrax Response Plan, herd veterinarians have the following role:

Carcass Side Tests

Anthrax cases can be detected by carcass-side tests or laboratory diagnosis. Carcass side test kits will be provided to practitioners. All kits that are used, along with a blood sample (blood-soaked swab) must be sent to the Saskatchewan Disease Control Laboratory in Regina for confirmation regardless of the test result. Further information on sampling and submission information will be supplied with the test kits.

Sample Collection, Submission and Testing

It is important to collect specimens as soon as possible after death of the animal. Samples taken early usually yield a pure isolate, speeding the testing process. If anthrax is highly suspected – DO NOT OPEN THE CARCASS

Sampling

Samples are listed in order of preference.

  1. Whole blood taken by syringe and needle from the jugular or tail vein and placed in a sterile vial. This remains the first choice and the best sample to submit to the lab. The blood-filled syringe can be submitted, providing that it can be sealed and is then placed in a sealed bag to avoid leakage; however, the needle MUST be removed first.
  2. Blood soaked swab taken carefully through a small incision into the jugular. Cover the opening to capture any leakage. Place swab in a sterile tube, adding a few drops of saline to keep it moistened.
  3. Swabs taken from blood-tinged fluids exuding from anus, vulva, nostrils or mouth. Place swab in a sterile tube, adding a few drops of saline to keep it moistened.
  4. Exudate-contaminated soil - examine the ground near the nostrils/mouth and anus/vulva for exudate stained soil. Place a small portion of the stained soil in a sterile tube or plastic leak-proof container.
  5. As a last resort, submit a swab soaked with fluid from the spleen if the animal has been eaten by predators or if a necropsy was performed. Alternatively, swabs may be taken from turbinate bones of livestock and wildlife that have been dead for an extended period of time. Place swab in a sterile tube, adding a few drops of saline to keep it moistened.
  6. The submission of solid tissues from organs is discouraged, unless no other sample is available. 

 

DO NOT SUBMIT ears, tongue or hide. AVOID CONTAMINATING THE OUTSIDE OF CONTAINERS CONTAINING THE SPECIMEN.

Packaging

  1. Provide a complete history for each animal. Fill out one separate test requisition form for each animal submitted. Please include the following information on the form when submitting samples:
    1. Name of submitting veterinary clinic/veterinarian
    2. Owner’s name, phone number and address
    3. Land location and RM number where the suspect animal(s) is (are) located
    4. Species and number of animals on the premises
    5. Number of dead animals
    6. Date of first death
    7. Vaccination status for anthrax
  2. Label each specimen as to origin (jugular blood, environmental swab, etc.). Please use rigid plastic containers with leak-proof lids for all samples.
  3. Refrigerate sample if there are delays in shipping to the lab; otherwise, ship all samples on ice packs.
  4. Dispose of used equipment and supplies separately - do not include them in the sample submitted.
  5. Pack to avoid leakage of the primary container! Place CLEAN submission forms between the inner and outer packing containers, so sample receiving staff can access them

Shipping

Submit samples to Prairie Diagnostic Services in Saskatoon. It is recommended to wait for confirmed laboratory results before discussing results with clients, as false positives by preliminary smear examination can occur.

Advance notice of these shipments to the diagnostic laboratory will assist the laboratory in planning for receiving and testing the sample. Please fax a copy of your pathology submission form to the provincial Chief Veterinary Officer at 306-787-1315.

Testing

Testing involves examination by direct microscopy after the polychrome methylene blue- or Giemsa-stained smears to visualize the anthrax capsule. The sample is also cultured on blood agar to evaluate growth characteristics and colony morphology. Positive results, reported by PDS as “Bacillus anthracis seen” or “Bacillus anthracis isolated” are reported to the Canadian Food Inspection Agency and the Saskatchewan Ministry of Agriculture.

Carcass Control

In cases where anthrax is highly suspicious, practitioners will play a role in educating the client in proper carcass management until laboratory diagnosis is confirmed. In the event the carcass is positive, the Ministry of Agriculture will confirm the carcass(es) have been disposed of in an appropriate manner. However, carcass management should begin prior to the lab results being received.

It is expected that when veterinary practitioners are called to examine the carcass of an animal that has died suddenly on pasture, they may have opened the carcass to make a tentative diagnosis. In highly suspicious cases for anthrax, after samples are collected, the producer should be advised how to properly dispose of the carcass to prevent further environmental contamination with spores. Please refer to the document “Information for Producers” for information on disposal.

When anthrax is possible but lower on your differential list and a full post-mortem exam is required, conduct the examination in a manner that minimizes environmental contamination, and be prepared to control or dispose of the carcass. Place a large piece of heavy duty plastic or 6 mil polyethylene sheeting in front of the carcass, and lay out any removed organs, etc. on it. When finished 5 with the exam, roll up the plastic and parts and place inside carcass. Cover carcass with 6 mil polyethylene sheeting and stake down. Heating and putrefaction under the plastic cover will destroy the vegetative form of bacteria within 48 to 72 hours in warm weather conditions. Or burn or bury carcass immediately.

It is the responsibility of the owner of the premises where the carcass is located to insure that all provincial and municipal regulations that apply to the burial or burning of carcasses are complied with.

As per the provincial anthrax response plan, a private veterinarian may act as an official inspector’s “designated representative”

Role of inspectors or designated representative

 

Protective Personal Equipment and Biosecurity

When attending a premise for the purpose of an investigation or implementation of anthrax control measures, the inspectors or designated representatives must:

Note that face masks are not essential PPE when handling potentially contaminated animals or material since anthrax spores are not easily aerosolized in the natural environment.

For general information on preparing to attend premises, attending premises, routine farm inspection and biosecurity protocol while attending premises refer to the following pages for Biosecurity Recommendations for Visiting a Farm.

Biosecurity Recommendations for Visiting a Farm

What is biosecurity?

Biosecurity is management practices used to reduce the potential for infectious diseases to be carried onto a farm by new animals, wildlife and other animals, equipment, people, insects, pests, feed and water. Biosecurity practices can also help limit the spread of disease within a farm. 

Why should you be concerned about biosecurity?

When farm visits are required, personnel must take steps to prevent the unintentional spread of disease-causing bacteria, viruses and parasites to the farms they are visiting. This is especially important in situations where several different farms are visited in a short period of time.

Many employees have livestock at home; therefore, it is also important when duties require visiting client’s farms, employees take similar steps to prevent the spread of disease to their own herd/flock, or vice versa.

How should I prepare for an on-farm visit?

You should always call the producer before coming to the farm; this is a good practice because you can ask the farmer about:

 

Vehicle Preparation

 

Equipment and Clothing

What if the farm already has biosecurity protocols in place?

Many livestock facilities have very stringent biosecurity protocols in place for their operation. These may exceed the recommendations stated here and employees must strictly follow the individual farm biosecurity protocols when they are provided.

What are some recommended procedures I should follow when entering the farm?

What are some of the procedures I should follow when leaving the farm?

What should I do when I return to the office?

What are the procedures if I am not physically touching any animals?

You do not have to physically contact any of the animals to pick up and spread pathogens. You can transfer infectious agents by touching livestock directly or by contacting any animal secretions or excretion including, milk, blood, saliva, semen, manure, urine, mucus, or other discharges.

Cleaning and Decontamination of Contaminated Sites and Materials

Information in Appendix 8 obtained from: World Organisation for Animal Health. 2008. Anthrax in humans and animals, 4th Ed. Retrieved from http://www.who.int/csr/resources/publications/anthrax_webs.pdf

Soil

Equipment and Structures

Stage 1: Preliminary Disinfection

One of the following disinfectants may be used in amounts of 1–1.5 litres per square metre for an exposure time of 2 hours:

Stage 2: Cleaning

Where practical, cleaning of all surfaces should be done by straightforward washing and scrubbing using ample hot water or mild hypochlorite solution (5000 ppm active chlorine). The operator should wear protective clothing, face and hands included. Cleaning should be continued until the original colours and surfaces are restored and the 10 wastewater is free of dirt particles. At the end of the process, residual water should be removed and disinfected and the surfaces dried.

Stage 3: Final Decontamination

For final disinfection, one of the following disinfectants should be applied at a rate of 0.4 litres per square metre for an exposure time of at least 2 hours:

After the final disinfection, closed spaces such as rooms or animal houses should be well ventilated before recommissioning. The effectiveness of the disinfection procedure cannot be assumed, and attempts should be made to confirm that it has been adequate by means of swabs and culture.

Clothing and Boots

Wherever possible, contaminated materials should be incinerated or autoclaved at 121 °C for 60 minutes. Use of disposable items facilitates this. In the case of contaminated non-disposable items such as clothing, boots, tools, etc., excess dirt should be scraped off and incinerated and the items themselves should be soaked overnight (at least 8 hours) in 10% formalin. (Caution: avoid skin contact with formalin solutions or inhalation of their vapors). Bleach is a possible alternative if discoloration or corrosion is not of consequence, and there is little organic material left on the items after scraping.

Manure, bedding and feed

Wherever possible, contaminated materials such as bedding, feedstuffs, and manure should be incinerated.

Anthrax contaminated feed can safely be fed once two weeks have passed since animals have been vaccinated; however, care should be taken to make sure no dust is produced i.e. do not use a bale shredder.