Highly pathogenic avian influenza (HPAI) in cattle: Guidance for private veterinarians

The following guidance serves as a reference for private veterinarians to collect and submit samples for highly pathogenic avian influenza (HPAI) in dairy cattle, both for suspect and non-clinical animals. It also includes information on reporting requirements for suspect cases of HPAI in cattle.

On this page

• Checklist for sampling and testing for HPAI in cattle
• Clinical signs of HPAI in cattle
• Biosecurity
  • Guidance for participation in United States agricultural exhibitions to mitigate the risk of highly pathogenic avian influenza in Canadian cattle
• Collecting and submitting samples
• Laboratory testing fees
• Sampling guidance
  • Samples required for post-return testing of Canadian dairy cattle returning from U.S. shows or exhibitions
• CFIA's response to a suspect case report
• Results
• CFIA's response to a positive case
• Additional information
  • Transmission
  • Personal safety
• Appendix
• Related links

Checklist for sampling and testing for HPAI in cattle

• report suspicion to your local CFIA district office and province/territory when applicable (there is no reporting requirement when HPAI is not suspected)
• collect necessary samples which may include 1 or more of:
  • individual milk samples from lactating dairy cattle;
  • individual nasal swabs from non-lactating dairy cattle; or
  • a bulk tank milk sample.
• submit samples to an approved Canadian Animal Health Surveillance Network (CAHSN) laboratory; your district office can provide information on available CAHSN laboratories
• results are reported by your CAHSN lab
• non-negative results at a CAHSN lab will be sent to the CFIA's National Centre for Foreign Animal Disease for confirmatory testing
• for suspect case submissions, the private veterinarian is required to report negative test results back to the district office upon receipt

Clinical signs of HPAI in cattle

Clinical signs of HPAI infections that have been reported in dairy cattle in the U.S. include:

• decreased feed intake with a simultaneous decrease in rumination and rumen motility
• respiratory signs, including clear nasal discharge
• sudden and significant decrease in milk production
• colostrum-like consistency of milk in 1 or more quarters
• dry manure or diarrhea
• lethargy
• dehydration
• fever

Clinical signs in some cattle improve over 4 to 7 days, but some do not recover in milk production.

Veterinarians are required to contact their local CFIA district office and where required, the provincial or territorial Chief Veterinary Officer, if they highly suspect an HPAI infection in cattle. Criteria that contribute to a higher level of suspicion include:

• clinical presentation consistent with the signs described above, without an alternative diagnosis
• an epidemiological link with a confirmed infected animal or herd/flock
• recent introductions into the herd within the last 30 days
• the discovery of dead or neurologic animals on the premises (for example, wild birds, raccoons, cats)
• potential for feed or water contamination by infected animals (for example, wild birds or mammals)

Biosecurity

To prevent exposure and spread of HPAI in cattle, producers and veterinarians should continue to follow good biosecurity measures, such as those outlined in the National Biosecurity Standards (Animal biosecurity). Dairy producers are required to adhere to biosecurity plans outlined in Dairy Farmers of Canada's proAction program.

In addition to emphasizing the value of good routine biosecurity practices to their clients, veterinarians are encouraged to highlight the following:

• to prevent HPAI introduction onto a farm:
  • avoid bringing new animals onto the farm
  • if new animals must be added to a herd, or if animals have had contact with animals from other herds (for example returning from a show or sale yard), it is recommended to:
    • test cattle within 7 days prior to moving into the herd whenever possible
    • isolate new animals entering the herd for a minimum of 14 days
    • monitor the entire herd for clinical signs of HPAI
    • re-test individual animals, as well as test the bulk tank between 14 and 21 days after isolation began
    • release animals from isolation after all negative test results are received
    • test the bulk tank 30 days after re-integration of the new/returning animals
  • completely clean and disinfect the livestock trailer if moving cattle from other herds
  • minimize and restrict wildlife access to cattle and their environment including feed and water sources
• in addition to the list above, for herds where HPAI is suspected in cattle:
  • take personal safety precautions as outlined above
  • re-enforce good milking practices, such as equipment disinfection and milking sick or new cattle separately or last
  • isolate sick cattle from the herd
  • avoid housing multiple species together; where other species are kept on the same premises, particularly birds or pigs, emphasize the need for heightened biosecurity measures between different species on the farm
  • limit animal movements as much as possible within and off the farm
  • do not consume raw milk or feed it to other animals on farm

For further information on biosecurity practices to keep livestock safe, contact your provincial or territorial Chief Veterinary Officer.

Guidance for participation in United States agricultural exhibitions to mitigate the risk of highly pathogenic avian influenza in Canadian cattle

Due to the presence of HPAI (H5N1) in the United States dairy cattle population, the CFIA advises against all Canadian cattle travelling to and participating in agricultural exhibitions in the U.S. at this time. For more information, read the advisory.

Collecting and submitting samples

Private veterinarians are responsible for sample collection both for suspect cases and in cattle with no clinical signs.

Private veterinarians may send samples to a CAHSN laboratory that is approved to test samples in domestic animals. These are the same laboratories that have been testing poultry samples during the current H5N1 HPAI outbreak. For more information on approved CAHSN laboratories, contact your local CFIA district office.

Laboratory testing fees

Until further notice, CFIA will cover the fees for laboratory testing at any CAHSN laboratory that is approved to test samples in domestic animals. CFIA does not pay for associated veterinary fees for sample collection or shipment to the lab.

Sampling guidance

Samples may be submitted from lactating dairy cows and non-lactating dairy cattle (dairy calves, heifers and dry cows), when HPAI is suspected or from non-clinical animals for enhanced biosecurity purposes.

When HPAI is suspected, include samples from up to 10 clinically affected animals. A bulk tank milk sample may also be collected and submitted for testing.

Samples must be refrigerated until they are submitted to the lab. Each sample must be individually labelled with the animal identification number. If a bulk tank sample is submitted for testing, identify it as such.

Lactating dairy cattle

Milk is the only sample required for lactating dairy cattle. Cows shed the highest level of virus in their milk, which makes milk the ideal sample to test.

Individual cow sample

When sampling individual lactating cattle, clean the udder and be sure to remove any visible debris. Collect up to 10 mls total sample volume from all 4 quarters into a plastic specimen container with a secure lid (for example, screwed).

Bulk tank milk sample

When sampling the bulk tank, agitate the tank for 5 minutes before taking any samples. Collect 10 mls of milk from the bulk tank into a plastic specimen container with a secure lid (for example, screwed).

Non-lactating dairy cattle

Nasal swabs are the only sample required for non-lactating dairy cattle.

Use a single sterile swab (synthetic fibre swabs only) to sample both nostrils. Ensure the mucosa in the nasal passage is brushed firmly with the swab. After both nasal passages have been sampled, gently agitate the swab in the Universal Transport Medium (UTM). Do not leave the swab in the UTM but instead swirl the swab into the UTM tube and thoroughly squeeze out the fluid against the side of the tube. Discard the swab.

Samples required for post-return testing of Canadian dairy cattle returning from U.S. shows or exhibitions

For herds in which dairy cattle have returned from a U.S. show or exhibition, collect the following samples between 14 and 21 days following return of the animals, and share the results of the tests with your local CFIA district office:

1. individual animal samples for dairy cattle that have been in the U.S.
   1. milk sample for lactating animals; or
   2. nasal swab for non-lactating animals; and
2. bulk tank milk sample

CFIA's response to a suspect case report

When a suspect case is reported to a CFIA district office, CFIA staff will collect basic information, including premises location, species/signalment/history of suspect animal(s), presence of other livestock species on the premises and reason for HPAI suspicion. CFIA may share this information with the Chief Veterinary Officer in your province or territory.

CFIA staff will provide guidance on sampling and information on where to submit samples for testing.

For the most up-to-date information on HPAI in livestock in Canada, refer to Highly pathogenic avian influenza (HPAI) in livestock.

Results

Results are reported back to the submitting veterinarian by the CAHSN lab. For suspect case submissions, the private veterinarian is required to report negative test results back to the district office upon receipt. There is no requirement to report negative results to CFIA for samples that were not originally submitted as a suspect case. Samples returning non-negative results are forwarded to the CFIA's National Centre for Foreign Animal Disease for confirmatory testing. Notification to the submitting veterinarian may be delayed until confirmatory testing is complete.

Understanding negative test results

The HPAI screening test is a PCR (polymerase chain reaction). A negative test indicates no detection of influenza A virus in the sample. A negative test on a cow with no clinical signs typically means no HPAI infection.

Rarely, a false negative result occurs when the cow is infected, but HPAI is not detected by the test. Possible causes may include poor sampling technique, or if the cow is not yet shedding high levels of HPAI virus, for instance if the cow was infected very recently.

CFIA's response to a positive case

CFIA's response to detections of HPAI in cattle differs from the role CFIA plays for HPAI detections in domestic birds. Currently, CFIA's role for HPAI in cattle means that CFIA will set national objectives for the response to HPAI in dairy cattle and will work collaboratively with provincial authorities to achieve these objectives. In addition, the CFIA continues to provide scientific advice, diagnostic support, and international reporting related to HPAI.

Together with the provinces, territories and industry, the CFIA works to reduce the risk of HPAI transmission from an affected farm to other premises by requiring that:

• personal safety and on-farm biosecurity measures are observed
• cattle movement (particularly lactating cattle) onto and off the premises is stopped or limited until the herd has been cleared from the disease
• all milk from clinically affected animals does not enter the bulk tank and undergoes an inactivation process if being fed to other animals, or is appropriately discarded
• all milk from the bulk tank goes for pasteurization
• epidemiological information pertaining to the infected herd is collected
• local public health authorities are involved to further assess any potential human health risk

For more information about the response in your area, contact your provincial or territorial Chief Veterinary Officer.

The CFIA will continue to reassess its position as new information becomes available.

Additional information

Transmission

Epidemiologic and genomic analysis suggests a single spillover event from wild birds with subsequent cow-to-cow transmission. Evidence suggests cow-to-cow transmission may occur through milk via fomites. However, other means of transmission are being considered. Non-clinical animals can also shed the virus in their milk, indicating that testing lactating animals prior to movement is valuable in reducing between-farm disease transmission risk. Many herds infected with HPAI have a history of introduction of new animals from an affected area or herd.

The United States Department of Agriculture (USDA) reports transmission from affected dairy herds to nearby poultry flocks based on epidemiologic and genomic analysis. Transmission is suspected to be via fomites (humans and/or equipment).

Personal safety

Avian influenza viruses, such as the highly pathogenic A(H5N1) currently circulating in wild birds in Canada, can, on rare occasions, cause disease in humans. Canada has never reported a locally acquired case of HPAI A(H5N1) in a person and the risk of avian influenza transmission to humans remains low.

People in contact with animals, including cattle and animal products, suspected or confirmed to be infected with avian influenza, or those exposed to highly contaminated environments, should take extra precautions to protect themselves by wearing personal protective equipment (PPE). This includes face masks, non-ventilated goggles, gloves, coveralls and boots. Boots, coveralls and other reusable PPE should be fully cleaned and disinfected between farms. Disposable gloves and face masks should be discarded on farm in a sealed bag.

The Public Health Agency of Canada's (PHAC) website has more information for people in contact with potentially infected animals or heavily contaminated environments: Infection prevention recommendations for individuals involved in animal outbreak situations.

Additionally, PHAC has partnered with the Canadian Centre for Occupational Health and Safety to provide advice on how to protect against avian influenza at work. For more information, please visit Protecting yourself from avian influenza A(H5N1) in dairy cattle.

Additional information on avian influenza A (H5N1) in people is available from the Public Health Agency of Canada.

Appendix – Provincial and territorial reporting requirements and contact information

Provinces and territories where HPAI in cattle is a reporting requirement

Provinces and territories where HPAI in cattle is not a reporting requirement

Related links

• Advisory: Guidance and precautions for participation in United States agricultural exhibitions to mitigate the risk of highly pathogenic avian influenza in Canadian cattle - inspection.canada.ca
• Canadian Animal Health Surveillance System – Dairy
• Animal Health Canada Update – US Detections of H5N1 in Dairy Cattle
• Canadian Association of Bovine Practitioners
• World Organisation for Animal Health
• Canadian Wildlife Health Cooperative
• Highly pathogenic avian influenza (HPAI) in livestock
• Public Health Agency of Canada – Guidance on human health issues related to avian influenza in Canada (HHAI)
• United States Department of Agriculture – Highly Pathogenic Avian Influenza (HPAI) Detections in Livestock