Highly Pathogenic Avian Influenza (HPAI) H5N1 Virus in Livestock

Information about HPAI in dairy cattle is an evolving, fluid situation with ongoing research and policy development. Please check back frequently as the information below will be updated as it becomes available.

Bovine Health Alert

September 17, 2024: Highly Pathogenic Avian Influenza (HPAI) Confirmed in Two Additional Dairies in California

SACRAMENTO, CA – Following an investigation by the California Department of Food and Agriculture (CDFA) and rapid disease detection by California Animal Health and Food Safety Laboratory System (CAHFS), the U.S. Department of Agriculture’s (USDA) National Veterinary Services Laboratories (NVSL) has confirmed highly pathogenic avian influenza (HPAI) in two (2) new dairies, for a total of ten (10) affected dairies in the Central California. The two new HPAI-confirmed dairies were in a group targeted for testing due to elevated risks from their recent connections with the initial affected premises. These recent findings are not unexpected and support CDFA’s implementation of current surveillance strategies with the goal of finding affected farms as early as possible. Early detection provides the opportunity to work with farms to quickly implement enhanced biosecurity, cow care, and employee protection.

This nationwide outbreak of HPAI H5N1 began in poultry in 2022 and was first detected in US dairy cattle in March 2024. All national detections in cattle can be found on the USDA website under: HPAI Confirmed Cases in Livestock | Animal and Plant Health Inspection Service (usda.gov). Note that the website is updated at noon Eastern Standard Time.

All affected dairies have been placed under quarantine. Enhanced biosecurity measures are in place to prevent the spread of the virus. Sick cows are isolated and being treated at the dairies. Most infected livestock and dairy cattle can fully recover from HPAI infection within a few weeks.

California's supply of milk and dairy foods is safe and has not been impacted by these events. Healthy cows have been cleared to continue shipping milk for pasteurization. Pasteurization of milk is fully effective at inactivating the virus, so there is no cause for concern for consumers of milk or dairy products that have undergone this process. Pasteurized milk and dairy items, as well as properly handled meat and eggs, continue to be safe to consume.

No human cases of HPAI related to this incident have been confirmed in California. According to the California Department of Public Health (CDPH) and the Centers for Disease Control (CDC), this influenza virus is not considered a significant public health threat, and the risk to humans continue to be considered low.

Stay Informed:
For the most up-to-date information regarding highly pathogenic avian influenza (HPAI) in livestock in California, please visit CDFA - AHFSS - AHB - Highly Pathogenic Avian Influenza (HPAI) H5N1 Virus in Livestock.

For public inquiries regarding highly pathogenic avian influenza in California, please send an e-mail to cdfa.HPAIinfo@cdfa.ca.gov or call 916-217-7517. For media inquiries, please call 916-654-0462 or send an e-mail to OfficeOfPublicAffairs@cdfa.ca.gov.

September 12, 2024: Highly Pathogenic Avian Influenza (HPAI) Confirmed in Two Additional Dairies in California

SACRAMENTO, CA – Following an investigation by the California Department of Food and Agriculture (CDFA) and rapid disease detection by California Animal Health and Food Safety Laboratory System (CAHFS), the U.S. Department of Agriculture’s National Veterinary Services Laboratories (NVSL) has confirmed highly pathogenic avian influenza (HPAI) in two (2) new dairies, for a total of eight (8) affected dairies in the Central Valley of California. The two (2) dairies, in addition to the last three (dairies) confirmed for HPAI, were in a group targeted for testing due to elevated risks from their recent connections with the initial affected premises. These recent findings are not unexpected and support CDFA’s implementation of current surveillance strategies with the goal of finding affected farms as early as possible. This provides the opportunity to work with farms to quickly implement enhanced biosecurity, cow care, and employee protection.

All affected dairies have been placed under quarantine and enhanced biosecurity measures are in place to prevent the spread of the virus. Sick cows are isolated and are being treated at the dairies. Most infected livestock and dairy cattle can fully recover from HPAI infection within a few weeks.

California's supply of milk and dairy foods is safe and has not been impacted by these events. Healthy cows have been cleared to continue shipping milk for pasteurization. Pasteurization of milk is fully effective at inactivating the virus so, there is no cause for concern for consumers from milk or dairy products. Pasteurized milk and dairy items, as well as properly handled meat and eggs, continue to be safe to consume.

No human cases of HPAI have been confirmed in California related to this incident. According to the California Department of Public Health (CDPH) and the Centers for Disease Control (CDC), this influenza virus is not considered a significant public health threat and the risk to humans is considered to be low.

September 11, 2024: Highly Pathogenic Avian Influenza (HPAI) Confirmed in Three Additional Dairies in California

SACRAMENTO, CA — Following an investigation by the California Department of Food and Agriculture (CDFA) and rapid disease detection by California Animal Health and Food Safety Laboratory System (CAHFS), the U.S. Department of Agriculture’s National Veterinary Services Laboratories (NVSL) has confirmed highly pathogenic avian influenza (HPAI) in three new dairies in the Central Valley of California. These dairies were in a group targeted for testing due to elevated risks from their recent connections with the initial affected premises. These findings are not unexpected and support CDFA’s implementation of current surveillance strategies with the goal of finding affected farms as early as possible. This provides the opportunity to work with farms to quickly implement enhanced biosecurity, cow care, and employee protection.

California's supply of milk and dairy foods is safe and has not been impacted by these events. Healthy cows have been cleared to continue shipping milk for pasteurization. Pasteurization of milk is fully effective at inactivating the virus so, there is no cause for concern for consumers from milk or dairy products. Pasteurized milk and dairy items, as well as properly handled meat and eggs, continue to be safe to consume.

HIGHLY PATHOGENIC AVIAN INFLUENZA (HPAI) CONFIRMED IN THREE CALIFORNIA DAIRY HERDS

Three Central Valley farms quarantined; no human cases detected; no threat to the milk and food supply

SACRAMENTO, August 30, 2024 – Cows at three California dairies located in the Central Valley have tested positive for highly pathogenic avian influenza (HPAI). When the herds began showing clinical signs consistent with HPAI on August 23-25, 2024, samples from these three sites were submitted to our California Animal Health and Food Safety (CAHFS) laboratory network for preliminary determination, then submitted to the National Veterinary Services Laboratory (NVSL), where the test results were confirmed today.

No human cases of HPAI have been confirmed in California related to this incident. The California Department of Health (CDPH) will provide official confirmation of any human cases associated with this incident.

"We have been preparing for this eventuality since earlier this year when HPAI detections were confirmed at dairy farms in other states," said CDFA Secretary Karen Ross. "Our extensive experience with HPAI in poultry has given us ample preparation and expertise to address this incident, with workers' health and public health as our top priorities."

According to CDPH and the Centers for Disease Control (CDC), this influenza virus is not considered a significant public health threat and the risk to humans is considered to be low. The primary concern is for dairy workers who come into close contact with infected dairy cows. As we have learned from recent cases in other states, these workers may be at risk of contracting avian influenza. The CDC has confirmed four human cases of HPAI in dairy workers in other states since April 2024: one each in Texas and Colorado, and two in Michigan. CDFA is working with public health officials and dairy owners to inform and monitor workers at the affected dairies in California, and to assist the dairies with providing personal protective equipment.

California’s supply of milk and dairy foods is safe and has not been impacted by these events. As a precaution, and according to longstanding state and federal requirements, milk from sick cows is not permitted in the public milk supply. Also, pasteurization of milk is fully effective at inactivating the virus, so there is no cause for concern for consumers from milk or dairy products. Pasteurized milk and dairy items, as well as properly handled meat and eggs, continue to be safe to consume.

The detection of HPAI in cattle is by no means unexpected. The HPAI virus has been detected in North American wild birds in the U.S. since 2022, with occasional transmission into domestic poultry or wild mammals in almost all states, including California. In March, 2024, the first US detection in cattle was confirmed in Texas, most likely due to a single spillover event from wild birds. Since that time, the USDA has linked new detections in cattle to the interstate and regional movement of infected or contaminated livestock, people, and equipment.

The affected dairies have been placed under quarantine on the authority of CDFA’s State Veterinarian, and enhanced biosecurity measures are in place. Sick cows are isolated and are being treated at the dairies; healthy cows have been cleared to continue shipping milk for pasteurization. Animal movement is being tracked and evaluated, as are other potential introduction pathways. Additional testing will be prioritized according to epidemiologic risk. CDFA's preliminary investigation has confirmed that cows have been moved among these dairies recently. The investigation and response are ongoing.

Background on HPAI in California

CDFA has been engaged for years now with an extensive network of private veterinarians, farmers and ranchers, backyard bird enthusiasts, and local, state and federal partners to actively monitor for this disease in livestock and poultry throughout California. The department has taken steps to reduce the risk of entry of infected dairy cattle into the state, has extensive experience responding quickly and effectively to past detections of HPAI in poultry, and is fully prepared to respond to detections in cattle.

Most infected livestock and dairy cattle are able to fully recover from an HPAI infection within a few weeks. As we are seeing with this current incident, dairy herds can show clinical signs of infection such as reduced milk production; thicker, concentrated, colostrum‐like milk; a decrease in feed consumption; abnormal, tacky or loose feces; lethargy; dehydration; and fever.

No California domestic poultry flocks are affected by the current incident. Avian influenza viruses continue to circulate normally among migratory and wild birds. Monitoring of both wild and domestic bird populations is performed on a continuous basis by multiple public agencies, as well as farmers and ranchers and private bird owners.

At the federal level, USDA has implemented or expanded a number of programs to support affected dairy premises. These include the Dairy Herd Status Program and financial assistance for the heat treatment and disposal of milk, veterinary costs, personal protective equipment (PPE), milk loss offset via the Emergency Livestock Assistance Program (ELAP), biosecurity planning and implementation, as well as shipping cost offset for H5N1 testing. Information about all US detections in cattle can be found on the USDA website under: HPAI in Livestock | Animal and Plant Health Inspection Service (usda.gov).

For the most up-to-date information regarding highly pathogenic avian influenza (HPAI) in livestock in California, please visit CDFA - AHFSS - AHB - Highly Pathogenic Avian Influenza (HPAI) H5N1 Virus in Livestock.

Media Contact:
Steve Lyle, CDFA, 916-654-0462, officeofpublicaffairs@cdfa.ca.gov

H5N1 HPAI in CA Dairy Cow Q & A 2024 (9/3/2024)

Current HPAI H5N1 in Livestock Guidance For California Producers

Clinical Signs

Infected cattle may be asymptomatic (subclinical) or symptomatic (clinical) and virus is predominantly found in milk and mammary tissue regardless of symptoms.

Clinical signs may include:

Decrease in feed consumption with a simultaneous decrease in rumination and rumen motility
Respiratory signs including clear nasal discharge
Acute drop in milk production. Severely affected cattle may have thicker, concentrated, colostrum-like milk or produce no milk at all.
Abnormal tacky or loose feces
Lethargy
Dehydration
Fever

Sampling Protocol for HPAI in Livestock

Protocol for cows with clinical signs of HPAI
1. For dairies with suspect clinical signs contact your district office for regulatory personnel to conduct a Foreign Animal Disease investigation (FADi).
Protocol for lactating dairy cattle moving interstate (not direct to slaughter movements)
1. All lactating dairy cattle moving interstate require a Certificate of Veterinary Inspection (CVI) and matrix-A negative HPAI test from a National Animal Health Laboratory Network (NALHN) laboratory within seven (7) days of movement.
2. Samples must be collected by an accredited veterinarian, a sample collector approved by a state animal health official, or a designated individual at a farm that was trained to collect milk and nasal swab samples.
3. The sample must be sent to an approved NAHLN laboratory (UC Davis California Animal Health and Food Safety (CAHFS) Laboratory is currently only approved laboratory in California)
4. For groups/lots of 30 or fewer animals moving interstate, all animals being moved must be tested. If more than 30 animals are moving interstate, only 30 animals total must be tested.
Protocol for non-lactating dairy cattle moving interstate and any dairy cattle moving interstate direct to slaughter:
1. Currently no testing required, must have CVI within seven (7) days of movement.

California Movement Restrictions and Interstate Movement Requirements for Dairy Cattle

All dairy breed cattle originating from Highly Pathogenic Avian Influenza (H5N1) affected state(s): Must be accompanied by a Certificate of Veterinary Inspection (CVI) and signed by an accredited veterinarian within seven (7) days of transport that includes the following statement: "All animals identified on this Certificate of Veterinary Inspection (CVI) have been inspected within seven (7) days and do not originate from a premises with a confirmed detection of Highly Pathogenic Avian Influenza (H5N1) or that is currently under investigation as a suspect premises."

All lactating dairy cattle moving interstate require a CVI and matrix-A negative HPAI test from a NALHN laboratory within seven (7) days of movement, in addition to any state-specific entry requirements of destination state.
Dairy cattle moving interstate direct to slaughter are exempt from the test requirement but do require a CVI or a state-approved owner shipper statement and Premises ID (NPIN), in addition to any state-specific entry requirements of destination state.
Lactating dairy cattle from herds which have tested positive for Influenza A are not eligible for interstate movement for thirty (30) days from the most recent collection of any sample that tests positive from any individual animal in the herd. Re-testing may occur after this 30-day period.
Lactating dairy cattle with clinical signs consistent with HPAI in dairy cattle are ineligible for interstate movement (including to slaughter) as per 9 C.F.R. 71.3(b).

Recommended Biosecurity Measures for Livestock Operations

CDFA strongly encourages dairy farms and processors to:

Review biosecurity protocols, including industry biosecurity resources such as those that may be found on the CDFA website for the Secure Food Supply Program, as well as the resources that can be found on the FARM/NMPF Everyday Biosecurity manual (Biosecurity - National Dairy FARM Program) and the Secure Milk Supply website (Secure Milk Supply Plan).
Continue to be vigilant to observe for clinical signs consistent with this outbreak such as acute loss of animal appetite and rumination; significant/acute drop in milk; changes in manure consistency.
Contact your herd veterinarian if you observe animal conditions outside of the ordinary. This has not currently been reported in California, but it is a reminder to enforce biosecurity on your dairy operation or when visiting other dairy operations.

Disease Spread

The primary introduction of disease into dairy herds has been predominantly via exposure to wild birds. The exact mechanism of spread is currently unknown, although there is potential for viral spread through milk. USDA has identified spread between cows within the same herd, spread from cows to poultry, spread between dairies associated with cattle movements, and cows without clinical signs that have tested positive. On April 16, APHIS microbiologists identified a shift in an H5N1 sample from a cow in Kansas that could indicate that the virus has an adaptation to mammals.

Diagnosis & Prevention

There is no specific treatment or cure for animals infected with HPAI H5N1 and there are currently no vaccines available to prevent this disease. Veterinarians and livestock owners who suspect an animal may have Highly Pathogenic Avian Influenza (HPAI) H5N1 should immediately contact a State or Federal animal health authority.

Testing for HPAI H5N1 in milk samples (lactating cattle) or nasal swab samples (non-lactating cattle) can confirm HPAI H5N1 viral infections.

Even with the best defense measures, HPAI H5N1 can still affect your herd. The following are ways to help protect livestock:

No movement of clinical dairy cattle for 30 days past last matrix-A positive HPAI test
Ensure cattle trailers are only used to haul your cattle or thoroughly clean and disinfect trailers between use.
Adhere to an isolation period of a minimum of 30 days for new arrivals with active observational surveillance for clinical signs.
Feed only heat treated/pasteurized milk to calves and other livestock and heat treat/pasteurize any milk being discarded.
Milk affected animals last with thorough cleaning and disinfection of milking equipment (utilizing dedicated milking units if possible)
Separate animals with clinical signs from healthy animals
Use dedicated coveralls and boots when handling clinical animals (use dedicated farm personnel to only handle clinical animals where possible).
Use good personal hygiene measures including freshly laundered clothes and showering before visiting dairy farms or processing facilities.
Limit vehicle/visitor traffic to strictly essential deliveries/visits (feed, milk, waste removal).
Clean and disinfect vehicles crossing the line of separation and entering/leaving the farm or obtain a commercial car wash before and after visiting a livestock operation.
Engage state and federal wildlife agencies for wild bird mitigation.

CDFA appreciates your efforts to protect livestock health in California on a daily basis. Remember, people, equipment, and vehicles can easily spread dangerous diseases from one location to another.