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Highly Pathogenic Avian Influenza identified in Idaho and Michigan dairy cattle

Officials from the U.S. Department of Agriculture Animal & Plant Health Inspection Service (USDA APHIS) announced today that they have also confirmed the presence of HPAI in a Michigan dairy herd that recently received cows from Texas. USDA APHIS also shared that they have presumptive positive samples from New Mexico, Idaho, Ohio, and Texas. 

According to the Idaho State Department of Agriculture, cattle from a facility in Idaho have tested positive for Highly Pathogenic Avian Influenza (HPAI).

HPAI historically infects birds but has been documented to infect mammals such as cats, skunks, and foxes. Based on the recent findings from Michigan the USDA announced the virus is very similar to the viruses found in Texas and Kansas and reported the virus appears to have been introduced by wild birds.

According to the Idaho State Department of Agriculture (ISDA), the virus may have been transmitted from cow to cow. This is based on the dairy recently importing cattle from another state that has had cattle test positive for HPAI. According to USDA, the Michigan herd with confirmed HPAI presence recently received cattle from Texas. USDA stated that cow-to-cow transmission cannot be ruled out.

Pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk. The U.S. Food and Drug Administration’s (FDA) longstanding position is that unpasteurized, raw milk can harbor dangerous microorganisms that can pose serious health risks to consumers. FDA is reminding consumers of the risks associated with raw milk consumption in light of the HPAI detections. 

USDA stated that initial testing has not found changes to the virus that would make it more transmissible to humans. While cases among humans in direct contact with infected animals are possible, this indicates that the current risk to the public remains low.

If you work directly with cattle that have tested positive or fit the case profile and experience flu-like symptoms, please consult your physician. Human cases of influenza must be confirmed with testing; they cannot be diagnosed based on symptoms alone.

USDA and federal agencies are moving quickly to conduct additional testing for HPAI and additional viral genome sequencing to better understand the situation, including characterization of the HPAI strain or strains associated with these detections.

Veterinarians working with potentially impacted farms should consult with state health officials and their diagnostic laboratories to ensure they follow established diagnostic sampling guidelines. 

At this time, impacted herds do not appear to be experiencing mortalities associated with this disease syndrome. In impacted herds, approximately 10% of cattle are affected, with most cases being mid to late-lactation mature cows. Impacted herds are experiencing approximately 10 to 20% reduction in milk production for a 14- to 21-day period. At this time, dry cows, fresh cows, heifers and calves do not appear to be affected. 

Cattle symptoms

  • Symptoms last between 10 and 14 days with the worst of the symptoms peaking in the first 3 to 5 days.
  • A sudden drop in milk production, with severe cases producing thicker, more concentrated milk that appears colostrum-like. 
  • A drop in feed intake and rumination activity. 
  • Mostly have tacky, dehydrated feces, but a small number have loose feces.
  • Can experience secondary infections including pneumonia and mastitis.

If you feel your herd’s symptoms are consistent with the reported illness consult with your herd veterinarian or the MN Board of Animal Health (https://www.bah.state.mn.us/) immediately. 

Follow biosecurity practices

Based on these cases, cattle (dairy and beef) owners are encouraged to follow recommended biosecurity practices for mitigating livestock and avian interaction including:

  • Minimize or eliminate (when possible) poultry and livestock species access to ponds, wetlands, and other stagnant water sources frequented by wild waterfowl (ducks, geese, swans).
  • Monitor cattle for signs of illness, this includes decreased milk production, decreased feed intake, fever, dry or tacky feces, and depression.
  • Monitor domestic poultry for illness, this includes reduced appetite, reduced water intake, and unexplained deaths.
  • Monitor cats, wild waterfowl, and wildlife that are frequently found around livestock facilities for illness or unexplained deaths.
  • Consider housing poultry separately from other livestock species and minimize poultry access to pasture areas that are grazed by other livestock species.
  • Minimize or eliminate (when possible) poultry, waterfowl, and wildlife access to potentially shared water sources and feedstuffs (e.g., cover and secure feed piles).

At this time, it is unclear if the illness can be spread from cow to cow or by inanimate objects such as vehicles or equipment. Cattle (dairy and beef) owners are encouraged to follow these biosecurity practices for livestock:

  • Limit visitors to your farm and consider having meetings away from the farm when possible.
  • Minimize the interaction of on-farm vehicle routes and off-farm vehicle routes.
  • Ensure equipment used to transport animals (i.e. trailers) is clean and washed between uses, this includes your trailers in addition to outside-hired transport. Inspect these trailers before use to ensure they have been cleaned.
  • Cattle transported to a new premise should be quarantined and isolated for 21 days to monitor for clinical signs before joining the herd.

Authors: Joe Armstrong, DVM, University of Minnesota Extension and Tim Goldsmith DVM, MPH, University of Minnesota College of Veterinary Medicine

Permission is granted to news media to republish our news articles with credit to University of Minnesota Extension. Images also may be republished; please check for specific photographer credits or limited use restrictions in the photo title.

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