States with HPAI-infected dairy cows grows to six

USDA provides guidance for veterinarians, producers on protecting cattle from the virus

A herd of dairy cattle in Ohio has been infected with highly pathogenic avian influenza (HPAI), increasing the number of states with dairy operations affected by the virus to six.

The Ohio Department of Agriculture (ODA) on April 3 announced it had received confirmation from the U.S. Department of Agriculture’s (USDA) National Veterinary Services Laboratory (NVSL) of HPAI infection in a dairy cattle herd in Wood County, Ohio.

The USDA previously confirmed the H5N1 strain of HPAI in dairy cattle on seven Texas farms, two in Kansas, and one each in New Mexico, Michigan, and Idaho.

Row of cows being milked in a dairy barn

The affected Ohio dairy operation reportedly received cows on March 8 from a Texas dairy that later reported a confirmed detection of HPAI. Ohio’s animal health officials were notified of this when the livestock began showing clinical signs consistent with those in sick, lactating dairy cows in other states.

Common clinical signs in affected cows have been reduced milk production and low appetite. Affected animals have recovered after isolation with little to no associated mortality reported.

Cats found with HPAI

Another new development in the ongoing HPAI outbreak is that three sick cats on one of the affected Texas farms have tested positive for the virus. Wild birds are the primary vector of the virus, which has been shown capable of infecting several species of mammals, including cats.

As previously reported, the viral strain found in Michigan, New Mexico, and Idaho cows is very similar to the strain confirmed in Texas and Kansas, according to the USDA, which appears to have been introduced by wild birds.

The Michigan dairy herd had recently received cows from Texas. The Idaho herd also had recently received cattle from another state with HPAI-infected cattle. Whether these imported cattle originated from infected herds is unclear. Spread of clinical signs among cows in the Michigan herd indicates that HPAI transmission between cattle cannot be ruled out.

Government response

Currently, the USDA’s Animal and Plant Health Inspection Service (APHIS) is not requiring dairy cattle to be tested for HPAI infection.

“This is a rapidly evolving situation and new information is being received, reviewed, and analyzed constantly to inform and adjust recommendations accordingly,” according to an APHIS guidance document on testing cattle for HPAI that was issued April 1. “Testing may be done on a voluntary basis and is a tool producers may use to help manage this disease or reduce the risk of introducing the disease.”

The following day, APHIS issued another series of HPAI-related recommendations, this time for state animal health officials, accredited veterinarians, and producers, addressing such areas as biosecurity, monitoring of sick animals, worker safety, and movement of cattle.

“At this time, USDA will not be issuing federal quarantine orders, nor is APHIS recommending any state regulatory quarantines or official hold orders on cattle,” the agency announced. “However, we strongly recommend minimizing movement of cattle as much as possible, with special attention to evaluating risk and factoring that risk into movement decisions. Do not move sick or exposed animals.”

If cattle must be moved, then APHIS strongly encourages “extreme diligence” by producers, veterinarians, and animal health officials to ensure only healthy cattle are moving and to ensure the validity of interstate health certificates.

APHIS recommends premovement testing of milk samples from lactating cows and nasal swabs for nonlactating cattle, preferably by polymerase chain reaction–based assays for Influenza A and H5 virus, at a National Animal Health Laboratory Network (NAHLN) laboratory for individual animals.

Additionally, APHIS encourages states and industry to use its established foreign animal disease investigation process to investigate credible reports of HPAI virus in dairy cattle, beef cattle, or other domestic livestock species.

For the most current information about highly pathogenic avian influenza, visit the AVMA website or the U.S. Department of Agriculture Animal and Plant Health Inspection Service’s news and announcements page.