Iowa State University College of Veterinary Medicine and Veterinary Diagnostic Laboratory has revealed that domestic cats died from Highly Pathogenic Avian Influenza A(H5N1) (bird flu) in Texas.

The research, which was released by the Centres for Disease Control and Prevention (CDC) on Monday, April 29, revealed that the domestic cats had consumed “contaminated” milk.

On March 21, milk, serum, and tissue samples from cattle located in affected dairies in Texas and two deceased cats from an affected Texas dairy farm, were received at the Iowa State University Veterinary Diagnostic Laboratory.

The milk from the affected cows had a thickened, creamy yellow appearance similar to colostrum. This tapered off within 10 to 14 days, and most animals were slowly returned to regular milking.

The cats were found dead with no apparent signs of injury, and were from a resident population of 24 domestic cats that had been fed milk from sick cows, according to ISUVDL.

Clinical disease in cows on the farm was first noted on March 16, the cats became sick on March 17, and several cats died in a cluster from March 19 to March 20.

Both of the cats that were received at ISUVDL were reported to have had microscopic lesions, with “severe systemic virus infection”.

The findings suggested to the ISUVDL that cross-species mammal-to-mammal transmission of bird flu virus was happening. This raises new concerns regarding the potential for virus spread within mammal populations.

The college showed that dairy cattle are susceptible to infection with avain influenza virus and can shed this virus in milk, therefore they are potentially transmitting infection to other mammals via “unpasteurized milk”.

Milk and tissue samples from cattle and tissue samples from the cats tested positive for influenza A virus (IAV) by screening PCR, which was confirmed and characterized as HPAI H5N1 virus by the US Department of Agriculture National Veterinary Services Laboratory.