Bird flu virus

Highly Pathogenic Avian Influenza (HPAI) is a highly contagious and often deadly disease in birds, caused by certain strains of avian influenza viruses, specifically types A (H5) and A (H7). Commonly known as bird flu, this illness can spread rapidly among domestic poultry and other bird and animal species, primarily transmitted by wild birds. While bird flu viruses typically don’t infect humans, isolated cases of human infections have been reported. It’s crucial to understand that the term “highly pathogenic” refers to the severe impact the virus has on birds rather than on humans.

The FDA is sharing additional findings from our ongoing national commercial milk sampling study conducted in collaboration with USDA. We’ve analyzed 297 retail dairy samples in total. Our latest preliminary results from egg inoculation tests conducted on a second batch of 201 retail dairy samples, which include cottage cheese and sour cream alongside fluid milk, indicate that pasteurization effectively deactivates Highly Pathogenic Avian Influenza (HPAI).

In this recent round of testing, we found no evidence of live, infectious virus.

Building on previous findings released last week concerning an initial set of 96 retail milk samples, these results confirm our belief that the commercial milk supply remains safe.

In our commitment to safeguarding milk-derived products for infants and young children, we’ve also examined samples of retail powdered infant formula and powdered milk marketed as toddler formula. All test results using quantitative polymerase chain reaction (qPCR) were negative, indicating no presence of HPAI viral fragments or virus in these powdered formula products, thus eliminating the need for further testing on these samples. The FDA continues to identify other products for potential testing.

Furthermore, we’re conducting ongoing tests on pooled raw milk destined for pasteurization and commercial processing. This data will help us understand the virus levels pasteurization may encounter and guide further validation studies.

As we monitor developments, the FDA will stay abreast of scientific research on the effectiveness of pasteurization against HPAI in bovine milk. We’re dedicated to continuous surveillance of milk production, processing, and pasteurization to uphold milk supply safety. Collaboration with state partners remains essential, and we’re actively engaged with them. Our collaboration with state co-regulators on managing this emerging disease continues as well.

The FDA reiterates its strong recommendation against consuming raw milk and advises the industry against manufacturing or selling raw milk or its products.

The FDA has received additional findings from an initial targeted set of samples as part of its national commercial milk sampling study, conducted in collaboration with USDA. While the FDA is still analyzing this data, early results from egg inoculation tests on quantitative polymerase chain reaction (qPCR)-positive retail milk samples indicate that pasteurization successfully deactivates Highly Pathogenic Avian Influenza (HPAI).

No live, infectious virus was detected in this additional testing. These results reinforce our confidence in the safety of the commercial milk supply.

Furthermore, several samples of retail powdered infant formula and powdered milk products marketed as toddler formula were examined. All qPCR results from these formula tests were negative, indicating no presence of viral fragments or virus in powdered formula products.

The FDA is continuing its assessment of retail samples from the broader study, which includes 297 samples of retail dairy products from 38 states. Samples that tested positive via PCR are undergoing egg inoculation tests, considered the gold standard for identifying the presence of infectious virus. These efforts are ongoing, and we remain dedicated to promptly sharing further testing outcomes. Subsequent results will contribute to our ongoing evaluation of the effectiveness of pasteurization against this virus and the safety of the commercial milk supply.

Epidemiological data from our CDC partners continue to indicate no increase in human flu cases and no instances of H5N1, specifically, apart from the single known case linked to direct contact with infected cattle.

On April 25, 2024, the FDA received initial findings from its nationally representative commercial milk sampling study. While the agency is still reviewing this data, early results indicate that approximately 1 in 5 of the retail samples tested positive for HPAI viral fragments via quantitative polymerase chain reaction (qPCR). Notably, a higher proportion of positive results originated from milk sourced in regions with infected herds. It’s essential to clarify that qPCR-positive results do not necessarily indicate the presence of actual infectious virus that poses a risk to consumers. Further testing is imperative to ascertain if intact pathogen is still present and if it remains capable of causing illness, which would aid in determining any potential risk associated with consuming the product.

The FDA is conducting additional assessments on positive findings through egg inoculation tests, regarded as the gold standard for detecting infectious virus. Preliminary findings from NIH-funded investigators suggest the absence of infectious virus in their studies of retail milk. Thus far, the retail milk studies have not yielded any results that alter our assessment of the safety of the commercial milk supply.

Epidemiological data from our partners at the CDC continue to indicate no increase in human flu cases, including no instances of H5N1 beyond the single known case linked to direct contact with infected cattle.

These ongoing efforts are critical, and we are committed to promptly sharing results from both the qPCR and egg inoculation tests as they become available.