#18,197
Late yesterday the CDC announced the confirmation of the (previously known) 5th and an additional 6th human H5 infection from the poultry farm in Weld County, Colorado. This brings the total number of H5 infections in the United States since March of this year to 10.
This report comes on the heels of the report of a second large poultry farm in Weld County testing positive for H5N1 (see CIDRAP report H5N1 strikes another large layer farm in Colorado), and on the eve of the start of the Weld Country Fair (Jul 20th-29th).
First the brief announcement from the Colorado Health Department.
State health officials provide updated data on human cases of avian flu in poultry workers
Workers were culling poultry at a farm in northeast Colorado
Denver (July 19, 2024) — In coordination with the Colorado Department of Agriculture, the State Emergency Operations Center, and Centers for Disease Control and Prevention, the Colorado Department of Public Health and Environment reports an additional confirmed human case of avian flu, bringing the total to six confirmed human cases of avian flu in people who were working directly with infected poultry at a commercial egg layer operation in Weld County.
The workers, who were culling poultry, had mild symptoms, including conjunctivitis (pink eye) and common respiratory infection symptoms. None were hospitalized. CDC continues to state that the risk of avian flu to the general public is low. Epidemiologists both here in Colorado and at CDC are monitoring for genetic variations in the virus and changes in transmission patterns.
It is safe to eat properly handled and cooked poultry products. The proper handling and cooking of poultry, meat, and eggs kills bacteria and viruses, including avian flu viruses.
If you work with dairy cows or poultry that may have avian flu and you start to feel sick, seek medical care or call CDPHE at 303-692-2700 (after normal business hours: 303-370-9395). The Department can help you get a flu test and medicine if needed. More information about avian flu in humans is available at https://cdphe.colorado.gov/animal-related-diseases/hpai-h5n1.
The CDC's announcement was published in their weekly avian flu update.
CDC Update
July 19, 2024 – CDC continues to respond to the public health challenge posed by a multistate outbreak of avian influenza A(H5N1) virus, or “H5N1 bird flu,” in dairy cows, poultry and other animals in the United States. CDC is working in collaboration with the U.S. Department of Agriculture (USDA), the Food and Drug Administration (FDA), Administration for Strategic Preparedness and Response (ASPR), state public health and animal health officials, and other partners using a One Health approach.Since April 2024, 10 human cases of avian influenza A(H5) infection have been reported in the United States. Four of these cases were associated with exposure to sick dairy cows and six were associated with exposure to H5N1-infected poultry.* [A][B]This includes two additional cases in Colorado that were confirmed by CDC this week and not previously reported. The two new cases were in poultry workers with exposure to infected poultry during depopulation and disposal activities. Similar to previous cases, illness was mild.Based on the information available at this time, CDC’s current H5N1 bird flu human health risk assessment for the U.S. general public remains low.
On the animal health side, USDA is reporting that 157 dairy cow herds in 13 U.S. states have confirmed cases of avian influenza A(H5N1) virus infections in dairy cows as the number of infected herds continues to grow. USDA reports that since April 2024, there have been A(H5) detections in 34 commercial flocks and 16 backyard flocks, for a total of 18.32 million birds affected.
We continue to get more reassurance than details from federal agencies, although it is unclear how much of that is due to difficulties getting information and/or cooperation from local entities.
Genetic sequences continue to be deposited belatedly, and are often missing critical meta-data (see GISAID comment below), making independent analysis difficult.
This collection includes many virus sequences from dairy cows, but also closely related viruses detected in poultry and wild birds and in mice, cats and other mammals as well as the recent human infections. Although metadata such as sampling date and location are unfortunately missing from recent datasets, the available data allow a close watch on mutations that may arise as a consequence of virus adaptation to new hosts.
Unknown is how the bovine B3.13 genotype has managed to spillover into poultry, and whether it is now spreading via wild birds.
Other than reporting that PPE use by poultry workers was `not optimal' (blamed on excessive heat and fans inside barns), we've seen little in the way of epidemiological data (not even onset dates) on these cases.
For now, HPAI H5N1 appears to lack the ability to spark a human pandemic, but that happy state of affairs could literally change overnight. Unfortunately, we continue to treat HPAI as more of an economic or political problem, than a true public health concern.
A risky strategy that may work in the short term, but has the potential to end very badly.
