#18,180
Colorado, which reported their first dairy-linked human HPAI H5 infection last week, has reported overnight the detection of 3 presumptive positive HPAI cases in poultry workers. Confirmatory tests are still awaited from the CDC (see statements below), but all 3 cases reported mild illness, respiratory symptoms, and conjunctivitis.
Colorado previously reported a single poultry-related HPAI H5 infection in 2022.
The CDC has sent - at the state's request - an investigative team. Based on anecdotal reports from veterinarians attending to infected herds, there have likely been more human infections that just the 4 reported up until yesterday, but testing wasn't done.
First official statements from the State of Colorado and the CDC, after which I'll have a brief update on the CDC's testing of Colorado's case from the first week of July.
Colorado state health officials identify possible cases of avian flu in Colorado poultry workers
The risk to the public remains low; all cases had direct contact with infected animals
Denver (July 12, 2024) — The Colorado Department of Public Health and Environment, in coordination with the Colorado Department of Agriculture and State Emergency Operations Center, has identified three presumptive positive cases of avian influenza in workers responding to the avian flu outbreak at a commercial egg layer operation. CDPHE’s State Public Health Laboratory sent the specimens generating the preliminary results to the Centers for Disease Control and Prevention for confirmatory testing. The workers were culling poultry at a farm in northeast Colorado and exhibited mild symptoms, including conjunctivitis (pink eye) and common respiratory infection symptoms. None of the individuals were hospitalized.
State public health officials have collected additional samples from symptomatic workers, which will be tested this weekend. State epidemiologists suspect the poultry workers’ cases are a result of working directly with infected poultry. The investigation is ongoing with support from CDC. On July 3, CDPHE identified a case of avian flu in a Colorado dairy worker.
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 cdphe.colorado.gov/animal-related-diseases/hpai-h5n1.
And this from the CDC.
Colorado Reports Three Presumptive Positive H5 Cases in Poultry Workers
CDC Standing by to Confirm Specimens, Sending Team to Support State Investigation
For Immediate Release: July 12, 2024Contact: Media Relations
(404) 639-3286
July 12, 2024 – The state of Colorado has announced that three people have tested presumptive positive for highly pathogenic avian influenza (HPAI) A(H5) (“H5 bird flu”) virus infection. Specimens have been sent to CDC for confirmatory testing. All of the people who tested presumptive positive experienced mild symptoms and were workers who were involved in the depopulation of poultry at a poultry facility experiencing an outbreak of the H5N1 virus that is circulating in wild birds and has been causing multistate outbreaks in dairy cows and poultry. At the state’s request, CDC is sending a team to Colorado to support their investigation, which is ongoing.
CDC’s current risk assessment for the general public remains low. As we learn more, we will continue to assess the situation and provide updates. These preliminary results again underscore the risk of exposure to infected animals. There are no signs of unexpected increases in flu activity otherwise in Colorado, or in other states affected by H5 bird flu outbreaks in cows and poultry.
Human infections with this novel influenza virus (and others) are concerning because of the potential to cause severe disease. The other reason these types of human infections are concerning is because of their pandemic potential. If these viruses were to change to spread easily from person-to-person, it could trigger a pandemic, though, to date, we have not seen genetic changes in the virus that would make it more likely to transmit between humans.
CDC’s recommendations related to H5 have not changed at this time. Findings from the investigation will inform whether guidance changes are needed. The investigation will include looking into compliance with the recommended use of personal protective equipment. Historically, most human cases of bird flu infection have happened in people who are not wearing recommended personal protective equipment. An analysis of the virus sequences from this outbreak also will be important to determine if a change in the risk assessment is warranted.
CDC Recommendations
- People should avoid close, long, or unprotected exposures to sick or dead animals, including wild birds, poultry, other domesticated birds, and other wild or domesticated animals (including cows).
- People should also avoid unprotected exposures to animal poop, bedding (litter), unpasteurized (“raw”) milk, or materials that have been touched by, or close to, birds or other animals with suspected or confirmed A(H5N1) virus.
- CDC has interim recommendations for prevention, monitoring, and public health investigations of A(H5N1) virus infections in people. CDC also has updated recommendations for worker protection and use of personal protective equipment (PPE). Following these recommendations is central to reducing a person’s risk and containing the overall public health risk.
The finding of additional presumed positive cases isn't unexpected, and more will likely be identified over time.
Late yesterday, in their weekly avian flu update (see CDC A(H5N1) Bird Flu Response Update, July 12, 2024) the CDC confirmed that they have been unable to fully sequence (and subtype) the sample collected from last week's H5N1 case in Colorado.
Among other activities previously reported in past spotlights and still ongoing, recent highlights of CDC's response to this include:Reporting that despite extensive efforts, CDC has been unable to sequence or isolate virus from the recent human case in Colorado. Attempts to sequence viral RNA from the Colorado case were unsuccessful most likely due to insufficient virus in the clinical sample. As a result, CDC has not been able to conclusively determine the neuraminidase (NA) subtype of the virus. Given that cows on the farm where the patient worked were confirmed positive for A(H5N1) virus infection, it is likely this was an N1 also, but that cannot be conclusively demonstrated. Virus isolation attempts in eggs and cells were similarly unsuccessful.
While disappointing, this is not that unusual.
Depending on severity of infection, the timing of collecting samples, and the collection methods used (see CDC Flyer on Conjunctival Swab Specimen Collection), sometimes there is insufficient virus to test completely.
Follow this link to read the rest of the CDC's weekly updates.
