Avian Flu Detected in Maricopa County Wastewater Sampling Sites

As part of routine wastewater surveillance in Maricopa County, Maricopa County Department of Public Health (MCDPH) is reporting the detection of an influenza subtype associated with avian flu in local wastewater. No human cases of avian flu have been detected in Maricopa County, and the risk to the general population remains low.

Wastewater monitoring is a tool used to detect genetic material from microbes, like influenza A and its subtypes, in untreated wastewater, helping inform public health and partners on changing disease activity. The influenza A(H5) subtype, which can include H5N1 that is associated with avian influenza (also known as bird flu), was detected by all three cities within Maricopa County that conduct wastewater monitoring—Phoenix, Surprise, and Tempe—but it is not currently possible to confirm a precise source location of the viral detection.

Avian influenza has been detected in Arizona, including a commercial poultry farm in Pinal County, and a backyard flock and animals at a zoo in Maricopa County. The H5N1 detections in Pinal and Maricopa counties where further genomic testing was done are the same strain of H5N1 that is occurring in wild birds. Tests with other samples are pending. The same strain-specific testing in wastewater samples is not available so this link cannot be confirmed. There have been no detections of H5N1 in dairy cattle in Arizona. 

“Wastewater monitoring is one of multiple tools we have to proactively monitor for avian flu in our community,” said Dr. Nick Staab, assistant medical director at MCDPH. “Given that no human cases have been identified in Maricopa County through our other disease detection methods and there is no recent documented spread of H5N1 influenza from human to human, the overall risk of avian flu to people remains low.”

Avian flu is most often seen in wild and domestic birds; human cases have been rare and primarily in people with close, unprotected contact with sick or dead animals, their bedding, or their droppings. While wastewater monitoring may provide limited details, it provides important information about the presence of the H5 subtype, so that people can take appropriate precautions. This includes avoiding contact with sick or dead birds and wearing appropriate protective gear when handling sick or dead animals, their droppings, or their bedding. It is also advised to avoid consuming unpasteurized (raw) dairy products. Pasteurization kills viruses, including H5 influenza strains, that could come from infected dairy cows.  

There is currently an increase in seasonal respiratory viruses, such as COVID-19 and seasonal flu strains, making it more likely that people in the community will come into contact with those viruses than avian flu. “To prevent illness, we want residents and visitors to focus on taking general respiratory virus prevention measures,” said Dr. Staab.

People can reduce their risk of illness with basic steps: 

  • Practice good hand hygiene, which includes hand washing and using hand sanitizer when soap and water are not available. 
  • Get your seasonal flu and COVID-19 vaccines
    • Seasonal flu vaccination will not prevent infection with bird flu viruses but can reduce the risk of getting sick with human influenza viruses and thus the risk for seasonal and bird flu co-infection. 
    • Seasonal flu and COVID-19 vaccines are safe and effective at reducing severity of symptoms, and they also reduce the likelihood of getting infected with flu or COVID-19. 
  • Talk with your healthcare provider about other vaccines that are recommended for certain groups, such as the RSV vaccine and pneumococcal vaccine. 
  • Stay home and away from others if you are sick. 
  • If symptoms worsen or you are at higher risk of severe illness, contact your medical provider. Consider wearing a mask if you seek healthcare for your symptoms.

If you see signs of illness in your poultry, report them immediately to USDA at 1-866-536-7593. If you see sick or dead wild birds, please contact the Arizona Game and Fish Department at 623-236-7201.

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