PHX Reporter

The Maricopa County Department of Public Health (MCDPH) has detected an influenza subtype linked to avian flu in local wastewater. Despite this finding, no human cases have been reported in the county, and officials maintain that the risk to the public remains low.

Wastewater monitoring helps identify genetic material from microbes such as influenza A and its subtypes in untreated water. This process assists public health authorities and partners in understanding changes in disease activity. The subtype identified, influenza A(H5), which includes H5N1 associated with bird flu, was found by Phoenix, Surprise, and Tempe—three cities within Maricopa County conducting wastewater monitoring. However, pinpointing the exact source of the viral detection is currently not feasible.

Arizona has seen avian flu cases before, including at a commercial poultry farm in Pinal County and among animals at a zoo and backyard flock in Maricopa County. The H5N1 strain detected matches those found in wild birds; further genomic testing is ongoing. At present, similar testing for wastewater samples is unavailable to confirm any direct link.

Dr. Nick Staab, assistant medical director at MCDPH, noted: “Wastewater monitoring is one of multiple tools we have to proactively monitor for avian flu in our community.” He emphasized that since no human cases have been identified through other methods and there’s no recent documented spread from person to person of H5N1 influenza, "the overall risk of avian flu to people remains low."

Avian flu primarily affects wild and domestic birds; human infections are rare and typically involve close contact with sick or deceased animals or their waste. While providing limited detail, wastewater monitoring offers crucial information about the presence of the H5 subtype so that appropriate precautions can be taken. Recommendations include avoiding contact with sick or dead birds and wearing protective gear when handling such animals or their droppings.

With seasonal respiratory viruses like COVID-19 more prevalent now than avian flu, Dr. Staab advises focusing on general respiratory virus prevention measures: practicing good hand hygiene; receiving seasonal flu and COVID-19 vaccines; staying home when ill; consulting healthcare providers if symptoms worsen; reporting signs of illness in poultry to USDA at 1-866-536-7593; contacting Arizona Game and Fish Department at 623-236-7201 if encountering sick or dead wild birds.

For further details on avian influenza or wastewater monitoring in Maricopa County visit their respective web pages provided by MCDPH.