MARICOPA COUNTY, Ariz. — The Maricopa County Department of Public Health announced Monday that a subtype of influenza related to avian influenza has been detected in local wastewater.

No human cases have been reported in the county, and the risk of humans contracting bird flu is considered low.

The influenza subtype was found in three Maricopa County cities that conduct wastewater monitoring: Phoenix, Surprise and Tempe. However, only these three cities have systems to monitor wastewater. Dr. Nick Staab, assistant medical director for the county health department, said it’s very likely the virus is present in other cities’ sewage as well.

The health department has not been able to confirm the exact source location of the virus detection.

“Given that there have been no confirmed human cases in Maricopa County using other disease detection methods and no recent records of human-to-human transmission of H5N1 influenza, the overall prevalence of avian influenza in humans is The risk remains low,” Dr. Staab said. statement.

Dr Staab also said that although surveillance would notify authorities if avian influenza was detected in sewage, there was no way to know what the source was. Transmission from infected humans or wild birds.

“Our best guess is that these detections are related to other confirmed animal positive cases in Maricopa County and Arizona,” Staab said.

Over the past few weeks, traces of bird flu have been detected in several locations in Arizona. A flu outbreak reported earlier this month has killed multiple animals at the Valley Wildlife Park.

Residents are advised to avoid contact with sick or dead birds and to avoid consuming unpasteurized dairy products. The health department said no H5N1 virus has been detected in dairy cows in Arizona.

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Locals refer to the Phoenix metropolitan area as “The Valley.” It is considered the largest metropolitan area in the Southwest.

In addition to Phoenix, the Valley is made up of a variety of other major cities, including:

• mesa
• chandler
• scottsdale
• Tempe
• glendale
• surprise
• Peoria
• gilbert
• El Mirage
• Avondale
• Litchfield Park
• goodyear
• buckeye

Whether a city is in the “East Valley” or “West Valley” depends on where the city is in relation to Phoenix.

According to the 2020 U.S. Census, the total population of Valley cities is 4,845,832. This makes it the 11th largest metropolitan area in the country, behind the Boston and Atlanta areas.

How large is Maricopa County?

According to the 2020 Census, Maricopa County is the fourth largest county in the United States with a population of 4,485,414 people.

The county contains approximately 63% of Arizona’s population and covers an area of ​​9,224 square miles. This makes the county larger than seven U.S. states: Rhode Island, Delaware, Connecticut, Hawaii, New Jersey, Massachusetts, and New Hampshire.

One of the largest park systems in the United States is also located in Maricopa County. The county has an estimated 120,000 acres of open space parks, including hundreds of miles of trails, nature centers, and campgrounds.

The county seat is Phoenix, which is also the state capital and the fifth most populous city in the United States according to the census.

The county is named after the Maricopa or Piipaash Native American tribe.