Gallatin County, MT

Infectious Disease Detection in Wastewater


November 2020: Now monitoring Gallatin County for Influenza A!

In October of 2020, Archer Biologicals, LLC was selected to test wastewater sites in Gallatin County, MT for SARS-CoV2, the virus that causes COVID-19. Archer will report weekly viral quantities reported in Big Sky, Three Forks, and West Yellowstone, MT. Archer Biologicals uses techniques established in the Seth Walk Lab at Montana State University. Archer Biologicals is based in Bozeman, MT and deeply cares about the health of fellow Montanans.


-In November 2020, Gallatin County added the city of Belgrade to its wastewater surveillance program.

-In late November 2020, Gallatin County began a pilot program with Archer to determine the feasibility of Influenza A detection in wastewater. Preliminary data suggest that the novel methods applied by Archer to detect SARS-CoV2 can be applied to detect Influenza A. To our knowledge, this is one of the first projects of its kind in the country. Results will be posted as part of the SARS-CoV2 reports on this website.



Data above show the estimated genomes per liter in wastewater collected from each respective site at weekly intervals. Points indicate mean genomes/liter and error bars are standard error of the mean. Most sites saw spikes in mid-late November, correlating with increasing case numbers in Gallatin County. No data is available for Belgrade prior to November 2020.


Individuals infected with SARS-CoV2, whether symptomatic or asymptomatic, can shed virus in their stool. Archer Biologicals tests for the presence and quantity of SARS-CoV2 in wastewater using commercial kits approved by the CDC. Wastewater is disinfected and viral particles are concentrated. RNA is extracted from viral particles and reverse-transcribed to generate cDNA prior to quantitative PCR. Samples below a Ct of 40 are considered positive. Genome concentration is estimated using a standard curve generated with a commercially available positive control at known concentration. Wastewater surveillance for SARS-CoV2 is a novel and developing technology. Virus concentration may fluctuate depending on flow rates, flow volumes, and other factors. Lack of viral signal in wastewater may not mean a complete absence of infections, however the presence of signal in wastewater certainly is due to an infected user at the time of collection.

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