Wastewater Monitoring

Please be advised that of as of February 7, 2024, the weekly wastewater monitoring reports will be temporarily paused for quality improvement updates. For any wastewater-related inquiries during this period, kindly contact us at Epidemiology@gov.nt.ca.  We appreciate your understanding as we work to enhance our reporting. 

 

The GNWT wastewater monitoring program collects regular samples of wastewater (sewage) from participating communities to test for COVID-19, Influenza, and Respiratory Syncytial Virus (RSV). This form of monitoring can uncover trends of these viruses 4-10 days earlier than clinical data would.

The presence of COVID-19, Influenza, and RSV in wastewater samples does not mean that there is an active presence of these viruses in the community.

However, collecting this information can still serve as an early warning system, helping the health and social services system provide targeted advice to communities.

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Wastewater Monitoring

The Wastewater Monitoring Report is updated on Mondays by 2 p.m. In the event of a holiday, information will be updated on the next business day. A slight delay in data may occur due to the time it takes to transport and analyze the samples.

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Understanding Wastewater Data

The solid-coloured lines show the 7-day rolling average of each virus for each community. The 7-day rolling average is calculated by determining the average amount of each virus (or viral load) in community wastewater each sample collection day. Wastewater in the NWT is handled either through traditional piped and plumbed sewage systems or through trucked systems – wastewater is collected in an internal tank in homes and collected by trucks and delivered to the community’s wastewater treatment facility.

Trucked wastewater systems can collect or discharge wastewater unevenly, making it hard to follow the spikes. To address this, the following formula is used to analyze and remove the outlier strength before applying the 7-day rolling average.

 

ModZ=(x-median(x)/sqrt(x))

 

ModZ represents what is called a modified z-score (a standardized score that measures how much the amount of virus in a given wastewater sample differs from the typical amount of virus seen in our wastewater samples. This helps us identify outliers)

X represents the amount of viral RNA in each sample (viral copies per mL of wastewater).

 

Please use caution when interpreting daily and short-term changes in viral load, as the wastewater signal can change from day to day.

If the wastewater signals are high or increasing, this may indicate a high level of COVID-19, Influenza, or and/or RSV in your community. It’s important to pay attention to public health alerts and to follow public health advice.

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NWT Wastewater Monitoring Report

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Download the data

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