Please see below for the latest update on Merced, Stanislaus, and Yolo County wastewater data.

  • Weeks 121-122: 02/11 - 02/24
  • Weeks 123-124: 02/25 - 03/09

General Update at County Level

Aggregated trend lines for counties are calculated using the right-aligned 10-day trimmed average for each site (\(\text{trimmed } target/PMMoV\)). For each date, an individual site trimmed smoothed value, i, for the day t (\(\text{trimmed } target/PMMoV_{i,t}\)) is multiplied by the plant’s population, \(pop_i\). Then these are summed and divided by the total population of all selected sites. This calculation results in the trimmed weighted average \(\text{county } target/PMMoV_{t}\) for day t, as in the following equation for the m selected plants: \[\text{county } target/PMMoV_{t} = \frac {\sum_{i=1}^m pop_i \times \text{trimmed } target/PMMoV_{i,t}}{\sum_{i=1}^m pop_i}\]

Percentage of change

Percent change
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 -26.9% -71.7% +28%
Norovirus +36.1% +5.1% +4.9%
RSV -47.5% -55.8% -22.8%
Influenza A -45.6% -41.3% +41.2%
Influenza B +51.8% -24.6% +14.2%
HMPV -42.6% +11.3% +305%
Parainfluenza +72.5% +53.3% -11.1%
Percent change is calculated here using the average of measurements over the past two weeks compared to the average of measurements from the prior two weeks. Results below the limit of detection are included in the averages as half the limit of detection.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
NA: if the above criteria is not met and there were no data available in the last 7 days.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.
ND: Non-detect (i.e., below the limit of detection) if there were no detections in the last 14 days.
+LL: increasing but at low levels. If the above criteria is met but there were no positive detections or no data in the prior 14 days.
+Sharply: percent change is greater than 500%.

Current wastewater level

Current wastewater level
Virus Merced Stanislaus Yolo
SARS-CoV-2 Low Low High
Norovirus Medium Medium Low
RSV Low Low Low
Influenza A Low Low Low
Influenza B High High High
HMPV Medium Medium Medium
Parainfluenza Low Low Low
For non-seasonal pathogens, the boundaries of the low, medium, and high labels are defined as the tertiles of all data available for that pathogen within a given site or county.
For seasonal pathogens, the boundaries of the low, medium, and high labels are defined as the thirds of the 95th percentile value for all of the data available for that pathogen within a given site or county.
If there have not been at least one positive sample in the last 7 days and at least three positive samples in the last 14 days, a low categorization is assigned.

Trend test at County level

Mann-Kendall trend test

Mann-Kendall trend test
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 Likely downward Very likely downward Very likely upward
Norovirus Likely downward Very likely downward Very likely downward
Rotavirus Likely upward No Trend Likely upward
Hepatitis A Virus No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend
Enterovirus D68 Likely upward No Trend No Trend
RSV Downward Very likely downward Upward
Influenza A Very likely downward No Trend No Trend
Influenza B Likely downward No Trend Likely upward
HMPV No Trend No Trend Likely upward
Parainfluenza Very likely upward No Trend Very likely downward
Week 124: 02/25 - 03/09
* The Mann-Kendall (MK) trend test is a nonparametric test that evaluates whether there is a monotonic trend in a time-series dataset. We applied the MK trend test to smothed N/PMMoV data and used a 14-day lookback period from the last datapoint available. We interpreted positive values of the test statistic, tau, with p <= 0.005, p <= 0.05, and p <= 0.01 as upward, likely upward, and very likely upward trends, respectively. We interpreted negative tau values with p <= 0.005, p <= 0.05, and p <= 0.01 as downward, likely downward, and very likely downward trends, respectively.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.

Percent change (PC)

Percent change in the last 14 days
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 Very likely downward Very likely downward Very likely upward
Norovirus No Trend Very likely downward Very likely downward
Rotavirus Very likely upward Upward Very likely upward
Hepatitis A Virus No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend
Enterovirus D68 Upward No Trend No Trend
RSV Downward Very likely downward Very likely upward
Influenza A Very likely downward No Trend No Trend
Influenza B Likely downward No Trend Likely upward
HMPV No Trend No Trend Very likely upward
Parainfluenza Very likely upward No Trend Very likely downward
Week 124: 02/25 - 03/09
* The slope is calculated from a least-squares linear regression of log10-transformed values of the N/PMMoV data versus day. We used a 14-day look-back period to calculate the slope. For each slope estimate, we extracted the 90%, 95%, and 99% confidence intervals (CIs) to calculate the 90%, 95%, and 99% CIs for each PC estimate. We interpreted PC values greater than 0 for the 90%, 95%, and 99% upper CIs as upward, likely upward, and very likely upward trends, respectively. We interpreted PC values less than 0 for the 90%, 95%, and 99% lower CIs as downward, likely downward, and very likely downward trends day and previous n - 1 days.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.

Relative Strength Index

The Relative Strength Index
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 No Trend No Trend No Trend
Norovirus No Trend No Trend Downward
Rotavirus Likely upward No Trend Likely upward
Hepatitis A Virus Downward No Trend Very likely upward
Candida auris No Trend No Trend No Trend
Enterovirus D68 Very likely upward Very likely upward No Trend
RSV No Trend Downward No Trend
Influenza A No Trend Downward No Trend
Influenza B No Trend No Trend No Trend
HMPV No Trend No Trend No Trend
Parainfluenza Upward No Trend No Trend
Week 124: 02/25 - 03/09
* The Relative Strength Index (RSI) calculates a ratio of the recent upward price movements to the absolute price movement. Developed by J. Welles Wilder.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.

General Update at City Level

Percentage of change

Percent change
Virus Merced County Stanislaus County Yolo County
Merced Los Banos Modesto Turlock Davis Esparto Winters Woodland
SARS-CoV-2 +86.3% -43.5% Sporadic -33.6% -19.4% -64% +17.2% +84.7%
Norovirus +377% -63.9% +53.1% -57.7% -22.5% -36.8% -67.3% -28.6%
Rotavirus +Sharply +272% +38.5% +89.7% +Sharply +Sharply Sporadic -45.3%
Hepatitis A Virus ND ND ND ND ND ND ND ND
Candida auris ND ND ND ND ND ND ND ND
Enterovirus D68 ND +191% ND ND ND ND ND ND
RSV +48.9% Sporadic ND Sporadic +36.4% ND ND +Sharply
Influenza A Sporadic -68.5% ND ND -38.4% +Sharply ND +54%
Influenza B +241% +40.2% -20.4% -26% -41.7% +101% +32.6% +110%
HMPV +276% -36.8% Sporadic -14.4% +51.3% Sporadic Sporadic +281%
Parainfluenza +Sharply +309% ND +167% -27.5% +192% Sporadic -17.2%
Percent change is calculated here using the average of measurements over the past two weeks compared to the average of measurements from the prior two weeks. Results below the limit of detection are included in the averages as half the limit of detection.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
NA: if the above criteria is not met and there were no data available in the last 7 days.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.
ND: Non-detect (i.e., below the limit of detection) if there were no detections in the last 14 days.
+LL: increasing but at low levels. If the above criteria is met but there were no positive detections or no data in the prior 14 days.
+Sharply: percent change is greater than 500%.

Current wastewater level

Current wastewater level
Virus Merced County Stanislaus County Yolo County
Merced Los Banos Modesto Turlock Davis Esparto Winters Woodland
SARS-CoV-2 Medium Low Low Low Medium Medium High High
Norovirus High Medium High Medium Medium Medium Low Low
Rotavirus High High High High High High Low Medium
Hepatitis A Virus Low Low Low Low Low Low Low Low
Candida auris Low Low Low Low Low Low Low Low
Enterovirus D68 Low High Low Low Low Low Low Low
RSV Medium Low Low Low Low Low Low Low
Influenza A Low Low Low Low Low Low Low Low
Influenza B High High High High High Medium High High
HMPV High Low Low Medium Low Low Low Medium
Parainfluenza Low Low Low Low Low Low Low Low
For non-seasonal pathogens, the boundaries of the low, medium, and high labels are defined as the tertiles of all data available for that pathogen within a given site or county.
For seasonal pathogens, the boundaries of the low, medium, and high labels are defined as the thirds of the 95th percentile value for all of the data available for that pathogen within a given site or county.
If there have not been at least one positive sample in the last 7 days and at least three positive samples in the last 14 days, a low categorization is assigned.

Trend test at City level

Mann-Kendall trend test

Mann-Kendall trend test
Virus Merced County Stanislaus County Yolo County
Merced Los Banos Modesto Turlock Davis Esparto Winters Woodland
SARS-CoV-2 No Trend Very likely downward Sporadic Very likely downward No Trend No Trend No Trend Upward
Norovirus Very likely upward Very likely downward Upward Very likely downward No Trend Very likely downward Likely downward Very likely downward
Rotavirus Very likely upward No Trend No Trend Very likely upward Very likely upward Likely upward Sporadic No Trend
Hepatitis A Virus No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Enterovirus D68 No Trend Likely upward No Trend No Trend No Trend No Trend No Trend No Trend
RSV No Trend Sporadic No Trend Sporadic No Trend No Trend No Trend Likely upward
Influenza A Sporadic Very likely downward No Trend No Trend Downward Very likely upward No Trend No Trend
Influenza B No Trend Likely downward No Trend No Trend Downward No Trend Very likely upward Likely upward
HMPV Very likely upward Likely downward Sporadic No Trend Upward Sporadic Sporadic No Trend
Parainfluenza No Trend Very likely upward No Trend No Trend No Trend No Trend Sporadic Likely downward
Week 124: 02/25 - 03/09
* The Mann-Kendall (MK) trend test is a nonparametric test that evaluates whether there is a monotonic trend in a time-series dataset. We applied the MK trend test to smothed N/PMMoV data and used a 14-day lookback period from the last datapoint available. We interpreted positive values of the test statistic, tau, with p <= 0.005, p <= 0.05, and p <= 0.01 as upward, likely upward, and very likely upward trends, respectively. We interpreted negative tau values with p <= 0.005, p <= 0.05, and p <= 0.01 as downward, likely downward, and very likely downward trends, respectively.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.

Percent change (PC)

Percent change in the last 14 days
Virus Merced County Stanislaus County Yolo County
Merced Los Banos Modesto Turlock Davis Esparto Winters Woodland
SARS-CoV-2 No Trend Very likely downward Sporadic Very likely downward No Trend No Trend No Trend Very likely upward
Norovirus Very likely upward Very likely downward Likely upward Very likely downward No Trend Very likely downward Very likely downward Very likely downward
Rotavirus Very likely upward No Trend No Trend Very likely upward Very likely upward Very likely upward Sporadic No Trend
Hepatitis A Virus No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Enterovirus D68 No Trend Upward No Trend No Trend No Trend No Trend No Trend No Trend
RSV No Trend Sporadic No Trend Sporadic No Trend No Trend No Trend Very likely upward
Influenza A Sporadic Very likely downward No Trend No Trend No Trend Very likely upward No Trend No Trend
Influenza B No Trend Likely downward No Trend No Trend Likely downward No Trend Very likely upward Likely upward
HMPV Very likely upward Very likely downward Sporadic No Trend Very likely upward Sporadic Sporadic Very likely upward
Parainfluenza No Trend Very likely upward No Trend No Trend No Trend Upward Sporadic Likely downward
Week 124: 02/25 - 03/09
* The slope is calculated from a least-squares linear regression of log10-transformed values of the N/PMMoV data versus day. We used a 14-day look-back period to calculate the slope. For each slope estimate, we extracted the 90%, 95%, and 99% confidence intervals (CIs) to calculate the 90%, 95%, and 99% CIs for each PC estimate. We interpreted PC values greater than 0 for the 90%, 95%, and 99% upper CIs as upward, likely upward, and very likely upward trends, respectively. We interpreted PC values less than 0 for the 90%, 95%, and 99% lower CIs as downward, likely downward, and very likely downward trends day and previous n - 1 days.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.

Relative Strength Index

The Relative Strength Index
Virus Merced County Stanislaus County Yolo County
Merced Los Banos Modesto Turlock Davis Esparto Winters Woodland
SARS-CoV-2 No Trend No Trend Sporadic No Trend No Trend No Trend No Trend Upward
Norovirus Upward No Trend Upward No Trend No Trend No Trend No Trend No Trend
Rotavirus Very likely upward Upward Upward No Trend Likely upward Very likely upward Sporadic No Trend
Hepatitis A Virus No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Enterovirus D68 No Trend Very likely upward No Trend No Trend No Trend No Trend No Trend No Trend
RSV No Trend Sporadic No Trend Sporadic Downward No Trend No Trend No Trend
Influenza A Sporadic No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Influenza B Upward No Trend No Trend No Trend No Trend No Trend No Trend No Trend
HMPV Likely upward No Trend Sporadic No Trend No Trend Sporadic Sporadic No Trend
Parainfluenza Upward No Trend No Trend No Trend No Trend No Trend Sporadic No Trend
Week 124: 02/25 - 03/09
* The Relative Strength Index (RSI) calculates a ratio of the recent upward price movements to the absolute price movement. Developed by J. Welles Wilder.
Criteria: need at least three positive detections in the last 14 days to report a percent change.
Sporadic: Labeled as sporadic detections if the above criteria is not met, but there is at least 1 positive detection in the last 14 days.

Merced County

SARS-CoV-2

Merced’s average SARS-CoV-2 concentrations (N/PMMoV) increased ⬆️ by 86.3% between the most recent two weeks and the two weeks prior to that. Los Banos’s average decreased ⬇️ by 43.5%.

Influenza A

Merced’s average Influenza A concentrations (Flu A/PMMoV) sporatic detection between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 68.5%.

Influenza B

Merced’s average Influenza B concentrations (Flu B/PMMoV) increased ⬆️ by 241% between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 40.2%.

RSV

Merced’s average RSV concentrations (RSV/PMMoV) increased ⬆️ by 48.9% between the most recent two weeks and the two weeks prior to that. Los Banos’ average sporatic detection.

HMPV

Merced’s HMPV concentrations (HMPV/PMMoV) increased ⬆️ by 276% between the most recent two weeks and the two weeks prior to that. Los Banos’s average decreased ⬇️ by 36.8%.

Norovirus

Merced’s average Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 377% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 63.9%.

Hepatitis A Virus

Merced’s average Hepatitis A Virus concentrations (HAV/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Los Banos’ average showed no detection.

Rotavirus

Merced’s average Rotavirus concentrations (Rotavirus/PMMoV) increased ⬆️ sharply between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 272%.

Enterovirus D68

Merced’s average Enterovirus D68 concentrations (EV_D68/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 191%.

Candida auris

Merced’s average Candida auris concentrations (C_auris/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Los Banos’ average showed no detection.

Parainfluenza

Merced’s average Parainfluenza concentrations (HPIV/PMMoV) increased ⬆️ sharply between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 309%.

Stanislaus County

SARS-CoV-2

Modesto’s average SARS-CoV-2 concentrations (N/PMMoV) sporatic detection between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 33.6%.

Influenza A

Modesto’s average Influenza A concentrations (Flu A/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Turlock’s average showed no detection.

Influenza B

Modesto’s average Influenza B concentrations (Flu B/PMMoV) decreased ⬇️ by 20.4% between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 26%.

RSV

Modesto’s average RSV concentrations (RSV/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Turlock’s average sporatic detection.

HMPV

Modesto’s average HMPV concentrations (HMPV/PMMoV) sporatic detection between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 14.4%.

Norovirus

Modesto’s average Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 53.1% between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 57.7%.

Hepatitis A Virus

Modesto’s average Hepatitis A Virus concentrations (HAV/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Turlock’s average showed no detection.

Rotavirus

Modesto’s average Rotavirus concentrations (Rotavirus/PMMoV) increased ⬆️ by 38.5% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 89.7%.

Enterovirus D68

Modesto’s average Enterovirus D68 concentrations (EV_D68/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Turlock’s average showed no detection.

Candida auris

Modesto’s average Candida auris concentrations (C_auris/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Turlock’s average showed no detection.

Parainfluenza

Modesto’s average Parainfluenza concentrations (HPIV/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 167%.

Yolo County

SARS-CoV-2

Davis’ average SARS-CoV-2 concentrations (N/PMMoV) decreased ⬇️ by 19.4% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 64%. Winters’ average increased ⬆️ by 17.2%. Woodland’s average increased ⬆️ by 84.7%.

Influenza A

Davis’ average Influenza A concentrations (Flu A/PMMoV) decreased ⬇️ by 38.4% between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ sharply. Winters’ average showed no detection. Woodland’s average increased ⬆️ by 54%.

Influenza B

Davis’ average Influenza B concentrations (Flu B/PMMoV) decreased ⬇️ by 41.7% between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ by 101%. Winters’ average increased ⬆️ by 32.6%. Woodland’s average increased ⬆️ by 110%.

RSV

Davis’ average RSV concentrations (RSV/PMMoV) increased ⬆️ by 36.4% between the most recent two weeks and the two weeks prior to that. Esparto’s average showed no detection. Winters’ average showed no detection. Woodland’s average increased ⬆️ sharply.

HMPV

Davis’ HMPV concentrations (HMPV/PMMoV) increased ⬆️ by 51.3% between the most recent two weeks and the two weeks prior to that. Esparto’s average sporatic detection. Winters’ average sporatic detection. Woodland’s average increased ⬆️ by 281%.

Norovirus

Davis’ Norovirus concentrations (Norovirus/PMMoV) decreased ⬇️ by 22.5% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 36.8%. Winters’ average decreased ⬇️ by 67.3%. Woodland’s average decreased ⬇️ by 28.6%.

Hepatitis A Virus

Davis’ Hepatitis A Virus concentrations (HAV/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Esparto’s average showed no detection. Winters’ average showed no detection. Woodland’s average showed no detection.

Rotavirus

Davis’ Rotavirus concentrations (Rotavirus/PMMoV) increased ⬆️ sharply between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ sharply. Winters’ average sporatic detection. Woodland’s average decreased ⬇️ by 45.3%.

Enterovirus D68

Davis’ Enterovirus D68 concentrations (EV_D68/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Esparto’s average showed no detection. Winters’ average showed no detection. Woodland’s average showed no detection.

Candida auris

Davis’ Candida auris concentrations (C_auris/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Esparto’s average showed no detection. Winters’ average showed no detection. Woodland’s average showed no detection.

Parainfluenza

Davis’ Parainfluenza concentrations (HPIV/PMMoV) decreased ⬇️ by 27.5% between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ by 192%. Winters’ average sporatic detection. Woodland’s average decreased ⬇️ by 17.2%.

All Counties

Mpox Update

Davis’ average Mpox concentrations (Mpox/PMMoV) No data available between the most recent two weeks and the two weeks prior to that. Esparto’s average No data available. Winters’ average No data available. Woodland’s average No data available. Merced’s average No data available. Los Banos’ average No data available. Modesto’s average No data available. Turlock’s average No data available https://healthycvtogether.org/monkeypox-data/