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

  • Weeks 124-125: 03/03 - 03/16
  • Weeks 126-127: 03/17 - 03/30

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 -28.9% +26.5% -70.9%
Norovirus +12.6% +25.2% -7%
RSV -64.7% -32.3% -46.3%
Influenza A -77.9% +3% -29.5%
Influenza B +8% +18.8% -36%
HMPV -23.5% +75.5% -17.4%
Parainfluenza +26.6% +15% -25.8%
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 Medium
Norovirus Medium Medium Medium
RSV Low Low Low
Influenza A Low Low Low
Influenza B Medium Medium Medium
HMPV Low High High
Parainfluenza Medium 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 Very likely downward No Trend Very likely downward
Norovirus Very likely downward Very likely downward Very likely upward
Rotavirus Likely upward No Trend Downward
Hepatitis A Virus No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend
Enterovirus D68 Very likely downward No Trend No Trend
RSV Very likely downward No Trend Likely downward
Influenza A No Trend No Trend Very likely downward
Influenza B Very likely downward No Trend Very likely downward
HMPV Very likely downward No Trend Upward
Parainfluenza Very likely upward Very likely upward No Trend
Week 127: 03/17 - 03/30
* 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 No Trend Very likely downward
Norovirus Very likely downward Very likely downward Very likely upward
Rotavirus Very likely upward No Trend Likely downward
Hepatitis A Virus No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend
Enterovirus D68 Very likely downward No Trend No Trend
RSV Downward No Trend Likely downward
Influenza A No Trend No Trend Very likely downward
Influenza B Very likely downward No Trend Very likely downward
HMPV Very likely downward No Trend Likely upward
Parainfluenza Very likely upward Very likely upward No Trend
Week 127: 03/17 - 03/30
* 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 Downward
Norovirus No Trend No Trend No Trend
Rotavirus Upward No Trend No Trend
Hepatitis A Virus Downward No Trend Very likely upward
Candida auris No Trend No Trend No Trend
Enterovirus D68 No Trend Very likely upward No Trend
RSV Downward Downward No Trend
Influenza A Downward No Trend No Trend
Influenza B No Trend No Trend Downward
HMPV No Trend No Trend No Trend
Parainfluenza Upward Upward No Trend
Week 127: 03/17 - 03/30
* 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 -78.9% -39.6% -39.3% +9% -78.3% -73.4% Sporadic -68.6%
Norovirus -58.2% -64.8% +1.9% -44.5% +36.5% -55.7% +195% +77.1%
Rotavirus -45% -55% -45.8% +81.1% +39.6% -93.9% Sporadic -27.6%
Hepatitis A Virus ND ND ND ND ND ND ND ND
Candida auris ND ND ND ND ND ND ND ND
Enterovirus D68 ND Sporadic ND ND ND ND ND ND
RSV Sporadic ND Sporadic Sporadic -35% ND Sporadic Sporadic
Influenza A Sporadic ND ND Sporadic +71.8% -98.5% ND Sporadic
Influenza B -64.1% Sporadic -22.9% -10% -14.5% -7.1% Sporadic -6.2%
HMPV -55.2% -47.6% +65.7% +86.9% +365% Sporadic ND +11%
Parainfluenza -39.3% +82% Sporadic +165% +38.8% Sporadic +93.8% Sporadic
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 Low Low Low Low Low Low Low Medium
Norovirus High Medium High Medium Medium Low Medium High
Rotavirus High High High High High Medium 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 Low Low Low Low Low Low Low
RSV Low Low Low Low Low Low Low Low
Influenza A Low Low Low Low Low Low Low Low
Influenza B High Low Low Medium Medium Low Low Medium
HMPV Medium Low High High High Low Low Low
Parainfluenza Low Medium 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 Very likely downward No Trend Likely downward Likely upward No Trend Very likely downward Sporadic No Trend
Norovirus Very likely downward Very likely downward Very likely upward Very likely downward Very likely upward Very likely downward Very likely upward Likely upward
Rotavirus Likely upward Likely upward No Trend Upward Very likely upward Very likely downward Sporadic Very likely upward
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 Sporadic No Trend No Trend No Trend No Trend No Trend No Trend
RSV Sporadic No Trend Sporadic Sporadic No Trend No Trend Sporadic Sporadic
Influenza A Sporadic No Trend No Trend Sporadic Likely upward Very likely downward No Trend Very likely downward
Influenza B Likely downward Sporadic No Trend No Trend Likely upward Very likely downward Sporadic No Trend
HMPV Very likely downward No Trend Very likely upward No Trend Very likely upward Sporadic No Trend No Trend
Parainfluenza Very likely upward Likely upward Sporadic Very likely upward No Trend Sporadic Very likely upward Sporadic
Week 127: 03/17 - 03/30
* 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 Very likely downward Downward Likely downward Upward No Trend Very likely downward Sporadic No Trend
Norovirus Very likely downward Very likely downward Likely upward Very likely downward Very likely upward Very likely downward Very likely upward Likely upward
Rotavirus Likely upward Likely upward No Trend Upward Very likely upward Very likely downward Sporadic Very likely upward
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 Sporadic No Trend No Trend No Trend No Trend No Trend No Trend
RSV Sporadic No Trend Sporadic Sporadic Likely downward No Trend Sporadic Sporadic
Influenza A Sporadic No Trend No Trend Sporadic Very likely upward Very likely downward No Trend Very likely downward
Influenza B Very likely downward Sporadic No Trend Likely downward Very likely upward Very likely downward Sporadic Likely downward
HMPV Very likely downward Likely downward Very likely upward No Trend Very likely upward Sporadic No Trend No Trend
Parainfluenza Very likely upward Very likely upward Sporadic Very likely upward No Trend Sporadic Very likely upward Sporadic
Week 127: 03/17 - 03/30
* 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 No Trend No Trend No Trend Downward Sporadic No Trend
Norovirus No Trend No Trend No Trend Downward No Trend Downward No Trend Upward
Rotavirus Upward No Trend No Trend No Trend No Trend No Trend 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 Sporadic No Trend No Trend No Trend No Trend No Trend No Trend
RSV Sporadic No Trend Sporadic Sporadic Downward No Trend Sporadic Sporadic
Influenza A Sporadic No Trend No Trend Sporadic No Trend No Trend No Trend No Trend
Influenza B No Trend Sporadic No Trend No Trend No Trend No Trend Sporadic Downward
HMPV No Trend No Trend No Trend No Trend Upward Sporadic No Trend No Trend
Parainfluenza No Trend Upward Sporadic Upward No Trend Sporadic No Trend Sporadic
Week 127: 03/17 - 03/30
* 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) decreased ⬇️ by 78.9% between the most recent two weeks and the two weeks prior to that. Los Banos’s average decreased ⬇️ by 39.6%.

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 showed no detection.

Influenza B

Merced’s average Influenza B concentrations (Flu B/PMMoV) decreased ⬇️ by 64.1% between the most recent two weeks and the two weeks prior to that. Los Banos’ average sporatic detection.

RSV

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

HMPV

Merced’s HMPV concentrations (HMPV/PMMoV) decreased ⬇️ by 55.2% between the most recent two weeks and the two weeks prior to that. Los Banos’s average decreased ⬇️ by 47.6%.

Norovirus

Merced’s average Norovirus concentrations (Norovirus/PMMoV) decreased ⬇️ by 58.2% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 64.8%.

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) decreased ⬇️ by 45% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 55%.

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 sporatic detection.

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) decreased ⬇️ by 39.3% between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 82%.

Stanislaus County

SARS-CoV-2

Modesto’s average SARS-CoV-2 concentrations (N/PMMoV) decreased ⬇️ by 39.3% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 9%.

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 sporatic detection.

Influenza B

Modesto’s average Influenza B concentrations (Flu B/PMMoV) decreased ⬇️ by 22.9% between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 10%.

RSV

Modesto’s average RSV concentrations (RSV/PMMoV) sporatic 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) increased ⬆️ by 65.7% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 86.9%.

Norovirus

Modesto’s average Norovirus concentrations (Norovirus/PMMoV) remained the same 🔄 between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 44.5%.

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) decreased ⬇️ by 45.8% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 81.1%.

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) sporatic detection between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 165%.

Yolo County

SARS-CoV-2

Davis’ average SARS-CoV-2 concentrations (N/PMMoV) decreased ⬇️ by 78.3% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 73.4%. Winters’ average sporatic detection. Woodland’s average decreased ⬇️ by 68.6%.

Influenza A

Davis’ average Influenza A concentrations (Flu A/PMMoV) increased ⬆️ by 71.8% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 98.5%. Winters’ average showed no detection. Woodland’s average sporatic detection.

Influenza B

Davis’ average Influenza B concentrations (Flu B/PMMoV) decreased ⬇️ by 14.5% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 7.1%. Winters’ average sporatic detection. Woodland’s average decreased ⬇️ by 6.2%.

RSV

Davis’ average RSV concentrations (RSV/PMMoV) decreased ⬇️ by 35% between the most recent two weeks and the two weeks prior to that. Esparto’s average showed no detection. Winters’ average sporatic detection. Woodland’s average sporatic detection.

HMPV

Davis’ HMPV concentrations (HMPV/PMMoV) increased ⬆️ by 365% between the most recent two weeks and the two weeks prior to that. Esparto’s average sporatic detection. Winters’ average showed no detection. Woodland’s average increased ⬆️ by 11%.

Norovirus

Davis’ Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 36.5% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 55.7%. Winters’ average increased ⬆️ by 195%. Woodland’s average increased ⬆️ by 77.1%.

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 ⬆️ by 39.6% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 93.9%. Winters’ average sporatic detection. Woodland’s average decreased ⬇️ by 27.6%.

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) increased ⬆️ by 38.8% between the most recent two weeks and the two weeks prior to that. Esparto’s average sporatic detection. Winters’ average increased ⬆️ by 93.8%. Woodland’s average sporatic detection.

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/