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

  • Weeks 132-133: 04/28 - 05/11
  • Weeks 134-135: 05/12 - 05/25

General Update at County Level

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

Percentage of change

Percent change
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 +112% +24.7% +3.6%
Norovirus +69.2% +12.6% +18.5%
RSV ND 13.5% 42.9%
Influenza A 29.1% +48.1% +96.3%
Influenza B +33.2% +19.4% 14.6%
HMPV 40.5% +81.7% 90.2%
Parainfluenza +20.7% 22.9% 61.1%
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%.
Weeks 132-133: 04/28 - 05/11
Weeks 134-135: 05/12 - 05/25

Current wastewater level

Current wastewater level
Virus Merced Stanislaus Yolo
SARS-CoV-2 Medium Low Medium
Norovirus High Medium Medium
RSV Low Low Low
Influenza A Low Low Low
Influenza B Medium Low Low
HMPV Low Low Low
Parainfluenza Medium Medium Low
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.
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.

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 upward Likely upward No Trend
Norovirus Very likely upward No Trend No Trend
Human Adenovirus Group F NA NA NA
Rotavirus Very likely upward Very likely downward Downward
Hepatitis A Virus No Trend No Trend Likely downward
Candida auris No Trend No Trend No Trend
Enterovirus D68 No Trend No Trend No Trend
RSV No Trend No Trend No Trend
Influenza A Downward Likely upward Likely upward
Influenza B No Trend No Trend Very likely downward
HMPV Very likely downward Likely upward Very likely downward
Parainfluenza Likely upward Very likely downward Very likely downward
Week 135: 05/12 - 05/25
* 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 upward Likely upward No Trend
Norovirus Very likely upward No Trend No Trend
Human Adenovirus Group F NA NA NA
Rotavirus Likely upward Very likely downward Likely downward
Hepatitis A Virus No Trend No Trend No Trend
Candida auris No Trend No Trend No Trend
Enterovirus D68 No Trend No Trend No Trend
RSV No Trend No Trend No Trend
Influenza A No Trend Upward Very likely upward
Influenza B No Trend No Trend Very likely downward
HMPV Very likely downward Likely upward Very likely downward
Parainfluenza Likely upward Very likely downward Very likely downward
Week 135: 05/12 - 05/25
* 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 Upward No Trend No Trend
Norovirus Likely upward No Trend No Trend
Human Adenovirus Group F NA NA NA
Rotavirus No Trend Downward No Trend
Hepatitis A Virus Downward Very likely downward Very likely downward
Candida auris No Trend No Trend No Trend
Enterovirus D68 No Trend Very likely downward Downward
RSV Downward Very likely downward No Trend
Influenza A No Trend No Trend No Trend
Influenza B No Trend Downward No Trend
HMPV No Trend No Trend Downward
Parainfluenza No Trend No Trend Downward
Week 135: 05/12 - 05/25
* 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 +57.9% +153% 38.2% +202% +155% 99.3% +236% Sporadic
Norovirus +46.1% +262% +121% 44.9% +64.4% +118% +164% Sporadic
Human Adenovirus Group F NA NA NA NA NA NA NA NA
Rotavirus +7.7% +39.5% 45.6% 27.3% +3% +Sharply 82.9% Sporadic
Hepatitis A Virus ND ND ND ND ND ND ND Sporadic
Candida auris ND ND ND ND ND ND ND ND
Enterovirus D68 ND ND ND ND ND ND ND Sporadic
RSV ND ND ND ND 67.5% ND ND Sporadic
Influenza A +225% 78% +248% +163% +41.5% +92.1% 92.4% Sporadic
Influenza B +20.1% ND 52.5% 78.3% 54.7% 74.8% +26.8% Sporadic
HMPV +2.8% ND ND 95.9% 59.8% 34.2% 97% Sporadic
Parainfluenza Sporadic Sporadic +57% Sporadic Sporadic Sporadic Sporadic 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%.
Weeks 132-133: 04/28 - 05/11
Weeks 134-135: 05/12 - 05/25

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 Medium Low Low High Low Low Low
Norovirus High High High High High High High Medium
Human Adenovirus Group F Low Low Low Low Low Low Low Low
Rotavirus Medium High High High High Medium High High
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 High Low Low Low Low Low
Influenza B High Low Low Low Low Low Low Low
HMPV Low Low Low Medium Low Low Low Low
Parainfluenza Medium Low Low Medium Low Low Low Low
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.
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.

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 upward Very likely upward Upward Likely upward Very likely upward No Trend Very likely downward Very likely downward
Norovirus Very likely upward Very likely upward No Trend Very likely upward Very likely upward Likely upward No Trend No Trend
Human Adenovirus Group F NA NA NA NA NA NA NA NA
Rotavirus Downward Very likely upward Very likely downward No Trend No Trend Very likely upward Likely upward 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 No Trend No Trend No Trend No Trend No Trend No Trend Sporadic
RSV No Trend No Trend No Trend No Trend Sporadic No Trend No Trend No Trend
Influenza A Downward Sporadic Likely upward Sporadic Very likely upward Very likely upward Sporadic Very likely upward
Influenza B Upward No Trend Sporadic Upward Sporadic Very likely upward Sporadic Sporadic
HMPV Very likely downward No Trend No Trend Likely upward Sporadic Sporadic Sporadic Very likely downward
Parainfluenza Very likely upward No Trend Sporadic Likely downward Very likely downward No Trend Very likely downward Very likely downward
Week 135: 05/12 - 05/25
* 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 upward Very likely upward No Trend Very likely upward Very likely upward No Trend Very likely downward Very likely downward
Norovirus Very likely upward Very likely upward No Trend Very likely upward Very likely upward Upward No Trend No Trend
Human Adenovirus Group F NA NA NA NA NA NA NA NA
Rotavirus No Trend Likely upward Very likely downward No Trend No Trend Very likely upward Very likely upward 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 No Trend No Trend No Trend No Trend No Trend No Trend Sporadic
RSV No Trend No Trend No Trend No Trend Sporadic No Trend No Trend No Trend
Influenza A No Trend Sporadic Likely upward Sporadic Very likely upward Very likely upward Sporadic Very likely upward
Influenza B Upward No Trend Sporadic Likely upward Sporadic Very likely upward Sporadic Sporadic
HMPV Very likely downward No Trend No Trend Likely upward Sporadic Sporadic Sporadic Very likely downward
Parainfluenza Very likely upward No Trend Sporadic Likely downward Very likely downward No Trend Very likely downward Very likely downward
Week 135: 05/12 - 05/25
* 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 Likely upward No Trend No Trend Likely upward No Trend No Trend No Trend
Norovirus Very likely upward Likely upward Upward No Trend Upward No Trend No Trend No Trend
Human Adenovirus Group F NA NA NA NA NA NA NA NA
Rotavirus No Trend No Trend Downward Upward No Trend No Trend No Trend 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 No Trend No Trend No Trend No Trend No Trend No Trend Sporadic
RSV No Trend No Trend No Trend No Trend Sporadic No Trend No Trend No Trend
Influenza A No Trend Sporadic No Trend Sporadic No Trend No Trend Sporadic Upward
Influenza B No Trend No Trend Sporadic No Trend Sporadic No Trend Sporadic Sporadic
HMPV No Trend No Trend No Trend No Trend Sporadic Sporadic Sporadic Downward
Parainfluenza No Trend No Trend Sporadic No Trend Downward No Trend No Trend No Trend
Week 135: 05/12 - 05/25
* 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 57.9% between the most recent two weeks and the two weeks prior to that. Los Banos’s average increased ⬆️ by 153%.

Influenza A

Merced’s average Influenza A concentrations (Flu A/PMMoV) increased ⬆️ by 225% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 78%.

Influenza B

Merced’s average Influenza B concentrations (Flu B/PMMoV) increased ⬆️ by 20.1% between the most recent two weeks and the two weeks prior to that. Los Banos’ average showed no detection.

RSV

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

Norovirus

Merced’s average Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 46.1% between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 262%.

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.

Human Adenovirus Group F

Merced’s average Human Adenovirus Group F concentrations (HAdV_F/PMMoV) No data available between the most recent two weeks and the two weeks prior to that. Los Banos’ average No data available.

Rotavirus

Merced’s average Rotavirus concentrations (Rotavirus/PMMoV) increased ⬆️ by 7.7% between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 39.5%.

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 showed no 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) sporatic detection between the most recent two weeks and the two weeks prior to that. Los Banos’ average sporatic detection.

Stanislaus County

SARS-CoV-2

Modesto’s average SARS-CoV-2 concentrations (N/PMMoV) decreased ⬇️ by 38.2% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 202%.

Influenza A

Modesto’s average Influenza A concentrations (Flu A/PMMoV) increased ⬆️ by 248% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 163%.

Influenza B

Modesto’s average Influenza B concentrations (Flu B/PMMoV) decreased ⬇️ by 52.5% between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 78.3%.

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 showed no detection.

HMPV

Modesto’s average HMPV concentrations (HMPV/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 95.9%.

Norovirus

Modesto’s average Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 121% between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 44.9%.

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.

Human Adenovirus Group F

Modesto’s average Human Adenovirus Group F concentrations (HAdV_F/PMMoV) No data available between the most recent two weeks and the two weeks prior to that. Turlock’s average No data available.

Rotavirus

Modesto’s average Rotavirus concentrations (Rotavirus/PMMoV) decreased ⬇️ by 45.6% between the most recent two weeks and the two weeks prior to that. Turlock’s average decreased ⬇️ by 27.3%.

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) increased ⬆️ by 57% between the most recent two weeks and the two weeks prior to that. Turlock’s average sporatic detection.

Yolo County

SARS-CoV-2

Davis’ average SARS-CoV-2 concentrations (N/PMMoV) increased ⬆️ by 155% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 99.3%. Winters’ average increased ⬆️ by 236%. Woodland’s average sporatic detection.

Influenza A

Davis’ average Influenza A concentrations (Flu A/PMMoV) increased ⬆️ by 41.5% between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ by 92.1%. Winters’ average decreased ⬇️ by 92.4%. Woodland’s average sporatic detection.

Influenza B

Davis’ average Influenza B concentrations (Flu B/PMMoV) decreased ⬇️ by 54.7% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 74.8%. Winters’ average increased ⬆️ by 26.8%. Woodland’s average sporatic detection.

RSV

Davis’ average RSV concentrations (RSV/PMMoV) decreased ⬇️ by 67.5% 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 sporatic detection.

HMPV

Davis’ HMPV concentrations (HMPV/PMMoV) decreased ⬇️ by 59.8% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 34.2%. Winters’ average decreased ⬇️ by 97%. Woodland’s average sporatic detection.

Norovirus

Davis’ Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 64.4% between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ by 118%. Winters’ average increased ⬆️ by 164%. Woodland’s average sporatic detection.

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 sporatic detection.

Human Adenovirus Group F

Davis’ Human Adenovirus Group F concentrations (HAdV/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.

Rotavirus

Davis’ Rotavirus concentrations (Rotavirus/PMMoV) remained the same 🔄 between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ sharply. Winters’ average decreased ⬇️ by 82.9%. Woodland’s average sporatic detection.

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 sporatic 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) sporatic detection 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 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/