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

  • Weeks 105-106: 10/22 - 11/04
  • Weeks 107-108: 11/05 - 11/18

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 +30.4% +6.7% +7.8%
Influenza A +321% +146% +158%
RSV +133% +LL +2437%
HMPV ND +LL +2945%
Norovirus 20.5% +47.7% +11.3%
Percent change is calculated here using average of measurements over the past two weeks comparedto the average of measurements from the prior two weeks. ND appears if there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks.
ND- Non-detect (below detection limit)
+LL increasing but at low levels
Weeks 105-106: 10/22 - 11/04
Weeks 107-108: 11/05 - 11/18

Current wastewater level

Current wastewater level
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 High Medium Medium
Influenza A Low Medium Low
RSV Low Low Low
HMPV Low Low Low
Norovirus Low Low Medium
The current wastewater levels are estimated using the 10-day rolling average (10-d.m.a). The 33rd and 66th percentiles are calculated over the past 365 days before 14 days ago. For counties with less than 365 days, all days before 14 days ago are used. The current wastewater level is classified as:
- Low: The current 10-dma is below 33rd percentile
- Medium: The current 10-dma is between the 33rd and 66th percentile
- High: The current 10-dma is above 66th Percentile
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned a Low categorization.

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 Very likely upward Upward
Influenza A Likely upward Likely upward Very likely upward
RSV No Trend Very likely upward Very likely upward
HMPV No Trend Very likely upward Very likely upward
Norovirus No Trend Very likely upward No Trend
Week 108: 11/05 - 11/18
* 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 raw N/PMMoV data and used a 14-day lookback period. 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.
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned No Trend.

Percent change (PC)

Percent change in the last 14 days
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 Very likely upward Very likely upward Likely upward
Influenza A Upward Very likely upward Very likely upward
RSV No Trend Very likely upward Very likely upward
HMPV No Trend Very likely upward Very likely upward
Norovirus No Trend Very likely upward No Trend
Week 108: 11/05 - 11/18
* 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.
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned No Trend.

Relative Strength Index

The Relative Strength Index
Virus Merced County Stanislaus County Yolo County
SARS-CoV-2 Upward No Trend No Trend
Influenza A No Trend Upward Upward
RSV No Trend Likely upward Likely upward
HMPV No Trend Very likely upward Very likely upward
Norovirus Downward Upward No Trend
Week 108: 11/05 - 11/18
* The Relative Strength Index (RSI) calculates a ratio of the recent upward price movements to the absolute price movement. Developed by J. Welles Wilder.
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned No Trend.

Trend at County level: SARS-CoV-2

Merced County

Stanislaus County

Yolo County

Trend at County level: Influenza A

Merced County

Stanislaus County

Yolo County

Trend at County level: RSV

Merced County

Stanislaus County

Yolo County

Trend at County level: Norovirus

Merced County

Stanislaus County

Yolo County

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 +53.7% +2405% 41.4% +186% +46.2% +383% ND 32.3%
Influenza A +LL +59.9% +127% +335% +131% ND +LL 14.8%
Influenza B ND +152% ND ND ND +LL ND ND
RSV +161% 31.9% ND +17612% +523% ND ND +450%
HMPV ND ND ND +LL ND ND ND +LL
Norovirus +48.7% 16.9% +74.2% +407% +135% +32.7% +34.1% +160%
Hepatitis A Virus ND ND ND +773% ND ND ND ND
Candida auris ND ND ND ND ND ND ND ND
Human Adenovirus Group F +20.5% 91.3% +56.2% +465% +112% 79.6% +LL 92.8%
Rotavirus +49.9% +1090% 53.9% +LL 38.1% ND +1835% +256%
Enterovirus D68 ND ND ND ND ND ND ND ND
Parainfluenza +65.1% 55.4% +25% +152% +3.3% 31.7% ND +161%
Percent change is calculated here using average of measurements over the past two weeks comparedto the average of measurements from the prior two weeks. ND appears if there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks.
ND- Non-detect (below detection limit)
+LL increasing but at low levels
Weeks 105-106: 10/22 - 11/04
Weeks 107-108: 11/05 - 11/18

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 High High Low Medium Medium High Low Medium
Influenza A Low Low High Low Low Low Low Low
Influenza B Low High Low Low Low High Low Low
RSV Low Low Low Medium Low Low Low Low
HMPV Low Low Low Low Low Low Low Medium
Norovirus Low Low Medium Low Medium High High Medium
Hepatitis A Virus Low Low Low High Low Low Low Low
Candida auris Low Low Low Low Low Low Low Low
Human Adenovirus Group F Medium Low High High Low Low Low Low
Rotavirus High High Low Low Low Low Low Medium
Enterovirus D68 Low Low Low Low Low Low Low Low
Parainfluenza High Medium Low Medium High High Low Medium
The current wastewater levels are estimated using the 10-day rolling average (10-d.m.a). The 33rd and 66th percentiles are calculated over the past 365 days before 14 days ago. For counties with less than 365 days, all days before 14 days ago are used. The current wastewater level is classified as:
- Low: The current 10-dma is below 33rd percentile
- Medium: The current 10-dma is between the 33rd and 66th percentile
- High: The current 10-dma is above 66th Percentile
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned a Low categorization.

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 upward No Trend Likely upward Likely upward Very likely upward No Trend Likely downward
Influenza A Very likely upward No Trend Very likely upward Upward Very likely upward No Trend No Trend Likely upward
Influenza B No Trend Very likely upward No Trend No Trend No Trend Very likely upward No Trend No Trend
RSV Very likely upward Downward No Trend Very likely upward Very likely upward No Trend No Trend Very likely upward
HMPV No Trend No Trend No Trend Very likely upward Very likely upward No Trend No Trend Very likely upward
Norovirus No Trend No Trend Very likely upward Upward Likely upward Very likely upward Very likely upward No Trend
Hepatitis A Virus No Trend No Trend No Trend Very likely upward 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
Human Adenovirus Group F Very likely downward Very likely downward Very likely upward Very likely upward No Trend Very likely downward No Trend Very likely downward
Rotavirus Very likely upward Very likely upward Very likely downward Very likely upward No Trend No Trend No Trend Likely upward
Enterovirus D68 No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Parainfluenza No Trend Very likely downward No Trend No Trend No Trend No Trend Very likely downward No Trend
Week 108: 11/05 - 11/18
* 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 raw N/PMMoV data and used a 14-day lookback period. 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.
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned No Trend.

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 upward No Trend Very likely upward Upward Very likely upward No Trend Very likely downward
Influenza A Very likely upward No Trend Very likely upward No Trend Likely upward No Trend No Trend Very likely upward
Influenza B No Trend Upward No Trend No Trend No Trend Very likely upward No Trend No Trend
RSV Likely upward No Trend No Trend Very likely upward Very likely upward No Trend No Trend Very likely upward
HMPV No Trend No Trend No Trend Very likely upward No Trend No Trend No Trend Very likely upward
Norovirus No Trend No Trend Very likely upward Likely upward Likely upward Very likely upward Very likely upward Upward
Hepatitis A Virus No Trend No Trend No Trend Very likely upward 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
Human Adenovirus Group F Likely downward Very likely downward Very likely upward Very likely upward No Trend Very likely downward No Trend Very likely downward
Rotavirus Very likely upward Very likely upward Very likely downward Very likely upward Likely downward No Trend No Trend No Trend
Enterovirus D68 No Trend No Trend No Trend No Trend No Trend No Trend No Trend No Trend
Parainfluenza No Trend Very likely downward No Trend No Trend No Trend Upward Likely downward No Trend
Week 108: 11/05 - 11/18
* 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.
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned No Trend.

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 No Trend Likely upward No Trend No Trend
Influenza A No Trend No Trend Upward Likely upward Upward No Trend Very likely upward Upward
Influenza B No Trend Upward No Trend No Trend No Trend Very likely upward No Trend No Trend
RSV No Trend No Trend No Trend Very likely upward Upward No Trend No Trend Likely upward
HMPV No Trend No Trend No Trend Very likely upward No Trend No Trend No Trend Very likely upward
Norovirus No Trend No Trend Upward No Trend Upward Upward Likely upward 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
Human Adenovirus Group F No Trend No Trend Upward Upward No Trend No Trend No Trend Downward
Rotavirus Upward Very likely upward 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 No Trend
Parainfluenza Upward No Trend No Trend No Trend Upward No Trend No Trend Upward
Week 108: 11/05 - 11/18
* The Relative Strength Index (RSI) calculates a ratio of the recent upward price movements to the absolute price movement. Developed by J. Welles Wilder.
If there have not been at least one positive sample in the last week or at least two positive samples in the last two weeks, it is assigned No Trend.

Merced County

SARS-CoV-2

Merced’s average SARS-CoV-2 concentrations (N/PMMoV) increased ⬆️ by 53.7% between the most recent two weeks and the two weeks prior to that. Los Banos’s average increased ⬆️ by 2405%.

Fig 1. Merced

Fig 2. Los Banos

Influenza A

Merced’s average Influenza A concentrations (Flu A/PMMoV) +LL between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 59.9%.

Influenza B

Merced’s average Influenza B concentrations (Flu B/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 152%.

RSV

Merced’s average RSV concentrations (RSV/PMMoV) increased ⬆️ by 161% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 31.9%.

HMPV

Merced’s HMPV concentrations (HMPV/PMMoV) showed no detection 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 48.7% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 16.9%.

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.

Human Adenovirus Group F

Merced’s average Human Adenovirus Group F concentrations (HAdV_F/PMMoV) increased ⬆️ by 20.5% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 91.3%.

Rotavirus

Merced’s average Rotavirus concentrations (Rotavirus/PMMoV) increased ⬆️ by 49.9% between the most recent two weeks and the two weeks prior to that. Los Banos’ average increased ⬆️ by 1090%.

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) increased ⬆️ by 65.1% between the most recent two weeks and the two weeks prior to that. Los Banos’ average decreased ⬇️ by 55.4%.

Stanislaus County

SARS-CoV-2

Modesto’s average SARS-CoV-2 concentrations (N/PMMoV) decreased ⬇️ by 41.4% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 186%.

Fig 1. Modesto

Fig 2. Turlock

Influenza A

Modesto’s average Influenza A concentrations (Flu A/PMMoV) increased ⬆️ by 127% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 335%.

Influenza B

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

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 increased ⬆️ by 17612%.

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 +LL.

Norovirus

Modesto’s average Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 74.2% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 407%.

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 increased ⬆️ by 773%.

Human Adenovirus Group F

Modesto’s average Human Adenovirus Group F concentrations (HAdV_F/PMMoV) increased ⬆️ by 56.2% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 465%.

Rotavirus

Modesto’s average Rotavirus concentrations (Rotavirus/PMMoV) decreased ⬇️ by 53.9% between the most recent two weeks and the two weeks prior to that. Turlock’s average +LL.

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 25% between the most recent two weeks and the two weeks prior to that. Turlock’s average increased ⬆️ by 152%.

Yolo County

SARS-CoV-2

Davis’ average SARS-CoV-2 concentrations (N/PMMoV) increased ⬆️ by 46.2% between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ by 383%. Winters’ average showed no detection. Woodland’s average decreased ⬇️ by 32.3%.

Fig 1. Davis

Fig 2. Esparto

Fig 3. Winters

Fig 4. Woodland

Influenza A

Davis’ average Influenza A concentrations (Flu A/PMMoV) increased ⬆️ by 131% between the most recent two weeks and the two weeks prior to that. Esparto’s average showed no detection. Winters’ average +LL. Woodland’s average decreased ⬇️ by 14.8%.

Influenza B

Davis’ average Influenza B concentrations (Flu B/PMMoV) showed no detection between the most recent two weeks and the two weeks prior to that. Esparto’s average +LL. Winters’ average showed no detection. Woodland’s average showed no detection.

RSV

Davis’ average RSV concentrations (RSV/PMMoV) increased ⬆️ by 523% 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 ⬆️ by 450%.

HMPV

Davis’ HMPV concentrations (HMPV/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 +LL.

Norovirus

Davis’ Norovirus concentrations (Norovirus/PMMoV) increased ⬆️ by 135% between the most recent two weeks and the two weeks prior to that. Esparto’s average increased ⬆️ by 32.7%. Winters’ average increased ⬆️ by 34.1%. Woodland’s average increased ⬆️ by 160%.

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.

Human Adenovirus Group F

Davis’ Human Adenovirus Group F concentrations (HAdV/PMMoV) increased ⬆️ by 112% between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 79.6%. Winters’ average +LL. Woodland’s average decreased ⬇️ by 92.8%.

Rotavirus

Davis’ Rotavirus concentrations (Rotavirus/PMMoV) decreased ⬇️ by 38.1% between the most recent two weeks and the two weeks prior to that. Esparto’s average showed no detection. Winters’ average increased ⬆️ by 1835%. Woodland’s average increased ⬆️ by 256%.

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) remained the same 🔄 between the most recent two weeks and the two weeks prior to that. Esparto’s average decreased ⬇️ by 31.7%. Winters’ average showed no detection. Woodland’s average increased ⬆️ by 161%.

All Counties

Mpox Update

There are no detections for samples taken at our plants from the last two weeks. https://healthycvtogether.org/monkeypox-data/