SARS-CoV-2 Infection in Captive Hippos (Hippopotamus amphibius), Belgium.

Two adult female hippos in Zoo Antwerp who were naturally infected with SARS-CoV-2 showed nasal discharge for a few days. Virus was detected by immunocytochemistry and PCR in nasal swab samples and by PCR in faeces and pool water. Serology was also positive. No treatment was necessary.

Analyses of the nucleic acids of SARS-CoV-2 from pharyngeal swabs and fecal specimens in COVID-19 patients and asymptomatic SARS-CoV-2 infected persons at different exposure times

The coronavirus disease 2019 (COVID-19) pandemic has become a public-health crisis worldwide. Accurate identification of the virus that causes COVID-19, SARS-CoV-2, carriers of SARS-CoV-2, and infected people is crucial for the prevention and control of this pandemic. Detection of the nucleic acids (NAs) of SARS-CoV-2 is one of the main criteria for COVID-19 diagnosis. Pharyngeal swabs (PSs) and fecal specimens (FSs) tend to be positive for SARS-CoV-2. However, there have been no reports of differences in the detection results of SARS-CoV-2 NAs in PSs and FSs of COVID-19 patients and asymptomatic SARS-CoV-2 infected persons at different exposure times. Forty-six patients diagnosed with COVID 19 in Nanyang City, China, from 2 February to 17 February 2020 and 27 asymptomatic SARS-CoV-2 infected persons screened through epidemiologic history and PSs and FSs at different exposure times were evaluated through detection of SARS-CoV-2 NAs. COVID-19 patients and asymptomatic SARS-CoV-2 infected persons had the highest positive rate of NAs in PSs at week 2 and the highest positive rate for NAs in FSs at week 3. The positive rate of NAs in PSs was significantly higher than that of FSs (P < 0.05). The difference in the positive rate of NAs in PSs between the two groups at 1, 3, and 4 weeks was significant (P < 0.05). The difference in the positive rate of NM in FSs between the two groups at 1-4 weeks was not significant (P > 0.05). The time for SARS-CoV-2 NAs to test positive in FSs lagged behind that for SARS-CoV-2 NAs to test positive in PSs (P > 0.05). The time for SARS-CoV-2 NAs to test positive in the PSs and FSs of asymptomatic SARS-CoV-2 infected persons lagged behind that for COVID-19 patients (P > 0.05). There was no significant difference in the average cycle threshold (Ct) value of the ORFlab gene and N gene of PSs and FSs between COVID-19 patients and asymptomatic SARS-Cov-2 infected persons at each exposure time tested (P > 0.05). The more severe the COVID-19, the higher was the positive rate of SARS-CoV-2 NAs in PSs and FSs, and the shorter was the time taken for SARS-CoV-2 NAs to test positive (P < 0.05). The re-positive rate of asymptomatic SARS-CoV-2 infected persons was 14.81% (4/27), higher than that of COVID-19 patients (6.52%;3/46), and the difference was significant (X2=8.193, P=0.016). Our study suggests that SARS-CoV-2 has a fecal mouth transmission route. The time taken for SARS-CoV-2 NM from FSs to turn positive lags behind that for SARS-CoV-2 NAs in PSs to turn positive, and the positive rate is lower. Test specimens should be selected according to different exposure times. Attention should he paid to younger asymptomatic SARS-CoV-2 infected persons.

Characteristics of SARS - CoV - 2 nucleic acids and serum antibodies in different clinical specimens and their correlation with the course of COVID -19

To investigate the characteristics of the nucleic acids of severe acute respiratory syndrome coronavirus (SARS-CoV) -2 and antibodies in different specimens obtained from coronavirus disease 2019 (COVID-19) patients;if a correlation between these parameters and the disease course was present. The throat swabs and stool samples of 39 COVID-19 patients admitted to our hospital were collected in this study. Real-time reverse transcription-quantitative polymerase chain reaction (RT-PCR) was undertaken on throat swabs and stool samples. Peripheral blood was taken and serum levels of immunoglobulin IgM and IgG measured. Results showed That, Throat swabs and stool samples tested positive for the nucleic acid of SARS-CoV-Z, but nucleic acid levels were reduced significantly 15 days after disease onset compared with that upon diagnosis. The Ct value of the nucleic acid test was increased significantly. Serum levels of IgM and IgG were significantly higher than those of healthy people. nucleic acid loads in throat swabs and stool samples as well as serum levels of IgM and IgG were highly correlated with the disease course (r = 0.7387,0.5696, -0.546 and 0.6117,respectively, P < 0.05). In this study nucleic acid loads in throat swabs and stool samples as well as serum levels of IgM and IgG are highly correlated with the course of COVID-19.

Case report on cured COVID-19 patients with viral nucleic acid test positive in fecal specimens in Chongqing, China

The outbreak of the novel coronavirus in China (2019-nCoV) has spread to all 31 provinces in China and more than 24 countries in the world. The cure criterion was based on the negative results with respiratory specimens in real-time reverse transcription polymerise chain reaction (RT-PCR) assays with an interval of 24 hrs. This report describes the controversial viral nucleic acid test in 27 cases after hospitalization for medical treatment for various periods. Of 27 cases, 6 cases showed positive results for fecal specimen, and 2 cases showed negative results with respiratory secretion but positive with fecal specimen. In summary, the consistence of results of nucleic acid test with different type of specimens from patients infected with 2019-nCoV varied, deeper research is needed to reveal the criteria of nucleic acid detection during different stages of the 2019-nCoV infection.

Critical role of Hyssop plant in the possible transmission of SARS-CoV-2 in contaminated human Feces and its implications for the prevention of the virus spread in sewage.

The significant issue affecting wastewater treatment is human faeces containing SARS-CoV-2. SARS-CoV-2, as a novel coronavirus, has expanded globally. While the current focus on the COVID-19 epidemic is rightly on preventing direct transmission, the risk of secondary transmission via wastewater should not be overlooked. Many researchers have demonstrated various methods and tools for preventing and declining this virus in wastewater treatment, especially for SARS-CoV-2 in human faeces. This research reports two people tested for 30 d, with written consent, at Mosa-Ebne-Jafar Hospital of Quchan, Iran, from September 1st to October 9th, 2021. The two people's conditions are the same. The Hyssop plant was used, which boosts the immune system's effectiveness and limonene, rosemary, caffeic acids and flavonoids, all biologically active compounds in this plant, cause improved breathing problems, colds, and especially for SARS-CoV-2. As a result, utilising the Hyssop plant can help in reducing SARS-CoV-2 in faeces. This plant's antioxidant properties effectively reduce SARS-CoV-2 in faeces by 30%; nevertheless, depending on the patient's condition. This plant is also beneficial for respiratory and digestive health.

COVID-19 GIT affection: an updated review

Background: Although it was initially believed that the coronavirus disease 2019 (COVID-19) only attacked the respiratory system, reports over time demonstrated that this disease could attack the gastrointestinal tract (GIT) as well. The predominant presenting symptoms in patients infected with COVID-19 were gastrointestinal, resulting in gastrointestinal (GI) pathological changes. While clinicians' concerns are mostly related to respiratory system manifestations, GI symptoms should be monitored and managed appropriately. Objectives: This review summarizes the essential information about COVID-19 GIT infection in terms of pathogenesis, major pathological changes, microbiological bases of infection and the possibility of feco-oral transmission, the severity of associated symptoms, the major radiological findings, the impact on GI surgery, the role of therapeutic agents in induction or magnification of GI symptoms, and a pitfall on the nutritional supplementation in COVID-19 patients.

Coronavirus disease (COVID-19): water quality, sanitation and hygiene management in light of coronavirus disease (COVID-19)

This paper describes the different ways to properly manage water quality, sanitation and hygiene in South Africa amidst COVID-19. These are: (1) use of safe disinfectants in the form of bleach, hyphochlorite or chlorine to disinfect the water before use;(2) virus inactivation through boiling (meaning, rolling boiling water for 2-3 minutes), irradiation (solar and UV) disinfection, and sedimentation and filtration techniques;(3) reclamation of wastewater and the use of sanitation services;safe practices in households through safe confinement of human wastes (faeces and urine);and (4) frequent and proper hand hygiene.

First isolation and genomic characterization of bovine parechovirus from faecal samples of cattle in Japan.

A novel picornavirus was isolated from the faeces of a diarrhoeic cow using MA-104 cells at the third blind passage. This virus, named Den1/2021/JPN, was completely sequenced using total RNA from the cell culture supernatant by deep sequencing. The genome of Den1/2021/JPN had a standard picornavirus genome organisation with conserved picornaviral motifs. The 5' untranslated region harboured a type-II internal ribosomal entry site. Den1/2021/JPN was most closely related to a bovine parechovirus (Bo_ParV) named cow/2018/4, which has been recently identified in publicly available databases. Phylogenetic analyses and pairwise sequence comparison revealed that Den1/2021/JPN and Bo_ParV cow/2018/4 clustered with parechoviruses and were most closely related to Parechovirus E identified in birds of prey, exhibiting nucleotide sequence similarity of 64.2-64.5 %, 58.6-59.7 % and 66.3-66.4 % in the polyprotein, P1 and 2C+3 CD coding regions, respectively. This study presents the first report on the isolation of Bo_ParV. Den1/2021/JPN and Bo_ParV cow/2018/4, which are candidates for a novel species in the genus Parechovirus.

Bacteriological and molecular detectionof Compylobacter species in human and animals in Diyala province

Campylobacteriosis is one of the most well-characterized bacterial foodborne infections worldwide, the species are the most common zoonotic pathogens. Chicken and chicken products are known to be the major sources of Campylobacter infection in humans. Campylobacter species represent one of the most common causes of bacterial diarrheal illness worldwide, it is the main cause of bacterial gastrointestinal infections occurring at any age, but it peaks in children and young adults. This study aims to investigate the presence and prevalence of Campylobacter bacteria in humans and chicken and aims for determination the extent of the contamination of this bacteria. The study involved two parts;the first part designed for isolation Campylobacter species from chickens which were alive, while the second part was about isolation Campylobacter species from human stool samples for different ages. The current study based on analysis of three hundred and fifty (350) stool samples taken from humans with different ages. The patients samples were collected from Al-Batool Teaching Hospital for Maternity and Pediatric, Baquba Teaching Hospital and Central Health Laboratories in Diyala, these patients were had vary clinical aspects like : (diarrhea, Fever, nausea, vomiting, abdominal pain and cramp, fatigue and muscle pain). On the other hand, one hundred seventy five (175) stool samples of chicken which they apparently had diarrhea were collected randomly from different areas of Diyala Governorate. The collection of both humans and chicken samples were during 2020 - 2021. The analysis of 350 samples of patients their ages ranged from 3 months to 59 years showed that the mean +or- SD of age was 24.5 +or- 14.3 years. The most predominant age group was 20-29 years (26.9%), while the lowest age group was 50-59 years (4.9%). Regarding the gender, 151 (43.1%) of the included patients were male and 199 (56.9%) were female. Patients included in the current study were collected from four districts of Diyala province. The highest collection rate was from Baquba district 217(62.0%), while the lowest collection rate was from Baladrooz district 18 (5.1%). the distribution of clinical signs and symptoms of included patients. Persistent diarrhea forming the predominance of signs 179 (51.1%), followed by watery diarrhea 55 (15.7%), while the least sign was vomiting 1(3%). Furthermore, 15 (4.3%) of patients showed all that signs and symptoms. The signs and symptoms were : diarrhea was found in 194 (55.4%) patients, followed by watery diarrhea in 77 (22.0%) patients. Fever was found in 30 (8.6%) patients. The least sign was nausea which was found in 15 (4.3%) patients. Abdominal pain and cramps were detected in 22 (6.3%) patients. Out of 350 stool specimens submitted for bacteriological culture, 62 (17.7%) were positive versus 288 (82.3%) were negative. Among the 62-culture positive, 13 specimens yield Campylobacter growth, so the campylobacter detection rate among human specimens was 3.7%. The isolated Campylobacter were as follow;11(3.1%) were Campylobacter jejuni, one (0.3%) was Campylobacter coli, one (0.3%) was undifferentiated campylobacter. On the other hand, 58 (16.6%) of the specimens yield bacterial growth other than Campylobacter, as follows: E. coli was detected in 28 (8.0%), Proteus Spp. was detected in 12 (3.4%), H. pylori was detected in 10 (2.9%) and Klebsiella Spp. was detected in 8 (2.3%). The remaining specimens 279 (79.7%) yield no growth. The results of the PCR technique revealed that 8 (2.38%) specimens were positive for Campylobacter, while the majority 335 (95.7%) were negative and 7(2.0%) of the specimens were not done. While the analysis of 175 chicken fecal samples taken from chickens were mainly suffering from diarrhea showed that the distribution of chickens according to their ages in days showed predominance was those 30-39 (40.6%) days old. It is clear that the majority of specimens (74.3%) were collected from Baquba districts. The results showed that specimens collected Al- Muqdadiya district farms had yielded the high

Investigation on the prevalence of Clonorchis sinensis infection in human population of Heilongjiang Province, 2015

To understand the current status of Clonorchis sinensis infection in the population of Heilongjiang Province, the survey sites were selected from 104 rural areas and 15 urban areas in the Province in April-June 2015, using stratified cluster random sampling method, in accordance to the guideline of the National Survey, Program for Key Human Parasitic Diseases. The rural areas were divided into four ecoregions: Changbai Mountain-Qianshan Mountains, the Eastern Northeast Plain, Sanjiang Plain, and Xiaoxing'an Mountain coniferous and broad-leaved mixed forest. The number of people surveyed at each survey site was no less than 250. The modified Kato thick smear method was used to examine the participants' fecal samples (two slide-reading/sample) for C. sinensis eggs and counted. Of the 30 280 examinees, 747 were found infected, with an infection rate of 2.47%. The infection rate in rural and urban areas was 2.77% (734/26 456) and 0.34% (13/3 824) respectively, with the difference being statistically significant (X2 = 82.295, P < 0.05). Most of the infected showed mild infection (82.33%, 615/747). The infection rate was 3.05% (462/15 171) in males and 1.89% (285/15 109) in females, showing significant difference between the sexes (X2 = 42.261, P < 0.05). The highest infection rate was seen in the age group of 30-39 years (3.32%, 147/4 430), revealing significant difference between the age groups (X2 = 122.182, P < 0.05). The highest infection rate was found in farmers (animal husbandry and fishery) (3.16%, 692/21 914), with the difference between occupation groups being statistically significant (X2 = 164.846, P < 0.05). The infection rate differed significantly among the participants with different levels of education (X2 = 124.596, P < 0.05) and was highest in the group with junior high school education (3.46%, 499/14 425). The rate was significantly different between different ethnic groups (X2 = 8.395, P < 0.05), with the Han group having the highest infection rate (2.51%, 739/29 487). In rural areas, most of the infected people showed mild infection intensity (82.56%, 606/734). The infection rate was 3.39% (454/13 378) in males and 2.14 (280/13 078) in females, thus differing significantly between the sexes (X2 = 38.468, P < 0.05). The infection rate differed significantly with age (X2 = 111.315, P < 0.05) and was highest in the 30-39 year age group (3.78%, 145/3 841). Significant difference in infection rate was found also in occupation distribution (X2 = 103.863, P < 0.05), with the highest seen in the group of servants and enterprise-institution employees (5.05%, 10/198). The infection rate differed significantly in education distribution (X2 = 127.308, P < 0.05), and was highest in the group at the education level of junior high school (3.88%, 496/12 792). It also differed significantly between different ethnic groups (X2 = 8.903, P < 0.05), and was highest in the Han group (2.82%, 726/25 734). The Sanjiang Plain ecoregion showed the highest infection rate (8.75%, 575/6 574), and the rate differed significantly between ecoregions (X2 = 1 177.510, P < 0.05). In urban areas, the majority of the infected had mild infection (9/13). The infection rate in males was 0.45% (8/1 793) and that in females was 0.25% (5/2 031). The highest infection rate was detected in the age group 50-59 years (0.79%, 5/636), and among different occupations, the group of servants and enterprise-institution employees had the highest infection rate (0.97%, 4/411). In the education distribution, the illiterate group showed the highest infection rate (1.14%, 2/176). C. sinensis infection was only detected in Han ethnicity, with an infection rate of 0.35% (13/3 753). The C. sinensis infection found in Heilongjiang Province was largely mild, and the highest infection rate was seen in the Sanjiang Plain ecoregion, thus, it is imperative to actively explore feasible control strategies and measures appropriate to the

Surveillance on soil-transmitted nematode infections in population in Guangxi Zhuang Autonomous Region during 2016-2020

Objective: To understand and analyze the epidemic status and development trends of soil-transmitted nematodiasis in Guangxi Zhuang Autonomous Region (Guangxi), to provide scientific basis for formulating the disease control strategy, and evaluating the control effect.

Prevalence of Rotavirus and Coronavirus in feces of newborn calves with diarrhea

A 1:1 matched case-control study of calves under 1 month of age was carried out by weekly visits to 7 dairy farms in Mashhad, Iran. Fecal samples were collected from 112 calves with diarrhea and 112 controls matched assessed by scoring. Rotavirus and Coronavirus were isolated by antigen capture ELISA test. We found Rotavirus antigen in 29.5% in diarrheic and 17% in normal calves. We detected Coronavirus antigen in 2.7% and 1.8%, respectively. In diarrheic calves Rotavirus was most prevalent at 3rd week age whereas Coronavirus was found in very few cases by 2nd week. Excretion of Rotavirus in feces of scouring calves was greater (P < 0.03) than controls with odds ratio of 1.9 (1.05 - 3.76). We found no relationship between shedding Coronavirus in feces and diarrhea (P value =0.66) with odds ratio equals to 1.4 (0.24 -9.05). We find that Rotavirus is associated with newborn calf diarrhea in industrial dairy farms in Iran.

Nucleic acid detection of fecal samples from confirmed cases of COVID-19

To investigate the status of viral infection in the feces of confirmed COVID-19, cases fecal samples or anal swabs from 36 confirmed cases were collected, 2019-nCoV was detected by real-time fluorescence RT-PCR, and the infection rates of the cases were compared by statistical analysis software SPSS 19.0. Among the 36 samples, 20 (55.56%) were positive for 2019-nCoV. The positive rate of critical cases (2/3) and severe cases(6/9) were both 66.67%, the positive rate of common pneumonia was 62.50% (10/16), and the positive rate of mild pneumonia was 25.00% (2/8). The 36 confirmed COVID-19 cases included 22 males and 14 females, with a detection rate of 54.55% and 57.14%, respectively. The age distribution range of the cases was ranging between 17 and 86 years old, with an average age of 48.75 years. Among the 36 samples, 2 positive specimens in 5 anal swab specimens and 18 positive specimens in 31 fecal specimens were detected. There were no statistically significant differences in the positive detection rates among clinical types, genders, ages and specimen types, respectively. From these results, we deduced that fecal samples of confirmed COVID-19 cases contained 2019-nCoV, which can cause infection through potential fecal-oral transmission and be significant for clinical treatment and epidemiological study.

Spillover of SARS-CoV-2 into novel wild hosts in North America: a conceptual model for perpetuation of the pathogen

There is evidence that the current outbreak of the novel coronavirus SARS-CoV-2, which causes COVID-19, is of animal origin. As with a number of zoonotic pathogens, there is a risk of spillover into novel hosts. Here, we propose a hypothesized conceptual model that illustrates the mechanism whereby the SARS-CoV-2 could spillover from infected humans to naive wildlife hosts in North America. This proposed model is premised on transmission of SARS-CoV-2 from human feces through municipal waste water treatment plants into the natural aquatic environment where potential wildlife hosts become infected. We use the existing literature on human coronaviruses, including SARS CoV, to support the potential pathways and mechanisms in the conceptual model. Although we focus on North America, our conceptual model could apply to other parts of the globe as well.

Detection and monitoring of the SARS-CoV-2 virus in Diluvio stream, Porto Alegre, RS, associated with parameters of environmental quality

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), which causes COVID-19 disease, is accompanied by the presence and dissemination of the virus in the feces of symptomatic and asymptomatic individuals. Several studies have pointed out the presence of virus fragments in the environment and viral loads for long periods in sewage systems and wastewater. The rapid spread of the infection has severely impacted public health and the global economy, demanding coping strategies and solutions for the pandemic. In this study, sewage-based epidemiology (WBE) was adapted as a complementary methodological strategy to clinical monitoring of the occurrence of COVID-19 in Porto Alegre. For 12 months, starting in August 2020, biweekly composite collections of water, flow determination and field parameters were carried out at the mouth of the Diluvio stream. From these samples, analyzes of quantitative viral RNA and water quality parameters associated with sewage discharges were performed. During the period evaluated, a correlation was observed between the concentration values of virus particles at the mouth of the stream and the number of clinical cases of COVID-19 officially notified by the State Health Department for Porto Alegre. The results, partially presented here, demonstrate the efficiency of the WBE strategy applied to the urban watercourse, in monitoring the SARS-CoV-2 pandemic.

Rectally shed SARS-CoV-2 in COVID-19 inpatients is consistently lower than respiratory shedding and lacks infectivity.

OBJECTIVES: Assessment of whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been propagated during intestinal passage and infectivity is conserved when shed rectally by hospitalized individuals. METHODS: An exploratory cohort study including 28 inpatients with coronavirus disease 2019 with estimation of RNA levels by RT-PCR and of viral infectivity by culturing of viral material sampled concomitantly and identically from pharynx and rectum. RESULTS: SARS-CoV-2 RNA was detected more frequently (91%, 30/33 versus 42%, 14/33, p <0.0001) and at higher concentrations (median levels 2 190 186 IU/mL versus 13 014 IU/mL, p <0.0001) in the pharyngeal swabs than in the rectal swabs. For all sample pairs (n = 33) the rectal swabs contained undetectable or lower SARS-CoV-2 RNA concentrations than their paired pharyngeal swabs. Replicative virus was found in 37% (11/30) of the PCR-positive pharyngeal swabs, whereas none of the PCR-positive rectal swabs could be cultured (0%, 0/14) despite containing SARS-CoV-2 RNA concentrations up to 1 544 691 IU/mL. CONCLUSIONS: Our data draw into question whether SARS-CoV-2 is transmitted readily from faeces.

Epidemiology investigation of PRRSV discharged by faecal and genetic variation of ORF5.

To obtain more information of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) transmission via faeces in/between farms, 360 swine faecal samples were randomly collected from different farms in China from 2017 to 2019. Sixty-two ORF5 genes were amplified by PCR from 120 positive samples identified by real-time RT-PCR and further characterized by sequencing. Phylogenetic analysis based on the ORF5 gene revealed that these strains can be divided into four lineages: lineage 1 (NADC30-like), lineage 3 (QYYZ-like), lineage 5.1 (VR2332-like) and lineage 8.7 (JXA1-like), with 62.9% (39/62) NADC30-like virus, 21% (13/62) QYYZ-like virus, 1.6% (1/62) VR2332-like virus and 14.5% (9/62) for JAX1-like virus. In particular, 14 PRRSVs including lineage 1, 5.1 and 8.7 can be isolated from 120 positive faecal samples, which further suggests that faecal transmission may be an important factor in the spread of PRRSV in farms. Full-length genome sequencing analysis showed that 14 isolates share 83.1%-97.7% homology with each other and 82.3%-96.1% identity with NADC30, 83.2%-99.7% with VR2332, 79.6%-87.2% with QYYZ and 82.6%-98.9% with JXA1 and CH-1a, and only 60.1%-60.7% with LV. Recombination events were observed in the six out of 14 strains. Collectively, the data of this study are useful for understanding the spread of PRRSV via faeces. Additionally, the virus was isolated from positive faecal samples, suggesting that faecal transmission may be an important factor in the spread of PRRSV in farms.

Duration of SARS-CoV-2 viral shedding in faeces as a parameter for wastewater-based epidemiology: Re-analysis of patient data using a shedding dynamics model.

Wastewater-based epidemiology (WBE) is one of the most promising approaches to effectively monitor the spread of COVID-19. The virus concentration in faeces and its temporal variations are essential information for WBE. While some clinical studies have reported SARS-CoV-2 concentrations in faeces, the value varies amongst patients and changes over time. The present study aimed to examine how the temporal variations in the concentration of virus in faeces affect the monitoring of disease incidence. We reanalysed the experimental findings of clinical studies to estimate the duration of virus shedding and the faecal virus concentration. Available experimental data as of 23 October 2020 were collected. The viral shedding kinetics was modelled, and the dynamic model was fitted to the collected data by a Bayesian framework. Using posterior distributions, the duration of viral shedding and the concentration of virus copies in faeces over time were computed. We estimated the median concentration of SARS-CoV-2 in faeces as 3.4 (95% CrI: 0.24-6.5) log copies per gram-faeces over the shedding period, and our model implied that the duration of viral shedding was 26.0 days (95% CrI: 21.7-34.9), given the current standard quantification limit (Ct = 40). With simulated incidences, our results also indicated that a one-week delay between symptom onset and wastewater sampling increased the estimation of incidence by a factor of 17.2 (i.e., 101.24 times higher). Our results demonstrated that the temporal variation in virus concentration in faeces affects microbial monitoring systems such as WBE. The present study also implied the need for adjusting the estimates of virus concentration in faeces by incorporating the kinetics of unobserved concentrations. The method used in this study is easily implemented in further simulations; therefore, the results of this study might contribute to enhancing disease surveillance and risk assessments that require quantities of virus to be excreted into the environment.

SARS-CoV-2 from faeces to wastewater treatment: What do we know? A review.

SARS-CoV-2, the virus that causes COVID-19, has been found in the faeces of infected patients in numerous studies. Stool may remain positive for SARS-CoV-2, even when the respiratory tract becomes negative, and the interaction with the gastrointestinal tract poses a series of questions about wastewater and its treatments. This review aims to understand the viral load of SARS-CoV-2 in faeces and sewage and its fate in wastewater treatment plants (WWTPs). The viral load in the faeces of persons testing positive for SARS-CoV-2 was estimated at between 5·103 to 107.6 copies/mL, depending on the infection course. In the sewerage, faeces undergo dilution and viral load decreases considerably in the wastewater entering a WWTP with a range from 2 copies/100 mL to 3·103 copies/mL, depending on the level of the epidemic. Monitoring of SARS-CoV-2 in sewage, although no evidence of COVID-19 transmission has been found via this route, could be advantageously exploited as an early warning of outbreaks. Preliminary studies on WBE seem promising; but high uncertainty of viral loads in wastewater and faeces remains, and further research is needed. The detection of SARS-CoV-2 in sewage, based on RNA sequences and RT-PCR, requires a shared approach on sample pre-treatment and on-site collection to ensure comparable results. The finding of viral RNA in stools does not imply that the virus is viable and infectious. Viability of CoVs such as SARS-CoV-2 decreases in wastewater - due to temperature, pH, solids, micropollutants - but high inactivation in WWTPs can be obtained only by using disinfection (free chlorine, UVC light). A reduction in the quantity of disinfectants can be obtained by implementing Membrane-Bioreactors with ultrafiltration to separate SARS-CoV-2 virions with a size of 60-140 nm. In sludge treatment, thermophilic digestion is effective, based on the general consensus that CoVs are highly sensitive to increased temperatures.