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Coronaviruses in water & wastewatersurvival and inactivation

Shahid Beheshti University of Medical SciencesSchool of Public Health and Safety

By: Dr Yazdanbakhsh

1398

Coronaviruses in water and wastewater 1

In the name of god

Coronaviruses in water & wastewater: survival and inactivation

Coronaviruses (CoV)

Coronaviruses (CoV) are a large family of viruses that cause illness rangingfrom the common cold to more severe diseases such as: Middle EastRespiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome(SARS-CoV). A novel coronavirus (nCoV) is a new strain that has not beenpreviously identified in humans.

Coronaviruses are zoonotic, meaning they are transmitted between animalsand people. Detailed investigations found that SARS-CoV was transmittedfrom civet cats to humans and MERS-CoV from dromedary camels tohumans. Several known coronaviruses are circulating in animals that have notyet infected humans.

Reference: (WHO)Coronaviruses in water and wastewater 2

https://www.who.int/emergencies/mers-cov/en/

https://www.who.int/csr/sars/en/

https://www.who.int/emergencies/diseases/novel-coronavirus-2019


Coronaviruses are primarily respiratory pathogens.

Its major source of transmission is person-to-person contact through respiratorysecretions and animal to human.

The fecal-oral transmission may be possible as well.

Coronaviruses were not considered of concern for waterborne transmission,until a new coronavirus, the causative agent of severe acute respiratorysyndrome (SARS), was detected in the feces of infected patients.

In addition, large clusters of cases suggest the possibility of environmentalcontamination via sewage or ventilation systems.

Reference: [Heymann DL. Status of the global SARS outbreak and lessons for the immediate future. Geneva: WHO;2003. Available from: www.who.int/csr/sarsarchive/2003_04_11/en/.]


• Modes of Transmission of coronaviruses


• Corona Viruses in Environment

In general, a given pathogen must remain viable outside the host to allow forenvironmental spread, and the combined effect of many biotic and abiotic factorsdetermines how long such viability can be retained. While environmental survival ofcoronaviruses has been studied to some degree under experimental conditionsincluding SARS, we know much less about the types and relative significance ofvehicles in the in-nature spread of coronaviruses, in particular those that can infecthumans.



• Coronaviruses in EnvironmentThe following is a summary of the available information on the environmental survival and spread of coronaviruses:

• Persistance and inactivation Coronaviruses in AIR:

The effect of relative humidity (RH) and air temperature has been studied on the airbornesurvival of experimentally aerosolized human coronavirus 229E. As is true for envelopedviruses in general, 229E survived better at 30-50% RH than at 80% RH when the airtemperature was about 20°C.

Under these conditions, the half-lives of the virus at 30%, 50% and 80% RH were 27, 67 and 3hours, respectively. Lowering the air temperature to 6°C increased the half-lives of the virus at30% and 50% RH to 34 and 103 hours, respectively. But the lower air temperature produced themost dramatic effect on virus survival at 80% RH and changed its half-life from 3 to over 86hours.

• Reference: Manfred H.Wolff,1 Syed A. Sattar,2 Olusola Adegbunrin2 and Jason Tetro2 Environmental survival and microbicideinactivation of coronaviruses, Coronaviruses with Special Emphasis on First Insights Concerning SARS 201 ed. by A. Schmidt, M.H. Wolffand O. Weber© 2005 Birkhäuser Verlag Basel/Switzerland


• Persistence and inactivation of coronavirus on Environmental surfaces

SARS-CoV and 229E and OC43 can retain their infectivity for several hours onporous and non-porous environmental surfaces. While such survival is better thanthat of other enveloped human pathogens, there is no evidence to suggest thatenvironmental surfaces play any direct or indirect role in the spread of coronaviruses.

Most data were described with the endemic human coronavirus strain (HCoV-) 229E. On different types of materials it can remain infectious for from 2 hours up to 9 days. A higher temperature such as 30°C or 40°C reduced the duration of persistence of highly pathogenic MERS-CoV, TGEV and MHV. However, at 4°C persistence of TGEV and MHV can be increased to ≥ 28 days. Few comparative data obtained with SARS-CoV indicate that persistence was longer with higher inoculate (Table 1,2). In addition it was shown at room temperature that HCoV-229E persists better at 50 compared to 30% relative humidity.


Reference: Duan SM, Zhao XS,Wen RF, Huang JJ, Pi GH, Zhang SX, Han J, Bi SL, Ruan L, Dong XP; SARS Research Team (2003) Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation. Biomed Environ Sci 16: 246–255

Reference: Ijaz MK, Brunner AH, Sattar SA, Nair RC, Johnson-Lussenburg CM. Survival characteristics of airborne human coronavirus 229E. The Journal of general virology 1985; 66 ( Pt 12): 2743-8.


Table 1. Persistence of coronaviruses on different types of inanimate surfaces

Günter Kampf, Daniel Todt, Stephanie Pfaender, Eike Steinmann , Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidalAgents, Journal of Hospital Infection, preproof.


Table2. Inactivation of coronaviruses by different types of biocidal agents in suspension tests.


• Persistence and inactivation of coronavirus on Environmental surfaces…

Coronaviruses on surfaces were readily inactivated by:

ethanol,

isopropanol,

benzalkonium chloride,

iodophor,

sodium hypochlorite,

sodium chlorite,

cresol soap

formaldehyde

H2O2

Table3,4



Table3. Inactivation of coronaviruses by different types of biocidal agents in carrier tests.


Table4. Activity of microbicides against coronavirus 229E (Sattar et al., unpublished data)


Persistence and inactivation of coronavirus on Environmental surfaces…

In general: Human coronaviruses can remain infectious on inanimate surfaces for up to 9 days. Surface disinfection with 0.1% sodium hypochlorite or 62-71% ethanol significantly reduces coronavirus infectivity on surfaces within 1 min exposure time. We expect a similar effect against the 2019-nCoV.


• Water and wastewater

In the first time, transmission of the virus by aerosolized wastewater wassuspected during the investigation of the SARS outbreak at Amoy Gardens in HongKong In 2003.[Reference: Moe CL. What are the criteria for determining whether a diseaseis zoonotic and water related? In: World

Health Organization. Waterborne zoonoses: identification, causes and control. London,UK: IWA Publishing; 2004. ]

A study investigated the survival of representative coronaviruses in tap water andWastewater in 2009. The results showed that inactivation of coronaviruses in the testwater was highly dependent on temperature, level of organic matter, and presence ofbacteria.

Coronaviruses were inactivated faster in water at 23 °C (10 days) than in water at 4°C (> 100 days);

They died off rapidly in wastewaters (2-4 days). The results of this study indicatethat coronaviruses are much more sensitive to temperature than PV-1 and that thereis a considerable difference in survivability between PV-1 and the coronaviruses inwastewater.• [Reference: Gundy PM, Gerba CP, Pepper IL. Survival of coronaviruses in water and wastewater. Food

Environment Virology 2009;1(1):10-4.].


Water and wastewater…

Also, In this research, survival of the coronaviruses in primary wastewater was onlyslightly longer than secondary wastewater, probably due to the higher level ofsuspended solids that offer protection from inactivation.

This study demonstrates that the transmission of coronaviruses would be less thanenteroviruses in the aqueous environment due to the fact that coronaviruses are morerapidly inactivated in water and wastewater at ambient temperatures.

The ambient air from wastewater treatment plants has been considered as a potentialsource of pathogenic microorganisms to cause an occupational risk for the workersof the plants

Reference: Gundy PM, Gerba CP, Pepper IL. Survival of coronaviruses in water and wastewater. Food Environment Virology2009;1(1):10-4.].


Also, bioaerosols are suspected to have adverse health effects on the neighboringresidents of wastewater treatment processes.

Since viruses are smaller than other bioaerosols, they have the potential to travelfurther distances.

Reference: Núñez, Andrés; Amo de Paz, Guillermo; Rastrojo, Alberto; García, Ana M.; Alcamí, Antonio; Gutiérrez-Bustillo, A. Montserrat; Moreno, DiegoA. (2016-03-01). "Monitoring of airborne biological particles in outdoor atmosphere. Part 1: Importance, variability and ratios". International Microbiology.19 (1): 1–13


Water and wastewater

In a other research study, titled: “Concentration and detection of SARScoronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital”

was demonstrated in order to confirm whether sewage is a possible major route oftransmission of SARS-CoV?

Hospital sewage was collected daily from Xiao Tang Shan Hospital and the 309thHospital of PLA, specially assigned to receive SARS patients in Beijing. A novelstyle of electropositive filter media particle was used to concentrate the SARS-CoVfrom the sewage of hospitals receiving SARS patients in Beijing, China. Cell cultureand RT-PCR were utilized to detect and identify the viruses from sewage.

The nucleic acid of SARS-CoV was found in the sewage before disinfection fromboth hospitals by semi-nested PCR. The results provide strong evidence that SARS-CoV can be excreted through the stool/urine of patients into sewage system, thusmaking the sewage system a possible route of transmission.• Reference: Xin-Wei Wang et al, Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th

Hospital, Journal of Virological Methods 128 (2005) 156–161.


• Detection of viruses in water and wastewater

• Viruses are present in relatively small number in water and wastewater. Therefore,environmental samples of 10-100 L must be concentrated in order to detect thesepathogens. The most used approach is based on the adsorption of viruses tomicrofilters of various compositions like: nitrocellulose, fiberglass, chargemodified cellulose,…

• Reference: Bitton,G. Wastewater Microbiology: Second Edition, Wiley-Liss,1999.


Detection of viruses in water and wastewater

The following methods have been adapted for analysis of viruses in water and wastewater samples:

Polymerase Chain-Reaction (PCR)

Nucleic Acid Sequence—Based Amplification (NASBA)

microarray technique

Atomic Force Microscope (AFM)

fluorescent microscopy

electron microscopy

application of biosensors

Enzyme Linked Immunosorbent Assay (ELISA)

• Reference: Alicja Hryniszyn1, Magdalena Skonieczna2, Jarosław Wiszniowski1. Methods for Detection of Viruses in Water and Wastewater , Advances in Microbiology, 2013, 3, 442-449


Viruses Inactivation / removal from water and wastewater


Inactivation or removal of various viruses are possible by different treatment

processes in water and wastewater treatment plants, spatially disinfection is a very

effective process. Viruses could be removal or inactive by physical, chemical and

biological processes in wastewater treatment plant.

Physical processes such as sedimentation, adsorption, screening, nanofiltration,

reverse osmosis.

Chemical process such as: coagulation and chemical disinfectants such as chlorine

and ozone or application of UV

are the most processes that are used in water and wastewater treatment plants.

(Table5)


Table5. Log removal/inactivation of viruses by different treatment

processes

Reference: C.M. Zhang , Limei Xu, Elimination of viruses from domestic wastewater: requirements and

technologies, World J Microbiol Biotechnol (2016) 32:69

Disinfection of water and wastewater

Disinfection is the destruction of microorganisms capable of causing disease. Disinfection is an essential and final barrier against human exposure to disease-causing pathogenic microorganisms, including viruses, bacteria and protozoan parasites. The common disinfectants in water and wastewater are:

• Chlorine, chlorine dioxide

• Ozone

• Ultraviolet light

• Table 6-8



Table6. Microbial Inactivation by Chlorine: Ct Values (Temperature 5 58C; pH 5 6.0)a


Table7. Inactivation of Health-Related Microorganisms in Water by Chlorine Dioxidea: Ct values

Table8. Approximate Dosage for 90% Inactivation of Selected Microorganisms by UV


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