Viral Pollution Research Articles

Fate of viruses in artificial wetlands.

Little is known about the ability of wetlands to remove disease-causing viruses from municipal wastewater. In this study we examined the survival of several indicators of viral pollution (indigenous F-specific bacteriophages, seeded MS2 bacteriophage, and seeded human poliovirus type 1) applied in primary municipal wastewater to artificial wetland ecosystems. Only about 1% of the indigenous F-specific RNA bacteriophages survived flow through the vegetated wetland beds at a 5-cm-day-1 hydraulic application rate during the period from June through December 1985. The total number of indigenous F-specific bacteriophages (F-specific RNA and F-specific DNA phages) was also reduced by about 99% by wetland treatment, with the mean inflow concentration over the period of an entire year reduced from 3,129 to 33 PFU ml-1 in the outflow of a vegetated bed and to 174 PFU ml-1 in the outflow of an unvegetated bed. Such superior treatment by the vegetated bed demonstrates the significant role of higher aquatic plants in the removal process. Seeded MS2 bacteriophage and seeded poliovirus were removed more efficiently than were the indigenous bacteriophages, with less than 0.2% of MS2 and 0.1% of the poliovirus surviving flow at the same hydraulic application rate. The decay rate (k) of MS2 in a stagnant wetlands (k = 0.012 to 0.028 h-1) was lower than that for flowing systems (k = 0.44 to 0.052 h-1), reflecting the enhanced capacity for filtration or adsorption of viruses by the root-substrate complex (and associated biofilm).(ABSTRACT TRUNCATED AT 250 WORDS)

Viral Pollution of Coastal Waters Resulting from the Disposal of Untreated Sewage Effluents

The viral pollution of environmental waters results primarily from the discharge of domestic wastewaters which carry human enteric viruses. The present study examines the viral load of sewage effluents, before their treatment for virus removal, over a thirteen-month period. The maximum viral load detected during the study period was 880 viral cytopathic units per litre of sample. This was recorded in the month of November 1983. Out of 236 randomly selected field-isolates the following serotypes were distinguished as types: all three Polio, four Coxsackie B, three Echo and six Adeno. The serotypes with the highest frequency were Polio II, Coxsackie B4 and Adeno 7.

Human enteroviruses in marine sediments near a sewage outfall on the Otago Coast

Abstract Sediment and beach sand samples from around a sewer outfall were collected and tested for the presence of enteroviruses and faecal coliforms. Enteroviruses were recovered from 5 of 14 samples collected on three different occasions. Enteroviruses were recovered from two samples in which faecal coliform levels were low. These results suggest that the faecal coliform test may not be a reliable indicator of viral pollution. Virus types recovered were Poliovirus 2, Coxsackievirus B4 and B5, and a number of isolates unable to be identified using the Lim Benyesh‐Melnick pooled antisera.

Viral pollution of the marine environment

The marine environment is a vital global resource which continues to be used for the disposal of man's waste. Its role as a waste disposal medium, however, is inimical to its value as a source of food and recreation. The present article discusses the role of ocean disposal of municipal sludge in the recycling of human pathogens in the marine environment. Particular attention will be paid to the occurrence, fate, and transport of human enteric viruses in marine waters, sediments, and marine organisms. The relationship of fecal indicator bacteria with the occurrence of enteric viruses will also be delineated.

Viral pollution determination of superficial waters (river water and sea-water) from the urban area of Barcelona (Spain)

Various surface water systems in the metropolitan area of Barcelona (Spain), including two rivers and three beaches, were analysed for human viruses using glass powder as adsorbent to concentrate them. The method used allows concentration of large volumes (up to 2001), of water in a single step. Values obtained varied from 18.4 to values higher than 55 MPNCU 1 −1in the Besôs river and 0.44-44 MPNCU 1 −1in the Llobregat river. Viruses were isolated from approx. 70% of sea-water samples, the values ranging from 0 to 1.60 MPNCU 1 −1. Findings are discussed in terms of correlation between virus pollution and bacterial indicators of fecal contamination. Also, the suitability of glass powder adsorption to concentrate viruses in sea-water is discussed.

Sewage Disposal and Viral Pollution of the Ottawa River

Abstract The quality of water in the Ottawa River is being affected by the disposal of increased volumes of sewage into it. Some of the sewage disposal points are situated upstream of beaches and intake points for water purification plants. The aim of this study was to assess the impact of such waste disposal on the virological quality of recreational and drinking waters for the Ottawa area. A total of 132 weekly samples of raw sewage, chlorinated secondary effluents, raw and finished surface waters were examined for viruses from June to December 1977. In addition to these, ten samples of tap water, collected during the first two weeks of April 1978, were also included in this study. Virus concentration from these samples was carried out using the talc-Celite technique developed in the laboratory. Primary human embryonic kidney (HEK) cells and BS-C-1 cells were used for the detection and quantitation of viruses present in the sample concentrates. Virus isolates were identified by their cytopathology, examination under the electron microscope and serology. When 6 1. volumes were processed, nearly all the samples of raw sewage and 54% chlorinated effluent samples were found to be positive for virus. Approximately 50% of the surface water samples were also shown to contain virus using 40 1. sample volumes. Concentrates of some of the potable water samples showed virus-like degeneration in cell cultures. Although this degeneration was found to be transmissible, at this stage it is not possible to say if this effect was in fact due to a viral agent. The following major conclusions were drawn from this study: (a) All three major enteric virus groups were represented in the virus isolates. However, inherent limitations of sample concentration and virus isolation techniques may have resulted in the detection of only a small fraction of the viruses present in the samples. (b) There was no apparent correspondence between the numbers of indicator bacteria and the presence or absence of detectable virus in the samples. (c) Viruses detected in the recreational and raw water samples may be due to the presence of point sources of raw sewage discharge upstream. This could result in the dissemination of human pathogenic viruses through recreational and potable waters.

Viral Pollution of Surface Waters Due to Chlorinated Primary Effluents

The role of chlorinated primary effluents in viral pollution of the Ottawa River (Ontario) was assessed by examining 282 field samples of wastewaters from two different sewage treatment plants over a 2-year period. The talc-Celite technique was used for sample concentration, and BS-C-1 cells were employed for virus detection. Viruses were detected in 80% (75/94) of raw sewage, 72% (68/94) of primary effluent, and 56% (53/94) of chlorinated effluent samples. Both raw sewage and primary effluent samples contained about 100 viral infective units (VIU) per 100 ml. Chlorination produced a 10- to 50-fold reduction in VIU and gave nearly 2.7 VIU/100 ml of chlorinated primary effluent. With a combined daily chlorinated primary effluent output of approximately 3.7 x 10(8) liters, these two plants were discharging 1.0 x 10(10) VIU per day. Because the river has a mean annual flow of 8.0 x 10(10) liters per day, these two sources alone produced a virus loading of 1.0 VIU/8 liters of the river water. This river also receives at least 9.0 x 10(7) liters of raw sewage per day and undetermined but substantial amounts of storm waters and agricultural wastes. It is used for recreation and acts as a source of potable water for some 6.0 x 10(5) people. In view of the potential of water for disease transmission, discharge of such wastes into the water environment needs to be minimized.

Viruses in Water Supply

In comparison with information concerning bacterial contamination of water supplies, much less is known about viruses in water because few water systems determine the presence of viral pollutants in their supplies, although various techniques exist for delineating the presence of viruses. A summary of the advantages and disadvantages of the various techniques is given along with the recommendations of APHA concerning detection and control of waterborne viruses.

Fate of Animal Viruses in Effluent from Liquid Farm Wastes

Various aspects of viral pollution of the environment associated with disposal of liquid farm manure on agricultural land are being investigated. Techniques have been developed for concentration and recovery of animal viruses from various field samples. Seventeen of 22 samples of liquid manure from a swine fattening house yielded enteroviruses, adenoviruses, and a coronavirus. One enterovirus was isolated from six samples of waste from a swine farrowing house, but no virus was isolated from 18 samples of liquid cattle manure obtained from a dairy farm. A swine enterovirus was isolated from surface soil samples collected up to 8 days after liquid manure was spread on agricultural land. A swine enterovirus was also isolated from 2 of 26 samples of surface run-off collected from sites at which liquid pig manure was routinely spread on agricultural land. Thirty three samples of surface water and 36 samples of ground water were collected in areas in which liquid pig manure was routinely spread on farm land, and a swine enterovirus was isolated from one surface water sample. Field and laboratory experiments indicated that enteroviruses are more rapidly inactivated in aerated liquid manure than in untreated manure.

Bacteriophages as viral pollution indicators

f2 Phage, attenuated Polio I (LSC) strain introduced daily to a 350 l. experimental oxidation pond showed no decrease in bacterial viruses f2 or other coliphages or Polio I strain. Ratios of coliphages to human enteric viruses ranged in flood waters from concentrations as low as 1:1 to as high as 10 3:1; in wastewater at various seasons the ratio was 10 5:1; in trickling filter effluents in winter it was 10 4:1; in spring 10 5:1, in summer and fall 10 4:1, in oxidation pond effluents in winter 10 3:1; in spring 10 4:1; and in summer and fall 10 3:1. Out of three epidemics in small communities caused by failure of water supply, coliphages were found to be positive. At the same time only two samples of human enteric viruses were positive (the third was contaminated with yeasts). Chlorination experiments using the experimental oxidation pond showed that f2 was most resistant, MS 2 was very resistant, and coliphages were more resistant than attenuated Polio I virus. Experiments with the oxidation pond effluents showed that coliphages were at least as or even more resistant to chlorine than human enteric viruses.

Quantitative method of viral pollution determination for large volume of water using ferric hydroxide gel impregnated on the surface of glassfibre cartidge filter.

Quantitative method of viral pollution determination for large volume of water using ferric hydroxide gel impregnated on the surface of glassfibre cartridge filter. The use of ferric hydroxide gel, impregnated on the surface of glassfibre cartridge filter enable us to recover 62.5% of virus (Poliomylitis type I, Lsc strain) exsogeneously added to 400 liters of tap-water. The virus concentrator system consists of four cartridge filters, in which the three first one are clarifiers, where the contaminants are removed physically, without significant virus loss at this stage. The last cartridge filter is impregnated with ferric hydroxide gel, where the virus is adsorbed. After the required volume of water has been processed, the last filter is removed from the system and the viruses are recovered from the gel, using 1 liter of glycine/NaOH buffer, at pH 11. Immediately the eluate is clarified through series of cellulose acetate membranes mounted in a 142mm Millipore filter. For the second step of virus concentration, HC1 1N is added slowly to the eluate to achieve pH 3.5-4. MgC1, is added to give a final concentration of 0.05M and the viruses are readsorbed on a 0.45 , porosity (HA) cellulose acetate membrane, mounted in a 90 mm Millipore filter. The viruses are recovered using the same eluent plus 10% of fetal calf serum, to a final volume of 3 ml. In this way, it was possible to concentrate virus from 400 liters of tap-water, into 1 liter in the first stage of virus concentration and just to 3 ml of final volume in a second step. The efficiency, simplicity and low operational cost, provded by the method, make it feasible to study viral pollution of recreational and tap-water sources.

Relative chlorine resistance of poliovirus I and coliphages f2 and T 2 in water.

Phage f2 is markedly more resistant to chlorine in water than either poliovirus or coliphage T(2). Its potential use as an indicator of viral pollution is suggested.

Electro-osmosis: a new technique for concentrating viruses from water

THE ROLE of water-borne viral diseases of men and animals has been reviewed most recently at a Symposium entitled Virus and Water Quality: Occurrence and Control (SNoEYINK, 1971). It has been shown that pathogenic viruses can be recovered from waters, and although no definite epidemics (with the exception of infectious hepatitis) have been convincingly traced to them, a potential hazard is present which may increase and eventually prove to be a serious public health problem. Thus, it is apparent that methods of monitoring water supplies, as well as establishing standards of levels must be found. This is especially true as water reserves dwindle and lead to the use of renovated waste waters. In addition, the concentration of viral pollutants will increase with both industrial and urban growth. This growth may lead to inadequacies of the purification or renovation systems insofar as microbial contamination is concerned. Restated simply, with increased pollution, the minimal infectious or minimal disease-producing dose for man or animals may be reached, and thus set the stage for potential epidemic or endemic spread of the agents. Therefore, it appears to us that a monitoring system, both qualitative and quantitative, must be developed to establish guidelines for safety which will then be applied to run-off, surface, and processed waters. Monitoring of water for viruses has been, and remains, a long, difficult, and tedious task involving collection and sampling, concentration, detection (isolation) in animal or tissue culture systems, and identification by in vitro (serological or immunological) or in vivo methodologies. The isolation of small quantities of virus in large quantities of diluent (water) is basically a problem of concentration. The method to be used must be rapid, relatively gentle, and capable of handling large quantities of fluid effectively. Various biophysical and biochemical techniques have been used, including continuous flow centrifugation, density gradient methods, simple filtration, chemical concentration by biphasic systems, or co-precipitation with salts of heavy metals and/or by dehydration. All of the latter methods have some serious drawbacks, including the need for expensive equipment or not being suitable for large scale practical applications. In many instances the methods are harsh and slow and have led to inactivation of viral infectivity. One method, which has not been widely or adequately evaluated in terms of viral concentration procedures is electro-dialysis or filtration. On an experimental scale, it has been used under artificial conditions to concentrate bacteriophages (BIER, 1967). However, to our knowledge, no studies aside from those we have published (SWEET et al., 1971) have been reported utilizing the procedure with

Newer membrane concentration processes and their application to the detection of viral pollution of waters

HYPERFILTRATION using a new type of membranes has emerged in the past few years as one of the fastest growing and potentially useful methods for concentration and/or separation of macromolecular materials. The process, as it is used for concentration and detection of viral particles, treats the virus as the macromolecuiar species. In membrane hyperfiltration two methods of dehydration are applicable. First, the virus-containing solution is placed under pressure (Pressure Ultrafiltration) and is forced to flow past the surface of a supported membrane. The lower molecular weight species such as water or dissolved salts pass through the membrane and that retained is collected as a concentrate. Second, the transport of water out of a virus containing solution is achieved through an osmotically induced flow (Osmotic Ultrafiltration). In this case, the membrane is impermeable to both virus and osmotic solution and water flows from the virus side to the osmotic side by direct osmosis. In the osmotic ultrafiltration system, asymmetric cellulose acetate heat treated membranes (reverse osmosis type) have aUowed for high water reduction with minimal effective membrane area. Similarly, pressure filtration using Amicon membranes (polyelectrolyte coacervate) can be used for water reduction and a comparative study of the two systems is indicated in TABLE 1.

Viruses and Water Quality

There is a growing concern with the problem of possible viral pollution of water supplies in this country. From an epidemiological point of view, only the infectious hepatitis virus has been considered to be transmitted by water. Gross contamination of drinking water by sewage wastes was responsible for a major epidemic of infectious hepatitis in New Delhi (1955-1956), and resulted in 35,000 cases, 73 deaths, and a case rate of 2,000/100,000 in a single month. In the United States, the annual incidence of infectious hepatitis has remained at a level of 50,000 to 60,000 cases per year during most of the 1952 to 1970 period, while the total annual incidence of typhoid fever dropped continuously from approximately 2,000 cases in 1952 to only 346 cases in 1970. There has been one significant waterborne outbreak of infectious hepatitis during each of the last three years, including the Worcester, Mass, episode that

Relative Chlorine Resistance of Poliovirus I and Coliphages f2 and T2 in Water

Phage f2 is markedly more resistant to chlorine in water than either poliovirus or coliphage T(2). Its potential use as an indicator of viral pollution is suggested.

Virus in water. I. A preliminary study on a flow-through gauze sampler for recovering virus from waters.

A preliminary study was carried out on evaluating a flow-through gauze sampler for its efficiency in recovering virus from both fresh and seawater. An attenuated type 1 poliovirus was used as the working model. When tap water was sampled, the amounts of virus adsorbed by the gauze pads were very small, about 2% of the total number of virus particles flowing through the device. The virus adsorption and recovery increased to 15 to 19% when seawater was sampled. Addition of NaCl to tap water produced a much better effect on virus adsorption and recovery by this device, i.e., 47% of the total virus particles in each sample. The best viral elution from the pads was obtained by using buffer solution of pH 8.0 to 9.0 containing a small amount of animal serum. Repeated elutions from the pads were necessary to recover the most virus although the first eluate contained approximately 50% of the adsorbed virus. Further development of this device appears warranted, because of (i) the simplicity of the procedure, (ii) its capability of sampling large volume of water, (iii) the low cost of collecting samples, and (iv) the feasibility of obtaining a rough quantitative assessment of viral pollutants in water examined.

Virus in Water

A preliminary study was carried out on evaluating a flow-through gauze sampler for its efficiency in recovering virus from both fresh and seawater. An attenuated type 1 poliovirus was used as the working model. When tap water was sampled, the amounts of virus adsorbed by the gauze pads were very small, about 2% of the total number of virus particles flowing through the device. The virus adsorption and recovery increased to 15 to 19% when seawater was sampled. Addition of NaCl to tap water produced a much better effect on virus adsorption and recovery by this device, i.e., 47% of the total virus particles in each sample. The best viral elution from the pads was obtained by using buffer solution of pH 8.0 to 9.0 containing a small amount of animal serum. Repeated elutions from the pads were necessary to recover the most virus although the first eluate contained approximately 50% of the adsorbed virus. Further development of this device appears warranted, because of (i) the simplicity of the procedure, (ii) its capability of sampling large volume of water, (iii) the low cost of collecting samples, and (iv) the feasibility of obtaining a rough quantitative assessment of viral pollutants in water examined.

Erratum for “Viral Pollution of Shellfish in Estuary Waters”

Erratum for “Viral Pollution of Shellfish in Estuary Waters”

Viral Pollution of Shellfish in Estuary Waters

Enteroviruses appear in oysters following pollution of estuary waters by waste-treatment plant effluents. Primary treatment, with or without chlorination, and stabilization pond effluents are regul...