There's a lot to know about influenza that we don't know. Unfortunately a lot of is things you thought we knew but don't. Like whether there is a risk from influenza virus in drinking water. Admittedly this hasn't been at the top of the list for seasonal flu, since the main reservoir for this virus is other people and that's who you catch it from. But with avian viruses there is the problem of aquatic birds (the main reservoir in the wild) shedding virus into ocean littorals and surface waters, including drinking water reservoirs. In addition, agricultural run-off, including fecal waste from large poultry operations, can contaminate surface and groundwaters with virus. So it's something to think about. It would be nice if we knew that current and conventional methods of water treatment inactivated highly pathogenic avian influenza (HPAI). It would be one less thing to worry about. If we knew it. Viruses can vary widely in their sensitivity to chlorine. Unfortuantely until just recently the only data we had was from low pathogenic H5 subtypes (specifically H5N2, which we posted about here) and even that data were scarce (epidemiologists like to use data as a plural, BTW; it's a peccadillo of the profession). Now a paper has come out looking specifically at chlorine inactivation of HPAI H5N1. So what do we know?
The authors (Rice et al. from EPA, University of Georgia and USDA) grew H5N1 (clade 2) in chicken eggs and exposed it to chlorinated buffer for 60 seconds, testing it for ability to infect tissue culture (primary cultures of chicken embryo fibroblasts). The inactivation was carried out at 5o C. Preliminary data indicated that inactivation at room temperature was higher than at colder ones. Many surface waters can be this cold so this is a necessary precaution. The results indicate better than three orders of inactivation (99.9%) after 60 seconds at free chlorine levels typical of US water treatment plants. Reassuring (if not surprising) news.
So this fills in a little more of the picture. However there are other ways to disinfect water (chloramination, ozonation), so these need to be looked at as well, especially as many systems are moving away from straight chlorination to meet new disinfection by-product rules. Chlorine is not only bad for viruses, but can produce by-products that are bad for people too.
Life is complicated.
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Revere-whats chlorinated buffer? Chloronated water?
Chlorinated buffer is just the solution the researchers used to apply the chlorine. Chloronated? Do you mean chloraminated? Chloramination is combining chlorine with ammonia. It is much longer lasting and is used to disinfect the distribution sytem and now as primary disinfection in many systems as a way to reduce disinfection by-products. However it has given rise to complaints in some places. Disinfecting water is a classic public health trade-off issue. Disinfecting water is extremely important, but we are all so used to water uncontaminated by pathogens in the US we tend to focus on the other effects of disinfectants, forgetting it is a trade-off.
I am on well water now. I have to send a sample off to the Health Dept every year now and they produce a report showing heavy metals, VOC's (none) and bacteria (very little). Anything I should watch for that aint on the general list?
Randy: Depends what's in your neighborhood. Presumably you don't disinfect at all and your water is effectively filtered (it's groundwater) so you don't have to worry about parasite cysts. Viruses they don't and can't really test for, so you need to make sure the zone of influence of the well (where it draws its water from) doesn't have a source you wouldn't like and that wouldn't show up on routine testing.
"Reassuring news" ?
Rice EW, Adcock NJ, Sivaganesan M, Brown JD, Stallknecht DE, Swayne DE.
Chlorine inactivation of highly pathogenic avian influenza virus (H5N1).
Emerg Infect Dis. 2007 Oct; [Epub ahead of print]:
"... Briefly, virus-infected allantoic fluid was diluted (1:1,000) into continuously stirred, chlorinated, chlorine demand-free phosphate buffer (0.05 M, pH 7.0 and 8.0). ... To slow the rate of inactivation, experiments were conducted at 5°C. ..."
"Ct (Ct value is the chlorine concentration, C [mg/L], multiplied by the exposure time, t [min]) apply to microorganisms in suspension, not embedded in particles." [GUIDELINES FOR DRINKING-WATER QUALITY, 7. MICROBIAL ASPECTS, 7.3.2 Treatment, Table 7.6, footnote].
In (drinking-) water H5N1 viruses from faeces are embedded in faeces particles and drinking-water may be colder than 5°C and the pH often is > 8.0, perhaps 9.5 ...
"Reassuring news" ?
Dipl.-Ing. Wilfried Soddemann
soddemann-aachen@t-online.de
Wilfred: Your point?
H5N1 avian flu: Spread by drinking water
Human to human and contact transmission of influenza occur - but are overvalued immense. Influenza epidemics in Germany rarely appear together with recognized clusters (9% of the cases in the season 2004/2005). Recent research must worry: So far the virus had to reach the bronchi and the lungs in order to infect humans. Now in Indonesia it infects the upper respiratory system (mucous membranes of the throat e.g. when drinking and mucous membranes of the nose and probably also the conjunctiva of the eyes as well as the eardrum e.g. at showering). In three cases (Viet Nam, Thailand) stomach and intestine by the H5N1 virus were stricken but not the bronchi and the lungs. The virus must have been thus orally taken up, e.g. when drinking contaminated water.
http://www.cidrap.umn.edu/cidrap/content/influenza/avianflu/news/jun060…
http://www.who.int/mediacentre/factsheets/avian_influenza/en/index.html…
http://www.cidrap.umn.edu/cidrap/content/influenza/panflu/news/mar1307t…
http://www.cdc.gov/ncidod/EID/vol12no12/06-0829.htm?s_cid=eid06_0829_x
Influenza: Initial introduction of influenza viruses to the population via abiotic water supply versus biotic human viral respirated droplet shedding
The primary, initial transmission of the human influenza epidemics by the biotic droplet infection is not proven (BRANKSTON et al. 2007) and extremely improbably as influenza epidemics
-appear only in 9% of the cases (season 2004/2005 in Germany) together with recognized clusters.
-appear virologically locally singularly (influenza-subtypes and precision typing).
-appear geographically locally singularly.
-are not proven with priority in large cities and densely populated areas.
-appear predominantly in the colder regions of Germany.
-regularly reach their maxima in certain districts/cities.
-in temperate climates strictly run parallel to the course of the sum of coldness during the winter.
-can hardly spread via saliva droplets. Saliva contains far less Influenza viruses than the - heavier - droplets from throat and nose.
The facts
Influenza epidemics in Germany rarely appear together with recognized clusters (9% of the cases in the season 2004/2005) (RKI 2006).
Influenza epidemics appear virologically locally singularly (influenza-subtypes and precision typing) (AGI 2007).
Influenza epidemics also run geographically locally singularly. They are not proven with priority in large cities and densely populated areas. They arise predominantly in the colder regions of Germany (in the east with cold continental climate in the winter, southeast, altitudes) (RKI 2007). They reach their maxima regularly in certain districts/cities (RKI 2007).
In temperate climates Influenza epidemics run strictly parallel to the course of the sum of coldness during winter.
In hot climates/tropics the flood-related influenza is typical after extreme weather and natural after a flood. Virulence of influenza virus depends on temperature and time. If young and fresh contaminated water from a local low well, a cistern, tank, rain barrel or rice field is used water temperature may be higher. In the tropics there are often outdoor cisterns, tanks, rain barrels, rice fields or local low wells for water supply. In Germany about 98% inhabitants have a central public water supply with older and better protected water. In Germany therefore coldness is decisive as to virulence of influenza viruses in drinking water.
Influenza epidemics can hardly spread by saliva droplets. Saliva contains far less influenza viruses than the substantially heavier droplets from throat and nose (ANONYMOUS 2003) (GOLDMANN 2001).
Human influenza viruses could be proven in the excretions of mammals such as pigs (faecal and oronasal), wild boar (faecal and oronasal), cattle and goats, so that the transmission path from the environment over waters and the drinking water in principle is possible (BROWN 2004) (GRAVES et al. 1975) (KADEN et al. 2001) (KAWAOKA et al. 1986) (LANDOLT et al. 2003) (MARKOWSKA DANIEL et al. 1999) (RKI 1999) (VICENTE et al. 2002) (WEBSTER 1998) (ZHOU et al. 1996) (CARPENTER 2001). With considerable certainty further animal species that are infected with influenza A will be discovered in the future (WEBSTER 1998).
Elimination and inactivating of viruses during the drinking water treatment
Drinking water is often not or only roughly filtered in Germany. The very small viruses are not definitely removed thereby. For groundwater treatment fast speed filtration plants for the elimination of iron and manganese do not possess any effect regarding the elimination of viruses (WHO 2004). Even the plants in Germany which are known to be particularly efficient regarding the flocculation and filtration can not reach the elimination and inactivating goals demanded from the WHO (WHO 2004); not even under the consideration of the common disinfection procedures, whose efficiency decreases with sinking water temperature [Chlorine and ozone treatment] and that are only of limited efficiency when microorganisms are embedded in particles or in biofilm [Chlorine, ozone treatment and UV irradiation].
"Cooling chain of the public water supply"
Coldness is by far the most important parameter for the preservation of virulent influenza viruses in water. The temperature minimum of the dam water in Germany values in January and February 3-4?C. Every year, river water has its temperature minimum also in January and February. Close to the surface ground water in Germany has its temperature minimum - similar to the soil in 100 cm depth - at the ground water surface of about 3?C in February and March. Ground water taken from wells of larger depth can also be colder than the deeper ground water due to the affection of surface water that infiltrates in the case of unsatisfactory sealing between the fountain and the surrounding rock. River water draining away and reaching wells on short ways can have the same effect. Bank filtrate from wells, which was drilled near the bank from surface water, adopts the temperature of the cold surface water. The same applies to wells, from which ground water enriched with surface water is pumped. The soil temperatures in a meter of depth correspond to the temperatures of the drinking water pipelines that are laid frost-protected in the soils. The temperature minima of the soil temperatures in a 100 cm depth value in Germany during the months February and March 3-5?C (DWD 2007). The temperatures of the drinking water pipelines and the drinking water transported in them adapt themselves to the soil temperatures. In the winter cold raw water remains cold in the drinking water treatment plants and after the treatment to drinking water in the water tanks and water pipelines until the connection to the consumers. The temperature minimum of the drinking water when connecting to the consumers follows in particular the run of the wintry cold sum in the soil and in the water pipelines. It arises in the months February/March. The cold drinking water is first mixed in the dwellings at the taps with warm water from the house installation. Thus the continuous "cooling chain of the public water supply" is described from the water winning up to the consumers with a drinking water temperature of about 4-5?C in the months February/March. Cold, young, freshly by Influenzaviruses contaminated drinking water, taken out from surface water and badly protected surface near ground water as well as out of the ground water from karst can be the abiotic vehicle, which conserves virulent Influenzaviruses in the winter at 4-5?C and transports them over the "cooling chain of the public water supply" to humans.
Transmission paths of the drinking water
Infections by drinking water will not be transmitted alone by drinking the water. Further transmission paths are the inhalation of aerosols and the contact with the drinking water. Access for humans are the conjunctiva, the nose mucous membrane, the mouth mucous membrane, the eardrum, wounds and by catheters affected other mucous membranes.
Conclusions
The primary transmission of the influenza by the biotic ?warm? droplet infection from human to human is, already because of the strict dependence on environmental temperatures in temperate climates, extremely improbable. The influenza must be triggered by an abiotic vehicle, which is increasingly efficient regarding the spread of infections with increasingly cold environmental temperatures. Therefore it has to be searched for abiotic vehicles dependent on cold environmental temperatures for the transmission of the influenza in temperate climates. Drinking water is such an abiotic vehicle.
The stated references and indications show that cold drinking water can be that abiotic vehicle, by which virulent human Influenza viruses from the reservoirs reach humans and triggers predominantly the seasonal influenza epidemics.
That applies in particular also to the extremely lethal H5N1 bird flu, whose faecal transmission is indisputable.
References
AGI (2007): Arbeitsgemeinschaft Influenza http://influenza.rki.de/agi
ANONYM (2003): Understanding Sars and other Respiratory Infections May 2003.
http://www.ifh-homehygiene.org/2003/2downloadabledoc/SARS.pdf
BRANKSTON et al. (2007): Transmission of influenza A in human beings. Lancet Infect Dis. 2007 Apr;7 (4):257-65. http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&T…
BROWN (2004): Influenza Virus Infections of Pigs, Part 1: swine, avian & human influenza viruses. http://www.pighealth.com/influenza.htm ; Part 2: Transmission between pigs and other species. Veterinary Laboratories Agency, UK.
http://www.pighealth.com/influenzaB.htm
DWD (2007): Deutscher Wetterdienst (DWD), Wetterstation Erfurt-Bindersleben, Erdbodentemperaturen aus 100 cm Tiefe
GOLDMANN (2001): Epidemiology and Prevention of Pediatric Viral Respiratory Infections in Health-Care Institutions, Children?s Hospital and Harvard Medical School, Boston, Massachusetts, USA, Emerging Infectious Diseases, Special Issue.
http://www.cdc.gov/ncidod/eid/vol7no2/goldmann.htm
GRAVES et al. (1975): Human viruses in animals in West Bengal: An ecological analysis, Human Ecology, Volume 3, Number 2 / April, 1975, 105-130.
http://www.springerlink.com/content/u5408wx5t622ll82/
KADEN et al. (2001): Gef䨲liche Verwandtschaft. Schwarzwild - ein nat?es Reservoir f?ektionserreger und Ansteckungsquelle f?sschweine? Bundes-forschungsanstalt f?uskrankheiten der Tiere: Forschungsreport 1/2001: 24-28.
http://ticker-grosstiere.animal-health-online.de/20010902-00002/
KAWAOKA et al. (1986): Intestinal replication of influenza A viruses in two mammalian species, Archives of Virology, Volume 93, Numbers 3-4 / December, 1987, 303-308.
http://www.springerlink.com/content/g352726672xj5703/
LANDOLT et al. (2003): Comparison of the Pathogenesis of Two Genetically Different H3N2 Influenza A Viruses in Pigs, J Clin Microbiol. 2003 May; 41(5): 1936?1941.
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&rend…
MARKOWSKA-DANIEL et al. (1999): Seroprevalence of influenza virus among wild boars in Poland. National Veterinary Research Institute, Swine Diseases Departement, Pulawy, Poland. http://www.medwet.lublin.pl/Year%201999/vol99-05/art222-98.htm
RKI (1999): Robert Koch-Institut (RKI) Merkblatt f?te Influenza ? Verh?und Bekä°fung (Stand 1999).
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RKI (2006): Infektionsepidemiologisches Jahrbuch meldepflichtiger Krankheiten f?5, Datenstand: 1. M䲺 2006)
RKI (2007): Robert Koch-Institut Berlin, RKI, Datenbank der nach Infektionsschutzgesetz meldepflichtigen Infektionskrankheiten in Deutschland; http://www3.rki.de/SurvStat/
VICENTE et al. (2002): Antibodies to selected viral and bacterial pathogens in European wild boars from southcentral Spain. J Wildl Dis. 38(3): 649-52.
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WEBSTER (1998): Influenza: An Emerging Disease. Emerging Infectious Diseases 4(3). http://www.cdc.gov/ncidod/eid/vol4no3/webster.htm
WHO (2004): World Health Organization (WHO), 2004, Guidelines for drinking-water quality, 3rd Ed., http://www.who.int/water_sanitation_health/dwq/gdwq3/en/print.html
ZHOU et al. (1996): Influenza infection in humans and pigs in southeastern China, Archives of Virology, Volume 141, Numbers 3-4 / March, 1996, 649-661. http://www.springerlink.com/content/p220471r1r337521/
ZIMMERMANN (2001): Krankheiten des Schweines. Veterinä²edizinische Fakultä´ der Universitä´ Bern, Vorlesungsskript: 49-51.
http://www.vetmed.unibe.ch/studvet/download/year4/Erkr%20der%20Schweine…
Contact:
Bauassessor Dipl.-Ing. Wilfried Soddemann
eMail: soddemann-aachen@t-online.de